From 5eb7fcbdea63fc91685ac0c89ceb42d3becc96d2 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:21 -0800 Subject: KVM: x86/pmu: Always treat Fixed counters as available when supported Treat fixed counters as available when they are supported, i.e. don't silently ignore an enabled fixed counter just because guest CPUID says the associated general purpose architectural event is unavailable. KVM originally treated fixed counters as always available, but that got changed as part of a fix to avoid confusing REF_CPU_CYCLES, which does NOT map to an architectural event, with the actual architectural event used associated with bit 7, TOPDOWN_SLOTS. The commit justified the change with: If the event is marked as unavailable in the Intel guest CPUID 0AH.EBX leaf, we need to avoid any perf_event creation, whether it's a gp or fixed counter. but that justification doesn't mesh with reality. The Intel SDM uses "architectural events" to refer to both general purpose events (the ones with the reverse polarity mask in CPUID.0xA.EBX) and the events for fixed counters, e.g. the SDM makes statements like: Each of the fixed-function PMC can count only one architectural performance event. but the fact that fixed counter 2 (TSC reference cycles) doesn't have an associated general purpose architectural makes trying to apply the mask from CPUID.0xA.EBX impossible. Furthermore, the lack of enumeration for an architectural event in CPUID only means the CPU doesn't officially support the architectural encoding, i.e. it doesn't mean using the architectural encoding _won't_ work, it sipmly means there are no guarantees that it will work as expected. E.g. if KVM is running in a VM that advertises a fixed counters but not the corresponding architectural event encoding, and perf decides to use a general purpose counter instead of a fixed counter, odds are very good that the underlying hardware actually does support the architectrual encoding, and that programming the encoding will count the right thing. In other words, asking perf to count the event will probably work, whereas intentionally doing nothing is obviously guaranteed to fail. Note, at the time of the change, KVM didn't enforce hardware support, i.e. didn't prevent userspace from enumerating support in guest CPUID.0xA.EBX for architectural events that aren't supported in hardware. I.e. silently dropping the fixed counter didn't somehow protection against counting the wrong event, it just enforced guest CPUID. And practically speaking, this issue is almost certainly limited to running KVM on a funky virtual CPU model. No known real hardware has an asymmetric PMU where a fixed counter is supported but the associated architectural event is not. Fixes: a21864486f7e ("KVM: x86/pmu: Fix available_event_types check for REF_CPU_CYCLES event") Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-2-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/pmu_intel.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index a6216c874729..8207f8c03585 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -108,11 +108,24 @@ static bool intel_hw_event_available(struct kvm_pmc *pmc) u8 unit_mask = (pmc->eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8; int i; + /* + * Fixed counters are always available if KVM reaches this point. If a + * fixed counter is unsupported in hardware or guest CPUID, KVM doesn't + * allow the counter's corresponding MSR to be written. KVM does use + * architectural events to program fixed counters, as the interface to + * perf doesn't allow requesting a specific fixed counter, e.g. perf + * may (sadly) back a guest fixed PMC with a general purposed counter. + * But if _hardware_ doesn't support the associated event, KVM simply + * doesn't enumerate support for the fixed counter. + */ + if (pmc_is_fixed(pmc)) + return true; + BUILD_BUG_ON(ARRAY_SIZE(intel_arch_events) != NR_INTEL_ARCH_EVENTS); /* * Disallow events reported as unavailable in guest CPUID. Note, this - * doesn't apply to pseudo-architectural events. + * doesn't apply to pseudo-architectural events (see above). */ for (i = 0; i < NR_REAL_INTEL_ARCH_EVENTS; i++) { if (intel_arch_events[i].eventsel != event_select || -- cgit v1.2.3 From cbbd1aa891398e9ddbdd05bc4e40a988175f22af Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:22 -0800 Subject: KVM: x86/pmu: Allow programming events that match unsupported arch events Remove KVM's bogus restriction that the guest can't program an event whose encoding matches an unsupported architectural event. The enumeration of an architectural event only says that if a CPU supports an architectural event, then the event can be programmed using the architectural encoding. The enumeration does NOT say anything about the encoding when the CPU doesn't report support the architectural event. Preventing the guest from counting events whose encoding happens to match an architectural event breaks existing functionality whenever Intel adds an architectural encoding that was *ever* used for a CPU that doesn't enumerate support for the architectural event, even if the encoding is for the exact same event! E.g. the architectural encoding for Top-Down Slots is 0x01a4. Broadwell CPUs, which do not support the Top-Down Slots architectural event, 0x01a4 is a valid, model-specific event. Denying guest usage of 0x01a4 if/when KVM adds support for Top-Down slots would break any Broadwell-based guest. Reported-by: Kan Liang Closes: https://lore.kernel.org/all/2004baa6-b494-462c-a11f-8104ea152c6a@linux.intel.com Fixes: a21864486f7e ("KVM: x86/pmu: Fix available_event_types check for REF_CPU_CYCLES event") Reviewed-by: Dapeng Mi Reviewed-by: Jim Mattson Reviewed-by: Kan Liang Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-3-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/include/asm/kvm-x86-pmu-ops.h | 1 - arch/x86/kvm/pmu.c | 1 - arch/x86/kvm/pmu.h | 1 - arch/x86/kvm/svm/pmu.c | 6 ------ arch/x86/kvm/vmx/pmu_intel.c | 38 ---------------------------------- 5 files changed, 47 deletions(-) diff --git a/arch/x86/include/asm/kvm-x86-pmu-ops.h b/arch/x86/include/asm/kvm-x86-pmu-ops.h index 058bc636356a..d7eebee4450c 100644 --- a/arch/x86/include/asm/kvm-x86-pmu-ops.h +++ b/arch/x86/include/asm/kvm-x86-pmu-ops.h @@ -12,7 +12,6 @@ BUILD_BUG_ON(1) * a NULL definition, for example if "static_call_cond()" will be used * at the call sites. */ -KVM_X86_PMU_OP(hw_event_available) KVM_X86_PMU_OP(pmc_idx_to_pmc) KVM_X86_PMU_OP(rdpmc_ecx_to_pmc) KVM_X86_PMU_OP(msr_idx_to_pmc) diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 87cc6c8809ad..30945fea6988 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -441,7 +441,6 @@ static bool check_pmu_event_filter(struct kvm_pmc *pmc) static bool pmc_event_is_allowed(struct kvm_pmc *pmc) { return pmc_is_globally_enabled(pmc) && pmc_speculative_in_use(pmc) && - static_call(kvm_x86_pmu_hw_event_available)(pmc) && check_pmu_event_filter(pmc); } diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h index 7caeb3d8d4fd..87ecf22f5b25 100644 --- a/arch/x86/kvm/pmu.h +++ b/arch/x86/kvm/pmu.h @@ -19,7 +19,6 @@ #define VMWARE_BACKDOOR_PMC_APPARENT_TIME 0x10002 struct kvm_pmu_ops { - bool (*hw_event_available)(struct kvm_pmc *pmc); struct kvm_pmc *(*pmc_idx_to_pmc)(struct kvm_pmu *pmu, int pmc_idx); struct kvm_pmc *(*rdpmc_ecx_to_pmc)(struct kvm_vcpu *vcpu, unsigned int idx, u64 *mask); diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c index b6a7ad4d6914..1475d47c821c 100644 --- a/arch/x86/kvm/svm/pmu.c +++ b/arch/x86/kvm/svm/pmu.c @@ -73,11 +73,6 @@ static inline struct kvm_pmc *get_gp_pmc_amd(struct kvm_pmu *pmu, u32 msr, return amd_pmc_idx_to_pmc(pmu, idx); } -static bool amd_hw_event_available(struct kvm_pmc *pmc) -{ - return true; -} - static bool amd_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); @@ -233,7 +228,6 @@ static void amd_pmu_init(struct kvm_vcpu *vcpu) } struct kvm_pmu_ops amd_pmu_ops __initdata = { - .hw_event_available = amd_hw_event_available, .pmc_idx_to_pmc = amd_pmc_idx_to_pmc, .rdpmc_ecx_to_pmc = amd_rdpmc_ecx_to_pmc, .msr_idx_to_pmc = amd_msr_idx_to_pmc, diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index 8207f8c03585..1a7d021a6c7b 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -101,43 +101,6 @@ static struct kvm_pmc *intel_pmc_idx_to_pmc(struct kvm_pmu *pmu, int pmc_idx) } } -static bool intel_hw_event_available(struct kvm_pmc *pmc) -{ - struct kvm_pmu *pmu = pmc_to_pmu(pmc); - u8 event_select = pmc->eventsel & ARCH_PERFMON_EVENTSEL_EVENT; - u8 unit_mask = (pmc->eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8; - int i; - - /* - * Fixed counters are always available if KVM reaches this point. If a - * fixed counter is unsupported in hardware or guest CPUID, KVM doesn't - * allow the counter's corresponding MSR to be written. KVM does use - * architectural events to program fixed counters, as the interface to - * perf doesn't allow requesting a specific fixed counter, e.g. perf - * may (sadly) back a guest fixed PMC with a general purposed counter. - * But if _hardware_ doesn't support the associated event, KVM simply - * doesn't enumerate support for the fixed counter. - */ - if (pmc_is_fixed(pmc)) - return true; - - BUILD_BUG_ON(ARRAY_SIZE(intel_arch_events) != NR_INTEL_ARCH_EVENTS); - - /* - * Disallow events reported as unavailable in guest CPUID. Note, this - * doesn't apply to pseudo-architectural events (see above). - */ - for (i = 0; i < NR_REAL_INTEL_ARCH_EVENTS; i++) { - if (intel_arch_events[i].eventsel != event_select || - intel_arch_events[i].unit_mask != unit_mask) - continue; - - return pmu->available_event_types & BIT(i); - } - - return true; -} - static bool intel_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); @@ -780,7 +743,6 @@ void intel_pmu_cross_mapped_check(struct kvm_pmu *pmu) } struct kvm_pmu_ops intel_pmu_ops __initdata = { - .hw_event_available = intel_hw_event_available, .pmc_idx_to_pmc = intel_pmc_idx_to_pmc, .rdpmc_ecx_to_pmc = intel_rdpmc_ecx_to_pmc, .msr_idx_to_pmc = intel_msr_idx_to_pmc, -- cgit v1.2.3 From db9e008a0f37bd31ac3d77d650812612b7c873da Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:23 -0800 Subject: KVM: x86/pmu: Remove KVM's enumeration of Intel's architectural encodings Drop KVM's enumeration of Intel's architectural event encodings, and instead open code the three encodings (of which only two are real) that KVM uses to emulate fixed counters. Now that KVM doesn't incorrectly enforce the availability of architectural encodings, there is no reason for KVM to ever care about the encodings themselves, at least not in the current format of an array indexed by the encoding's position in CPUID. Opportunistically add a comment to explain why KVM cares about eventsel values for fixed counters. Suggested-by: Jim Mattson Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-4-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/pmu_intel.c | 72 ++++++++++++++------------------------------ 1 file changed, 23 insertions(+), 49 deletions(-) diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index 1a7d021a6c7b..f3c44ddc09f8 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -22,52 +22,6 @@ #define MSR_PMC_FULL_WIDTH_BIT (MSR_IA32_PMC0 - MSR_IA32_PERFCTR0) -enum intel_pmu_architectural_events { - /* - * The order of the architectural events matters as support for each - * event is enumerated via CPUID using the index of the event. - */ - INTEL_ARCH_CPU_CYCLES, - INTEL_ARCH_INSTRUCTIONS_RETIRED, - INTEL_ARCH_REFERENCE_CYCLES, - INTEL_ARCH_LLC_REFERENCES, - INTEL_ARCH_LLC_MISSES, - INTEL_ARCH_BRANCHES_RETIRED, - INTEL_ARCH_BRANCHES_MISPREDICTED, - - NR_REAL_INTEL_ARCH_EVENTS, - - /* - * Pseudo-architectural event used to implement IA32_FIXED_CTR2, a.k.a. - * TSC reference cycles. The architectural reference cycles event may - * or may not actually use the TSC as the reference, e.g. might use the - * core crystal clock or the bus clock (yeah, "architectural"). - */ - PSEUDO_ARCH_REFERENCE_CYCLES = NR_REAL_INTEL_ARCH_EVENTS, - NR_INTEL_ARCH_EVENTS, -}; - -static struct { - u8 eventsel; - u8 unit_mask; -} const intel_arch_events[] = { - [INTEL_ARCH_CPU_CYCLES] = { 0x3c, 0x00 }, - [INTEL_ARCH_INSTRUCTIONS_RETIRED] = { 0xc0, 0x00 }, - [INTEL_ARCH_REFERENCE_CYCLES] = { 0x3c, 0x01 }, - [INTEL_ARCH_LLC_REFERENCES] = { 0x2e, 0x4f }, - [INTEL_ARCH_LLC_MISSES] = { 0x2e, 0x41 }, - [INTEL_ARCH_BRANCHES_RETIRED] = { 0xc4, 0x00 }, - [INTEL_ARCH_BRANCHES_MISPREDICTED] = { 0xc5, 0x00 }, - [PSEUDO_ARCH_REFERENCE_CYCLES] = { 0x00, 0x03 }, -}; - -/* mapping between fixed pmc index and intel_arch_events array */ -static int fixed_pmc_events[] = { - [0] = INTEL_ARCH_INSTRUCTIONS_RETIRED, - [1] = INTEL_ARCH_CPU_CYCLES, - [2] = PSEUDO_ARCH_REFERENCE_CYCLES, -}; - static void reprogram_fixed_counters(struct kvm_pmu *pmu, u64 data) { struct kvm_pmc *pmc; @@ -440,8 +394,29 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) return 0; } +/* + * Map fixed counter events to architectural general purpose event encodings. + * Perf doesn't provide APIs to allow KVM to directly program a fixed counter, + * and so KVM instead programs the architectural event to effectively request + * the fixed counter. Perf isn't guaranteed to use a fixed counter and may + * instead program the encoding into a general purpose counter, e.g. if a + * different perf_event is already utilizing the requested counter, but the end + * result is the same (ignoring the fact that using a general purpose counter + * will likely exacerbate counter contention). + * + * Note, reference cycles is counted using a perf-defined "psuedo-encoding", + * as there is no architectural general purpose encoding for reference cycles. + */ static void setup_fixed_pmc_eventsel(struct kvm_pmu *pmu) { + const struct { + u8 eventsel; + u8 unit_mask; + } fixed_pmc_events[] = { + [0] = { 0xc0, 0x00 }, /* Instruction Retired / PERF_COUNT_HW_INSTRUCTIONS. */ + [1] = { 0x3c, 0x00 }, /* CPU Cycles/ PERF_COUNT_HW_CPU_CYCLES. */ + [2] = { 0x00, 0x03 }, /* Reference Cycles / PERF_COUNT_HW_REF_CPU_CYCLES*/ + }; int i; BUILD_BUG_ON(ARRAY_SIZE(fixed_pmc_events) != KVM_PMC_MAX_FIXED); @@ -449,10 +424,9 @@ static void setup_fixed_pmc_eventsel(struct kvm_pmu *pmu) for (i = 0; i < pmu->nr_arch_fixed_counters; i++) { int index = array_index_nospec(i, KVM_PMC_MAX_FIXED); struct kvm_pmc *pmc = &pmu->fixed_counters[index]; - u32 event = fixed_pmc_events[index]; - pmc->eventsel = (intel_arch_events[event].unit_mask << 8) | - intel_arch_events[event].eventsel; + pmc->eventsel = (fixed_pmc_events[index].unit_mask << 8) | + fixed_pmc_events[index].eventsel; } } -- cgit v1.2.3 From 61bb2ad795a72a7a75add3ffc257660fd6c7cfea Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:24 -0800 Subject: KVM: x86/pmu: Setup fixed counters' eventsel during PMU initialization Set the eventsel for all fixed counters during PMU initialization, the eventsel is hardcoded and consumed if and only if the counter is supported, i.e. there is no reason to redo the setup every time the PMU is refreshed. Configuring all KVM-supported fixed counter also eliminates a potential pitfall if/when KVM supports discontiguous fixed counters, in which case configuring only nr_arch_fixed_counters will be insufficient (ignoring the fact that KVM will need many other changes to support discontiguous fixed counters). Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-5-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/pmu_intel.c | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-) diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index f3c44ddc09f8..98e92b9ece09 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -407,27 +407,21 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) * Note, reference cycles is counted using a perf-defined "psuedo-encoding", * as there is no architectural general purpose encoding for reference cycles. */ -static void setup_fixed_pmc_eventsel(struct kvm_pmu *pmu) +static u64 intel_get_fixed_pmc_eventsel(int index) { const struct { - u8 eventsel; + u8 event; u8 unit_mask; } fixed_pmc_events[] = { [0] = { 0xc0, 0x00 }, /* Instruction Retired / PERF_COUNT_HW_INSTRUCTIONS. */ [1] = { 0x3c, 0x00 }, /* CPU Cycles/ PERF_COUNT_HW_CPU_CYCLES. */ [2] = { 0x00, 0x03 }, /* Reference Cycles / PERF_COUNT_HW_REF_CPU_CYCLES*/ }; - int i; BUILD_BUG_ON(ARRAY_SIZE(fixed_pmc_events) != KVM_PMC_MAX_FIXED); - for (i = 0; i < pmu->nr_arch_fixed_counters; i++) { - int index = array_index_nospec(i, KVM_PMC_MAX_FIXED); - struct kvm_pmc *pmc = &pmu->fixed_counters[index]; - - pmc->eventsel = (fixed_pmc_events[index].unit_mask << 8) | - fixed_pmc_events[index].eventsel; - } + return (fixed_pmc_events[index].unit_mask << 8) | + fixed_pmc_events[index].event; } static void intel_pmu_refresh(struct kvm_vcpu *vcpu) @@ -493,7 +487,6 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu) kvm_pmu_cap.bit_width_fixed); pmu->counter_bitmask[KVM_PMC_FIXED] = ((u64)1 << edx.split.bit_width_fixed) - 1; - setup_fixed_pmc_eventsel(pmu); } for (i = 0; i < pmu->nr_arch_fixed_counters; i++) @@ -571,6 +564,7 @@ static void intel_pmu_init(struct kvm_vcpu *vcpu) pmu->fixed_counters[i].vcpu = vcpu; pmu->fixed_counters[i].idx = i + INTEL_PMC_IDX_FIXED; pmu->fixed_counters[i].current_config = 0; + pmu->fixed_counters[i].eventsel = intel_get_fixed_pmc_eventsel(i); } lbr_desc->records.nr = 0; -- cgit v1.2.3 From 7a277c22412cf72cf6376f21c6d826e8f4a44cc3 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:25 -0800 Subject: KVM: x86/pmu: Get eventsel for fixed counters from perf Get the event selectors used to effectively request fixed counters for perf events from perf itself instead of hardcoding them in KVM and hoping that they match the underlying hardware. While fixed counters 0 and 1 use architectural events, as of ffbe4ab0beda ("perf/x86/intel: Extend the ref-cycles event to GP counters") fixed counter 2 (reference TSC cycles) may use a software-defined pseudo-encoding or a real hardware-defined encoding. Reported-by: Kan Liang Closes: https://lkml.kernel.org/r/4281eee7-6423-4ec8-bb18-c6aeee1faf2c%40linux.intel.com Reviewed-by: Kan Liang Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-6-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/pmu_intel.c | 30 +++++++++++++++++------------- 1 file changed, 17 insertions(+), 13 deletions(-) diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index 98e92b9ece09..ec4feaef3d55 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -404,24 +404,28 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) * result is the same (ignoring the fact that using a general purpose counter * will likely exacerbate counter contention). * - * Note, reference cycles is counted using a perf-defined "psuedo-encoding", - * as there is no architectural general purpose encoding for reference cycles. + * Forcibly inlined to allow asserting on @index at build time, and there should + * never be more than one user. */ -static u64 intel_get_fixed_pmc_eventsel(int index) +static __always_inline u64 intel_get_fixed_pmc_eventsel(unsigned int index) { - const struct { - u8 event; - u8 unit_mask; - } fixed_pmc_events[] = { - [0] = { 0xc0, 0x00 }, /* Instruction Retired / PERF_COUNT_HW_INSTRUCTIONS. */ - [1] = { 0x3c, 0x00 }, /* CPU Cycles/ PERF_COUNT_HW_CPU_CYCLES. */ - [2] = { 0x00, 0x03 }, /* Reference Cycles / PERF_COUNT_HW_REF_CPU_CYCLES*/ + const enum perf_hw_id fixed_pmc_perf_ids[] = { + [0] = PERF_COUNT_HW_INSTRUCTIONS, + [1] = PERF_COUNT_HW_CPU_CYCLES, + [2] = PERF_COUNT_HW_REF_CPU_CYCLES, }; + u64 eventsel; - BUILD_BUG_ON(ARRAY_SIZE(fixed_pmc_events) != KVM_PMC_MAX_FIXED); + BUILD_BUG_ON(ARRAY_SIZE(fixed_pmc_perf_ids) != KVM_PMC_MAX_FIXED); + BUILD_BUG_ON(index >= KVM_PMC_MAX_FIXED); - return (fixed_pmc_events[index].unit_mask << 8) | - fixed_pmc_events[index].event; + /* + * Yell if perf reports support for a fixed counter but perf doesn't + * have a known encoding for the associated general purpose event. + */ + eventsel = perf_get_hw_event_config(fixed_pmc_perf_ids[index]); + WARN_ON_ONCE(!eventsel && index < kvm_pmu_cap.num_counters_fixed); + return eventsel; } static void intel_pmu_refresh(struct kvm_vcpu *vcpu) -- cgit v1.2.3 From ecb490770ad42c7d3dc08f06efe7bf0779990745 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:26 -0800 Subject: KVM: x86/pmu: Don't ignore bits 31:30 for RDPMC index on AMD Stop stripping bits 31:30 prior to validating/consuming the RDPMC index on AMD. Per the APM's documentation of RDPMC, *values* greater than 27 are reserved. The behavior of upper bits being flags is firmly Intel-only. Fixes: ca724305a2b0 ("KVM: x86/vPMU: Implement AMD vPMU code for KVM") Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-7-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/svm/pmu.