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-rw-r--r--Documentation/virt/kvm/api.rst8
-rw-r--r--arch/x86/include/asm/kvm_host.h3
-rw-r--r--arch/x86/include/uapi/asm/kvm.h1
-rw-r--r--arch/x86/kvm/mmu/mmu.c42
-rw-r--r--tools/testing/selftests/kvm/memslot_modification_stress_test.c19
-rw-r--r--tools/testing/selftests/kvm/memslot_perf_test.c12
-rw-r--r--tools/testing/selftests/kvm/set_memory_region_test.c29
7 files changed, 101 insertions, 13 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index b3be87489108..b4d1cf2e4628 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -8082,6 +8082,14 @@ KVM_X86_QUIRK_MWAIT_NEVER_UD_FAULTS By default, KVM emulates MONITOR/MWAIT (if
guest CPUID on writes to MISC_ENABLE if
KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT is
disabled.
+
+KVM_X86_QUIRK_SLOT_ZAP_ALL By default, KVM invalidates all SPTEs in
+ fast way for memslot deletion when VM type
+ is KVM_X86_DEFAULT_VM.
+ When this quirk is disabled or when VM type
+ is other than KVM_X86_DEFAULT_VM, KVM zaps
+ only leaf SPTEs that are within the range of
+ the memslot being deleted.
=================================== ============================================
7.32 KVM_CAP_MAX_VCPU_ID
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 4a68cb3eba78..e4fc362ba3da 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -2345,7 +2345,8 @@ int memslot_rmap_alloc(struct kvm_memory_slot *slot, unsigned long npages);
KVM_X86_QUIRK_OUT_7E_INC_RIP | \
KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT | \
KVM_X86_QUIRK_FIX_HYPERCALL_INSN | \
- KVM_X86_QUIRK_MWAIT_NEVER_UD_FAULTS)
+ KVM_X86_QUIRK_MWAIT_NEVER_UD_FAULTS | \
+ KVM_X86_QUIRK_SLOT_ZAP_ALL)
/*
* KVM previously used a u32 field in kvm_run to indicate the hypercall was
diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index bf57a824f722..a8debbf2f702 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -439,6 +439,7 @@ struct kvm_sync_regs {
#define KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT (1 << 4)
#define KVM_X86_QUIRK_FIX_HYPERCALL_INSN (1 << 5)
#define KVM_X86_QUIRK_MWAIT_NEVER_UD_FAULTS (1 << 6)
+#define KVM_X86_QUIRK_SLOT_ZAP_ALL (1 << 7)
#define KVM_STATE_NESTED_FORMAT_VMX 0
#define KVM_STATE_NESTED_FORMAT_SVM 1
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index de05a26b0b7d..b278efb1d179 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -6999,10 +6999,50 @@ void kvm_arch_flush_shadow_all(struct kvm *kvm)
kvm_mmu_zap_all(kvm);
}
+/*
+ * Zapping leaf SPTEs with memslot range when a memslot is moved/deleted.
+ *
+ * Zapping non-leaf SPTEs, a.k.a. not-last SPTEs, isn't required, worst
+ * case scenario we'll have unused shadow pages lying around until they
+ * are recycled due to age or when the VM is destroyed.
+ */
+static void kvm_mmu_zap_memslot_leafs(struct kvm *kvm, struct kvm_memory_slot *slot)
+{
+ struct kvm_gfn_range range = {
+ .slot = slot,
+ .start = slot->base_gfn,
+ .end = slot->base_gfn + slot->npages,
+ .may_block = true,
+ };
+ bool flush = false;
+
+ write_lock(&kvm->mmu_lock);
+
+ if (kvm_memslots_have_rmaps(kvm))
+ flush = kvm_handle_gfn_range(kvm, &range, kvm_zap_rmap);
+
+ if (tdp_mmu_enabled)
+ flush = kvm_tdp_mmu_unmap_gfn_range(kvm, &range, flush);
+
+ if (flush)
+ kvm_flush_remote_tlbs_memslot(kvm, slot);
+
+ write_unlock(&kvm->mmu_lock);
+}
+
+static inline bool kvm_memslot_flush_zap_all(struct kvm *kvm)
+{
+ return kvm->arch.vm_type == KVM_X86_DEFAULT_VM &&
+ kvm_check_has_quirk(kvm, KVM_X86_QUIRK_SLOT_ZAP_ALL);
+}
+
void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
struct kvm_memory_slot *slot)
{
- kvm_mmu_zap_all_fast(kvm);
+ if (kvm_memslot_flush_zap_all(kvm))
+ kvm_mmu_zap_all_fast(kvm);
+ else
+ kvm_mmu_zap_memslot_leafs(kvm, slot);
}
void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen)
diff --git a/tools/testing/selftests/kvm/memslot_modification_stress_test.c b/tools/testing/selftests/kvm/memslot_modification_stress_test.c
index 49f162573126..e3343f0df9e1 100644
--- a/tools/testing/selftests/kvm/memslot_modification_stress_test.c
+++ b/tools/testing/selftests/kvm/memslot_modification_stress_test.c
@@ -79,6 +79,7 @@ struct test_params {
useconds_t delay;
uint64_t nr_iterations;
bool partition_vcpu_memory_access;
+ bool disable_slot_zap_quirk;
};
static void run_test(enum vm_guest_mode mode, void *arg)
@@ -89,6 +90,13 @@ static void run_test(enum vm_guest_mode mode, void *arg)
vm = memstress_create_vm(mode, nr_vcpus, guest_percpu_mem_size, 1,
VM_MEM_SRC_ANONYMOUS,
p->partition_vcpu_memory_access);
+#ifdef __x86_64__
+ if (p->disable_slot_zap_quirk)
+ vm_enable_cap(vm, KVM_CAP_DISABLE_QUIRKS2, KVM_X86_QUIRK_SLOT_ZAP_ALL);
+
+ pr_info("Memslot zap quirk %s\n", p->disable_slot_zap_quirk ?
