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2024-06-03KVM: SEV-ES: Delegate LBR virtualization to the processorRavi Bangoria
As documented in APM[1], LBR Virtualization must be enabled for SEV-ES guests. Although KVM currently enforces LBRV for SEV-ES guests, there are multiple issues with it: o MSR_IA32_DEBUGCTLMSR is still intercepted. Since MSR_IA32_DEBUGCTLMSR interception is used to dynamically toggle LBRV for performance reasons, this can be fatal for SEV-ES guests. For ex SEV-ES guest on Zen3: [guest ~]# wrmsr 0x1d9 0x4 KVM: entry failed, hardware error 0xffffffff EAX=00000004 EBX=00000000 ECX=000001d9 EDX=00000000 Fix this by never intercepting MSR_IA32_DEBUGCTLMSR for SEV-ES guests. No additional save/restore logic is required since MSR_IA32_DEBUGCTLMSR is of swap type A. o KVM will disable LBRV if userspace sets MSR_IA32_DEBUGCTLMSR before the VMSA is encrypted. Fix this by moving LBRV enablement code post VMSA encryption. [1]: AMD64 Architecture Programmer's Manual Pub. 40332, Rev. 4.07 - June 2023, Vol 2, 15.35.2 Enabling SEV-ES. https://bugzilla.kernel.org/attachment.cgi?id=304653 Fixes: 376c6d285017 ("KVM: SVM: Provide support for SEV-ES vCPU creation/loading") Co-developed-by: Nikunj A Dadhania <nikunj@amd.com> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com> Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com> Message-ID: <20240531044644.768-4-ravi.bangoria@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-03KVM: SEV-ES: Disallow SEV-ES guests when X86_FEATURE_LBRV is absentRavi Bangoria
As documented in APM[1], LBR Virtualization must be enabled for SEV-ES guests. So, prevent SEV-ES guests when LBRV support is missing. [1]: AMD64 Architecture Programmer's Manual Pub. 40332, Rev. 4.07 - June 2023, Vol 2, 15.35.2 Enabling SEV-ES. https://bugzilla.kernel.org/attachment.cgi?id=304653 Fixes: 376c6d285017 ("KVM: SVM: Provide support for SEV-ES vCPU creation/loading") Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com> Message-ID: <20240531044644.768-3-ravi.bangoria@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-03KVM: SEV-ES: Prevent MSR access post VMSA encryptionNikunj A Dadhania
KVM currently allows userspace to read/write MSRs even after the VMSA is encrypted. This can cause unintentional issues if MSR access has side- effects. For ex, while migrating a guest, userspace could attempt to migrate MSR_IA32_DEBUGCTLMSR and end up unintentionally disabling LBRV on the target. Fix this by preventing access to those MSRs which are context switched via the VMSA, once the VMSA is encrypted. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com> Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com> Message-ID: <20240531044644.768-2-ravi.bangoria@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-05-23KVM: SVM: WARN on vNMI + NMI window iff NMIs are outright maskedSean Christopherson
When requesting an NMI window, WARN on vNMI support being enabled if and only if NMIs are actually masked, i.e. if the vCPU is already handling an NMI. KVM's ABI for NMIs that arrive simultanesouly (from KVM's point of view) is to inject one NMI and pend the other. When using vNMI, KVM pends the second NMI simply by setting V_NMI_PENDING, and lets the CPU do the rest (hardware automatically sets V_NMI_BLOCKING when an NMI is injected). However, if KVM can't immediately inject an NMI, e.g. because the vCPU is in an STI shadow or is running with GIF=0, then KVM will request an NMI window and trigger the WARN (but still function correctly). Whether or not the GIF=0 case makes sense is debatable, as the intent of KVM's behavior is to provide functionality that is as close to real hardware as possible. E.g. if two NMIs are sent in quick succession, the probability of both NMIs arriving in an STI shadow is infinitesimally low on real hardware, but significantly larger in a virtual environment, e.g. if the vCPU is preempted in the STI shadow. For GIF=0, the argument isn't as clear cut, because the window where two NMIs can collide is much larger in bare metal (though still small). That said, KVM should not have divergent behavior for the GIF=0 case based on whether or not vNMI support is enabled. And KVM has allowed simultaneous NMIs with GIF=0 for over a decade, since commit 7460fb4a3400 ("KVM: Fix simultaneous NMIs"). I.e. KVM's GIF=0 handling shouldn't be modified without a *really* good reason to do so, and if KVM's behavior were to be modified, it should be done irrespective of vNMI support. Fixes: fa4c027a7956 ("KVM: x86: Add support for SVM's Virtual NMI") Cc: stable@vger.kernel.org Cc: Santosh Shukla <Santosh.Shukla@amd.com> Cc: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-ID: <20240522021435.1684366-1-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-05-10Merge tag 'loongarch-kvm-6.10' of ↵Paolo Bonzini
git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson into HEAD LoongArch KVM changes for v6.10 1. Add ParaVirt IPI support. 2. Add software breakpoint support. 3. Add mmio trace events support.