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c index 1475d47c821c..1fafc46f61c9 100644 --- a/arch/x86/kvm/svm/pmu.c +++ b/arch/x86/kvm/svm/pmu.c @@ -77,8 +77,6 @@ static bool amd_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); - idx &= ~(3u << 30); - return idx < pmu->nr_arch_gp_counters; } @@ -86,7 +84,7 @@ static bool amd_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx) static struct kvm_pmc *amd_rdpmc_ecx_to_pmc(struct kvm_vcpu *vcpu, unsigned int idx, u64 *mask) { - return amd_pmc_idx_to_pmc(vcpu_to_pmu(vcpu), idx & ~(3u << 30)); + return amd_pmc_idx_to_pmc(vcpu_to_pmu(vcpu), idx); } static struct kvm_pmc *amd_msr_idx_to_pmc(struct kvm_vcpu *vcpu, u32 msr) -- cgit v1.2.3 From 7bb7fce13601d2e6818be500ef3ce0b60cd59603 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:27 -0800 Subject: KVM: x86/pmu: Prioritize VMX interception over #GP on RDPMC due to bad index Apply the pre-intercepts RDPMC validity check only to AMD, and rename all relevant functions to make it as clear as possible that the check is not a standard PMC index check. On Intel, the basic rule is that only invalid opcodes and privilege/permission/mode checks have priority over VM-Exit, i.e. RDPMC with an invalid index should VM-Exit, not #GP. While the SDM doesn't explicitly call out RDPMC, it _does_ explicitly use RDMSR of a non-existent MSR as an example where VM-Exit has priority over #GP, and RDPMC is effectively just a variation of RDMSR. Manually testing on various Intel CPUs confirms this behavior, and the inverted priority was introduced for SVM compatibility, i.e. was not an intentional change for Intel PMUs. On AMD, *all* exceptions on RDPMC have priority over VM-Exit. Check for a NULL kvm_pmu_ops.check_rdpmc_early instead of using a RET0 static call so as to provide a convenient location to document the difference between Intel and AMD, and to again try to make it as obvious as possible that the early check is a one-off thing, not a generic "is this PMC valid?" helper. Fixes: 8061252ee0d2 ("KVM: SVM: Add intercept checks for remaining twobyte instructions") Cc: Jim Mattson Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-8-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/include/asm/kvm-x86-pmu-ops.h | 2 +- arch/x86/kvm/emulate.c | 2 +- arch/x86/kvm/kvm_emulate.h | 2 +- arch/x86/kvm/pmu.c | 16 +++++++++++++--- arch/x86/kvm/pmu.h | 4 ++-- arch/x86/kvm/svm/pmu.c | 9 ++++++--- arch/x86/kvm/vmx/pmu_intel.c | 12 ------------ arch/x86/kvm/x86.c | 9 +++------ 8 files changed, 27 insertions(+), 29 deletions(-) diff --git a/arch/x86/include/asm/kvm-x86-pmu-ops.h b/arch/x86/include/asm/kvm-x86-pmu-ops.h index d7eebee4450c..f0cd48222133 100644 --- a/arch/x86/include/asm/kvm-x86-pmu-ops.h +++ b/arch/x86/include/asm/kvm-x86-pmu-ops.h @@ -15,7 +15,7 @@ BUILD_BUG_ON(1) KVM_X86_PMU_OP(pmc_idx_to_pmc) KVM_X86_PMU_OP(rdpmc_ecx_to_pmc) KVM_X86_PMU_OP(msr_idx_to_pmc) -KVM_X86_PMU_OP(is_valid_rdpmc_ecx) +KVM_X86_PMU_OP_OPTIONAL(check_rdpmc_early) KVM_X86_PMU_OP(is_valid_msr) KVM_X86_PMU_OP(get_msr) KVM_X86_PMU_OP(set_msr) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index e223043ef5b2..695ab5b6055c 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -3962,7 +3962,7 @@ static int check_rdpmc(struct x86_emulate_ctxt *ctxt) * protected mode. */ if ((!(cr4 & X86_CR4_PCE) && ctxt->ops->cpl(ctxt)) || - ctxt->ops->check_pmc(ctxt, rcx)) + ctxt->ops->check_rdpmc_early(ctxt, rcx)) return emulate_gp(ctxt, 0); return X86EMUL_CONTINUE; diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h index e6d149825169..4351149484fb 100644 --- a/arch/x86/kvm/kvm_emulate.h +++ b/arch/x86/kvm/kvm_emulate.h @@ -208,7 +208,7 @@ struct x86_emulate_ops { int (*set_msr_with_filter)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 data); int (*get_msr_with_filter)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 *pdata); int (*get_msr)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 *pdata); - int (*check_pmc)(struct x86_emulate_ctxt *ctxt, u32 pmc); + int (*check_rdpmc_early)(struct x86_emulate_ctxt *ctxt, u32 pmc); int (*read_pmc)(struct x86_emulate_ctxt *ctxt, u32 pmc, u64 *pdata); void (*halt)(struct x86_emulate_ctxt *ctxt); void (*wbinvd)(struct x86_emulate_ctxt *ctxt); diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 30945fea6988..0b0d804ee239 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -524,10 +524,20 @@ void kvm_pmu_handle_event(struct kvm_vcpu *vcpu) kvm_pmu_cleanup(vcpu); } -/* check if idx is a valid index to access PMU */ -bool kvm_pmu_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx) +int kvm_pmu_check_rdpmc_early(struct kvm_vcpu *vcpu, unsigned int idx) { - return static_call(kvm_x86_pmu_is_valid_rdpmc_ecx)(vcpu, idx); + /* + * On Intel, VMX interception has priority over RDPMC exceptions that + * aren't already handled by the emulator, i.e. there are no additional + * check needed for Intel PMUs. + * + * On AMD, _all_ exceptions on RDPMC have priority over SVM intercepts, + * i.e. an invalid PMC results in a #GP, not #VMEXIT. + */ + if (!kvm_pmu_ops.check_rdpmc_early) + return 0; + + return static_call(kvm_x86_pmu_check_rdpmc_early)(vcpu, idx); } bool is_vmware_backdoor_pmc(u32 pmc_idx) diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h index 87ecf22f5b25..51bbb01b21c8 100644 --- a/arch/x86/kvm/pmu.h +++ b/arch/x86/kvm/pmu.h @@ -23,7 +23,7 @@ struct kvm_pmu_ops { struct kvm_pmc *(*rdpmc_ecx_to_pmc)(struct kvm_vcpu *vcpu, unsigned int idx, u64 *mask); struct kvm_pmc *(*msr_idx_to_pmc)(struct kvm_vcpu *vcpu, u32 msr); - bool (*is_valid_rdpmc_ecx)(struct kvm_vcpu *vcpu, unsigned int idx); + int (*check_rdpmc_early)(struct kvm_vcpu *vcpu, unsigned int idx); bool (*is_valid_msr)(struct kvm_vcpu *vcpu, u32 msr); int (*get_msr)(struct kvm_vcpu *vcpu, struct msr_data *msr_info); int (*set_msr)(struct kvm_vcpu *vcpu, struct msr_data *msr_info); @@ -215,7 +215,7 @@ static inline bool pmc_is_globally_enabled(struct kvm_pmc *pmc) void kvm_pmu_deliver_pmi(struct kvm_vcpu *vcpu); void kvm_pmu_handle_event(struct kvm_vcpu *vcpu); int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned pmc, u64 *data); -bool kvm_pmu_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx); +int kvm_pmu_check_rdpmc_early(struct kvm_vcpu *vcpu, unsigned int idx); bool kvm_pmu_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr); int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info); int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info); diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c index 1fafc46f61c9..e886300f0f97 100644 --- a/arch/x86/kvm/svm/pmu.c +++ b/arch/x86/kvm/svm/pmu.c @@ -73,11 +73,14 @@ static inline struct kvm_pmc *get_gp_pmc_amd(struct kvm_pmu *pmu, u32 msr, return amd_pmc_idx_to_pmc(pmu, idx); } -static bool amd_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx) +static int amd_check_rdpmc_early(struct kvm_vcpu *vcpu, unsigned int idx) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); - return idx < pmu->nr_arch_gp_counters; + if (idx >= pmu->nr_arch_gp_counters) + return -EINVAL; + + return 0; } /* idx is the ECX register of RDPMC instruction */ @@ -229,7 +232,7 @@ struct kvm_pmu_ops amd_pmu_ops __initdata = { .pmc_idx_to_pmc = amd_pmc_idx_to_pmc, .rdpmc_ecx_to_pmc = amd_rdpmc_ecx_to_pmc, .msr_idx_to_pmc = amd_msr_idx_to_pmc, - .is_valid_rdpmc_ecx = amd_is_valid_rdpmc_ecx, + .check_rdpmc_early = amd_check_rdpmc_early, .is_valid_msr = amd_is_valid_msr, .get_msr = amd_pmu_get_msr, .set_msr = amd_pmu_set_msr, diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index ec4feaef3d55..1b1f888ad32b 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -55,17 +55,6 @@ static struct kvm_pmc *intel_pmc_idx_to_pmc(struct kvm_pmu *pmu, int pmc_idx) } } -static bool intel_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx) -{ - struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); - bool fixed = idx & (1u << 30); - - idx &= ~(3u << 30); - - return fixed ? idx < pmu->nr_arch_fixed_counters - : idx < pmu->nr_arch_gp_counters; -} - static struct kvm_pmc *intel_rdpmc_ecx_to_pmc(struct kvm_vcpu *vcpu, unsigned int idx, u64 *mask) { @@ -718,7 +707,6 @@ struct kvm_pmu_ops intel_pmu_ops __initdata = { .pmc_idx_to_pmc = intel_pmc_idx_to_pmc, .rdpmc_ecx_to_pmc = intel_rdpmc_ecx_to_pmc, .msr_idx_to_pmc = intel_msr_idx_to_pmc, - .is_valid_rdpmc_ecx = intel_is_valid_rdpmc_ecx, .is_valid_msr = intel_is_valid_msr, .get_msr = intel_pmu_get_msr, .set_msr = intel_pmu_set_msr, diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 363b1c080205..cbee277254f0 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8389,12 +8389,9 @@ static int emulator_get_msr(struct x86_emulate_ctxt *ctxt, return kvm_get_msr(emul_to_vcpu(ctxt), msr_index, pdata); } -static int emulator_check_pmc(struct x86_emulate_ctxt *ctxt, - u32 pmc) +static int emulator_check_rdpmc_early(struct x86_emulate_ctxt *ctxt, u32 pmc) { - if (kvm_pmu_is_valid_rdpmc_ecx(emul_to_vcpu(ctxt), pmc)) - return 0; - return -EINVAL; + return kvm_pmu_check_rdpmc_early(emul_to_vcpu(ctxt), pmc); } static int emulator_read_pmc(struct x86_emulate_ctxt *ctxt, @@ -8526,7 +8523,7 @@ static const struct x86_emulate_ops emulate_ops = { .set_msr_with_filter = emulator_set_msr_with_filter, .get_msr_with_filter = emulator_get_msr_with_filter, .get_msr = emulator_get_msr, - .check_pmc = emulator_check_pmc, + .check_rdpmc_early = emulator_check_rdpmc_early, .read_pmc = emulator_read_pmc, .halt = emulator_halt, .wbinvd = emulator_wbinvd, -- cgit v1.2.3 From d652981db08fe2db185e00ad9cd41871f49807b0 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:28 -0800 Subject: KVM: x86/pmu: Apply "fast" RDPMC only to Intel PMUs Move the handling of "fast" RDPMC instructions, which drop bits 63:32 of the count, to Intel. The "fast" flag, and all modifiers for that matter, are Intel-only and aren't supported by AMD. Opportunistically replace open coded bit crud with proper #defines, and add comments to try and disentangle the flags vs. values mess for non-architectural vs. architectural PMUs. Fixes: ca724305a2b0 ("KVM: x86/vPMU: Implement AMD vPMU code for KVM") Reviewed-by: Dapeng Mi Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-9-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/pmu.c | 3 +-- arch/x86/kvm/vmx/pmu_intel.c | 16 ++++++++++++++-- 2 files changed, 15 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 0b0d804ee239..09b0feb975c3 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -576,10 +576,9 @@ static int kvm_pmu_rdpmc_vmware(struct kvm_vcpu *vcpu, unsigned idx, u64 *data) int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data) { - bool fast_mode = idx & (1u << 31); struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); struct kvm_pmc *pmc; - u64 mask = fast_mode ? ~0u : ~0ull; + u64 mask = ~0ull; if (!pmu->version) return 1; diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index 1b1f888ad32b..03bd188b5754 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -20,6 +20,15 @@ #include "nested.h" #include "pmu.h" +/* + * Perf's "BASE" is wildly misleading, architectural PMUs use bits 31:16 of ECX + * to encode the "type" of counter to read, i.e. this is not a "base". And to + * further confuse things, non-architectural PMUs use bit 31 as a flag for + * "fast" reads, whereas the "type" is an explicit value. + */ +#define INTEL_RDPMC_FIXED INTEL_PMC_FIXED_RDPMC_BASE +#define INTEL_RDPMC_FAST BIT(31) + #define MSR_PMC_FULL_WIDTH_BIT (MSR_IA32_PMC0 - MSR_IA32_PERFCTR0) static void reprogram_fixed_counters(struct kvm_pmu *pmu, u64 data) @@ -59,11 +68,14 @@ static struct kvm_pmc *intel_rdpmc_ecx_to_pmc(struct kvm_vcpu *vcpu, unsigned int idx, u64 *mask) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); - bool fixed = idx & (1u << 30); + bool fixed = idx & INTEL_RDPMC_FIXED; struct kvm_pmc *counters; unsigned int num_counters; - idx &= ~(3u << 30); + if (idx & INTEL_RDPMC_FAST) + *mask &= GENMASK_ULL(31, 0); + + idx &= ~(INTEL_RDPMC_FIXED | INTEL_RDPMC_FAST); if (fixed) { counters = pmu->fixed_counters; num_counters = pmu->nr_arch_fixed_counters; -- cgit v1.2.3 From 5728a4a0ea79e2f2e650db4793170900e57359a7 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:29 -0800 Subject: KVM: x86/pmu: Disallow "fast" RDPMC for architectural Intel PMUs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Inject #GP on RDPMC if the "fast" flag is set for architectural Intel PMUs, i.e. if the PMU version is non-zero. Per Intel's SDM, and confirmed on bare metal, the "fast" flag is supported only for non-architectural PMUs, and is reserved for architectural PMUs. If the processor does not support architectural performance monitoring (CPUID.0AH:EAX[7:0]=0), ECX[30:0] specifies the index of the PMC to be read. Setting ECX[31] selects “fast” read mode if supported. In this mode, RDPMC returns bits 31:0 of the PMC in EAX while clearing EDX to zero. If the processor does support architectural performance monitoring (CPUID.0AH:EAX[7:0] ≠ 0), ECX[31:16] specifies type of PMC while ECX[15:0] specifies the index of the PMC to be read within that type. The following PMC types are currently defined: — General-purpose counters use type 0. The index x (to read IA32_PMCx) must be less than the value enumerated by CPUID.0AH.EAX[15:8] (thus ECX[15:8] must be zero). — Fixed-function counters use type 4000H. The index x (to read IA32_FIXED_CTRx) can be used if either CPUID.0AH.EDX[4:0] > x or CPUID.0AH.ECX[x] = 1 (thus ECX[15:5] must be 0). — Performance metrics use type 2000H. This type can be used only if IA32_PERF_CAPABILITIES.PERF_METRICS_AVAILABLE[bit 15]=1. For this type, the index in ECX[15:0] is implementation specific. Opportunistically WARN if KVM ever actually tries to complete RDPMC for a non-architectural PMU, and drop the non-existent "support" for fast RDPMC, as KVM doesn't support such PMUs, i.e. kvm_pmu_rdpmc() should reject the RDPMC before getting to the Intel code. Fixes: f5132b01386b ("KVM: Expose a version 2 architectural PMU to a guests") Fixes: 67f4d4288c35 ("KVM: x86: rdpmc emulation checks the counter incorrectly") Reviewed-by: Dapeng Mi Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-10-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/pmu_intel.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index 03bd188b5754..5a5dfae6055c 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -27,7 +27,6 @@ * "fast" reads, whereas the "type" is an explicit value. */ #define INTEL_RDPMC_FIXED INTEL_PMC_FIXED_RDPMC_BASE -#define INTEL_RDPMC_FAST BIT(31) #define MSR_PMC_FULL_WIDTH_BIT (MSR_IA32_PMC0 - MSR_IA32_PERFCTR0) @@ -72,10 +71,25 @@ static struct kvm_pmc *intel_rdpmc_ecx_to_pmc(struct kvm_vcpu *vcpu, struct kvm_pmc *counters; unsigned int num_counters; - if (idx & INTEL_RDPMC_FAST) - *mask &= GENMASK_ULL(31, 0); + /* + * The encoding of ECX for RDPMC is different for architectural versus + * non-architecturals PMUs (PMUs with version '0'). For architectural + * PMUs, bits 31:16 specify the PMC type and bits 15:0 specify the PMC + * index. For non-architectural PMUs, bit 31 is a "fast" flag, and + * bits 30:0 specify the PMC index. + * + * Yell and reject attempts to read PMCs for a non-architectural PMU, + * as KVM doesn't support such PMUs. + */ + if (WARN_ON_ONCE(!pmu->version)) + return NULL; - idx &= ~(INTEL_RDPMC_FIXED | INTEL_RDPMC_FAST); + /* + * Fixed PMCs are supported on all architectural PMUs. Note, KVM only + * emulates fixed PMCs for PMU v2+, but the flag itself is still valid, + * i.e. let RDPMC fail due to accessing a non-existent counter. + */ + idx &= ~INTEL_RDPMC_FIXED; if (fixed) { counters = pmu->fixed_counters; num_counters = pmu->nr_arch_fixed_counters; -- cgit v1.2.3 From 7a0fc734c20dd1ad9bc1b8b922b61616f31d3823 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:30 -0800 Subject: KVM: x86/pmu: Treat "fixed" PMU type in RDPMC as index as a value, not flag Refactor KVM's handling of ECX for RDPMC to treat the FIXED modifier as an explicit value, not a flag (minus one wart). While non-architectural PMUs do use bit 31 as a flag (for "fast" reads), architectural PMUs use the upper half of ECX to encode the type. From the SDM: ECX[31:16] specifies type of PMC while ECX[15:0] specifies the index of the PMC to be read within that type Note, that the known supported types are 4000H and 2000H, i.e. look a lot like flags, doesn't contradict the above statement that ECX[31:16] holds the type, at least not by any sane reading of the SDM. Keep the explicitly clearing of the FIXED "flag", as KVM subtly relies on that behavior to disallow unsupported types while allowing the correct indices for fixed counters. This wart will be cleaned up in short order. Opportunistically grab the per-type bitmask in the if-else blocks to eliminate the one-off usage of the local "fixed" bool. Reported-by: Jim Mattson Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-11-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/pmu_intel.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index 5a5dfae6055c..c37dd3aa056b 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -28,6 +28,9 @@ */ #define INTEL_RDPMC_FIXED INTEL_PMC_FIXED_RDPMC_BASE +#define INTEL_RDPMC_TYPE_MASK GENMASK(31, 16) +#define INTEL_RDPMC_INDEX_MASK GENMASK(15, 0) + #define MSR_PMC_FULL_WIDTH_BIT (MSR_IA32_PMC0 - MSR_IA32_PERFCTR0) static void reprogram_fixed_counters(struct kvm_pmu *pmu, u64 data) @@ -66,10 +69,11 @@ static struct kvm_pmc *intel_pmc_idx_to_pmc(struct kvm_pmu *pmu, int pmc_idx) static struct kvm_pmc *intel_rdpmc_ecx_to_pmc(struct kvm_vcpu *vcpu, unsigned int idx, u64 *mask) { + unsigned int type = idx & INTEL_RDPMC_TYPE_MASK; struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); - bool fixed = idx & INTEL_RDPMC_FIXED; struct kvm_pmc *counters; unsigned int num_counters; + u64 bitmask; /* * The encoding of ECX for RDPMC is different for architectural versus @@ -90,16 +94,20 @@ static struct kvm_pmc *intel_rdpmc_ecx_to_pmc(struct kvm_vcpu *vcpu, * i.e. let RDPMC fail due to accessing a non-existent counter. */ idx &= ~INTEL_RDPMC_FIXED; - if (fixed) { + if (type == INTEL_RDPMC_FIXED) { counters = pmu->fixed_counters; num_counters = pmu->nr_arch_fixed_counters; + bitmask = pmu->counter_bitmask[KVM_PMC_FIXED]; } else { counters = pmu->gp_counters; num_counters = pmu->nr_arch_gp_counters; + bitmask = pmu->counter_bitmask[KVM_PMC_GP]; } + if (idx >= num_counters) return NULL; - *mask &= pmu->counter_bitmask[fixed ? KVM_PMC_FIXED : KVM_PMC_GP]; + + *mask &= bitmask; return &counters[array_index_nospec(idx, num_counters)]; } -- cgit v1.2.3 From a634c76b2c1a642d11f5d6e1810181daedcbe0ab Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:31 -0800 Subject: KVM: x86/pmu: Explicitly check for RDPMC of unsupported Intel PMC types MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Explicitly check for attempts to read unsupported PMC types instead of letting the bounds check fail. Functionally, letting the check fail is ok, but it's unnecessarily subtle and does a poor job of documenting the architectural behavior that KVM is emulating. Reviewed-by: Dapeng Mi  Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-12-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/pmu_intel.