+ "disabled" : "enabled");
+#endif
pr_info("Finished creating vCPUs\n");
@@ -107,11 +115,12 @@ static void run_test(enum vm_guest_mode mode, void *arg)
static void help(char *name)
{
puts("");
- printf("usage: %s [-h] [-m mode] [-d delay_usec]\n"
+ printf("usage: %s [-h] [-m mode] [-d delay_usec] [-q]\n"
" [-b memory] [-v vcpus] [-o] [-i iterations]\n", name);
guest_modes_help();
printf(" -d: add a delay between each iteration of adding and\n"
" deleting a memslot in usec.\n");
+ printf(" -q: Disable memslot zap quirk.\n");
printf(" -b: specify the size of the memory region which should be\n"
" accessed by each vCPU. e.g. 10M or 3G.\n"
" Default: 1G\n");
@@ -137,7 +146,7 @@ int main(int argc, char *argv[])
guest_modes_append_default();
- while ((opt = getopt(argc, argv, "hm:d:b:v:oi:")) != -1) {
+ while ((opt = getopt(argc, argv, "hm:d:qb:v:oi:")) != -1) {
switch (opt) {
case 'm':
guest_modes_cmdline(optarg);
@@ -160,6 +169,12 @@ int main(int argc, char *argv[])
case 'i':
p.nr_iterations = atoi_positive("Number of iterations", optarg);
break;
+ case 'q':
+ p.disable_slot_zap_quirk = true;
+
+ TEST_REQUIRE(kvm_check_cap(KVM_CAP_DISABLE_QUIRKS2) &
+ KVM_X86_QUIRK_SLOT_ZAP_ALL);
+ break;
case 'h':
default:
help(argv[0]);
diff --git a/tools/testing/selftests/kvm/memslot_perf_test.c b/tools/testing/selftests/kvm/memslot_perf_test.c
index 579a64f97333..893366982f77 100644
--- a/tools/testing/selftests/kvm/memslot_perf_test.c
+++ b/tools/testing/selftests/kvm/memslot_perf_test.c
@@ -113,6 +113,7 @@ static_assert(ATOMIC_BOOL_LOCK_FREE == 2, "atomic bool is not lockless");
static sem_t vcpu_ready;
static bool map_unmap_verify;
+static bool disable_slot_zap_quirk;
static bool verbose;
#define pr_info_v(...) \
@@ -578,6 +579,9 @@ static bool test_memslot_move_prepare(struct vm_data *data,
uint32_t guest_page_size = data->vm->page_size;
uint64_t movesrcgpa, movetestgpa;
+ if (disable_slot_zap_quirk)
+ vm_enable_cap(data->vm, KVM_CAP_DISABLE_QUIRKS2, KVM_X86_QUIRK_SLOT_ZAP_ALL);
+
movesrcgpa = vm_slot2gpa(data, data->nslots - 1);
if (isactive) {
@@ -896,6 +900,7 @@ static void help(char *name, struct test_args *targs)
pr_info(" -h: print this help screen.\n");
pr_info(" -v: enable verbose mode (not for benchmarking).\n");
pr_info(" -d: enable extra debug checks.\n");
+ pr_info(" -q: Disable memslot zap quirk during memslot move.\n");
pr_info(" -s: specify memslot count cap (-1 means no cap; currently: %i)\n",
targs->nslots);
pr_info(" -f: specify the first test to run (currently: %i; max %zu)\n",
@@ -954,7 +959,7 @@ static bool parse_args(int argc, char *argv[],
uint32_t max_mem_slots;
int opt;
- while ((opt = getopt(argc, argv, "hvds:f:e:l:r:")) != -1) {
+ while ((opt = getopt(argc, argv, "hvdqs:f:e:l:r:")) != -1) {
switch (opt) {
case 'h':
default:
@@ -966,6 +971,11 @@ static bool parse_args(int argc, char *argv[],