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index c37dd3aa056b..b41bdb0a0995 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -26,6 +26,7 @@ * further confuse things, non-architectural PMUs use bit 31 as a flag for * "fast" reads, whereas the "type" is an explicit value. */ +#define INTEL_RDPMC_GP 0 #define INTEL_RDPMC_FIXED INTEL_PMC_FIXED_RDPMC_BASE #define INTEL_RDPMC_TYPE_MASK GENMASK(31, 16) @@ -89,21 +90,29 @@ static struct kvm_pmc *intel_rdpmc_ecx_to_pmc(struct kvm_vcpu *vcpu, return NULL; /* - * Fixed PMCs are supported on all architectural PMUs. Note, KVM only - * emulates fixed PMCs for PMU v2+, but the flag itself is still valid, - * i.e. let RDPMC fail due to accessing a non-existent counter. + * General Purpose (GP) PMCs are supported on all PMUs, and fixed PMCs + * are supported on all architectural PMUs, i.e. on all virtual PMUs + * supported by KVM. Note, KVM only emulates fixed PMCs for PMU v2+, + * but the type itself is still valid, i.e. let RDPMC fail due to + * accessing a non-existent counter. Reject attempts to read all other + * types, which are unknown/unsupported. */ - idx &= ~INTEL_RDPMC_FIXED; - if (type == INTEL_RDPMC_FIXED) { + switch (type) { + case INTEL_RDPMC_FIXED: counters = pmu->fixed_counters; num_counters = pmu->nr_arch_fixed_counters; bitmask = pmu->counter_bitmask[KVM_PMC_FIXED]; - } else { + break; + case INTEL_RDPMC_GP: counters = pmu->gp_counters; num_counters = pmu->nr_arch_gp_counters; bitmask = pmu->counter_bitmask[KVM_PMC_GP]; + break; + default: + return NULL; } + idx &= INTEL_RDPMC_INDEX_MASK; if (idx >= num_counters) return NULL; -- cgit v1.2.3 From d7e68738e1aae940b54bfc03313e0ef5720e2e71 Mon Sep 17 00:00:00 2001 From: Jinrong Liang Date: Tue, 9 Jan 2024 15:02:32 -0800 Subject: KVM: selftests: Add vcpu_set_cpuid_property() to set properties Add vcpu_set_cpuid_property() helper function for setting properties, and use it instead of open coding an equivalent for MAX_PHY_ADDR. Future vPMU testcases will also need to stuff various CPUID properties. Reviewed-by: Jim Mattson Signed-off-by: Jinrong Liang Co-developed-by: Sean Christopherson Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-13-seanjc@google.com Signed-off-by: Sean Christopherson --- tools/testing/selftests/kvm/include/x86_64/processor.h | 4 +++- tools/testing/selftests/kvm/lib/x86_64/processor.c | 15 ++++++++++++--- .../kvm/x86_64/smaller_maxphyaddr_emulation_test.c | 2 +- 3 files changed, 16 insertions(+), 5 deletions(-) diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h index a84863503fcb..932944c4ea01 100644 --- a/tools/testing/selftests/kvm/include/x86_64/processor.h +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h @@ -995,7 +995,9 @@ static inline void vcpu_set_cpuid(struct kvm_vcpu *vcpu) vcpu_ioctl(vcpu, KVM_GET_CPUID2, vcpu->cpuid); } -void vcpu_set_cpuid_maxphyaddr(struct kvm_vcpu *vcpu, uint8_t maxphyaddr); +void vcpu_set_cpuid_property(struct kvm_vcpu *vcpu, + struct kvm_x86_cpu_property property, + uint32_t value); void vcpu_clear_cpuid_entry(struct kvm_vcpu *vcpu, uint32_t function); void vcpu_set_or_clear_cpuid_feature(struct kvm_vcpu *vcpu, diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c index d8288374078e..67eb82a6c754 100644 --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c @@ -752,12 +752,21 @@ void vcpu_init_cpuid(struct kvm_vcpu *vcpu, const struct kvm_cpuid2 *cpuid) vcpu_set_cpuid(vcpu); } -void vcpu_set_cpuid_maxphyaddr(struct kvm_vcpu *vcpu, uint8_t maxphyaddr) +void vcpu_set_cpuid_property(struct kvm_vcpu *vcpu, + struct kvm_x86_cpu_property property, + uint32_t value) { - struct kvm_cpuid_entry2 *entry = vcpu_get_cpuid_entry(vcpu, 0x80000008); + struct kvm_cpuid_entry2 *entry; + + entry = __vcpu_get_cpuid_entry(vcpu, property.function, property.index); + + (&entry->eax)[property.reg] &= ~GENMASK(property.hi_bit, property.lo_bit); + (&entry->eax)[property.reg] |= value << property.lo_bit; - entry->eax = (entry->eax & ~0xff) | maxphyaddr; vcpu_set_cpuid(vcpu); + + /* Sanity check that @value doesn't exceed the bounds in any way. */ + TEST_ASSERT_EQ(kvm_cpuid_property(vcpu->cpuid, property), value); } void vcpu_clear_cpuid_entry(struct kvm_vcpu *vcpu, uint32_t function) diff --git a/tools/testing/selftests/kvm/x86_64/smaller_maxphyaddr_emulation_test.c b/tools/testing/selftests/kvm/x86_64/smaller_maxphyaddr_emulation_test.c index 06edf00a97d6..9b89440dff19 100644 --- a/tools/testing/selftests/kvm/x86_64/smaller_maxphyaddr_emulation_test.c +++ b/tools/testing/selftests/kvm/x86_64/smaller_maxphyaddr_emulation_test.c @@ -63,7 +63,7 @@ int main(int argc, char *argv[]) vm_init_descriptor_tables(vm); vcpu_init_descriptor_tables(vcpu); - vcpu_set_cpuid_maxphyaddr(vcpu, MAXPHYADDR); + vcpu_set_cpuid_property(vcpu, X86_PROPERTY_MAX_PHY_ADDR, MAXPHYADDR); rc = kvm_check_cap(KVM_CAP_EXIT_ON_EMULATION_FAILURE); TEST_ASSERT(rc, "KVM_CAP_EXIT_ON_EMULATION_FAILURE is unavailable"); -- cgit v1.2.3 From ff76d771251003b28aeac2051cfe72384dff232f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:33 -0800 Subject: KVM: selftests: Drop the "name" param from KVM_X86_PMU_FEATURE() Drop the "name" parameter from KVM_X86_PMU_FEATURE(), it's unused and the name is redundant with the macro, i.e. it's truly useless. Reviewed-by: Jim Mattson Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-14-seanjc@google.com Signed-off-by: Sean Christopherson --- tools/testing/selftests/kvm/include/x86_64/processor.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h index 932944c4ea01..4f737d3b893c 100644 --- a/tools/testing/selftests/kvm/include/x86_64/processor.h +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h @@ -290,7 +290,7 @@ struct kvm_x86_cpu_property { struct kvm_x86_pmu_feature { struct kvm_x86_cpu_feature anti_feature; }; -#define KVM_X86_PMU_FEATURE(name, __bit) \ +#define KVM_X86_PMU_FEATURE(__bit) \ ({ \ struct kvm_x86_pmu_feature feature = { \ .anti_feature = KVM_X86_CPU_FEATURE(0xa, 0, EBX, __bit), \ @@ -299,7 +299,7 @@ struct kvm_x86_pmu_feature { feature; \ }) -#define X86_PMU_FEATURE_BRANCH_INSNS_RETIRED KVM_X86_PMU_FEATURE(BRANCH_INSNS_RETIRED, 5) +#define X86_PMU_FEATURE_BRANCH_INSNS_RETIRED KVM_X86_PMU_FEATURE(5) static inline unsigned int x86_family(unsigned int eax) { -- cgit v1.2.3 From 370d536322896cc9ad59eb8849ad8e1f9e985953 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:34 -0800 Subject: KVM: selftests: Extend {kvm,this}_pmu_has() to support fixed counters Extend the kvm_x86_pmu_feature framework to allow querying for fixed counters via {kvm,this}_pmu_has(). Like architectural events, checking for a fixed counter annoyingly requires checking multiple CPUID fields, as a fixed counter exists if: FxCtr[i]_is_supported := ECX[i] || (EDX[4:0] > i); Note, KVM currently doesn't actually support exposing fixed counters via the bitmask, but that will hopefully change sooner than later, and Intel's SDM explicitly "recommends" checking both the number of counters and the mask. Rename the intermedate "anti_feature" field to simply 'f' since the fixed counter bitmask (thankfully) doesn't have reversed polarity like the architectural events bitmask. Note, ideally the helpers would use BUILD_BUG_ON() to assert on the incoming register, but the expected usage in PMU tests can't guarantee the inputs are compile-time constants. Opportunistically define macros for all of the known architectural events and fixed counters. Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-15-seanjc@google.com Signed-off-by: Sean Christopherson --- .../selftests/kvm/include/x86_64/processor.h | 65 ++++++++++++++++------ 1 file changed, 47 insertions(+), 18 deletions(-) diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h index 4f737d3b893c..92d4f8ecc730 100644 --- a/tools/testing/selftests/kvm/include/x86_64/processor.h +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h @@ -282,24 +282,41 @@ struct kvm_x86_cpu_property { * that indicates the feature is _not_ supported, and a property that states * the length of the bit mask of unsupported features. A feature is supported * if the size of the bit mask is larger than the "unavailable" bit, and said - * bit is not set. + * bit is not set. Fixed counters also bizarre enumeration, but inverted from + * arch events for general purpose counters. Fixed counters are supported if a + * feature flag is set **OR** the total number of fixed counters is greater + * than index of the counter. * - * Wrap the "unavailable" feature to simplify checking whether or not a given - * architectural event is supported. + * Wrap the events for general purpose and fixed counters to simplify checking + * whether or not a given architectural event is supported. */ struct kvm_x86_pmu_feature { - struct kvm_x86_cpu_feature anti_feature; + struct kvm_x86_cpu_feature f; }; -#define KVM_X86_PMU_FEATURE(__bit) \ -({ \ - struct kvm_x86_pmu_feature feature = { \ - .anti_feature = KVM_X86_CPU_FEATURE(0xa, 0, EBX, __bit), \ - }; \ - \ - feature; \ +#define KVM_X86_PMU_FEATURE(__reg, __bit) \ +({ \ + struct kvm_x86_pmu_feature feature = { \ + .f = KVM_X86_CPU_FEATURE(0xa, 0, __reg, __bit), \ + }; \ + \ + kvm_static_assert(KVM_CPUID_##__reg == KVM_CPUID_EBX || \ + KVM_CPUID_##__reg == KVM_CPUID_ECX); \ + feature; \ }) -#define X86_PMU_FEATURE_BRANCH_INSNS_RETIRED KVM_X86_PMU_FEATURE(5) +#define X86_PMU_FEATURE_CPU_CYCLES KVM_X86_PMU_FEATURE(EBX, 0) +#define X86_PMU_FEATURE_INSNS_RETIRED KVM_X86_PMU_FEATURE(EBX, 1) +#define X86_PMU_FEATURE_REFERENCE_CYCLES KVM_X86_PMU_FEATURE(EBX, 2) +#define X86_PMU_FEATURE_LLC_REFERENCES KVM_X86_PMU_FEATURE(EBX, 3) +#define X86_PMU_FEATURE_LLC_MISSES KVM_X86_PMU_FEATURE(EBX, 4) +#define X86_PMU_FEATURE_BRANCH_INSNS_RETIRED KVM_X86_PMU_FEATURE(EBX, 5) +#define X86_PMU_FEATURE_BRANCHES_MISPREDICTED KVM_X86_PMU_FEATURE(EBX, 6) +#define X86_PMU_FEATURE_TOPDOWN_SLOTS KVM_X86_PMU_FEATURE(EBX, 7) + +#define X86_PMU_FEATURE_INSNS_RETIRED_FIXED KVM_X86_PMU_FEATURE(ECX, 0) +#define X86_PMU_FEATURE_CPU_CYCLES_FIXED KVM_X86_PMU_FEATURE(ECX, 1) +#define X86_PMU_FEATURE_REFERENCE_TSC_CYCLES_FIXED KVM_X86_PMU_FEATURE(ECX, 2) +#define X86_PMU_FEATURE_TOPDOWN_SLOTS_FIXED KVM_X86_PMU_FEATURE(ECX, 3) static inline unsigned int x86_family(unsigned int eax) { @@ -698,10 +715,16 @@ static __always_inline bool this_cpu_has_p(struct kvm_x86_cpu_property property) static inline bool this_pmu_has(struct kvm_x86_pmu_feature feature) { - uint32_t nr_bits = this_cpu_property(X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH); + uint32_t nr_bits; + + if (feature.f.reg == KVM_CPUID_EBX) { + nr_bits = this_cpu_property(X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH); + return nr_bits > feature.f.bit && !this_cpu_has(feature.f); + } - return nr_bits > feature.anti_feature.bit && - !this_cpu_has(feature.anti_feature); + GUEST_ASSERT(feature.f.reg == KVM_CPUID_ECX); + nr_bits = this_cpu_property(X86_PROPERTY_PMU_NR_FIXED_COUNTERS); + return nr_bits > feature.f.bit || this_cpu_has(feature.f); } static __always_inline uint64_t this_cpu_supported_xcr0(void) @@ -917,10 +940,16 @@ static __always_inline bool kvm_cpu_has_p(struct kvm_x86_cpu_property property) static inline bool kvm_pmu_has(struct kvm_x86_pmu_feature feature) { - uint32_t nr_bits = kvm_cpu_property(X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH); + uint32_t nr_bits; + + if (feature.f.reg == KVM_CPUID_EBX) { + nr_bits = kvm_cpu_property(X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH); + return nr_bits > feature.f.bit && !kvm_cpu_has(feature.f); + } - return nr_bits > feature.anti_feature.bit && - !kvm_cpu_has(feature.anti_feature); + TEST_ASSERT_EQ(feature.f.reg, KVM_CPUID_ECX); + nr_bits = kvm_cpu_property(X86_PROPERTY_PMU_NR_FIXED_COUNTERS); + return nr_bits > feature.f.bit || kvm_cpu_has(feature.f); } static __always_inline uint64_t kvm_cpu_supported_xcr0(void) -- cgit v1.2.3 From e6faa04970575622243d3a20782dde2d5813772d Mon Sep 17 00:00:00 2001 From: Jinrong Liang Date: Tue, 9 Jan 2024 15:02:35 -0800 Subject: KVM: selftests: Add pmu.h and lib/pmu.c for common PMU assets Add a PMU library for x86 selftests to help eliminate open-coded event encodings, and to reduce the amount of copy+paste between PMU selftests. Use the new common macro definitions in the existing PMU event filter test. Cc: Aaron Lewis Suggested-by: Sean Christopherson Signed-off-by: Jinrong Liang Co-developed-by: Sean Christopherson Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-16-seanjc@google.com Signed-off-by: Sean Christopherson --- tools/testing/selftests/kvm/Makefile | 1 + tools/testing/selftests/kvm/include/x86_64/pmu.h | 97 ++++++++++++++ tools/testing/selftests/kvm/lib/x86_64/pmu.c | 31 +++++ .../selftests/kvm/x86_64/pmu_event_filter_test.c | 141 +++++++-------------- 4 files changed, 173 insertions(+), 97 deletions(-) create mode 100644 tools/testing/selftests/kvm/include/x86_64/pmu.h create mode 100644 tools/testing/selftests/kvm/lib/x86_64/pmu.c diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index 492e937fab00..0f07ce8bd297 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -36,6 +36,7 @@ LIBKVM_x86_64 += lib/x86_64/apic.c LIBKVM_x86_64 += lib/x86_64/handlers.S LIBKVM_x86_64 += lib/x86_64/hyperv.c LIBKVM_x86_64 += lib/x86_64/memstress.c +LIBKVM_x86_64 += lib/x86_64/pmu.c LIBKVM_x86_64 += lib/x86_64/processor.c LIBKVM_x86_64 += lib/x86_64/svm.c LIBKVM_x86_64 += lib/x86_64/ucall.c diff --git a/tools/testing/selftests/kvm/include/x86_64/pmu.h b/tools/testing/selftests/kvm/include/x86_64/pmu.h new file mode 100644 index 000000000000..3c10c4dc0ae8 --- /dev/null +++ b/tools/testing/selftests/kvm/include/x86_64/pmu.h @@ -0,0 +1,97 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2023, Tencent, Inc. + */ +#ifndef SELFTEST_KVM_PMU_H +#define SELFTEST_KVM_PMU_H + +#include + +#define KVM_PMU_EVENT_FILTER_MAX_EVENTS 300 + +/* + * Encode an eventsel+umask pair into event-select MSR format. Note, this is + * technically AMD's format, as Intel's format only supports 8 bits for the + * event selector, i.e. doesn't use bits 24:16 for the selector. But, OR-ing + * in '0' is a nop and won't clobber the CMASK. + */ +#define RAW_EVENT(eventsel, umask) (((eventsel & 0xf00UL) << 24) | \ + ((eventsel) & 0xff) | \ + ((umask) & 0xff) << 8) + +/* + * These are technically Intel's definitions, but except for CMASK (see above), + * AMD's layout is compatible with Intel's. + */ +#define ARCH_PERFMON_EVENTSEL_EVENT GENMASK_ULL(7, 0) +#define ARCH_PERFMON_EVENTSEL_UMASK GENMASK_ULL(15, 8) +#define ARCH_PERFMON_EVENTSEL_USR BIT_ULL(16) +#define ARCH_PERFMON_EVENTSEL_OS BIT_ULL(17) +#define ARCH_PERFMON_EVENTSEL_EDGE BIT_ULL(18) +#define ARCH_PERFMON_EVENTSEL_PIN_CONTROL BIT_ULL(19) +#define ARCH_PERFMON_EVENTSEL_INT BIT_ULL(20) +#define ARCH_PERFMON_EVENTSEL_ANY BIT_ULL(21) +#define ARCH_PERFMON_EVENTSEL_ENABLE BIT_ULL(22) +#define ARCH_PERFMON_EVENTSEL_INV BIT_ULL(23) +#define ARCH_PERFMON_EVENTSEL_CMASK GENMASK_ULL(31, 24) + +/* RDPMC control flags, Intel only. */ +#define INTEL_RDPMC_METRICS BIT_ULL(29) +#define INTEL_RDPMC_FIXED BIT_ULL(30) +#define INTEL_RDPMC_FAST BIT_ULL(31) + +/* Fixed PMC controls, Intel only. */ +#define FIXED_PMC_GLOBAL_CTRL_ENABLE(_idx) BIT_ULL((32 + (_idx))) + +#define FIXED_PMC_KERNEL BIT_ULL(0) +#define FIXED_PMC_USER BIT_ULL(1) +#define FIXED_PMC_ANYTHREAD BIT_ULL(2) +#define FIXED_PMC_ENABLE_PMI BIT_ULL(3) +#define FIXED_PMC_NR_BITS 4 +#define FIXED_PMC_CTRL(_idx, _val) ((_val) << ((_idx) * FIXED_PMC_NR_BITS)) + +#define PMU_CAP_FW_WRITES BIT_ULL(13) +#define PMU_CAP_LBR_FMT 0x3f + +#define INTEL_ARCH_CPU_CYCLES RAW_EVENT(0x3c, 0x00) +#define INTEL_ARCH_INSTRUCTIONS_RETIRED RAW_EVENT(0xc0, 0x00) +#define INTEL_ARCH_REFERENCE_CYCLES RAW_EVENT(0x3c, 0x01) +#define INTEL_ARCH_LLC_REFERENCES RAW_EVENT(0x2e, 0x4f) +#define INTEL_ARCH_LLC_MISSES RAW_EVENT(0x2e, 0x41) +#define INTEL_ARCH_BRANCHES_RETIRED RAW_EVENT(0xc4, 0x00) +#define INTEL_ARCH_BRANCHES_MISPREDICTED RAW_EVENT(0xc5, 0x00) +#define INTEL_ARCH_TOPDOWN_SLOTS RAW_EVENT(0xa4, 0x01) + +#define AMD_ZEN_CORE_CYCLES RAW_EVENT(0x76, 0x00) +#define AMD_ZEN_INSTRUCTIONS_RETIRED RAW_EVENT(0xc0, 0x00) +#define AMD_ZEN_BRANCHES_RETIRED RAW_EVENT(0xc2, 0x00) +#define AMD_ZEN_BRANCHES_MISPREDICTED RAW_EVENT(0xc3, 0x00) + +/* + * Note! The order and thus the index of the architectural events matters as + * support for each event is enumerated via CPUID using the index of the event. + */ +enum intel_pmu_architectural_events { + INTEL_ARCH_CPU_CYCLES_INDEX, + INTEL_ARCH_INSTRUCTIONS_RETIRED_INDEX, + INTEL_ARCH_REFERENCE_CYCLES_INDEX, + INTEL_ARCH_LLC_REFERENCES_INDEX, + INTEL_ARCH_LLC_MISSES_INDEX, + INTEL_ARCH_BRANCHES_RETIRED_INDEX, + INTEL_ARCH_BRANCHES_MISPREDICTED_INDEX, + INTEL_ARCH_TOPDOWN_SLOTS_INDEX, + NR_INTEL_ARCH_EVENTS, +}; + +enum amd_pmu_zen_events { + AMD_ZEN_CORE_CYCLES_INDEX, + AMD_ZEN_INSTRUCTIONS_INDEX, + AMD_ZEN_BRANCHES_INDEX, + AMD_ZEN_BRANCH_MISSES_INDEX, + NR_AMD_ZEN_EVENTS, +}; + +extern const uint64_t intel_pmu_arch_events[]; +extern const uint64_t amd_pmu_zen_events[]; + +#endif /* SELFTEST_KVM_PMU_H */ diff --git a/tools/testing/selftests/kvm/lib/x86_64/pmu.c b/tools/testing/selftests/kvm/lib/x86_64/pmu.c new file mode 100644 index 000000000000..f31f0427c17c --- /dev/null +++ b/tools/testing/selftests/kvm/lib/x86_64/pmu.c @@ -0,0 +1,31 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2023, Tencent, Inc. + */ + +#include + +#include + +#include "kvm_util.h" +#include "pmu.h" + +const uint64_t intel_pmu_arch_events[] = { + INTEL_ARCH_CPU_CYCLES, + INTEL_ARCH_INSTRUCTIONS_RETIRED, + INTEL_ARCH_REFERENCE_CYCLES, + INTEL_ARCH_LLC_REFERENCES, + INTEL_ARCH_LLC_MISSES, + INTEL_ARCH_BRANCHES_RETIRED, + INTEL_ARCH_BRANCHES_MISPREDICTED, + INTEL_ARCH_TOPDOWN_SLOTS, +}; +kvm_static_assert(ARRAY_SIZE(intel_pmu_arch_events) == NR_INTEL_ARCH_EVENTS); + +const uint64_t amd_pmu_zen_events[] = { + AMD_ZEN_CORE_CYCLES, + AMD_ZEN_INSTRUCTIONS_RETIRED, + AMD_ZEN_BRANCHES_RETIRED, + AMD_ZEN_BRANCHES_MISPREDICTED, +}; +kvm_static_assert(ARRAY_SIZE(amd_pmu_zen_events) == NR_AMD_ZEN_EVENTS); diff --git a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c index 283cc55597a4..7ec9fbed92e0 100644 --- a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c +++ b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c @@ -11,72 +11,18 @@ */ #define _GNU_SOURCE /* for program_invocation_short_name */ -#include "test_util.h" + #include "kvm_util.h" +#include "pmu.h" #include "processor.h" - -/* - * In lieu of copying perf_event.h into tools... - */ -#define ARCH_PERFMON_EVENTSEL_OS (1ULL << 17) -#define ARCH_PERFMON_EVENTSEL_ENABLE (1ULL << 22) - -/* End of stuff taken from perf_event.h. */ - -/* Oddly, this isn't in perf_event.h. */ -#define ARCH_PERFMON_BRANCHES_RETIRED 5 +#include "test_util.h" #define NUM_BRANCHES 42 -#define INTEL_PMC_IDX_FIXED 32 - -/* Matches KVM_PMU_EVENT_FILTER_MAX_EVENTS in pmu.c */ -#define MAX_FILTER_EVENTS 300 #define MAX_TEST_EVENTS 10 #define PMU_EVENT_FILTER_INVALID_ACTION (KVM_PMU_EVENT_DENY + 1) #define PMU_EVENT_FILTER_INVALID_FLAGS (KVM_PMU_EVENT_FLAGS_VALID_MASK << 1) -#define PMU_EVENT_FILTER_INVALID_NEVENTS (MAX_FILTER_EVENTS + 1) - -/* - * This is how the event selector and unit mask are stored in an AMD - * core performance event-select register. Intel's format is similar, - * but the event selector is only 8 bits. - */ -#define EVENT(select, umask) ((select & 0xf00UL) << 24 | (select & 0xff) | \ - (umask & 0xff) << 8) - -/* - * "Branch instructions retired", from the Intel SDM, volume 3, - * "Pre-defined Architectural Performance Events." - */ - -#define INTEL_BR_RETIRED EVENT(0xc4, 0) - -/* - * "Retired branch instructions", from Processor Programming Reference - * (PPR) for AMD Family 17h Model 01h, Revision B1 Processors, - * Preliminary Processor Programming Reference (PPR) for AMD Family - * 17h Model 31h, Revision B0 Processors, and Preliminary Processor - * Programming Reference (PPR) for AMD Family 19h Model 01h, Revision - * B1 Processors Volume 1 of 2. - */ - -#define AMD_ZEN_BR_RETIRED EVENT(0xc2, 0) - - -/* - * "Retired instructions", from Processor Programming Reference - * (PPR) for AMD Family 17h Model 01h, Revision B1 Processors, - * Preliminary Processor Programming Reference (PPR) for AMD Family - * 17h Model 31h, Revision B0 Processors, and Preliminary Processor - * Programming Reference (PPR) for AMD Family 19h Model 01h, Revision - * B1 Processors Volume 1 of 2. - * --- and --- - * "Instructions retired", from the Intel SDM, volume 3, - * "Pre-defined Architectural Performance Events." - */ - -#define INST_RETIRED EVENT(0xc0, 0) +#define PMU_EVENT_FILTER_INVALID_NEVENTS (KVM_PMU_EVENT_FILTER_MAX_EVENTS + 1) struct __kvm_pmu_event_filter { __u32 action; @@ -84,26 +30,28 @@ struct __kvm_pmu_event_filter { __u32 fixed_counter_bitmap; __u32 flags; __u32 pad[4]; - __u64 events[MAX_FILTER_EVENTS]; + __u64 events[KVM_PMU_EVENT_FILTER_MAX_EVENTS]; }; /* - * This event list comprises Intel's eight architectural events plus - * AMD's "retired branch instructions" for Zen[123] (and possibly - * other AMD CPUs). + * This event list comprises Intel's known architectural events, plus AMD's + * "retired branch instructions" for Zen1-Zen3 (and* possibly other AMD CPUs). + * Note, AMD and Intel use the same encoding for instructions retired. */ +kvm_static_assert(INTEL_ARCH_INSTRUCTIONS_RETIRED == AMD_ZEN_INSTRUCTIONS_RETIRED); + static const struct __kvm_pmu_event_filter base_event_filter = { .nevents = ARRAY_SIZE(base_event_filter.events), .events = { - EVENT(0x3c, 0), - INST_RETIRED, - EVENT(0x3c, 1), - EVENT(0x2e, 0x4f), - EVENT(0x2e, 0x41), - EVENT(0xc4, 0), - EVENT(0xc5, 0), - EVENT(0xa4, 1), - AMD_ZEN_BR_RETIRED, + INTEL_ARCH_CPU_CYCLES, + INTEL_ARCH_INSTRUCTIONS_RETIRED, + INTEL_ARCH_REFERENCE_CYCLES, + INTEL_ARCH_LLC_REFERENCES, + INTEL_ARCH_LLC_MISSES, + INTEL_ARCH_BRANCHES_RETIRED, + INTEL_ARCH_BRANCHES_MISPREDICTED, + INTEL_ARCH_TOPDOWN_SLOTS, + AMD_ZEN_BRANCHES_RETIRED, }, }; @@ -165,9 +113,9 @@ static void intel_guest_code(void) for (;;) { wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0); wrmsr(MSR_P6_EVNTSEL0, ARCH_PERFMON_EVENTSEL_ENABLE | - ARCH_PERFMON_EVENTSEL_OS | INTEL_BR_RETIRED); + ARCH_PERFMON_EVENTSEL_OS | INTEL_ARCH_BRANCHES_RETIRED); wrmsr(MSR_P6_EVNTSEL1, ARCH_PERFMON_EVENTSEL_ENABLE | - ARCH_PERFMON_EVENTSEL_OS | INST_RETIRED); + ARCH_PERFMON_EVENTSEL_OS | INTEL_ARCH_INSTRUCTIONS_RETIRED); wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0x3); run_and_measure_loop(MSR_IA32_PMC0); @@ -189,9 +137,9 @@ static void amd_guest_code(void) for (;;) { wrmsr(MSR_K7_EVNTSEL0, 0); wrmsr(MSR_K7_EVNTSEL0, ARCH_PERFMON_EVENTSEL_ENABLE | - ARCH_PERFMON_EVENTSEL_OS | AMD_ZEN_BR_RETIRED); + ARCH_PERFMON_EVENTSEL_OS | AMD_ZEN_BRANCHES_RETIRED); wrmsr(MSR_K7_EVNTSEL1, ARCH_PERFMON_EVENTSEL_ENABLE | - ARCH_PERFMON_EVENTSEL_OS | INST_RETIRED); + ARCH_PERFMON_EVENTSEL_OS | AMD_ZEN_INSTRUCTIONS_RETIRED); run_and_measure_loop(MSR_K7_PERFCTR0); GUEST_SYNC(0); @@ -312,7 +260,7 @@ static void test_amd_deny_list(struct kvm_vcpu *vcpu) .action = KVM_PMU_EVENT_DENY, .nevents = 1, .events = { - EVENT(0x1C2, 0), + RAW_EVENT(0x1C2, 0), }, }; @@ -347,9 +295,9 @@ static void test_not_member_deny_list(struct kvm_vcpu *vcpu) f.action = KVM_PMU_EVENT_DENY; - remove_event(&f, INST_RETIRED); - remove_event(&f, INTEL_BR_RETIRED); - remove_event(&f, AMD_ZEN_BR_RETIRED); + remove_event(&f, INTEL_ARCH_INSTRUCTIONS_RETIRED); + remove_event(&f, INTEL_ARCH_BRANCHES_RETIRED); + remove_event(&f, AMD_ZEN_BRANCHES_RETIRED); test_with_filter(vcpu, &f); ASSERT_PMC_COUNTING_INSTRUCTIONS(); @@ -361,9 +309,9 @@ static void test_not_member_allow_list(struct kvm_vcpu *vcpu) f.action = KVM_PMU_EVENT_ALLOW; - remove_event(&f, INST_RETIRED); - remove_event(&f, INTEL_BR_RETIRED); - remove_event(&f, AMD_ZEN_BR_RETIRED); + remove_event(&f, INTEL_ARCH_INSTRUCTIONS_RETIRED); + remove_event(&f, INTEL_ARCH_BRANCHES_RETIRED); + remove_event(&f, AMD_ZEN_BRANCHES_RETIRED); test_with_filter(vcpu, &f); ASSERT_PMC_NOT_COUNTING_INSTRUCTIONS(); @@ -452,9 +400,9 @@ static bool use_amd_pmu(void) * - Sapphire Rapids, Ice Lake, Cascade Lake, Skylake. */ #define MEM_INST_RETIRED 0xD0 -#define MEM_INST_RETIRED_LOAD EVENT(MEM_INST_RETIRED, 0x81) -#define MEM_INST_RETIRED_STORE EVENT(MEM_INST_RETIRED, 0x82) -#define MEM_INST_RETIRED_LOAD_STORE EVENT(MEM_INST_RETIRED, 0x83) +#define MEM_INST_RETIRED_LOAD RAW_EVENT(MEM_INST_RETIRED, 0x81) +#define MEM_INST_RETIRED_STORE RAW_EVENT(MEM_INST_RETIRED, 0x82) +#define MEM_INST_RETIRED_LOAD_STORE RAW_EVENT(MEM_INST_RETIRED, 0x83) static bool supports_event_mem_inst_retired(void) { @@ -486,9 +434,9 @@ static bool supports_event_mem_inst_retired(void) * B1 Processors Volume 1 of 2. */ #define LS_DISPATCH 0x29 -#define LS_DISPATCH_LOAD EVENT(LS_DISPATCH, BIT(0)) -#define LS_DISPATCH_STORE EVENT(LS_DISPATCH, BIT(1)) -#define LS_DISPATCH_LOAD_STORE EVENT(LS_DISPATCH, BIT(2)) +#define LS_DISPATCH_LOAD RAW_EVENT(LS_DISPATCH, BIT(0)) +#define LS_DISPATCH_STORE RAW_EVENT(LS_DISPATCH, BIT(1)) +#define LS_DISPATCH_LOAD_STORE RAW_EVENT(LS_DISPATCH, BIT(2)) #define INCLUDE_MASKED_ENTRY(event_select, mask, match) \ KVM_PMU_ENCODE_MASKED_ENTRY(event_select, mask, match, false) @@ -729,14 +677,14 @@ static void add_dummy_events(uint64_t *events, int nevents) static void test_masked_events(struct kvm_vcpu *vcpu) { - int nevents = MAX_FILTER_EVENTS - MAX_TEST_EVENTS; - uint64_t events[MAX_FILTER_EVENTS]; + int nevents = KVM_PMU_EVENT_FILTER_MAX_EVENTS - MAX_TEST_EVENTS; + uint64_t events[KVM_PMU_EVENT_FILTER_MAX_EVENTS]; /* Run the test cases against a sparse PMU event filter. */ run_masked_events_tests(vcpu, events, 0); /* Run the test cases against a dense PMU event filter. */ - add_dummy_events(events, MAX_FILTER_EVENTS); + add_dummy_events(events, KVM_PMU_EVENT_FILTER_MAX_EVENTS); run_masked_events_tests(vcpu, events, nevents); } @@ -809,20 +757,19 @@ static void test_filter_ioctl(struct kvm_vcpu *vcpu) TEST_ASSERT(!r, "Masking non-existent fixed counters should be allowed"); } -static void intel_run_fixed_counter_guest_code(uint8_t fixed_ctr_idx) +static void intel_run_fixed_counter_guest_code(uint8_t idx) { for (;;) { wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0); - wrmsr(MSR_CORE_PERF_FIXED_CTR0 + fixed_ctr_idx, 0); + wrmsr(MSR_CORE_PERF_FIXED_CTR0 + idx, 0); /* Only OS_EN bit is enabled for fixed counter[idx]. */ - wrmsr(MSR_CORE_PERF_FIXED_CTR_CTRL, BIT_ULL(4 * fixed_ctr_idx)); - wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, - BIT_ULL(INTEL_PMC_IDX_FIXED + fixed_ctr_idx)); + wrmsr(MSR_CORE_PERF_FIXED_CTR_CTRL, FIXED_PMC_CTRL(idx, FIXED_PMC_KERNEL)); + wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, FIXED_PMC_GLOBAL_CTRL_ENABLE(idx)); __asm__ __volatile__("loop ." : "+c"((int){NUM_BRANCHES})); wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0); - GUEST_SYNC(rdmsr(MSR_CORE_PERF_FIXED_CTR0 + fixed_ctr_idx)); + GUEST_SYNC(rdmsr(MSR_CORE_PERF_FIXED_CTR0 + idx)); } } -- cgit v1.2.3 From 4f1bd6b16074aa5f9a0633a77fc87f471888a588 Mon Sep 17 00:00:00 2001 From: Jinrong Liang Date: Tue, 9 Jan 2024 15:02:36 -0800 Subject: KVM: selftests: Test Intel PMU architectural events on gp counters Add test cases to verify that Intel's Architectural PMU events work as expected when they are available according to guest CPUID. Iterate over a range of sane PMU versions, with and without full-width writes enabled, and over interesting combinations of lengths/masks for the bit vector that enumerates unavailable events. Test up to vPMU version 5, i.e. the current architectural max. KVM only officially supports up to version 2, but the behavior of the counters is backwards compatible, i.e. KVM shouldn't do something completely different for a higher, architecturally-defined vPMU version. Verify KVM behavior against the effective vPMU version, e.g. advertising vPMU 5 when KVM only supports vPMU 2 shouldn't magically unlock vPMU 5 features. According to Intel SDM, the number of architectural events is reported through CPUID.0AH:EAX[31:24] and the architectural event x is supported if EBX[x]=0 && EAX[31:24]>x. Handcode the entirety of the measured section so that the test can precisely assert on the number of instructions and branches retired. Co-developed-by: Like Xu Signed-off-by: Like Xu Signed-off-by: Jinrong Liang Co-developed-by: Sean Christopherson Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-17-seanjc@google.com Signed-off-by: Sean Christopherson --- tools/testing/selftests/kvm/Makefile | 1 + .../selftests/kvm/x86_64/pmu_counters_test.c | 321 +++++++++++++++++++++ 2 files changed, 322 insertions(+) create mode 100644 tools/testing/selftests/kvm/x86_64/pmu_counters_test.c diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index 0f07ce8bd297..ce58098d80fd 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -81,6 +81,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/kvm_pv_test TEST_GEN_PROGS_x86_64 += x86_64/monitor_mwait_test TEST_GEN_PROGS_x86_64 += x86_64/nested_exceptions_test TEST_GEN_PROGS_x86_64 += x86_64/platform_info_test +TEST_GEN_PROGS_x86_64 += x86_64/pmu_counters_test TEST_GEN_PROGS_x86_64 += x86_64/pmu_event_filter_test TEST_GEN_PROGS_x86_64 += x86_64/private_mem_conversions_test TEST_GEN_PROGS_x86_64 += x86_64/private_mem_kvm_exits_test diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c new file mode 100644 index 000000000000..5b8687bb4639 --- /dev/null +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c @@ -0,0 +1,321 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2023, Tencent, Inc. + */ + +#define _GNU_SOURCE /* for program_invocation_short_name */ +#include + +#include "pmu.h" +#include "processor.h" + +/* Number of LOOP instructions for the guest measurement payload. */ +#define NUM_BRANCHES 10 +/* + * Number of "extra" instructions that will be counted, i.e. the number of + * instructions that are needed to set up the loop and then disabled the + * counter. 2 MOV, 2 XOR, 1 WRMSR. + */ +#define NUM_EXTRA_INSNS 5 +#define NUM_INSNS_RETIRED (NUM_BRANCHES + NUM_EXTRA_INSNS) + +static uint8_t kvm_pmu_version; +static bool kvm_has_perf_caps; + +static struct kvm_vm *pmu_vm_create_with_one_vcpu(struct kvm_vcpu **vcpu, + void *guest_code, + uint8_t pmu_version, + uint64_t perf_capabilities) +{ + struct kvm_vm *vm; + + vm = vm_create_with_one_vcpu(vcpu, guest_code); + vm_init_descriptor_tables(vm); + vcpu_init_descriptor_tables(*vcpu); + + sync_global_to_guest(vm, kvm_pmu_version); + + /* + * Set PERF_CAPABILITIES before PMU version as KVM disallows enabling + * features via PERF_CAPABILITIES if the guest doesn't have a vPMU. + */ + if (kvm_has_perf_caps) + vcpu_set_msr(*vcpu, MSR_IA32_PERF_CAPABILITIES, perf_capabilities); + + vcpu_set_cpuid_property(*vcpu, X86_PROPERTY_PMU_VERSION, pmu_version); + return vm; +} + +static void run_vcpu(struct kvm_vcpu *vcpu) +{ + struct ucall uc; + + do { + vcpu_run(vcpu); + switch (get_ucall(vcpu, &uc)) { + case UCALL_SYNC: + break; + case UCALL_ABORT: + REPORT_GUEST_ASSERT(uc); + break; + case UCALL_PRINTF: + pr_info("%s", uc.buffer); + break; + case UCALL_DONE: + break; + default: + TEST_FAIL("Unexpected ucall: %lu", uc.cmd); + } + } while (uc.cmd != UCALL_DONE); +} + +static uint8_t guest_get_pmu_version(void) +{ + /* + * Return the effective PMU version, i.e. the minimum between what KVM + * supports and what is enumerated to the guest. The host deliberately + * advertises a PMU version to the guest beyond what is actually + * supported by KVM to verify KVM doesn't freak out and do something + * bizarre with an architecturally valid, but unsupported, version. + */ + return min_t(uint8_t, kvm_pmu_version, this_cpu_property(X86_PROPERTY_PMU_VERSION)); +} + +/* + * If an architectural event is supported and guaranteed to generate at least + * one "hit, assert that its count is non-zero. If an event isn't supported or + * the test can't guarantee the associated action will occur, then all bets are + * off regarding the count, i.e. no checks can be done. + * + * Sanity check that in all cases, the event doesn't count when it's disabled, + * and that KVM correctly emulates the write of an arbitrary value. + */ +static void guest_assert_event_count(uint8_t idx, + struct kvm_x86_pmu_feature event, + uint32_t pmc, uint32_t pmc_msr) +{ + uint64_t count; + + count = _rdpmc(pmc); + if (!this_pmu_has(event)) + goto sanity_checks; + + switch (idx) { + case INTEL_ARCH_INSTRUCTIONS_RETIRED_INDEX: + GUEST_ASSERT_EQ(count, NUM_INSNS_RETIRED); + break; + case INTEL_ARCH_BRANCHES_RETIRED_INDEX: + GUEST_ASSERT_EQ(count, NUM_BRANCHES); + break; + case INTEL_ARCH_CPU_CYCLES_INDEX: + case INTEL_ARCH_REFERENCE_CYCLES_INDEX: + GUEST_ASSERT_NE(count, 0); + break; + default: + break; + } + +sanity_checks: + __asm__ __volatile__("loop ." : "+c"((int){NUM_BRANCHES})); + GUEST_ASSERT_EQ(_rdpmc(pmc), count); + + wrmsr(pmc_msr, 0xdead); + GUEST_ASSERT_EQ(_rdpmc(pmc), 0xdead); +} + +static void __guest_test_arch_event(uint8_t idx, struct kvm_x86_pmu_feature event, + uint32_t pmc, uint32_t pmc_msr, + uint32_t ctrl_msr, uint64_t ctrl_msr_value) +{ + wrmsr(pmc_msr, 0); + + /* + * Enable and disable the PMC in a monolithic asm blob to ensure that + * the compiler can't insert _any_ code into the measured sequence. + * Note, ECX doesn't need to be clobbered as the input value, @pmc_msr, + * is restored before the end of the sequence. + */ + __asm__ __volatile__("wrmsr\n\t" + "mov $" __stringify(NUM_BRANCHES) ", %%ecx\n\t" + "loop .\n\t" + "mov %%edi, %%ecx\n\t" + "xor %%eax, %%eax\n\t" + "xor %%edx, %%edx\n\t" + "wrmsr\n\t" + :: "a"((uint32_t)ctrl_msr_value), + "d"(ctrl_msr_value >> 32), + "c"(ctrl_msr), "D"(ctrl_msr) + ); + + guest_assert_event_count(idx, event, pmc, pmc_msr); +} + +static void guest_test_arch_event(uint8_t idx) +{ + const struct { + struct kvm_x86_pmu_feature gp_event; + } intel_event_to_feature[] = { + [INTEL_ARCH_CPU_CYCLES_INDEX] = { X86_PMU_FEATURE_CPU_CYCLES }, + [INTEL_ARCH_INSTRUCTIONS_RETIRED_INDEX] = { X86_PMU_FEATURE_INSNS_RETIRED }, + [INTEL_ARCH_REFERENCE_CYCLES_INDEX] = { X86_PMU_FEATURE_REFERENCE_CYCLES }, + [INTEL_ARCH_LLC_REFERENCES_INDEX] = { X86_PMU_FEATURE_LLC_REFERENCES }, + [INTEL_ARCH_LLC_MISSES_INDEX] = { X86_PMU_FEATURE_LLC_MISSES }, + [INTEL_ARCH_BRANCHES_RETIRED_INDEX] = { X86_PMU_FEATURE_BRANCH_INSNS_RETIRED }, + [INTEL_ARCH_BRANCHES_MISPREDICTED_INDEX] = { X86_PMU_FEATURE_BRANCHES_MISPREDICTED }, + [INTEL_ARCH_TOPDOWN_SLOTS_INDEX] = { X86_PMU_FEATURE_TOPDOWN_SLOTS }, + }; + + uint32_t nr_gp_counters = this_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS); + uint32_t pmu_version = guest_get_pmu_version(); + /* PERF_GLOBAL_CTRL exists only for Architectural PMU Version 2+. */ + bool guest_has_perf_global_ctrl = pmu_version >= 2; + struct kvm_x86_pmu_feature gp_event; + uint32_t base_pmc_msr; + unsigned int i; + + /* The host side shouldn't invoke this without a guest PMU. */ + GUEST_ASSERT(pmu_version); + + if (this_cpu_has(X86_FEATURE_PDCM) && + rdmsr(MSR_IA32_PERF_CAPABILITIES) & PMU_CAP_FW_WRITES) + base_pmc_msr = MSR_IA32_PMC0; + else + base_pmc_msr = MSR_IA32_PERFCTR0; + + gp_event = intel_event_to_feature[idx].gp_event; + GUEST_ASSERT_EQ(idx, gp_event.f.bit); + + GUEST_ASSERT(nr_gp_counters); + + for (i = 0; i < nr_gp_counters; i++) { + uint64_t eventsel = ARCH_PERFMON_EVENTSEL_OS | + ARCH_PERFMON_EVENTSEL_ENABLE | + intel_pmu_arch_events[idx]; + + wrmsr(MSR_P6_EVNTSEL0 + i, 0); + if (guest_has_perf_global_ctrl) + wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, BIT_ULL(i)); + + __guest_test_arch_event(idx, gp_event, i, base_pmc_msr + i, + MSR_P6_EVNTSEL0 + i, eventsel); + } +} + +static void guest_test_arch_events(void) +{ + uint8_t i; + + for (i = 0; i < NR_INTEL_ARCH_EVENTS; i++) + guest_test_arch_event(i); + + GUEST_DONE(); +} + +static void test_arch_events(uint8_t pmu_version, uint64_t perf_capabilities, + uint8_t length, uint8_t unavailable_mask) +{ + struct kvm_vcpu *vcpu; + struct kvm_vm *vm; + + /* Testing arch events requires a vPMU (there are no negative tests). */ + if (!pmu_version) + return; + + vm = pmu_vm_create_with_one_vcpu(&vcpu, guest_test_arch_events, + pmu_version, perf_capabilities); + + vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH, + length); + vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_EVENTS_MASK, + unavailable_mask); + + run_vcpu(vcpu); + + kvm_vm_free(vm); +} + +static void test_intel_counters(void) +{ + uint8_t nr_arch_events = kvm_cpu_property(X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH); + uint8_t pmu_version = kvm_cpu_property(X86_PROPERTY_PMU_VERSION); + unsigned int i; + uint8_t v, j; + uint32_t k; + + const uint64_t perf_caps[] = { + 0, + PMU_CAP_FW_WRITES, + }; + + /* + * Test up to PMU v5, which is the current maximum version defined by + * Intel, i.e. is the last version that is guaranteed to be backwards + * compatible with KVM's existing behavior. + */ + uint8_t max_pmu_version = max_t(typeof(pmu_version), pmu_version, 5); + + /* + * Detect the existence of events that aren't supported by selftests. + * This will (obviously) fail any time the kernel adds support for a + * new event, but it's worth paying that price to keep the test fresh. + */ + TEST_ASSERT(nr_arch_events <= NR_INTEL_ARCH_EVENTS, + "New architectural event(s) detected; please update this test (length = %u, mask = %x)", + nr_arch_events, kvm_cpu_property(X86_PROPERTY_PMU_EVENTS_MASK)); + + /* + * Force iterating over known arch events regardless of whether or not + * KVM/hardware supports a given event. + */ + nr_arch_events = max_t(typeof(nr_arch_events), nr_arch_events, NR_INTEL_ARCH_EVENTS); + + for (v = 0; v <= max_pmu_version; v++) { + for (i = 0; i < ARRAY_SIZE(perf_caps); i++) { + if (!kvm_has_perf_caps && perf_caps[i]) + continue; + + pr_info("Testing arch events, PMU version %u, perf_caps = %lx\n", + v, perf_caps[i]); + /* + * To keep the total runtime reasonable, test every + * possible non-zero, non-reserved bitmap combination + * only with the native PMU version and the full bit + * vector length. + */ + if (v == pmu_version) { + for (k = 1; k < (BIT(nr_arch_events) - 1); k++) + test_arch_events(v, perf_caps[i], nr_arch_events, k); + } + /* + * Test single bits for all PMU version and lengths up + * the number of events +1 (to verify KVM doesn't do + * weird things if the guest length is greater than the + * host length). Explicitly test a mask of '0' and all + * ones i.e. all events being available and unavailable. + */ + for (j = 0; j <= nr_arch_events + 1; j++) { + test_arch_events(v, perf_caps[i], j, 0); + test_arch_events(v, perf_caps[i], j, 0xff); + + for (k = 0; k < nr_arch_events; k++) + test_arch_events(v, perf_caps[i], j, BIT(k)); + } + } + } +} + +int main(int argc, char *argv[]) +{ + TEST_REQUIRE(get_kvm_param_bool("enable_pmu")); + + TEST_REQUIRE(host_cpu_is_intel); + TEST_REQUIRE(kvm_cpu_has_p(X86_PROPERTY_PMU_VERSION)); + TEST_REQUIRE(kvm_cpu_property(X86_PROPERTY_PMU_VERSION) > 0); + + kvm_pmu_version = kvm_cpu_property(X86_PROPERTY_PMU_VERSION); + kvm_has_perf_caps = kvm_cpu_has(X86_FEATURE_PDCM); + + test_intel_counters(); + + return 0; +} -- cgit v1.2.3 From 3e26b825f87ddfa610e069ff3f668b942d8642bb Mon Sep 17 00:00:00 2001 From: Jinrong Liang Date: Tue, 9 Jan 2024 15:02:37 -0800 Subject: KVM: selftests: Test Intel PMU architectural events on fixed counters Extend the PMU counters test to validate architectural events using fixed counters. The core logic is largely the same, the biggest difference being that if a fixed counter exists, its associated event is available (the SDM doesn't explicitly state this to be true, but it's KVM's ABI and letting software program a fixed counter that doesn't actually count would be quite bizarre). Note, fixed counters rely on PERF_GLOBAL_CTRL. Reviewed-by: Jim Mattson Reviewed-by: Dapeng Mi Co-developed-by: Like Xu Signed-off-by: Like Xu Signed-off-by: Jinrong Liang Co-developed-by: Sean Christopherson Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-18-seanjc@google.com Signed-off-by: Sean Christopherson --- .../selftests/kvm/x86_64/pmu_counters_test.c | 54 ++++++++++++++++++---- 1 file changed, 45 insertions(+), 9 deletions(-) diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c index 5b8687bb4639..663e8fbe7ff8 100644 --- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c @@ -150,26 +150,46 @@ static void __guest_test_arch_event(uint8_t idx, struct kvm_x86_pmu_feature even guest_assert_event_count(idx, event, pmc, pmc_msr); } +#define X86_PMU_FEATURE_NULL \ +({ \ + struct kvm_x86_pmu_feature feature = {}; \ + \ + feature; \ +}) + +static bool pmu_is_null_feature(struct kvm_x86_pmu_feature event) +{ + return !(*(u64 *)&event); +} + static void guest_test_arch_event(uint8_t idx) { const struct { struct kvm_x86_pmu_feature gp_event; + struct kvm_x86_pmu_feature fixed_event; } intel_event_to_feature[] = { - [INTEL_ARCH_CPU_CYCLES_INDEX] = { X86_PMU_FEATURE_CPU_CYCLES }, - [INTEL_ARCH_INSTRUCTIONS_RETIRED_INDEX] = { X86_PMU_FEATURE_INSNS_RETIRED }, - [INTEL_ARCH_REFERENCE_CYCLES_INDEX] = { X86_PMU_FEATURE_REFERENCE_CYCLES }, - [INTEL_ARCH_LLC_REFERENCES_INDEX] = { X86_PMU_FEATURE_LLC_REFERENCES }, - [INTEL_ARCH_LLC_MISSES_INDEX] = { X86_PMU_FEATURE_LLC_MISSES }, - [INTEL_ARCH_BRANCHES_RETIRED_INDEX] = { X86_PMU_FEATURE_BRANCH_INSNS_RETIRED }, - [INTEL_ARCH_BRANCHES_MISPREDICTED_INDEX] = { X86_PMU_FEATURE_BRANCHES_MISPREDICTED }, - [INTEL_ARCH_TOPDOWN_SLOTS_INDEX] = { X86_PMU_FEATURE_TOPDOWN_SLOTS }, + [INTEL_ARCH_CPU_CYCLES_INDEX] = { X86_PMU_FEATURE_CPU_CYCLES, X86_PMU_FEATURE_CPU_CYCLES_FIXED }, + [INTEL_ARCH_INSTRUCTIONS_RETIRED_INDEX] = { X86_PMU_FEATURE_INSNS_RETIRED, X86_PMU_FEATURE_INSNS_RETIRED_FIXED }, + /* + * Note, the fixed counter for reference cycles is NOT the same + * as the general purpose architectural event. The fixed counter + * explicitly counts at the same frequency as the TSC, whereas + * the GP event counts at a fixed, but uarch specific, frequency. + * Bundle them here for simplicity. + */ + [INTEL_ARCH_REFERENCE_CYCLES_INDEX] = { X86_PMU_FEATURE_REFERENCE_CYCLES, X86_PMU_FEATURE_REFERENCE_TSC_CYCLES_FIXED }, + [INTEL_ARCH_LLC_REFERENCES_INDEX] = { X86_PMU_FEATURE_LLC_REFERENCES, X86_PMU_FEATURE_NULL }, + [INTEL_ARCH_LLC_MISSES_INDEX] = { X86_PMU_FEATURE_LLC_MISSES, X86_PMU_FEATURE_NULL }, + [INTEL_ARCH_BRANCHES_RETIRED_INDEX] = { X86_PMU_FEATURE_BRANCH_INSNS_RETIRED, X86_PMU_FEATURE_NULL }, + [INTEL_ARCH_BRANCHES_MISPREDICTED_INDEX] = { X86_PMU_FEATURE_BRANCHES_MISPREDICTED, X86_PMU_FEATURE_NULL }, + [INTEL_ARCH_TOPDOWN_SLOTS_INDEX] = { X86_PMU_FEATURE_TOPDOWN_SLOTS, X86_PMU_FEATURE_TOPDOWN_SLOTS_FIXED }, }; uint32_t nr_gp_counters = this_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS); uint32_t pmu_version = guest_get_pmu_version(); /* PERF_GLOBAL_CTRL exists only for Architectural PMU Version 2+. */ bool guest_has_perf_global_ctrl = pmu_version >= 2; - struct kvm_x86_pmu_feature gp_event; + struct kvm_x86_pmu_feature gp_event, fixed_event; uint32_t base_pmc_msr; unsigned int i; @@ -199,6 +219,22 @@ static void guest_test_arch_event(uint8_t idx) __guest_test_arch_event(idx, gp_event, i, base_pmc_msr + i, MSR_P6_EVNTSEL0 + i, eventsel); } + + if (!guest_has_perf_global_ctrl) + return; + + fixed_event = intel_event_to_feature[idx].fixed_event; + if (pmu_is_null_feature(fixed_event) || !this_pmu_has(fixed_event)) + return; + + i = fixed_event.f.bit; + + wrmsr(MSR_CORE_PERF_FIXED_CTR_CTRL, FIXED_PMC_CTRL(i, FIXED_PMC_KERNEL)); + + __guest_test_arch_event(idx, fixed_event, i | INTEL_RDPMC_FIXED, + MSR_CORE_PERF_FIXED_CTR0 + i, + MSR_CORE_PERF_GLOBAL_CTRL, + FIXED_PMC_GLOBAL_CTRL_ENABLE(i)); } static void guest_test_arch_events(void) -- cgit v1.2.3 From 7137cf751b9b14662adad61e35c236e141430aed Mon Sep 17 00:00:00 2001 From: Jinrong Liang Date: Tue, 9 Jan 2024 15:02:38 -0800 Subject: KVM: selftests: Test consistency of CPUID with num of gp counters Add a test to verify that KVM correctly emulates MSR-based accesses to general purpose counters based on guest CPUID, e.g. that accesses to non-existent counters #GP and accesses to existent counters succeed. Note, for compatibility reasons, KVM does not emulate #GP when MSR_P6_PERFCTR[0|1] is not present (writes should be dropped). Co-developed-by: Like Xu Signed-off-by: Like Xu Signed-off-by: Jinrong Liang Co-developed-by: Sean Christopherson Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-19-seanjc@google.com Signed-off-by: Sean Christopherson --- .../selftests/kvm/x86_64/pmu_counters_test.c | 99 ++++++++++++++++++++++ 1 file changed, 99 insertions(+) diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c index 663e8fbe7ff8..863418842ef8 100644 --- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c @@ -270,9 +270,103 @@ static void test_arch_events(uint8_t pmu_version, uint64_t perf_capabilities, kvm_vm_free(vm); } +/* + * Limit testing to MSRs that are actually defined by Intel (in the SDM). MSRs + * that aren't defined counter MSRs *probably* don't exist, but there's no + * guarantee that currently undefined MSR indices won't be used for something + * other than PMCs in the future. + */ +#define MAX_NR_GP_COUNTERS 8 +#define MAX_NR_FIXED_COUNTERS 3 + +#define GUEST_ASSERT_PMC_MSR_ACCESS(insn, msr, expect_gp, vector) \ +__GUEST_ASSERT(expect_gp ? vector == GP_VECTOR : !vector, \ + "Expected %s on " #insn "(0x%x), got vector %u", \ + expect_gp ? "#GP" : "no fault", msr, vector) \ + +#define GUEST_ASSERT_PMC_VALUE(insn, msr, val, expected) \ + __GUEST_ASSERT(val == expected_val, \ + "Expected " #insn "(0x%x) to yield 0x%lx, got 0x%lx", \ + msr, expected_val, val); + +static void guest_rd_wr_counters(uint32_t base_msr, uint8_t nr_possible_counters, + uint8_t nr_counters) +{ + uint8_t i; + + for (i = 0; i < nr_possible_counters; i++) { + /* + * TODO: Test a value that validates full-width writes and the + * width of the counters. + */ + const uint64_t test_val = 0xffff; + const uint32_t msr = base_msr + i; + const bool expect_success = i < nr_counters; + + /* + * KVM drops writes to MSR_P6_PERFCTR[0|1] if the counters are + * unsupported, i.e. doesn't #GP and reads back '0'. + */ + const uint64_t expected_val = expect_success ? test_val : 0; + const bool expect_gp = !expect_success && msr != MSR_P6_PERFCTR0 && + msr != MSR_P6_PERFCTR1; + uint8_t vector; + uint64_t val; + + vector = wrmsr_safe(msr, test_val); + GUEST_ASSERT_PMC_MSR_ACCESS(WRMSR, msr, expect_gp, vector); + + vector = rdmsr_safe(msr, &val); + GUEST_ASSERT_PMC_MSR_ACCESS(RDMSR, msr, expect_gp, vector); + + /* On #GP, the result of RDMSR is undefined. */ + if (!expect_gp) + GUEST_ASSERT_PMC_VALUE(RDMSR, msr, val, expected_val); + + vector = wrmsr_safe(msr, 0); + GUEST_ASSERT_PMC_MSR_ACCESS(WRMSR, msr, expect_gp, vector); + } + GUEST_DONE(); +} + +static void guest_test_gp_counters(void) +{ + uint8_t nr_gp_counters = 0; + uint32_t base_msr; + + if (guest_get_pmu_version()) + nr_gp_counters = this_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS); + + if (this_cpu_has(X86_FEATURE_PDCM) && + rdmsr(MSR_IA32_PERF_CAPABILITIES) & PMU_CAP_FW_WRITES) + base_msr = MSR_IA32_PMC0; + else + base_msr = MSR_IA32_PERFCTR0; + + guest_rd_wr_counters(base_msr, MAX_NR_GP_COUNTERS, nr_gp_counters); +} + +static void test_gp_counters(uint8_t pmu_version, uint64_t perf_capabilities, + uint8_t nr_gp_counters) +{ + struct kvm_vcpu *vcpu; + struct kvm_vm *vm; + + vm = pmu_vm_create_with_one_vcpu(&vcpu, guest_test_gp_counters, + pmu_version, perf_capabilities); + + vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_NR_GP_COUNTERS, + nr_gp_counters); + + run_vcpu(vcpu); + + kvm_vm_free(vm); +} + static void test_intel_counters(void) { uint8_t nr_arch_events = kvm_cpu_property(X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH); + uint8_t nr_gp_counters = kvm_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS); uint8_t pmu_version = kvm_cpu_property(X86_PROPERTY_PMU_VERSION); unsigned int i; uint8_t v, j; @@ -336,6 +430,11 @@ static void test_intel_counters(void) for (k = 0; k < nr_arch_events; k++) test_arch_events(v, perf_caps[i], j, BIT(k)); } + + pr_info("Testing GP counters, PMU version %u, perf_caps = %lx\n", + v, perf_caps[i]); + for (j = 0; j <= nr_gp_counters; j++) + test_gp_counters(v, perf_caps[i], j); } } } -- cgit v1.2.3 From c7d7c76ecf78f93b2bd7d40bccabc813c1ed0a49 Mon Sep 17 00:00:00 2001 From: Jinrong Liang Date: Tue, 9 Jan 2024 15:02:39 -0800 Subject: KVM: selftests: Test consistency of CPUID with num of fixed counters Extend the PMU counters test to verify KVM emulation of fixed counters in addition to general purpose counters. Fixed counters add an extra wrinkle in the form of an extra supported bitmask. Thus quoth the SDM: fixed-function performance counter 'i' is supported if ECX[i] || (EDX[4:0] > i) Test that KVM handles a counter being available through either method. Reviewed-by: Dapeng Mi Co-developed-by: Like Xu Signed-off-by: Like Xu Signed-off-by: Jinrong Liang Co-developed-by: Sean Christopherson Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-20-seanjc@google.com Signed-off-by: Sean Christopherson --- .../selftests/kvm/x86_64/pmu_counters_test.c | 60 ++++++++++++++++++++-- 1 file changed, 57 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c index 863418842ef8..b07294af71a3 100644 --- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c @@ -290,7 +290,7 @@ __GUEST_ASSERT(expect_gp ? vector == GP_VECTOR : !vector, \ msr, expected_val, val); static void guest_rd_wr_counters(uint32_t base_msr, uint8_t nr_possible_counters, - uint8_t nr_counters) + uint8_t nr_counters, uint32_t or_mask) { uint8_t i; @@ -301,7 +301,13 @@ static void guest_rd_wr_counters(uint32_t base_msr, uint8_t nr_possible_counters */ const uint64_t test_val = 0xffff; const uint32_t msr = base_msr + i; - const bool expect_success = i < nr_counters; + + /* + * Fixed counters are supported if the counter is less than the + * number of enumerated contiguous counters *or* the counter is + * explicitly enumerated in the supported counters mask. + */ + const bool expect_success = i < nr_counters || (or_mask & BIT(i)); /* * KVM drops writes to MSR_P6_PERFCTR[0|1] if the counters are @@ -343,7 +349,7 @@ static void guest_test_gp_counters(void) else base_msr = MSR_IA32_PERFCTR0; - guest_rd_wr_counters(base_msr, MAX_NR_GP_COUNTERS, nr_gp_counters); + guest_rd_wr_counters(base_msr, MAX_NR_GP_COUNTERS, nr_gp_counters, 0); } static void test_gp_counters(uint8_t pmu_version, uint64_t perf_capabilities, @@ -363,9 +369,50 @@ static void test_gp_counters(uint8_t pmu_version, uint64_t perf_capabilities, kvm_vm_free(vm); } +static void guest_test_fixed_counters(void) +{ + uint64_t supported_bitmask = 0; + uint8_t nr_fixed_counters = 0; + + /* Fixed counters require Architectural vPMU Version 2+. */ + if (guest_get_pmu_version() >= 2) + nr_fixed_counters = this_cpu_property(X86_PROPERTY_PMU_NR_FIXED_COUNTERS); + + /* + * The supported bitmask for fixed counters was introduced in PMU + * version 5. + */ + if (guest_get_pmu_version() >= 5) + supported_bitmask = this_cpu_property(X86_PROPERTY_PMU_FIXED_COUNTERS_BITMASK); + + guest_rd_wr_counters(MSR_CORE_PERF_FIXED_CTR0, MAX_NR_FIXED_COUNTERS, + nr_fixed_counters, supported_bitmask); +} + +static void test_fixed_counters(uint8_t pmu_version, uint64_t perf_capabilities, + uint8_t nr_fixed_counters, + uint32_t supported_bitmask) +{ + struct kvm_vcpu *vcpu; + struct kvm_vm *vm; + + vm = pmu_vm_create_with_one_vcpu(&vcpu, guest_test_fixed_counters, + pmu_version, perf_capabilities); + + vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_FIXED_COUNTERS_BITMASK, + supported_bitmask); + vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_NR_FIXED_COUNTERS, + nr_fixed_counters); + + run_vcpu(vcpu); + + kvm_vm_free(vm); +} + static void test_intel_counters(void) { uint8_t nr_arch_events = kvm_cpu_property(X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH); + uint8_t nr_fixed_counters = kvm_cpu_property(X86_PROPERTY_PMU_NR_FIXED_COUNTERS); uint8_t nr_gp_counters = kvm_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS); uint8_t pmu_version = kvm_cpu_property(X86_PROPERTY_PMU_VERSION); unsigned int i; @@ -435,6 +482,13 @@ static void test_intel_counters(void) v, perf_caps[i]); for (j = 0; j <= nr_gp_counters; j++) test_gp_counters(v, perf_caps[i], j); + + pr_info("Testing fixed counters, PMU version %u, perf_caps = %lx\n", + v, perf_caps[i]); + for (j = 0; j <= nr_fixed_counters; j++) { + for (k = 0; k <= (BIT(nr_fixed_counters) - 1); k++) + test_fixed_counters(v, perf_caps[i], j, k); + } } } } -- cgit v1.2.3 From 787071fd02625151b94a2f93a47cdc9a25884633 Mon Sep 17 00:00:00 2001 From: Jinrong Liang Date: Tue, 9 Jan 2024 15:02:40 -0800 Subject: KVM: selftests: Add functional test for Intel's fixed PMU counters Extend the fixed counters test to verify that supported counters can actually be enabled in the control MSRs, that unsupported counters cannot, and that enabled counters actually count. Co-developed-by: Like Xu Signed-off-by: Like Xu Signed-off-by: Jinrong Liang [sean: fold into the rd/wr access test, massage changelog] Reviewed-by: Dapeng Mi Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-21-seanjc@google.com Signed-off-by: Sean Christopherson --- .../selftests/kvm/x86_64/pmu_counters_test.c | 31 +++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c index b07294af71a3..f5dedd112471 100644 --- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c @@ -332,7 +332,6 @@ static void guest_rd_wr_counters(uint32_t base_msr, uint8_t nr_possible_counters vector = wrmsr_safe(msr, 0); GUEST_ASSERT_PMC_MSR_ACCESS(WRMSR, msr, expect_gp, vector); } - GUEST_DONE(); } static void guest_test_gp_counters(void) @@ -350,6 +349,7 @@ static void guest_test_gp_counters(void) base_msr = MSR_IA32_PERFCTR0; guest_rd_wr_counters(base_msr, MAX_NR_GP_COUNTERS, nr_gp_counters, 0); + GUEST_DONE(); } static void test_gp_counters(uint8_t pmu_version, uint64_t perf_capabilities, @@ -373,6 +373,7 @@ static void guest_test_fixed_counters(void) { uint64_t supported_bitmask = 0; uint8_t nr_fixed_counters = 0; + uint8_t i; /* Fixed counters require Architectural vPMU Version 2+. */ if (guest_get_pmu_version() >= 2) @@ -387,6 +388,34 @@ static void guest_test_fixed_counters(void) guest_rd_wr_counters(MSR_CORE_PERF_FIXED_CTR0, MAX_NR_FIXED_COUNTERS, nr_fixed_counters, supported_bitmask); + + for (i = 0; i < MAX_NR_FIXED_COUNTERS; i++) { + uint8_t vector; + uint64_t val; + + if (i >= nr_fixed_counters && !(supported_bitmask & BIT_ULL(i))) { + vector = wrmsr_safe(MSR_CORE_PERF_FIXED_CTR_CTRL, + FIXED_PMC_CTRL(i, FIXED_PMC_KERNEL)); + __GUEST_ASSERT(vector == GP_VECTOR, + "Expected #GP for counter %u in FIXED_CTR_CTRL", i); + + vector = wrmsr_safe(MSR_CORE_PERF_GLOBAL_CTRL, + FIXED_PMC_GLOBAL_CTRL_ENABLE(i)); + __GUEST_ASSERT(vector == GP_VECTOR, + "Expected #GP for counter %u in PERF_GLOBAL_CTRL", i); + continue; + } + + wrmsr(MSR_CORE_PERF_FIXED_CTR0 + i, 0); + wrmsr(MSR_CORE_PERF_FIXED_CTR_CTRL, FIXED_PMC_CTRL(i, FIXED_PMC_KERNEL)); + wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, FIXED_PMC_GLOBAL_CTRL_ENABLE(i)); + __asm__ __volatile__("loop ." : "+c"((int){NUM_BRANCHES})); + wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0); + val = rdmsr(MSR_CORE_PERF_FIXED_CTR0 + i); + + GUEST_ASSERT_NE(val, 0); + } + GUEST_DONE(); } static void test_fixed_counters(uint8_t pmu_version, uint64_t perf_capabilities, -- cgit v1.2.3 From b55e7adf633a8a13d5ede57b77509ea8fa157a56 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:41 -0800 Subject: KVM: selftests: Expand PMU counters test to verify LLC events Expand the PMU counters test to verify that LLC references and misses have non-zero counts when the code being executed while the LLC event(s) is active is evicted via CFLUSH{,OPT}. Note, CLFLUSH{,OPT} requires a fence of some kind to ensure the cache lines are flushed before execution continues. Use MFENCE for simplicity (performance is not a concern). Suggested-by: Jim Mattson Reviewed-by: Dapeng Mi Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-22-seanjc@google.com Signed-off-by: Sean Christopherson --- .../selftests/kvm/x86_64/pmu_counters_test.c | 59 +++++++++++++++------- 1 file changed, 40 insertions(+), 19 deletions(-) diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c index f5dedd112471..4c7133ddcda8 100644 --- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c @@ -14,9 +14,9 @@ /* * Number of "extra" instructions that will be counted, i.e. the number of * instructions that are needed to set up the loop and then disabled the - * counter. 2 MOV, 2 XOR, 1 WRMSR. + * counter. 1 CLFLUSH/CLFLUSHOPT/NOP, 1 MFENCE, 2 MOV, 2 XOR, 1 WRMSR. */ -#define NUM_EXTRA_INSNS 5 +#define NUM_EXTRA_INSNS 7 #define NUM_INSNS_RETIRED (NUM_BRANCHES + NUM_EXTRA_INSNS) static uint8_t kvm_pmu_version; @@ -107,6 +107,12 @@ static void guest_assert_event_count(uint8_t idx, case INTEL_ARCH_BRANCHES_RETIRED_INDEX: GUEST_ASSERT_EQ(count, NUM_BRANCHES); break; + case INTEL_ARCH_LLC_REFERENCES_INDEX: + case INTEL_ARCH_LLC_MISSES_INDEX: + if (!this_cpu_has(X86_FEATURE_CLFLUSHOPT) && + !this_cpu_has(X86_FEATURE_CLFLUSH)) + break; + fallthrough; case INTEL_ARCH_CPU_CYCLES_INDEX: case INTEL_ARCH_REFERENCE_CYCLES_INDEX: GUEST_ASSERT_NE(count, 0); @@ -123,29 +129,44 @@ sanity_checks: GUEST_ASSERT_EQ(_rdpmc(pmc), 0xdead); } +/* + * Enable and disable the PMC in a monolithic asm blob to ensure that the + * compiler can't insert _any_ code into the measured sequence. Note, ECX + * doesn't need to be clobbered as the input value, @pmc_msr, is restored + * before the end of the sequence. + * + * If CLFUSH{,OPT} is supported, flush the cacheline containing (at least) the + * start of the loop to force LLC references and misses, i.e. to allow testing + * that those events actually count. + */ +#define GUEST_MEASURE_EVENT(_msr, _value, clflush) \ +do { \ + __asm__ __volatile__("wrmsr\n\t" \ + clflush "\n\t" \ + "mfence\n\t" \ + "1: mov $" __stringify(NUM_BRANCHES) ", %%ecx\n\t" \ + "loop .\n\t" \ + "mov %%edi, %%ecx\n\t" \ + "xor %%eax, %%eax\n\t" \ + "xor %%edx, %%edx\n\t" \ + "wrmsr\n\t" \ + :: "a"((uint32_t)_value), "d"(_value >> 32), \ + "c"(_msr), "D"(_msr) \ + ); \ +} while (0) + static void __guest_test_arch_event(uint8_t idx, struct kvm_x86_pmu_feature event, uint32_t pmc, uint32_t pmc_msr, uint32_t ctrl_msr, uint64_t ctrl_msr_value) { wrmsr(pmc_msr, 0); - /* - * Enable and disable the PMC in a monolithic asm blob to ensure that - * the compiler can't insert _any_ code into the measured sequence. - * Note, ECX doesn't need to be clobbered as the input value, @pmc_msr, - * is restored before the end of the sequence. - */ - __asm__ __volatile__("wrmsr\n\t" - "mov $" __stringify(NUM_BRANCHES) ", %%ecx\n\t" - "loop .\n\t" - "mov %%edi, %%ecx\n\t" - "xor %%eax, %%eax\n\t" - "xor %%edx, %%edx\n\t" - "wrmsr\n\t" - :: "a"((uint32_t)ctrl_msr_value), - "d"(ctrl_msr_value >> 32), - "c"(ctrl_msr), "D"(ctrl_msr) - ); + if (this_cpu_has(X86_FEATURE_CLFLUSHOPT)) + GUEST_MEASURE_EVENT(ctrl_msr, ctrl_msr_value, "clflushopt 1f"); + else if (this_cpu_has(X86_FEATURE_CLFLUSH)) + GUEST_MEASURE_EVENT(ctrl_msr, ctrl_msr_value, "clflush 1f"); + else + GUEST_MEASURE_EVENT(ctrl_msr, ctrl_msr_value, "nop"); guest_assert_event_count(idx, event, pmc, pmc_msr); } -- cgit v1.2.3 From c85e986716b03bccfec2e5a577cc1aab4f172ffd Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:42 -0800 Subject: KVM: selftests: Add a helper to query if the PMU module param is enabled Add a helper to probe KVM's "enable_pmu" param, open coding strings in multiple places is just asking for false negatives and/or runtime errors due to typos. Reviewed-by: Dapeng Mi Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-23-seanjc@google.com Signed-off-by: Sean Christopherson --- tools/testing/selftests/kvm/include/x86_64/processor.h | 5 +++++ tools/testing/selftests/kvm/x86_64/pmu_counters_test.c | 2 +- tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c | 2 +- tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c | 2 +- 4 files changed, 8 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h index 92d4f8ecc730..ee082ae58f40 100644 --- a/tools/testing/selftests/kvm/include/x86_64/processor.h +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h @@ -1217,6 +1217,11 @@ static inline uint8_t xsetbv_safe(uint32_t index, uint64_t value) bool kvm_is_tdp_enabled(void); +static inline bool kvm_is_pmu_enabled(void) +{ + return get_kvm_param_bool("enable_pmu"); +} + uint64_t *__vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr, int *level); uint64_t *vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr); diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c index 4c7133ddcda8..9e9dc4084c0d 100644 --- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c @@ -545,7 +545,7 @@ static void test_intel_counters(void) int main(int argc, char *argv[]) { - TEST_REQUIRE(get_kvm_param_bool("enable_pmu")); + TEST_REQUIRE(kvm_is_pmu_enabled()); TEST_REQUIRE(host_cpu_is_intel); TEST_REQUIRE(kvm_cpu_has_p(X86_PROPERTY_PMU_VERSION)); diff --git a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c index 7ec9fbed92e0..fa407e2ccb2f 100644 --- a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c +++ b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c @@ -867,7 +867,7 @@ int main(int argc, char *argv[]) struct kvm_vcpu *vcpu, *vcpu2 = NULL; struct kvm_vm *vm; - TEST_REQUIRE(get_kvm_param_bool("enable_pmu")); + TEST_REQUIRE(kvm_is_pmu_enabled()); TEST_REQUIRE(kvm_has_cap(KVM_CAP_PMU_EVENT_FILTER)); TEST_REQUIRE(kvm_has_cap(KVM_CAP_PMU_EVENT_MASKED_EVENTS)); diff --git a/tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c b/tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c index 2a8d4ac2f020..8ded194c5a6d 100644 --- a/tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c +++ b/tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c @@ -237,7 +237,7 @@ int main(int argc, char *argv[]) { union perf_capabilities host_cap; - TEST_REQUIRE(get_kvm_param_bool("enable_pmu")); + TEST_REQUIRE(kvm_is_pmu_enabled()); TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_PDCM)); TEST_REQUIRE(kvm_cpu_has_p(X86_PROPERTY_PMU_VERSION)); -- cgit v1.2.3 From 45e4755c39fc2df55f58ea893615a7d45a0fbcc8 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:43 -0800 Subject: KVM: selftests: Add helpers to read integer module params Add helpers to read integer module params, which is painfully non-trivial because the pain of dealing with strings in C is exacerbated by the kernel inserting a newline. Don't bother differentiating between int, uint, short, etc. They all fit in an int, and KVM (thankfully) doesn't have any integer params larger than an int. Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-24-seanjc@google.com Signed-off-by: Sean Christopherson --- .../testing/selftests/kvm/include/kvm_util_base.h | 4 ++ tools/testing/selftests/kvm/lib/kvm_util.c | 62 +++++++++++++++++++--- 2 files changed, 60 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h index 9e5afc472c14..070f250036fc 100644 --- a/tools/testing/selftests/kvm/include/kvm_util_base.h +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h @@ -259,6 +259,10 @@ bool get_kvm_param_bool(const char *param); bool get_kvm_intel_param_bool(const char *param); bool get_kvm_amd_param_bool(const char *param); +int get_kvm_param_integer(const char *param); +int get_kvm_intel_param_integer(const char *param); +int get_kvm_amd_param_integer(const char *param); + unsigned int kvm_check_cap(long cap); static inline bool kvm_has_cap(long cap) diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index e066d584c656..9bafe44cb978 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -51,13 +51,13 @@ int open_kvm_dev_path_or_exit(void) return _open_kvm_dev_path_or_exit(O_RDONLY); } -static bool get_module_param_bool(const char *module_name, const char *param) +static ssize_t get_module_param(const char *module_name, const char *param, + void *buffer, size_t buffer_size) { const int path_size = 128; char path[path_size]; - char value; - ssize_t r; - int fd; + ssize_t bytes_read; + int fd, r; r = snprintf(path, path_size, "/sys/module/%s/parameters/%s", module_name, param); @@ -66,11 +66,46 @@ static bool get_module_param_bool(const char *module_name, const char *param) fd = open_path_or_exit(path, O_RDONLY); - r = read(fd, &value, 1); - TEST_ASSERT(r == 1, "read(%s) failed", path); + bytes_read = read(fd, buffer, buffer_size); + TEST_ASSERT(bytes_read > 0, "read(%s) returned %ld, wanted %ld bytes", + path, bytes_read, buffer_size); r = close(fd); TEST_ASSERT(!r, "close(%s) failed", path); + return bytes_read; +} + +static int get_module_param_integer(const char *module_name, const char *param) +{ + /* + * 16 bytes to hold a 64-bit value (1 byte per char), 1 byte for the + * NUL char, and 1 byte because the kernel sucks and inserts a newline + * at the end. + */ + char value[16 + 1 + 1]; + ssize_t r; + + memset(value, '\0', sizeof(value)); + + r = get_module_param(module_name, param, value, sizeof(value)); + TEST_ASSERT(value[r - 1] == '\n', + "Expected trailing newline, got char '%c'", value[r - 1]); + + /* + * Squash the newline, otherwise atoi_paranoid() will complain about + * trailing non-NUL characters in the string. + */ + value[r - 1] = '\0'; + return atoi_paranoid(value); +} + +static bool get_module_param_bool(const char *module_name, const char *param) +{ + char value; + ssize_t r; + + r = get_module_param(module_name, param, &value, sizeof(value)); + TEST_ASSERT_EQ(r, 1); if (value == 'Y') return true; @@ -95,6 +130,21 @@ bool get_kvm_amd_param_bool(const char *param) return get_module_param_bool("kvm_amd", param); } +int get_kvm_param_integer(const char *param) +{ + return get_module_param_integer("kvm", param); +} + +int get_kvm_intel_param_integer(const char *param) +{ + return get_module_param_integer("kvm_intel", param); +} + +int get_kvm_amd_param_integer(const char *param) +{ + return get_module_param_integer("kvm_amd", param); +} + /* * Capability * -- cgit v1.2.3 From 0326cc6b02c8e099bb6631168791924be097e1d9 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:44 -0800 Subject: KVM: selftests: Query module param to detect FEP in MSR filtering test Add a helper to detect KVM support for forced emulation by querying the module param, and use the helper to detect support for the MSR filtering test instead of throwing a noodle/NOP at KVM to see if it sticks. Cc: Aaron Lewis Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-25-seanjc@google.com Signed-off-by: Sean Christopherson --- .../selftests/kvm/include/x86_64/processor.h | 5 ++++ .../selftests/kvm/x86_64/userspace_msr_exit_test.c | 27 ++++++++-------------- 2 files changed, 14 insertions(+), 18 deletions(-) diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h index ee082ae58f40..d211cea188be 100644 --- a/tools/testing/selftests/kvm/include/x86_64/processor.h +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h @@ -1222,6 +1222,11 @@ static inline bool kvm_is_pmu_enabled(void) return get_kvm_param_bool("enable_pmu"); } +static inline bool kvm_is_forced_emulation_enabled(void) +{ + return !!get_kvm_param_integer("force_emulation_prefix"); +} + uint64_t *__vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr, int *level); uint64_t *vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr); diff --git a/tools/testing/selftests/kvm/x86_64/userspace_msr_exit_test.c b/tools/testing/selftests/kvm/x86_64/userspace_msr_exit_test.c index 3533dc2fbfee..9e12dbc47a72 100644 --- a/tools/testing/selftests/kvm/x86_64/userspace_msr_exit_test.c +++ b/tools/testing/selftests/kvm/x86_64/userspace_msr_exit_test.c @@ -14,8 +14,7 @@ /* Forced emulation prefix, used to invoke the emulator unconditionally. */ #define KVM_FEP "ud2; .byte 'k', 'v', 'm';" -#define KVM_FEP_LENGTH 5 -static int fep_available = 1; +static bool fep_available; #define MSR_NON_EXISTENT 0x474f4f00 @@ -260,13 +259,6 @@ static void guest_code_filter_allow(void) GUEST_ASSERT(data == 2); GUEST_ASSERT(guest_exception_count == 0); - /* - * Test to see if the instruction emulator is available (ie: the module - * parameter 'kvm.force_emulation_prefix=1' is set). This instruction - * will #UD if it isn't available. - */ - __asm__ __volatile__(KVM_FEP "nop"); - if (fep_available) { /* Let userspace know we aren't done. */ GUEST_SYNC(0); @@ -388,12 +380,6 @@ static void guest_fep_gp_handler(struct ex_regs *regs) &em_wrmsr_start, &em_wrmsr_end); } -static void guest_ud_handler(struct ex_regs *regs) -{ - fep_available = 0; - regs->rip += KVM_FEP_LENGTH; -} - static void check_for_guest_assert(struct kvm_vcpu *vcpu) { struct ucall uc; @@ -531,9 +517,11 @@ static void test_msr_filter_allow(void) { struct kvm_vcpu *vcpu; struct kvm_vm *vm; + uint64_t cmd; int rc; vm = vm_create_with_one_vcpu(&vcpu, guest_code_filter_allow); + sync_global_to_guest(vm, fep_available); rc = kvm_check_cap(KVM_CAP_X86_USER_SPACE_MSR); TEST_ASSERT(rc, "KVM_CAP_X86_USER_SPACE_MSR is available"); @@ -561,11 +549,11 @@ static void test_msr_filter_allow(void) run_guest_then_process_wrmsr(vcpu, MSR_NON_EXISTENT); run_guest_then_process_rdmsr(vcpu, MSR_NON_EXISTENT); - vm_install_exception_handler(vm, UD_VECTOR, guest_ud_handler); vcpu_run(vcpu); - vm_install_exception_handler(vm, UD_VECTOR, NULL); + cmd = process_ucall(vcpu); - if (process_ucall(vcpu) != UCALL_DONE) { + if (fep_available) { + TEST_ASSERT_EQ(cmd, UCALL_SYNC); vm_install_exception_handler(vm, GP_VECTOR, guest_fep_gp_handler); /* Process emulated rdmsr and wrmsr instructions. */ @@ -583,6 +571,7 @@ static void test_msr_filter_allow(void) /* Confirm the guest completed without issues. */ run_guest_then_process_ucall_done(vcpu); } else { + TEST_ASSERT_EQ(cmd, UCALL_DONE); printf("To run the instruction emulated tests set the module parameter 'kvm.force_emulation_prefix=1'\n"); } @@ -804,6 +793,8 @@ static void test_user_exit_msr_flags(void) int main(int argc, char *argv[]) { + fep_available = kvm_is_forced_emulation_enabled(); + test_msr_filter_allow(); test_msr_filter_deny(); -- cgit v1.2.3 From 00856e17da730299205270234cda30628ae53b92 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:45 -0800 Subject: KVM: selftests: Move KVM_FEP macro into common library header Move the KVM_FEP definition, a.k.a. the KVM force emulation prefix, into processor.h so that it can be used for other tests besides the MSR filter test. Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-26-seanjc@google.com Signed-off-by: Sean Christopherson --- tools/testing/selftests/kvm/include/x86_64/processor.h | 3 +++ tools/testing/selftests/kvm/x86_64/userspace_msr_exit_test.c | 2 -- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h index d211cea188be..6be365ac2a85 100644 --- a/tools/testing/selftests/kvm/include/x86_64/processor.h +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h @@ -23,6 +23,9 @@ extern bool host_cpu_is_intel; extern bool host_cpu_is_amd; +/* Forced emulation prefix, used to invoke the emulator unconditionally. */ +#define KVM_FEP "ud2; .byte 'k', 'v', 'm';" + #define NMI_VECTOR 0x02 #define X86_EFLAGS_FIXED (1u << 1) diff --git a/tools/testing/selftests/kvm/x86_64/userspace_msr_exit_test.c b/tools/testing/selftests/kvm/x86_64/userspace_msr_exit_test.c index 9e12dbc47a72..ab3a8c4f0b86 100644 --- a/tools/testing/selftests/kvm/x86_64/userspace_msr_exit_test.c +++ b/tools/testing/selftests/kvm/x86_64/userspace_msr_exit_test.c @@ -12,8 +12,6 @@ #include "kvm_util.h" #include "vmx.h" -/* Forced emulation prefix, used to invoke the emulator unconditionally. */ -#define KVM_FEP "ud2; .byte 'k', 'v', 'm';" static bool fep_available; #define MSR_NON_EXISTENT 0x474f4f00 -- cgit v1.2.3 From cd34fd8c758e968aae15944b1679c974af719648 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:46 -0800 Subject: KVM: selftests: Test PMC virtualization with forced emulation Extend the PMC counters test to use forced emulation to verify that KVM emulates counter events for instructions retired and branches retired. Force emulation for only a subset of the measured code to test that KVM does the right thing when mixing perf events with emulated events. Reviewed-by: Dapeng Mi Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-27-seanjc@google.com Signed-off-by: Sean Christopherson --- .../selftests/kvm/x86_64/pmu_counters_test.c | 44 +++++++++++++++------- 1 file changed, 30 insertions(+), 14 deletions(-) diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c index 9e9dc4084c0d..cb808ac827ba 100644 --- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c @@ -21,6 +21,7 @@ static uint8_t kvm_pmu_version; static bool kvm_has_perf_caps; +static bool is_forced_emulation_enabled; static struct kvm_vm *pmu_vm_create_with_one_vcpu(struct kvm_vcpu **vcpu, void *guest_code, @@ -34,6 +35,7 @@ static struct kvm_vm *pmu_vm_create_with_one_vcpu(struct kvm_vcpu **vcpu, vcpu_init_descriptor_tables(*vcpu); sync_global_to_guest(vm, kvm_pmu_version); + sync_global_to_guest(vm, is_forced_emulation_enabled); /* * Set PERF_CAPABILITIES before PMU version as KVM disallows enabling @@ -138,37 +140,50 @@ sanity_checks: * If CLFUSH{,OPT} is supported, flush the cacheline containing (at least) the * start of the loop to force LLC references and misses, i.e. to allow testing * that those events actually count. + * + * If forced emulation is enabled (and specified), force emulation on a subset + * of the measured code to verify that KVM correctly emulates instructions and + * branches retired events in conjunction with hardware also counting said + * events. */ -#define GUEST_MEASURE_EVENT(_msr, _value, clflush) \ +#define GUEST_MEASURE_EVENT(_msr, _value, clflush, FEP) \ do { \ __asm__ __volatile__("wrmsr\n\t" \ clflush "\n\t" \ "mfence\n\t" \ "1: mov $" __stringify(NUM_BRANCHES) ", %%ecx\n\t" \ - "loop .\n\t" \ - "mov %%edi, %%ecx\n\t" \ - "xor %%eax, %%eax\n\t" \ - "xor %%edx, %%edx\n\t" \ + FEP "loop .\n\t" \ + FEP "mov %%edi, %%ecx\n\t" \ + FEP "xor %%eax, %%eax\n\t" \ + FEP "xor %%edx, %%edx\n\t" \ "wrmsr\n\t" \ :: "a"((uint32_t)_value), "d"(_value >> 32), \ "c"(_msr), "D"(_msr) \ ); \ } while (0) +#define GUEST_TEST_EVENT(_idx, _event, _pmc, _pmc_msr, _ctrl_msr, _value, FEP) \ +do { \ + wrmsr(pmc_msr, 0); \ + \ + if (this_cpu_has(X86_FEATURE_CLFLUSHOPT)) \ + GUEST_MEASURE_EVENT(_ctrl_msr, _value, "clflushopt 1f", FEP); \ + else if (this_cpu_has(X86_FEATURE_CLFLUSH)) \ + GUEST_MEASURE_EVENT(_ctrl_msr, _value, "clflush 1f", FEP); \ + else \ + GUEST_MEASURE_EVENT(_ctrl_msr, _value, "nop", FEP); \ + \ + guest_assert_event_count(_idx, _event, _pmc, _pmc_msr); \ +} while (0) + static void __guest_test_arch_event(uint8_t idx, struct kvm_x86_pmu_feature event, uint32_t pmc, uint32_t pmc_msr, uint32_t ctrl_msr, uint64_t ctrl_msr_value) { - wrmsr(pmc_msr, 0); - - if (this_cpu_has(X86_FEATURE_CLFLUSHOPT)) - GUEST_MEASURE_EVENT(ctrl_msr, ctrl_msr_value, "clflushopt 1f"); - else if (this_cpu_has(X86_FEATURE_CLFLUSH)) - GUEST_MEASURE_EVENT(ctrl_msr, ctrl_msr_value, "clflush 1f"); - else - GUEST_MEASURE_EVENT(ctrl_msr, ctrl_msr_value, "nop"); + GUEST_TEST_EVENT(idx, event, pmc, pmc_msr, ctrl_msr, ctrl_msr_value, ""); - guest_assert_event_count(idx, event, pmc, pmc_msr); + if (is_forced_emulation_enabled) + GUEST_TEST_EVENT(idx, event, pmc, pmc_msr, ctrl_msr, ctrl_msr_value, KVM_FEP); } #define X86_PMU_FEATURE_NULL \ @@ -553,6 +568,7 @@ int main(int argc, char *argv[]) kvm_pmu_version = kvm_cpu_property(X86_PROPERTY_PMU_VERSION); kvm_has_perf_caps = kvm_cpu_has(X86_FEATURE_PDCM); + is_forced_emulation_enabled = kvm_is_forced_emulation_enabled(); test_intel_counters(); -- cgit v1.2.3 From ab3b6a7de8df00b380fb66a523c79e3b387aa877 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:47 -0800 Subject: KVM: selftests: Add a forced emulation variation of KVM_ASM_SAFE() Add KVM_ASM_SAFE_FEP() to allow forcing emulation on an instruction that might fault. Note, KVM skips RIP past the FEP prefix before injecting an exception, i.e. the fixup needs to be on the instruction itself. Do not check for FEP support, that is firmly the responsibility of whatever code wants to use KVM_ASM_SAFE_FEP(). Sadly, chaining variadic arguments that contain commas doesn't work, thus the unfortunate amount of copy+paste. Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-28-seanjc@google.com Signed-off-by: Sean Christopherson --- .../selftests/kvm/include/x86_64/processor.h | 30 ++++++++++++++++++++-- 1 file changed, 28 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h index 6be365ac2a85..fe891424ff55 100644 --- a/tools/testing/selftests/kvm/include/x86_64/processor.h +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h @@ -1154,16 +1154,19 @@ void vm_install_exception_handler(struct kvm_vm *vm, int vector, * r9 = exception vector (non-zero) * r10 = error code */ -#define KVM_ASM_SAFE(insn) \ +#define __KVM_ASM_SAFE(insn, fep) \ "mov $" __stringify(KVM_EXCEPTION_MAGIC) ", %%r9\n\t" \ "lea 1f(%%rip), %%r10\n\t" \ "lea 2f(%%rip), %%r11\n\t" \ - "1: " insn "\n\t" \ + fep "1: " insn "\n\t" \ "xor %%r9, %%r9\n\t" \ "2:\n\t" \ "mov %%r9b, %[vector]\n\t" \ "mov %%r10, %[error_code]\n\t" +#define KVM_ASM_SAFE(insn) __KVM_ASM_SAFE(insn, "") +#define KVM_ASM_SAFE_FEP(insn) __KVM_ASM_SAFE(insn, KVM_FEP) + #define KVM_ASM_SAFE_OUTPUTS(v, ec) [vector] "=qm"(v), [error_code] "=rm"(ec) #define KVM_ASM_SAFE_CLOBBERS "r9", "r10", "r11" @@ -1190,6 +1193,29 @@ void vm_install_exception_handler(struct kvm_vm *vm, int vector, vector; \ }) +#define kvm_asm_safe_fep(insn, inputs...) \ +({ \ + uint64_t ign_error_code; \ + uint8_t vector; \ + \ + asm volatile(KVM_ASM_SAFE(insn) \ + : KVM_ASM_SAFE_OUTPUTS(vector, ign_error_code) \ + : inputs \ + : KVM_ASM_SAFE_CLOBBERS); \ + vector; \ +}) + +#define kvm_asm_safe_ec_fep(insn, error_code, inputs...) \ +({ \ + uint8_t vector; \ + \ + asm volatile(KVM_ASM_SAFE_FEP(insn) \ + : KVM_ASM_SAFE_OUTPUTS(vector, error_code) \ + : inputs \ + : KVM_ASM_SAFE_CLOBBERS); \ + vector; \ +}) + static inline uint8_t rdmsr_safe(uint32_t msr, uint64_t *val) { uint64_t error_code; -- cgit v1.2.3 From b5e66df34cb0de716859595ce7a4d9d1d015a695 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:48 -0800 Subject: KVM: selftests: Add helpers for safe and safe+forced RDMSR, RDPMC, and XGETBV Add helpers for safe and safe-with-forced-emulations versions of RDMSR, RDPMC, and XGETBV. Use macro shenanigans to eliminate the rather large amount of boilerplate needed to get values in and out of registers. Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-29-seanjc@google.com Signed-off-by: Sean Christopherson --- .../selftests/kvm/include/x86_64/processor.h | 38 +++++++++++++++------- 1 file changed, 26 insertions(+), 12 deletions(-) diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h index fe891424ff55..abac816f6594 100644 --- a/tools/testing/selftests/kvm/include/x86_64/processor.h +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h @@ -1216,20 +1216,34 @@ void vm_install_exception_handler(struct kvm_vm *vm, int vector, vector; \ }) -static inline uint8_t rdmsr_safe(uint32_t msr, uint64_t *val) -{ - uint64_t error_code; - uint8_t vector; - uint32_t a, d; +#define BUILD_READ_U64_SAFE_HELPER(insn, _fep, _FEP) \ +static inline uint8_t insn##_safe ##_fep(uint32_t idx, uint64_t *val) \ +{ \ + uint64_t error_code; \ + uint8_t vector; \ + uint32_t a, d; \ + \ + asm volatile(KVM_ASM_SAFE##_FEP(#insn) \ + : "=a"(a), "=d"(d), \ + KVM_ASM_SAFE_OUTPUTS(vector, error_code) \ + : "c"(idx) \ + : KVM_ASM_SAFE_CLOBBERS); \ + \ + *val = (uint64_t)a | ((uint64_t)d << 32); \ + return vector; \ +} - asm volatile(KVM_ASM_SAFE("rdmsr") - : "=a"(a), "=d"(d), KVM_ASM_SAFE_OUTPUTS(vector, error_code) - : "c"(msr) - : KVM_ASM_SAFE_CLOBBERS); +/* + * Generate {insn}_safe() and {insn}_safe_fep() helpers for instructions that + * use ECX as in input index, and EDX:EAX as a 64-bit output. + */ +#define BUILD_READ_U64_SAFE_HELPERS(insn) \ + BUILD_READ_U64_SAFE_HELPER(insn, , ) \ + BUILD_READ_U64_SAFE_HELPER(insn, _fep, _FEP) \ - *val = (uint64_t)a | ((uint64_t)d << 32); - return vector; -} +BUILD_READ_U64_SAFE_HELPERS(rdmsr) +BUILD_READ_U64_SAFE_HELPERS(rdpmc) +BUILD_READ_U64_SAFE_HELPERS(xgetbv) static inline uint8_t wrmsr_safe(uint32_t msr, uint64_t val) { -- cgit v1.2.3 From a8a37f5556845b13be2df3d545e7245b574e0ff5 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:49 -0800 Subject: KVM: selftests: Extend PMU counters test to validate RDPMC after WRMSR Extend the read/write PMU counters subtest to verify that RDPMC also reads back the written value. Opportunsitically verify that attempting to use the "fast" mode of RDPMC fails, as the "fast" flag is only supported by non-architectural PMUs, which KVM doesn't virtualize. Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-30-seanjc@google.com Signed-off-by: Sean Christopherson --- .../selftests/kvm/x86_64/pmu_counters_test.c | 41 ++++++++++++++++++++++ 1 file changed, 41 insertions(+) diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c index cb808ac827ba..ae5f6042f1e8 100644 --- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c @@ -325,9 +325,30 @@ __GUEST_ASSERT(expect_gp ? vector == GP_VECTOR : !vector, \ "Expected " #insn "(0x%x) to yield 0x%lx, got 0x%lx", \ msr, expected_val, val); +static void guest_test_rdpmc(uint32_t rdpmc_idx, bool expect_success, + uint64_t expected_val) +{ + uint8_t vector; + uint64_t val; + + vector = rdpmc_safe(rdpmc_idx, &val); + GUEST_ASSERT_PMC_MSR_ACCESS(RDPMC, rdpmc_idx, !expect_success, vector); + if (expect_success) + GUEST_ASSERT_PMC_VALUE(RDPMC, rdpmc_idx, val, expected_val); + + if (!is_forced_emulation_enabled) + return; + + vector = rdpmc_safe_fep(rdpmc_idx, &val); + GUEST_ASSERT_PMC_MSR_ACCESS(RDPMC, rdpmc_idx, !expect_success, vector); + if (expect_success) + GUEST_ASSERT_PMC_VALUE(RDPMC, rdpmc_idx, val, expected_val); +} + static void guest_rd_wr_counters(uint32_t base_msr, uint8_t nr_possible_counters, uint8_t nr_counters, uint32_t or_mask) { + const bool pmu_has_fast_mode = !guest_get_pmu_version(); uint8_t i; for (i = 0; i < nr_possible_counters; i++) { @@ -352,6 +373,7 @@ static void guest_rd_wr_counters(uint32_t base_msr, uint8_t nr_possible_counters const uint64_t expected_val = expect_success ? test_val : 0; const bool expect_gp = !expect_success && msr != MSR_P6_PERFCTR0 && msr != MSR_P6_PERFCTR1; + uint32_t rdpmc_idx; uint8_t vector; uint64_t val; @@ -365,6 +387,25 @@ static void guest_rd_wr_counters(uint32_t base_msr, uint8_t nr_possible_counters if (!expect_gp) GUEST_ASSERT_PMC_VALUE(RDMSR, msr, val, expected_val); + /* + * Redo the read tests with RDPMC, which has different indexing + * semantics and additional capabilities. + */ + rdpmc_idx = i; + if (base_msr == MSR_CORE_PERF_FIXED_CTR0) + rdpmc_idx |= INTEL_RDPMC_FIXED; + + guest_test_rdpmc(rdpmc_idx, expect_success, expected_val); + + /* + * KVM doesn't support non-architectural PMUs, i.e. it should + * impossible to have fast mode RDPMC. Verify that attempting + * to use fast RDPMC always #GPs. + */ + GUEST_ASSERT(!expect_success || !pmu_has_fast_mode); + rdpmc_idx |= INTEL_RDPMC_FAST; + guest_test_rdpmc(rdpmc_idx, false, -1ull); + vector = wrmsr_safe(msr, 0); GUEST_ASSERT_PMC_MSR_ACCESS(WRMSR, msr, expect_gp, vector); } -- cgit v1.2.3 From f933b88e20150f15787390e2a1754a7e412754ed Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 9 Nov 2023 18:28:48 -0800 Subject: KVM: x86/pmu: Zero out PMU metadata on AMD if PMU is disabled Move the purging of common PMU metadata from intel_pmu_refresh() to kvm_pmu_refresh(), and invoke the vendor refresh() hook if and only if the VM is supposed to have a vPMU. KVM already denies access to the PMU based on kvm->arch.enable_pmu, as get_gp_pmc_amd() returns NULL for all PMCs in that case, i.e. KVM already violates AMD's architecture by not virtualizing a PMU (kernels have long since learned to not panic when the PMU is unavailable). But configuring the PMU as if it were enabled causes unwanted side effects, e.g. calls to kvm_pmu_trigger_event() waste an absurd number of cycles due to the all_valid_pmc_idx bitmap being non-zero. Fixes: b1d66dad65dc ("KVM: x86/svm: Add module param to control PMU virtualization") Reported-by: Konstantin Khorenko Closes: https://lore.kernel.org/all/20231109180646.2963718-2-khorenko@virtuozzo.com Link: https://lore.kernel.org/r/20231110022857.1273836-2-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/pmu.c | 20 ++++++++++++++++++-- arch/x86/kvm/vmx/pmu_intel.c | 16 ++-------------- 2 files changed, 20 insertions(+), 16 deletions(-) diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 09b0feb975c3..4d4366c6f7cd 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -749,6 +749,8 @@ static void kvm_pmu_reset(struct kvm_vcpu *vcpu) */ void kvm_pmu_refresh(struct kvm_vcpu *vcpu) { + struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); + if (KVM_BUG_ON(kvm_vcpu_has_run(vcpu), vcpu->kvm)) return; @@ -758,8 +760,22 @@ void kvm_pmu_refresh(struct kvm_vcpu *vcpu) */ kvm_pmu_reset(vcpu); - bitmap_zero(vcpu_to_pmu(vcpu)->all_valid_pmc_idx, X86_PMC_IDX_MAX); - static_call(kvm_x86_pmu_refresh)(vcpu); + pmu->version = 0; + pmu->nr_arch_gp_counters = 0; + pmu->nr_arch_fixed_counters = 0; + pmu->counter_bitmask[KVM_PMC_GP] = 0; + pmu->counter_bitmask[KVM_PMC_FIXED] = 0; + pmu->reserved_bits = 0xffffffff00200000ull; + pmu->raw_event_mask = X86_RAW_EVENT_MASK; + pmu->global_ctrl_mask = ~0ull; + pmu->global_status_mask = ~0ull; + pmu->fixed_ctr_ctrl_mask = ~0ull; + pmu->pebs_enable_mask = ~0ull; + pmu->pebs_data_cfg_mask = ~0ull; + bitmap_zero(pmu->all_valid_pmc_idx, X86_PMC_IDX_MAX); + + if (vcpu->kvm->arch.enable_pmu) + static_call(kvm_x86_pmu_refresh)(vcpu); } void kvm_pmu_init(struct kvm_vcpu *vcpu) diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index b41bdb0a0995..a87f4725a9be 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -471,19 +471,6 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu) u64 counter_mask; int i; - pmu->nr_arch_gp_counters = 0; - pmu->nr_arch_fixed_counters = 0; - pmu->counter_bitmask[KVM_PMC_GP] = 0; - pmu->counter_bitmask[KVM_PMC_FIXED] = 0; - pmu->version = 0; - pmu->reserved_bits = 0xffffffff00200000ull; - pmu->raw_event_mask = X86_RAW_EVENT_MASK; - pmu->global_ctrl_mask = ~0ull; - pmu->global_status_mask = ~0ull; - pmu->fixed_ctr_ctrl_mask = ~0ull; - pmu->pebs_enable_mask = ~0ull; - pmu->pebs_data_cfg_mask = ~0ull; - memset(&lbr_desc->records, 0, sizeof(lbr_desc->records)); /* @@ -495,8 +482,9 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu) return; entry = kvm_find_cpuid_entry(vcpu, 0xa); - if (!entry || !vcpu->kvm->arch.enable_pmu) + if (!entry) return; + eax.full = entry->eax; edx.full = entry->edx; -- cgit v1.2.3 From be6b067dae1573cf4d53c8b08175d8872d82f030 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 9 Nov 2023 18:28:49 -0800 Subject: KVM: x86/pmu: Add common define to capture fixed counters offset Add a common define to "officially" solidify KVM's split of counters, i.e. to commit to using bits 31:0 to track general purpose counters and bits 63:32 to track fixed counters (which only Intel supports). KVM already bleeds this behavior all over common PMU code, and adding a KVM- defined macro allows clarifying that the value is a _base_, as oppposed to the _flag_ that is used to access fixed PMCs via RDPMC (which perf confusingly calls INTEL_PMC_FIXED_RDPMC_BASE). No functional change intended. Link: https://lore.kernel.org/r/20231110022857.1273836-3-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/pmu.c | 8 ++++---- arch/x86/kvm/pmu.h | 4 +++- arch/x86/kvm/vmx/pmu_intel.c | 12 ++++++------ 3 files changed, 13 insertions(+), 11 deletions(-) diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 4d4366c6f7cd..67d589ac9363 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -67,7 +67,7 @@ static const struct x86_cpu_id vmx_pebs_pdist_cpu[] = { * all perf counters (both gp and fixed). The mapping relationship * between pmc and perf counters is as the following: * * Intel: [0 .. KVM_INTEL_PMC_MAX_GENERIC-1] <=> gp counters - * [INTEL_PMC_IDX_FIXED .. INTEL_PMC_IDX_FIXED + 2] <=> fixed + * [KVM_FIXED_PMC_BASE_IDX .. KVM_FIXED_PMC_BASE_IDX + 2] <=> fixed * * AMD: [0 .. AMD64_NUM_COUNTERS-1] and, for families 15H * and later, [0 .. AMD64_NUM_COUNTERS_CORE-1] <=> gp counters */ @@ -411,7 +411,7 @@ static bool is_gp_event_allowed(struct kvm_x86_pmu_event_filter *f, static bool is_fixed_event_allowed(struct kvm_x86_pmu_event_filter *filter, int idx) { - int fixed_idx = idx - INTEL_PMC_IDX_FIXED; + int fixed_idx = idx - KVM_FIXED_PMC_BASE_IDX; if (filter->action == KVM_PMU_EVENT_DENY && test_bit(fixed_idx, (ulong *)&filter->fixed_counter_bitmap)) @@ -465,7 +465,7 @@ static void reprogram_counter(struct kvm_pmc *pmc) if (pmc_is_fixed(pmc)) { fixed_ctr_ctrl = fixed_ctrl_field(pmu->fixed_ctr_ctrl, - pmc->idx - INTEL_PMC_IDX_FIXED); + pmc->idx - KVM_FIXED_PMC_BASE_IDX); if (fixed_ctr_ctrl & 0x1) eventsel |= ARCH_PERFMON_EVENTSEL_OS; if (fixed_ctr_ctrl & 0x2) @@ -841,7 +841,7 @@ static inline bool cpl_is_matched(struct kvm_pmc *pmc) select_user = config & ARCH_PERFMON_EVENTSEL_USR; } else { config = fixed_ctrl_field(pmc_to_pmu(pmc)->fixed_ctr_ctrl, - pmc->idx - INTEL_PMC_IDX_FIXED); + pmc->idx - KVM_FIXED_PMC_BASE_IDX); select_os = config & 0x1; select_user = config & 0x2; } diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h index 51bbb01b21c8..e8c6a1f4b8e8 100644 --- a/arch/x86/kvm/pmu.h +++ b/arch/x86/kvm/pmu.h @@ -18,6 +18,8 @@ #define VMWARE_BACKDOOR_PMC_REAL_TIME 0x10001 #define VMWARE_BACKDOOR_PMC_APPARENT_TIME 0x10002 +#define KVM_FIXED_PMC_BASE_IDX INTEL_PMC_IDX_FIXED + struct kvm_pmu_ops { struct kvm_pmc *(*pmc_idx_to_pmc)(struct kvm_pmu *pmu, int pmc_idx); struct kvm_pmc *(*rdpmc_ecx_to_pmc)(struct kvm_vcpu *vcpu, @@ -130,7 +132,7 @@ static inline bool pmc_speculative_in_use(struct kvm_pmc *pmc) if (pmc_is_fixed(pmc)) return fixed_ctrl_field(pmu->fixed_ctr_ctrl, - pmc->idx - INTEL_PMC_IDX_FIXED) & 0x3; + pmc->idx - KVM_FIXED_PMC_BASE_IDX) & 0x3; return pmc->eventsel & ARCH_PERFMON_EVENTSEL_ENABLE; } diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index a87f4725a9be..fe7a2ba51e1b 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -50,18 +50,18 @@ static void reprogram_fixed_counters(struct kvm_pmu *pmu, u64 data) pmc = get_fixed_pmc(pmu, MSR_CORE_PERF_FIXED_CTR0 + i); - __set_bit(INTEL_PMC_IDX_FIXED + i, pmu->pmc_in_use); + __set_bit(KVM_FIXED_PMC_BASE_IDX + i, pmu->pmc_in_use); kvm_pmu_request_counter_reprogram(pmc); } } static struct kvm_pmc *intel_pmc_idx_to_pmc(struct kvm_pmu *pmu, int pmc_idx) { - if (pmc_idx < INTEL_PMC_IDX_FIXED) { + if (pmc_idx < KVM_FIXED_PMC_BASE_IDX) { return get_gp_pmc(pmu, MSR_P6_EVNTSEL0 + pmc_idx, MSR_P6_EVNTSEL0); } else { - u32 idx = pmc_idx - INTEL_PMC_IDX_FIXED; + u32 idx = pmc_idx - KVM_FIXED_PMC_BASE_IDX; return get_fixed_pmc(pmu, idx + MSR_CORE_PERF_FIXED_CTR0); } @@ -516,7 +516,7 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu) for (i = 0; i < pmu->nr_arch_fixed_counters; i++) pmu->fixed_ctr_ctrl_mask &= ~(0xbull << (i * 4)); counter_mask = ~(((1ull << pmu->nr_arch_gp_counters) - 1) | - (((1ull << pmu->nr_arch_fixed_counters) - 1) << INTEL_PMC_IDX_FIXED)); + (((1ull << pmu->nr_arch_fixed_counters) - 1) << KVM_FIXED_PMC_BASE_IDX)); pmu->global_ctrl_mask = counter_mask; /* @@ -560,7 +560,7 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu) pmu->reserved_bits &= ~ICL_EVENTSEL_ADAPTIVE; for (i = 0; i < pmu->nr_arch_fixed_counters; i++) { pmu->fixed_ctr_ctrl_mask &= - ~(1ULL << (INTEL_PMC_IDX_FIXED + i * 4)); + ~(1ULL << (KVM_FIXED_PMC_BASE_IDX + i * 4)); } pmu->pebs_data_cfg_mask = ~0xff00000full; } else { @@ -586,7 +586,7 @@ static void intel_pmu_init(struct kvm_vcpu *vcpu) for (i = 0; i < KVM_PMC_MAX_FIXED; i++) { pmu->fixed_counters[i].type = KVM_PMC_FIXED; pmu->fixed_counters[i].vcpu = vcpu; - pmu->fixed_counters[i].idx = i + INTEL_PMC_IDX_FIXED; + pmu->fixed_counters[i].idx = i + KVM_FIXED_PMC_BASE_IDX; pmu->fixed_counters[i].current_config = 0; pmu->fixed_counters[i].eventsel = intel_get_fixed_pmc_eventsel(i); } -- cgit v1.2.3 From b31880ca2f41dc2196e31d97e498b0fa884c2b2a Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 9 Nov 2023 18:28:50 -0800 Subject: KVM: x86/pmu: Move pmc_idx => pmc translation helper to common code Add a common helper for *internal* PMC lookups, and delete the ops hook and Intel's implementation. Keep AMD's implementation, but rename it to amd_pmu_get_pmc() to make it somewhat more obvious that it's suited for both KVM-internal and guest-initiated lookups. Because KVM tracks all counters in a single bitmap, getting a counter when iterating over a bitmap, e.g. of all valid PMCs, requires a small amount of math, that while simple, isn't super obvious and doesn't use the same semantics as PMC lookups from RDPMC! Although AMD doesn't support fixed counters, the common PMU code still behaves as if there a split, the high half of which just happens to always be empty. Opportunstically add a comment to explain both what is going on, and why KVM uses a single bitmap, e.g. the boilerplate for iterating over separate bitmaps could be done via macros, so it's not (just) about deduplicating code. Link: https://lore.kernel.org/r/20231110022857.1273836-4-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/include/asm/kvm-x86-pmu-ops.h | 1 - arch/x86/kvm/pmu.c | 8 ++++---- arch/x86/kvm/pmu.h | 29 ++++++++++++++++++++++++++++- arch/x86/kvm/svm/pmu.c | 7 +++---- arch/x86/kvm/vmx/pmu_intel.c | 15 +-------------- 5 files changed, 36 insertions(+), 24 deletions(-) diff --git a/arch/x86/include/asm/kvm-x86-pmu-ops.h b/arch/x86/include/asm/kvm-x86-pmu-ops.h index f0cd48222133..f852b13aeefe 100644 --- a/arch/x86/include/asm/kvm-x86-pmu-ops.h +++ b/arch/x86/include/asm/kvm-x86-pmu-ops.h @@ -12,7 +12,6 @@ BUILD_BUG_ON(1) * a NULL definition, for example if "static_call_cond()" will be used * at the call sites. */ -KVM_X86_PMU_OP(pmc_idx_to_pmc) KVM_X86_PMU_OP(rdpmc_ecx_to_pmc) KVM_X86_PMU_OP(msr_idx_to_pmc) KVM_X86_PMU_OP_OPTIONAL(check_rdpmc_early) diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 67d589ac9363..0873937c90bc 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -505,7 +505,7 @@ void kvm_pmu_handle_event(struct kvm_vcpu *vcpu) int bit; for_each_set_bit(bit, pmu->reprogram_pmi, X86_PMC_IDX_MAX) { - struct kvm_pmc *pmc = static_call(kvm_x86_pmu_pmc_idx_to_pmc)(pmu, bit); + struct kvm_pmc *pmc = kvm_pmc_idx_to_pmc(pmu, bit); if (unlikely(!pmc)) { clear_bit(bit, pmu->reprogram_pmi); @@ -725,7 +725,7 @@ static void kvm_pmu_reset(struct kvm_vcpu *vcpu) bitmap_zero(pmu->reprogram_pmi, X86_PMC_IDX_MAX); for_each_set_bit(i, pmu->all_valid_pmc_idx, X86_PMC_IDX_MAX) { - pmc = static_call(kvm_x86_pmu_pmc_idx_to_pmc)(pmu, i); + pmc = kvm_pmc_idx_to_pmc(pmu, i); if (!pmc) continue; @@ -801,7 +801,7 @@ void kvm_pmu_cleanup(struct kvm_vcpu *vcpu) pmu->pmc_in_use, X86_PMC_IDX_MAX); for_each_set_bit(i, bitmask, X86_PMC_IDX_MAX) { - pmc = static_call(kvm_x86_pmu_pmc_idx_to_pmc)(pmu, i); + pmc = kvm_pmc_idx_to_pmc(pmu, i); if (pmc && pmc->perf_event && !pmc_speculative_in_use(pmc)) pmc_stop_counter(pmc); @@ -856,7 +856,7 @@ void kvm_pmu_trigger_event(struct kvm_vcpu *vcpu, u64 perf_hw_id) int i; for_each_set_bit(i, pmu->all_valid_pmc_idx, X86_PMC_IDX_MAX) { - pmc = static_call(kvm_x86_pmu_pmc_idx_to_pmc)(pmu, i); + pmc = kvm_pmc_idx_to_pmc(pmu, i); if (!pmc || !pmc_event_is_allowed(pmc)) continue; diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h index e8c6a1f4b8e8..56e8e665e1af 100644 --- a/arch/x86/kvm/pmu.h +++ b/arch/x86/kvm/pmu.h @@ -4,6 +4,8 @@ #include +#include + #define vcpu_to_pmu(vcpu) (&(vcpu)->arch.pmu) #define pmu_to_vcpu(pmu) (container_of((pmu), struct kvm_vcpu, arch.pmu)) #define pmc_to_pmu(pmc) (&(pmc)->vcpu->arch.pmu) @@ -21,7 +23,6 @@ #define KVM_FIXED_PMC_BASE_IDX INTEL_PMC_IDX_FIXED struct kvm_pmu_ops { - struct kvm_pmc *(*pmc_idx_to_pmc)(struct kvm_pmu *pmu, int pmc_idx); struct kvm_pmc *(*rdpmc_ecx_to_pmc)(struct kvm_vcpu *vcpu, unsigned int idx, u64 *mask); struct kvm_pmc *(*msr_idx_to_pmc)(struct kvm_vcpu *vcpu, u32 msr); @@ -56,6 +57,32 @@ static inline bool kvm_pmu_has_perf_global_ctrl(struct kvm_pmu *pmu) return pmu->version > 1; } +/* + * KVM tracks all counters in 64-bit bitmaps, with general purpose counters + * mapped to bits 31:0 and fixed counters mapped to 63:32, e.g. fixed counter 0 + * is tracked internally via index 32. On Intel, (AMD doesn't support fixed + * counters), this mirrors how fixed counters are mapped to PERF_GLOBAL_CTRL + * and similar MSRs, i.e. tracking fixed counters at base index 32 reduces the + * amounter of boilerplate needed to iterate over PMCs *and* simplifies common + * enabling/disable/reset operations. + * + * WARNING! This helper is only for lookups that are initiated by KVM, it is + * NOT safe for guest lookups, e.g. will do the wrong thing if passed a raw + * ECX value from RDPMC (fixed counters are accessed by setting bit 30 in ECX + * for RDPMC, not by adding 32 to the fixed counter index). + */ +static inline struct kvm_pmc *kvm_pmc_idx_to_pmc(struct kvm_pmu *pmu, int idx) +{ + if (idx < pmu->nr_arch_gp_counters) + return &pmu->gp_counters[idx]; + + idx -= KVM_FIXED_PMC_BASE_IDX; + if (idx >= 0 && idx < pmu->nr_arch_fixed_counters) + return &pmu->fixed_counters[idx]; + + return NULL; +} + static inline u64 pmc_bitmask(struct kvm_pmc *pmc) { struct kvm_pmu *pmu = pmc_to_pmu(pmc); diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c index e886300f0f97..dfcc38bd97d3 100644 --- a/arch/x86/kvm/svm/pmu.c +++ b/arch/x86/kvm/svm/pmu.c @@ -25,7 +25,7 @@ enum pmu_type { PMU_TYPE_EVNTSEL, }; -static struct kvm_pmc *amd_pmc_idx_to_pmc(struct kvm_pmu *pmu, int pmc_idx) +static struct kvm_pmc *amd_pmu_get_pmc(struct kvm_pmu *pmu, int pmc_idx) { unsigned int num_counters = pmu->nr_arch_gp_counters; @@ -70,7 +70,7 @@ static inline struct kvm_pmc *get_gp_pmc_amd(struct kvm_pmu *pmu, u32 msr, return NULL; } - return amd_pmc_idx_to_pmc(pmu, idx); + return amd_pmu_get_pmc(pmu, idx); } static int amd_check_rdpmc_early(struct kvm_vcpu *vcpu, unsigned int idx) @@ -87,7 +87,7 @@ static int amd_check_rdpmc_early(struct kvm_vcpu *vcpu, unsigned int idx) static struct kvm_pmc *amd_rdpmc_ecx_to_pmc(struct kvm_vcpu *vcpu, unsigned int idx, u64 *mask) { - return amd_pmc_idx_to_pmc(vcpu_to_pmu(vcpu), idx); + return amd_pmu_get_pmc(vcpu_to_pmu(vcpu), idx); } static struct kvm_pmc *amd_msr_idx_to_pmc(struct kvm_vcpu *vcpu, u32 msr) @@ -229,7 +229,6 @@ static void amd_pmu_init(struct kvm_vcpu *vcpu) } struct kvm_pmu_ops amd_pmu_ops __initdata = { - .pmc_idx_to_pmc = amd_pmc_idx_to_pmc, .rdpmc_ecx_to_pmc = amd_rdpmc_ecx_to_pmc, .msr_idx_to_pmc = amd_msr_idx_to_pmc, .check_rdpmc_early = amd_check_rdpmc_early, diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index fe7a2ba51e1b..845a964f22a6 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -55,18 +55,6 @@ static void reprogram_fixed_counters(struct kvm_pmu *pmu, u64 data) } } -static struct kvm_pmc *intel_pmc_idx_to_pmc(struct kvm_pmu *pmu, int pmc_idx) -{ - if (pmc_idx < KVM_FIXED_PMC_BASE_IDX) { - return get_gp_pmc(pmu, MSR_P6_EVNTSEL0 + pmc_idx, - MSR_P6_EVNTSEL0); - } else { - u32 idx = pmc_idx - KVM_FIXED_PMC_BASE_IDX; - - return get_fixed_pmc(pmu, idx + MSR_CORE_PERF_FIXED_CTR0); - } -} - static struct kvm_pmc *intel_rdpmc_ecx_to_pmc(struct kvm_vcpu *vcpu, unsigned int idx, u64 *mask) { @@ -718,7 +706,7 @@ void intel_pmu_cross_mapped_check(struct kvm_pmu *pmu) for_each_set_bit(bit, (unsigned long *)&pmu->global_ctrl, X86_PMC_IDX_MAX) { - pmc = intel_pmc_idx_to_pmc(pmu, bit); + pmc = kvm_pmc_idx_to_pmc(pmu, bit); if (!pmc || !pmc_speculative_in_use(pmc) || !pmc_is_globally_enabled(pmc) || !pmc->perf_event) @@ -735,7 +723,6 @@ void intel_pmu_cross_mapped_check(struct kvm_pmu *pmu) } struct kvm_pmu_ops intel_pmu_ops __initdata = { - .pmc_idx_to_pmc = intel_pmc_idx_to_pmc, .rdpmc_ecx_to_pmc = intel_rdpmc_ecx_to_pmc, .msr_idx_to_pmc = intel_msr_idx_to_pmc, .is_valid_msr = intel_is_valid_msr, -- cgit v1.2.3 From 004a0aa56edea3effc97bc90a620da1bcde5c63c Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 9 Nov 2023 18:28:51 -0800 Subject: KVM: x86/pmu: Snapshot and clear reprogramming bitmap before reprogramming Refactor the handling of the reprogramming bitmap to snapshot and clear to-be-processed bits before doing the reprogramming, and then explicitly set bits for PMCs that need to be reprogrammed (again). This will allow adding a macro to iterate over all valid PMCs without having to add special handling for the reprogramming bit, which (a) can have bits set for non-existent PMCs and (b) needs to clear such bits to avoid wasting cycles in perpetuity. Note, the existing behavior of clearing bits after reprogramming does NOT have a race with kvm_vm_ioctl_set_pmu_event_filter(). Setting a new PMU filter synchronizes SRCU _before_ setting the bitmap, i.e. guarantees that the vCPU isn't in the middle of reprogramming with a stale filter prior to setting the bitmap. Link: https://lore.kernel.org/r/20231110022857.1273836-5-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/pmu.c | 52 +++++++++++++++++++++++------------------ 2 files changed, 30 insertions(+), 23 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index b5b2d0fde579..ad5319a503f0 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -536,6 +536,7 @@ struct kvm_pmc { #define KVM_PMC_MAX_FIXED 3 #define MSR_ARCH_PERFMON_FIXED_CTR_MAX (MSR_ARCH_PERFMON_FIXED_CTR0 + KVM_PMC_MAX_FIXED - 1) #define KVM_AMD_PMC_MAX_GENERIC 6 + struct kvm_pmu { u8 version; unsigned nr_arch_gp_counters; diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 0873937c90bc..81a0c6719863 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -444,7 +444,7 @@ static bool pmc_event_is_allowed(struct kvm_pmc *pmc) check_pmu_event_filter(pmc); } -static void reprogram_counter(struct kvm_pmc *pmc) +static int reprogram_counter(struct kvm_pmc *pmc) { struct kvm_pmu *pmu = pmc_to_pmu(pmc); u64 eventsel = pmc->eventsel; @@ -455,7 +455,7 @@ static void reprogram_counter(struct kvm_pmc *pmc) emulate_overflow = pmc_pause_counter(pmc); if (!pmc_event_is_allowed(pmc)) - goto reprogram_complete; + return 0; if (emulate_overflow) __kvm_perf_overflow(pmc, false); @@ -476,43 +476,49 @@ static void reprogram_counter(struct kvm_pmc *pmc) } if (pmc->current_config == new_config && pmc_resume_counter(pmc)) - goto reprogram_complete; + return 0; pmc_release_perf_event(pmc); pmc->current_config = new_config; - /* - * If reprogramming fails, e.g. due to contention, leave the counter's - * regprogram bit set, i.e. opportunistically try again on the next PMU - * refresh. Don't make a new request as doing so can stall the guest - * if reprogramming repeatedly fails. - */ - if (pmc_reprogram_counter(pmc, PERF_TYPE_RAW, - (eventsel & pmu->raw_event_mask), - !(eventsel & ARCH_PERFMON_EVENTSEL_USR), - !(eventsel & ARCH_PERFMON_EVENTSEL_OS), - eventsel & ARCH_PERFMON_EVENTSEL_INT)) - return; - -reprogram_complete: - clear_bit(pmc->idx, (unsigned long *)&pmc_to_pmu(pmc)->reprogram_pmi); + return pmc_reprogram_counter(pmc, PERF_TYPE_RAW, + (eventsel & pmu->raw_event_mask), + !(eventsel & ARCH_PERFMON_EVENTSEL_USR), + !(eventsel & ARCH_PERFMON_EVENTSEL_OS), + eventsel & ARCH_PERFMON_EVENTSEL_INT); } void kvm_pmu_handle_event(struct kvm_vcpu *vcpu) { + DECLARE_BITMAP(bitmap, X86_PMC_IDX_MAX); struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); int bit; - for_each_set_bit(bit, pmu->reprogram_pmi, X86_PMC_IDX_MAX) { + bitmap_copy(bitmap, pmu->reprogram_pmi, X86_PMC_IDX_MAX); + + /* + * The reprogramming bitmap can be written asynchronously by something + * other than the task that holds vcpu->mutex, take care to clear only + * the bits that will actually processed. + */ + BUILD_BUG_ON(sizeof(bitmap) != sizeof(atomic64_t)); + atomic64_andnot(*(s64 *)bitmap, &pmu->__reprogram_pmi); + + for_each_set_bit(bit, bitmap, X86_PMC_IDX_MAX) { struct kvm_pmc *pmc = kvm_pmc_idx_to_pmc(pmu, bit); - if (unlikely(!pmc)) { - clear_bit(bit, pmu->reprogram_pmi); + if (unlikely(!pmc)) continue; - } - reprogram_counter(pmc); + /* + * If reprogramming fails, e.g. due to contention, re-set the + * regprogram bit set, i.e. opportunistically try again on the + * next PMU refresh. Don't make a new request as doing so can + * stall the guest if reprogramming repeatedly fails. + */ + if (reprogram_counter(pmc)) + set_bit(pmc->idx, pmu->reprogram_pmi); } /* -- cgit v1.2.3 From e5a65d4f723ab9997deab798c539e6bfd71f8440 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 9 Nov 2023 18:28:52 -0800 Subject: KVM: x86/pmu: Add macros to iterate over all PMCs given a bitmap Add and use kvm_for_each_pmc() to dedup a variety of open coded for-loops that iterate over valid PMCs given a bitmap (and because seeing checkpatch whine about bad macro style is always amusing). No functional change intended. Link: https://lore.kernel.org/r/20231110022857.1273836-6-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/pmu.c | 26 +++++++------------------- arch/x86/kvm/pmu.h | 6 ++++++ arch/x86/kvm/vmx/pmu_intel.c | 7 ++----- 3 files changed, 15 insertions(+), 24 deletions(-) diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 81a0c6719863..7b5563ff259c 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -493,6 +493,7 @@ void kvm_pmu_handle_event(struct kvm_vcpu *vcpu) { DECLARE_BITMAP(bitmap, X86_PMC_IDX_MAX); struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); + struct kvm_pmc *pmc; int bit; bitmap_copy(bitmap, pmu->reprogram_pmi, X86_PMC_IDX_MAX); @@ -505,12 +506,7 @@ void kvm_pmu_handle_event(struct kvm_vcpu *vcpu) BUILD_BUG_ON(sizeof(bitmap) != sizeof(atomic64_t)); atomic64_andnot(*(s64 *)bitmap, &pmu->__reprogram_pmi); - for_each_set_bit(bit, bitmap, X86_PMC_IDX_MAX) { - struct kvm_pmc *pmc = kvm_pmc_idx_to_pmc(pmu, bit); - - if (unlikely(!pmc)) - continue; - + kvm_for_each_pmc(pmu, pmc, bit, bitmap) { /* * If reprogramming fails, e.g. due to contention, re-set the * regprogram bit set, i.e. opportunistically try again on the @@ -730,11 +726,7 @@ static void kvm_pmu_reset(struct kvm_vcpu *vcpu) bitmap_zero(pmu->reprogram_pmi, X86_PMC_IDX_MAX); - for_each_set_bit(i, pmu->all_valid_pmc_idx, X86_PMC_IDX_MAX) { - pmc = kvm_pmc_idx_to_pmc(pmu, i); - if (!pmc) - continue; - + kvm_for_each_pmc(pmu, pmc, i, pmu->all_valid_pmc_idx) { pmc_stop_counter(pmc); pmc->counter = 0; pmc->emulated_counter = 0; @@ -806,10 +798,8 @@ void kvm_pmu_cleanup(struct kvm_vcpu *vcpu) bitmap_andnot(bitmask, pmu->all_valid_pmc_idx, pmu->pmc_in_use, X86_PMC_IDX_MAX); - for_each_set_bit(i, bitmask, X86_PMC_IDX_MAX) { - pmc = kvm_pmc_idx_to_pmc(pmu, i); - - if (pmc && pmc->perf_event && !pmc_speculative_in_use(pmc)) + kvm_for_each_pmc(pmu, pmc, i, bitmask) { + if (pmc->perf_event && !pmc_speculative_in_use(pmc)) pmc_stop_counter(pmc); } @@ -861,10 +851,8 @@ void kvm_pmu_trigger_event(struct kvm_vcpu *vcpu, u64 perf_hw_id) struct kvm_pmc *pmc; int i; - for_each_set_bit(i, pmu->all_valid_pmc_idx, X86_PMC_IDX_MAX) { - pmc = kvm_pmc_idx_to_pmc(pmu, i); - - if (!pmc || !pmc_event_is_allowed(pmc)) + kvm_for_each_pmc(pmu, pmc, i, pmu->all_valid_pmc_idx) { + if (!pmc_event_is_allowed(pmc)) continue; /* Ignore checks for edge detect, pin control, invert and CMASK bits */ diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h index 56e8e665e1af..fd18bc0b281c 100644 --- a/arch/x86/kvm/pmu.h +++ b/arch/x86/kvm/pmu.h @@ -83,6 +83,12 @@ static inline struct kvm_pmc *kvm_pmc_idx_to_pmc(struct kvm_pmu *pmu, int idx) return NULL; } +#define kvm_for_each_pmc(pmu, pmc, i, bitmap) \ + for_each_set_bit(i, bitmap, X86_PMC_IDX_MAX) \ + if (!