case 'd':
map_unmap_verify = true;
break;
+ case 'q':
+ disable_slot_zap_quirk = true;
+ TEST_REQUIRE(kvm_check_cap(KVM_CAP_DISABLE_QUIRKS2) &
+ KVM_X86_QUIRK_SLOT_ZAP_ALL);
+ break;
case 's':
targs->nslots = atoi_paranoid(optarg);
if (targs->nslots <= 1 && targs->nslots != -1) {
diff --git a/tools/testing/selftests/kvm/set_memory_region_test.c b/tools/testing/selftests/kvm/set_memory_region_test.c
index bb8002084f52..a8267628e9ed 100644
--- a/tools/testing/selftests/kvm/set_memory_region_test.c
+++ b/tools/testing/selftests/kvm/set_memory_region_test.c
@@ -175,7 +175,7 @@ static void guest_code_move_memory_region(void)
GUEST_DONE();
}
-static void test_move_memory_region(void)
+static void test_move_memory_region(bool disable_slot_zap_quirk)
{
pthread_t vcpu_thread;
struct kvm_vcpu *vcpu;
@@ -184,6 +184,9 @@ static void test_move_memory_region(void)
vm = spawn_vm(&vcpu, &vcpu_thread, guest_code_move_memory_region);
+ if (disable_slot_zap_quirk)
+ vm_enable_cap(vm, KVM_CAP_DISABLE_QUIRKS2, KVM_X86_QUIRK_SLOT_ZAP_ALL);
+
hva = addr_gpa2hva(vm, MEM_REGION_GPA);
/*
@@ -266,7 +269,7 @@ static void guest_code_delete_memory_region(void)
GUEST_ASSERT(0);
}
-static void test_delete_memory_region(void)
+static void test_delete_memory_region(bool disable_slot_zap_quirk)
{
pthread_t vcpu_thread;
struct kvm_vcpu *vcpu;
@@ -276,6 +279,9 @@ static void test_delete_memory_region(void)
vm = spawn_vm(&vcpu, &vcpu_thread, guest_code_delete_memory_region);
+ if (disable_slot_zap_quirk)
+ vm_enable_cap(vm, KVM_CAP_DISABLE_QUIRKS2, KVM_X86_QUIRK_SLOT_ZAP_ALL);
+
/* Delete the memory region, the guest should not die. */
vm_mem_region_delete(vm, MEM_REGION_SLOT);
wait_for_vcpu();
@@ -553,7 +559,10 @@ int main(int argc, char *argv[])
{
#ifdef __x86_64__
int i, loops;
+ int j, disable_slot_zap_quirk = 0;
+ if (kvm_check_cap(KVM_CAP_DISABLE_QUIRKS2) & KVM_X86_QUIRK_SLOT_ZAP_ALL)
+ disable_slot_zap_quirk = 1;
/*
* FIXME: the zero-memslot test fails on aarch64 and s390x because
* KVM_RUN fails with ENOEXEC or EFAULT.
@@ -579,13 +588,17 @@ int main(int argc, char *argv[])
else
loops = 10;
- pr_info("Testing MOVE of in-use region, %d loops\n", loops);
- for (i = 0; i < loops; i++)
- test_move_memory_region();
+ for (j = 0; j <= disable_slot_zap_quirk; j++) {
+ pr_info("Testing MOVE of in-use region, %d loops, slot zap quirk %s\n",
+ loops, j ? "disabled" : "enabled");
+ for (i = 0; i < loops; i++)
+ test_move_memory_region(!!j);
- pr_info("Testing DELETE of in-use region, %d loops\n", loops);
- for (i = 0; i < loops; i++)
- test_delete_memory_region();
+ pr_info("Testing DELETE of in-use region, %d loops, slot zap quirk %s\n",
+ loops, j ? "disabled" : "enabled");
+ for (i = 0; i < loops; i++)
+ test_delete_memory_region(!!j);
+ }
#endif
return 0;
generated by cgit v1.2.3 (git 2.46.0) at 2025-07-31 14:29:08 +0000