(pmc = kvm_pmc_idx_to_pmc(pmu, i))) \ + continue; \ + else \ + static inline u64 pmc_bitmask(struct kvm_pmc *pmc) { struct kvm_pmu *pmu = pmc_to_pmu(pmc); diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index 845a964f22a6..73b9943ceb17 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -704,11 +704,8 @@ void intel_pmu_cross_mapped_check(struct kvm_pmu *pmu) struct kvm_pmc *pmc = NULL; int bit, hw_idx; - for_each_set_bit(bit, (unsigned long *)&pmu->global_ctrl, - X86_PMC_IDX_MAX) { - pmc = kvm_pmc_idx_to_pmc(pmu, bit); - - if (!pmc || !pmc_speculative_in_use(pmc) || + kvm_for_each_pmc(pmu, pmc, bit, (unsigned long *)&pmu->global_ctrl) { + if (!pmc_speculative_in_use(pmc) || !pmc_is_globally_enabled(pmc) || !pmc->perf_event) continue; -- cgit v1.2.3 From d2b321ea9380564510d281d45ccd2b424da14e7f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 9 Nov 2023 18:28:53 -0800 Subject: KVM: x86/pmu: Process only enabled PMCs when emulating events in software Mask off disabled counters based on PERF_GLOBAL_CTRL *before* iterating over PMCs to emulate (branch) instruction required events in software. In the common case where the guest isn't utilizing the PMU, pre-checking for enabled counters turns a relatively expensive search into a few AND uops and a Jcc. Sadly, PMUs without PERF_GLOBAL_CTRL, e.g. most existing AMD CPUs, are out of luck as there is no way to check that a PMC isn't being used without checking the PMC's event selector. Cc: Konstantin Khorenko Link: https://lore.kernel.org/r/20231110022857.1273836-7-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/pmu.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 7b5563ff259c..c04c3f37a1b8 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -847,11 +847,20 @@ static inline bool cpl_is_matched(struct kvm_pmc *pmc) void kvm_pmu_trigger_event(struct kvm_vcpu *vcpu, u64 perf_hw_id) { + DECLARE_BITMAP(bitmap, X86_PMC_IDX_MAX); struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); struct kvm_pmc *pmc; int i; - kvm_for_each_pmc(pmu, pmc, i, pmu->all_valid_pmc_idx) { + BUILD_BUG_ON(sizeof(pmu->global_ctrl) * BITS_PER_BYTE != X86_PMC_IDX_MAX); + + if (!kvm_pmu_has_perf_global_ctrl(pmu)) + bitmap_copy(bitmap, pmu->all_valid_pmc_idx, X86_PMC_IDX_MAX); + else if (!bitmap_and(bitmap, pmu->all_valid_pmc_idx, + (unsigned long *)&pmu->global_ctrl, X86_PMC_IDX_MAX)) + return; + + kvm_for_each_pmc(pmu, pmc, i, bitmap) { if (!pmc_event_is_allowed(pmc)) continue; -- cgit v1.2.3 From f19063b1ca058b3971d6883b5ec45955b7f53f9c Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 9 Nov 2023 18:28:54 -0800 Subject: KVM: x86/pmu: Snapshot event selectors that KVM emulates in software Snapshot the event selectors for the events that KVM emulates in software, which is currently instructions retired and branch instructions retired. The event selectors a tied to the underlying CPU, i.e. are constant for a given platform even though perf doesn't manage the mappings as such. Getting the event selectors from perf isn't exactly cheap, especially if mitigations are enabled, as at least one indirect call is involved. Snapshot the values in KVM instead of optimizing perf as working with the raw event selectors will be required if KVM ever wants to emulate events that aren't part of perf's uABI, i.e. that don't have an "enum perf_hw_id" entry. Link: https://lore.kernel.org/r/20231110022857.1273836-8-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/pmu.c | 17 ++++++++--------- arch/x86/kvm/pmu.h | 13 ++++++++++++- arch/x86/kvm/vmx/nested.c | 2 +- arch/x86/kvm/x86.c | 6 +++--- 4 files changed, 24 insertions(+), 14 deletions(-) diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index c04c3f37a1b8..f40d8c1edca9 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -29,6 +29,9 @@ struct x86_pmu_capability __read_mostly kvm_pmu_cap; EXPORT_SYMBOL_GPL(kvm_pmu_cap); +struct kvm_pmu_emulated_event_selectors __read_mostly kvm_pmu_eventsel; +EXPORT_SYMBOL_GPL(kvm_pmu_eventsel); + /* Precise Distribution of Instructions Retired (PDIR) */ static const struct x86_cpu_id vmx_pebs_pdir_cpu[] = { X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_D, NULL), @@ -819,13 +822,6 @@ static void kvm_pmu_incr_counter(struct kvm_pmc *pmc) kvm_pmu_request_counter_reprogram(pmc); } -static inline bool eventsel_match_perf_hw_id(struct kvm_pmc *pmc, - unsigned int perf_hw_id) -{ - return !((pmc->eventsel ^ perf_get_hw_event_config(perf_hw_id)) & - AMD64_RAW_EVENT_MASK_NB); -} - static inline bool cpl_is_matched(struct kvm_pmc *pmc) { bool select_os, select_user; @@ -845,7 +841,7 @@ static inline bool cpl_is_matched(struct kvm_pmc *pmc) return (static_call(kvm_x86_get_cpl)(pmc->vcpu) == 0) ? select_os : select_user; } -void kvm_pmu_trigger_event(struct kvm_vcpu *vcpu, u64 perf_hw_id) +void kvm_pmu_trigger_event(struct kvm_vcpu *vcpu, u64 eventsel) { DECLARE_BITMAP(bitmap, X86_PMC_IDX_MAX); struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); @@ -865,7 +861,10 @@ void kvm_pmu_trigger_event(struct kvm_vcpu *vcpu, u64 perf_hw_id) continue; /* Ignore checks for edge detect, pin control, invert and CMASK bits */ - if (eventsel_match_perf_hw_id(pmc, perf_hw_id) && cpl_is_matched(pmc)) + if ((pmc->eventsel ^ eventsel) & AMD64_RAW_EVENT_MASK_NB) + continue; + + if (cpl_is_matched(pmc)) kvm_pmu_incr_counter(pmc); } } diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h index fd18bc0b281c..4d52b0b539ba 100644 --- a/arch/x86/kvm/pmu.h +++ b/arch/x86/kvm/pmu.h @@ -22,6 +22,11 @@ #define KVM_FIXED_PMC_BASE_IDX INTEL_PMC_IDX_FIXED +struct kvm_pmu_emulated_event_selectors { + u64 INSTRUCTIONS_RETIRED; + u64 BRANCH_INSTRUCTIONS_RETIRED; +}; + struct kvm_pmu_ops { struct kvm_pmc *(*rdpmc_ecx_to_pmc)(struct kvm_vcpu *vcpu, unsigned int idx, u64 *mask); @@ -171,6 +176,7 @@ static inline bool pmc_speculative_in_use(struct kvm_pmc *pmc) } extern struct x86_pmu_capability kvm_pmu_cap; +extern struct kvm_pmu_emulated_event_selectors kvm_pmu_eventsel; static inline void kvm_init_pmu_capability(const struct kvm_pmu_ops *pmu_ops) { @@ -212,6 +218,11 @@ static inline void kvm_init_pmu_capability(const struct kvm_pmu_ops *pmu_ops) pmu_ops->MAX_NR_GP_COUNTERS); kvm_pmu_cap.num_counters_fixed = min(kvm_pmu_cap.num_counters_fixed, KVM_PMC_MAX_FIXED); + + kvm_pmu_eventsel.INSTRUCTIONS_RETIRED = + perf_get_hw_event_config(PERF_COUNT_HW_INSTRUCTIONS); + kvm_pmu_eventsel.BRANCH_INSTRUCTIONS_RETIRED = + perf_get_hw_event_config(PERF_COUNT_HW_BRANCH_INSTRUCTIONS); } static inline void kvm_pmu_request_counter_reprogram(struct kvm_pmc *pmc) @@ -259,7 +270,7 @@ void kvm_pmu_init(struct kvm_vcpu *vcpu); void kvm_pmu_cleanup(struct kvm_vcpu *vcpu); void kvm_pmu_destroy(struct kvm_vcpu *vcpu); int kvm_vm_ioctl_set_pmu_event_filter(struct kvm *kvm, void __user *argp); -void kvm_pmu_trigger_event(struct kvm_vcpu *vcpu, u64 perf_hw_id); +void kvm_pmu_trigger_event(struct kvm_vcpu *vcpu, u64 eventsel); bool is_vmware_backdoor_pmc(u32 pmc_idx); diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 6329a306856b..994e014f8a50 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -3606,7 +3606,7 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) return 1; } - kvm_pmu_trigger_event(vcpu, PERF_COUNT_HW_BRANCH_INSTRUCTIONS); + kvm_pmu_trigger_event(vcpu, kvm_pmu_eventsel.BRANCH_INSTRUCTIONS_RETIRED); if (CC(evmptrld_status == EVMPTRLD_VMFAIL)) return nested_vmx_failInvalid(vcpu); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index cbee277254f0..a30df9f8d9d5 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8903,7 +8903,7 @@ int kvm_skip_emulated_instruction(struct kvm_vcpu *vcpu) if (unlikely(!r)) return 0; - kvm_pmu_trigger_event(vcpu, PERF_COUNT_HW_INSTRUCTIONS); + kvm_pmu_trigger_event(vcpu, kvm_pmu_eventsel.INSTRUCTIONS_RETIRED); /* * rflags is the old, "raw" value of the flags. The new value has @@ -9216,9 +9216,9 @@ writeback: */ if (!ctxt->have_exception || exception_type(ctxt->exception.vector) == EXCPT_TRAP) { - kvm_pmu_trigger_event(vcpu, PERF_COUNT_HW_INSTRUCTIONS); + kvm_pmu_trigger_event(vcpu, kvm_pmu_eventsel.INSTRUCTIONS_RETIRED); if (ctxt->is_branch) - kvm_pmu_trigger_event(vcpu, PERF_COUNT_HW_BRANCH_INSTRUCTIONS); + kvm_pmu_trigger_event(vcpu, kvm_pmu_eventsel.BRANCH_INSTRUCTIONS_RETIRED); kvm_rip_write(vcpu, ctxt->eip); if (r && (ctxt->tf || (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP))) r = kvm_vcpu_do_singlestep(vcpu); -- cgit v1.2.3 From afda2d7666f894d1d7b8406cf54801e6c11f63c2 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 9 Nov 2023 18:28:55 -0800 Subject: KVM: x86/pmu: Expand the comment about what bits are check emulating events Expand the comment about what bits are and aren't checked when emulating PMC events in software. As pointed out by Jim, AMD's mask includes bits 35:32, which on Intel overlap with the IN_TX and IN_TXCP bits (32 and 33) as well as reserved bits (34 and 45). Checking The IN_TX* bits is actually correct, as it's safe to assert that the vCPU can't be in an HLE/RTM transaction if KVM is emulating an instruction, i.e. KVM *shouldn't count if either of those bits is set. For the reserved bits, KVM is has equal odds of being right if Intel adds new behavior, i.e. ignoring them is just as likely to be correct as checking them. Opportunistically explain *why* the other flags aren't checked. Suggested-by: Jim Mattson Link: https://lore.kernel.org/r/20231110022857.1273836-9-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/pmu.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index f40d8c1edca9..d891a954b45a 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -860,7 +860,20 @@ void kvm_pmu_trigger_event(struct kvm_vcpu *vcpu, u64 eventsel) if (!pmc_event_is_allowed(pmc)) continue; - /* Ignore checks for edge detect, pin control, invert and CMASK bits */ + /* + * Ignore checks for edge detect (all events currently emulated + * but KVM are always rising edges), pin control (unsupported + * by modern CPUs), and counter mask and its invert flag (KVM + * doesn't emulate multiple events in a single clock cycle). + * + * Note, the uppermost nibble of AMD's mask overlaps Intel's + * IN_TX (bit 32) and IN_TXCP (bit 33), as well as two reserved + * bits (bits 35:34). Checking the "in HLE/RTM transaction" + * flags is correct as the vCPU can't be in a transaction if + * KVM is emulating an instruction. Checking the reserved bits + * might be wrong if they are defined in the future, but so + * could ignoring them, so do the simple thing for now. + */ if ((pmc->eventsel ^ eventsel) & AMD64_RAW_EVENT_MASK_NB) continue; -- cgit v1.2.3 From e35529fb4ac930a4a39e0c15bafcb28a30d26611 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 9 Nov 2023 18:28:56 -0800 Subject: KVM: x86/pmu: Check eventsel first when emulating (branch) insns retired When triggering events, i.e. emulating PMC events in software, check for a matching event selector before checking the event is allowed. The "is allowed" check *might* be cheap, but it could also be very costly, e.g. if userspace has defined a large PMU event filter. The event selector check on the other hand is all but guaranteed to be <10 uops, e.g. looks something like: 0xffffffff8105e615 <+5>: movabs $0xf0000ffff,%rax 0xffffffff8105e61f <+15>: xor %rdi,%rsi 0xffffffff8105e622 <+18>: test %rax,%rsi 0xffffffff8105e625 <+21>: sete %al Link: https://lore.kernel.org/r/20231110022857.1273836-10-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/pmu.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index d891a954b45a..8d81f176ab7b 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -857,9 +857,6 @@ void kvm_pmu_trigger_event(struct kvm_vcpu *vcpu, u64 eventsel) return; kvm_for_each_pmc(pmu, pmc, i, bitmap) { - if (!pmc_event_is_allowed(pmc)) - continue; - /* * Ignore checks for edge detect (all events currently emulated * but KVM are always rising edges), pin control (unsupported @@ -874,11 +871,11 @@ void kvm_pmu_trigger_event(struct kvm_vcpu *vcpu, u64 eventsel) * might be wrong if they are defined in the future, but so * could ignoring them, so do the simple thing for now. */ - if ((pmc->eventsel ^ eventsel) & AMD64_RAW_EVENT_MASK_NB) + if (((pmc->eventsel ^ eventsel) & AMD64_RAW_EVENT_MASK_NB) || + !pmc_event_is_allowed(pmc) || !cpl_is_matched(pmc)) continue; - if (cpl_is_matched(pmc)) - kvm_pmu_incr_counter(pmc); + kvm_pmu_incr_counter(pmc); } } EXPORT_SYMBOL_GPL(kvm_pmu_trigger_event); -- cgit v1.2.3 From 83bdfe04c968e0fe3181e4cd41b764e17ac73911 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 9 Nov 2023 18:28:57 -0800 Subject: KVM: x86/pmu: Avoid CPL lookup if PMC enabline for USER and KERNEL is the same Don't bother querying the CPL if a PMC is (not) counting for both USER and KERNEL, i.e. if the end result is guaranteed to be the same regardless of the CPL. Querying the CPL on Intel requires a VMREAD, i.e. isn't free, and a single CMP+Jcc is cheap. Link: https://lore.kernel.org/r/20231110022857.1273836-11-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/pmu.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 8d81f176ab7b..c397b28e3d1b 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -838,6 +838,13 @@ static inline bool cpl_is_matched(struct kvm_pmc *pmc) select_user = config & 0x2; } + /* + * Skip the CPL lookup, which isn't free on Intel, if the result will + * be the same regardless of the CPL. + */ + if (select_os == select_user) + return select_os; + return (static_call(kvm_x86_get_cpl)(pmc->vcpu) == 0) ? select_os : select_user; } -- cgit v1.2.3 From 4a447b135e45b49101417d54079df25b520299d9 Mon Sep 17 00:00:00 2001 From: Dapeng Mi Date: Sun, 18 Feb 2024 12:30:03 +0800 Subject: KVM: selftests: Test top-down slots event in x86's pmu_counters_test Although the fixed counter 3 and its exclusive pseudo slots event are not supported by KVM yet, the architectural slots event is supported by KVM and can be programmed on any GP counter. Thus add validation for this architectural slots event. Top-down slots event "counts the total number of available slots for an unhalted logical processor, and increments by machine-width of the narrowest pipeline as employed by the Top-down Microarchitecture Analysis method." As for the slot, it's an abstract concept which indicates how many uops (decoded from instructions) can be processed simultaneously (per cycle) on HW. In Top-down Microarchitecture Analysis (TMA) method, the processor is divided into two parts, frond-end and back-end. Assume there is a processor with classic 5-stage pipeline, fetch, decode, execute, memory access and register writeback. The former 2 stages (fetch/decode) are classified to frond-end and the latter 3 stages are classified to back-end. In modern Intel processors, a complicated instruction would be decoded into several uops (micro-operations) and so these uops can be processed simultaneously and then improve the performance. Thus, assume a processor can decode and dispatch 4 uops in front-end and execute 4 uops in back-end simultaneously (per-cycle), so the machine-width of this processor is 4 and this processor has 4 topdown slots per-cycle. If a slot is spare and can be used to process a new upcoming uop, then the slot is available, but if a uop occupies a slot for several cycles and can't be retired (maybe blocked by memory access), then this slot is stall and unavailable. Considering the testing instruction sequence can't be macro-fused on x86 platforms, the measured slots count should not be less than NUM_INSNS_RETIRED. Thus assert the slots count against NUM_INSNS_RETIRED. pmu_counters_test passed with this patch on Intel Sapphire Rapids. About the more information about TMA method, please refer the below link. https://www.intel.com/content/www/us/en/docs/vtune-profiler/cookbook/2023-0/top-down-microarchitecture-analysis-method.html Signed-off-by: Dapeng Mi Link: https://lore.kernel.org/r/20240218043003.2424683-1-dapeng1.mi@linux.intel.com Signed-off-by: Sean Christopherson --- tools/testing/selftests/kvm/x86_64/pmu_counters_test.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c index ae5f6042f1e8..29609b52f8fa 100644 --- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c @@ -119,6 +119,9 @@ static void guest_assert_event_count(uint8_t idx, case INTEL_ARCH_REFERENCE_CYCLES_INDEX: GUEST_ASSERT_NE(count, 0); break; + case INTEL_ARCH_TOPDOWN_SLOTS_INDEX: + GUEST_ASSERT(count >= NUM_INSNS_RETIRED); + break; default: break; } -- cgit v1.2.3 From 812d432373f629eb8d6cb696ea6804fca1534efa Mon Sep 17 00:00:00 2001 From: Like Xu Date: Wed, 6 Dec 2023 11:20:54 +0800 Subject: KVM: x86/pmu: Explicitly check NMI from guest to reducee false positives Explicitly check that the source of external interrupt is indeed an NMI in kvm_arch_pmi_in_guest(), which reduces perf-kvm false positive samples (host samples labelled as guest samples) generated by perf/core NMI mode if an NMI arrives after VM-Exit, but before kvm_after_interrupt(): # test: perf-record + cpu-cycles:HP (which collects host-only precise samples) # Symbol Overhead sys usr guest sys guest usr # ....................................... ........ ........ ........ ......... ......... # # Before: [g] entry_SYSCALL_64 24.63% 0.00% 0.00% 24.63% 0.00% [g] syscall_return_via_sysret 23.23% 0.00% 0.00% 23.23% 0.00% [g] files_lookup_fd_raw 6.35% 0.00% 0.00% 6.35% 0.00% # After: [k] perf_adjust_freq_unthr_context 57.23% 57.23% 0.00% 0.00% 0.00% [k] __vmx_vcpu_run 4.09% 4.09% 0.00% 0.00% 0.00% [k] vmx_update_host_rsp 3.17% 3.17% 0.00% 0.00% 0.00% In the above case, perf records the samples labelled '[g]', the RIPs behind the weird samples are actually being queried by perf_instruction_pointer() after determining whether it's in GUEST state or not, and here's the issue: If VM-Exit is caused by a non-NMI interrupt (such as hrtimer_interrupt) and at least one PMU counter is enabled on host, the kvm_arch_pmi_in_guest() will remain true (KVM_HANDLING_IRQ is set) until kvm_before_interrupt(). During this window, if a PMI occurs on host (since the KVM instructions on host are being executed), the control flow, with the help of the host NMI context, will be transferred to perf/core to generate performance samples, thus perf_instruction_pointer() and perf_guest_get_ip() is called. Since kvm_arch_pmi_in_guest() only checks if there is an interrupt, it may cause perf/core to mistakenly assume that the source RIP of the host NMI belongs to the guest world and use perf_guest_get_ip() to get the RIP of a vCPU that has already exited by a non-NMI interrupt. Error samples are recorded and presented to the end-user via perf-report. Such false positive samples could be eliminated by explicitly determining if the exit reason is KVM_HANDLING_NMI. Note that when VM-exit is indeed triggered by PMI and before HANDLING_NMI is cleared, it's also still possible that another PMI is generated on host. Also for perf/core timer mode, the false positives are still possible since those non-NMI sources of interrupts are not always being used by perf/core. For events that are host-only, perf/core can and should eliminate false positives by checking event->attr.exclude_guest, i.e. events that are configured to exclude KVM guests should never fire in the guest. Events that are configured to count host and guest are trickier, perhaps impossible to handle with 100% accuracy? And regardless of what accuracy is provided by perf/core, improving KVM's accuracy is cheap and easy, with no real downsides. Fixes: dd60d217062f ("KVM: x86: Fix perf timer mode IP reporting") Signed-off-by: Like Xu Reviewed-by: Maxim Levitsky Link: https://lore.kernel.org/r/20231206032054.55070-1-likexu@tencent.com [sean: massage changelog, squash !!in_nmi() fixup from Like] Signed-off-by: Sean Christopherson --- arch/x86/include/asm/kvm_host.h | 10 +++++++++- arch/x86/kvm/x86.h | 6 ------ 2 files changed, 9 insertions(+), 7 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index ad5319a503f0..672ea5e97478 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1880,8 +1880,16 @@ static inline int kvm_arch_flush_remote_tlbs_range(struct kvm *kvm, gfn_t gfn, } #endif /* CONFIG_HYPERV */ +enum kvm_intr_type { + /* Values are arbitrary, but must be non-zero. */ + KVM_HANDLING_IRQ = 1, + KVM_HANDLING_NMI, +}; + +/* Enable perf NMI and timer modes to work, and minimise false positives. */ #define kvm_arch_pmi_in_guest(vcpu) \ - ((vcpu) && (vcpu)->arch.handling_intr_from_guest) + ((vcpu) && (vcpu)->arch.handling_intr_from_guest && \ + (!!in_nmi() == ((vcpu)->arch.handling_intr_from_guest == KVM_HANDLING_NMI))) void __init kvm_mmu_x86_module_init(void); int kvm_mmu_vendor_module_init(void); diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h index 2f7e19166658..4dc38092d599 100644 --- a/arch/x86/kvm/x86.h +++ b/arch/x86/kvm/x86.h @@ -431,12 +431,6 @@ static inline bool kvm_notify_vmexit_enabled(struct kvm *kvm) return kvm->arch.notify_vmexit_flags & KVM_X86_NOTIFY_VMEXIT_ENABLED; } -enum kvm_intr_type { - /* Values are arbitrary, but must be non-zero. */ - KVM_HANDLING_IRQ = 1, - KVM_HANDLING_NMI, -}; - static __always_inline void kvm_before_interrupt(struct kvm_vcpu *vcpu, enum kvm_intr_type intr) { -- cgit v1.2.3