2024-05-10Merge branch 'kvm-sev-es-ghcbv2' into HEADPaolo Bonzini
While the main additions from GHCB protocol version 1 to version 2 revolve mostly around SEV-SNP support, there are a number of changes applicable to SEV-ES guests as well. Pluck a handful patches from the SNP hypervisor patchset for GHCB-related changes that are also applicable to SEV-ES. A KVM_SEV_INIT2 field lets userspace can control the maximum GHCB protocol version advertised to guests and manage compatibility across kernels/versions.
2024-05-07KVM: SEV: Allow per-guest configuration of GHCB protocol versionMichael Roth
The GHCB protocol version may be different from one guest to the next. Add a field to track it for each KVM instance and extend KVM_SEV_INIT2 to allow it to be configured by userspace. Now that all SEV-ES support for GHCB protocol version 2 is in place, go ahead and default to it when creating SEV-ES guests through the new KVM_SEV_INIT2 interface. Keep the older KVM_SEV_ES_INIT interface restricted to GHCB protocol version 1. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Michael Roth <michael.roth@amd.com> Message-ID: <20240501071048.2208265-5-michael.roth@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-05-07KVM: SEV: Add GHCB handling for termination requestsMichael Roth
GHCB version 2 adds support for a GHCB-based termination request that a guest can issue when it reaches an error state and wishes to inform the hypervisor that it should be terminated. Implement support for that similarly to GHCB MSR-based termination requests that are already available to SEV-ES guests via earlier versions of the GHCB protocol. See 'Termination Request' in the 'Invoking VMGEXIT' section of the GHCB specification for more details. Signed-off-by: Michael Roth <michael.roth@amd.com> Message-ID: <20240501071048.2208265-4-michael.roth@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-05-07KVM: SEV: Add GHCB handling for Hypervisor Feature Support requestsBrijesh Singh
Version 2 of the GHCB specification introduced advertisement of features that are supported by the Hypervisor. Now that KVM supports version 2 of the GHCB specification, bump the maximum supported protocol version. Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com> Signed-off-by: Michael Roth <michael.roth@amd.com> Message-ID: <20240501071048.2208265-3-michael.roth@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-05-07KVM: SEV: Add support to handle AP reset MSR protocolTom Lendacky
Add support for AP Reset Hold being invoked using the GHCB MSR protocol, available in version 2 of the GHCB specification. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com> Signed-off-by: Michael Roth <michael.roth@amd.com> Message-ID: <20240501071048.2208265-2-michael.roth@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-05-07KVM: x86: Move synthetic PFERR_* sanity checks to SVM's #NPF handlerSean Christopherson
Move the sanity check that hardware never sets bits that collide with KVM- define synthetic bits from kvm_mmu_page_fault() to npf_interception(), i.e. make the sanity check #NPF specific. The legacy #PF path already WARNs if _any_ of bits 63:32 are set, and the error code that comes from VMX's EPT Violatation and Misconfig is 100% synthesized (KVM morphs VMX's EXIT_QUALIFICATION into error code flags). Add a compile-time assert in the legacy #PF handler to make sure that KVM- define flags are covered by its existing sanity check on the upper bits. Opportunistically add a description of PFERR_IMPLICIT_ACCESS, since we are removing the comment that defined it. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Kai Huang <kai.huang@intel.com> Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com> Message-ID: <20240228024147.41573-8-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-04-19Merge x86 bugfixes from Linux 6.9-rc3Paolo Bonzini
Pull fix for SEV-SNP late disable bugs. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-04-12KVM: SEV: use u64_to_user_ptr throughoutPaolo Bonzini
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-04-11KVM: SEV: allow SEV-ES DebugSwap againPaolo Bonzini
The DebugSwap feature of SEV-ES provides a way for confidential guests to use data breakpoints. Its status is record in VMSA, and therefore attestation signatures depend on whether it is enabled or not. In order to avoid invalidating the signatures depending on the host machine, it was disabled by default (see commit 5abf6dceb066, "SEV: disable SEV-ES DebugSwap by default", 2024-03-09). However, we now have a new API to create SEV VMs that allows enabling DebugSwap based on what the user tells KVM to do, and we also changed the legacy KVM_SEV_ES_INIT API to never enable DebugSwap. It is therefore possible to re-enable the feature without breaking compatibility with kernels that pre-date the introduction of DebugSwap, so go ahead. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-ID: <20240404121327.3107131-14-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-04-11KVM: SEV: introduce KVM_SEV_INIT2 operationPaolo Bonzini
The idea that no parameter would ever be necessary when enabling SEV or SEV-ES for a VM was decidedly optimistic. In fact, in some sense it's already a parameter whether SEV or SEV-ES is desired. Another possible source of variability is the desired set of VMSA features, as that affects the measurement of the VM's initial state and cannot be changed arbitrarily by the hypervisor. Create a new sub-operation for KVM_MEMORY_ENCRYPT_OP that can take a struct, and put the new op to work by including the VMSA features as a field of the struct. The existing KVM_SEV_INIT and KVM_SEV_ES_INIT use the full set of supported VMSA features for backwards compatibility. The struct also includes the usual bells and whistles for future extensibility: a flags field that must be zero for now, and some padding at the end. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-ID: <20240404121327.3107131-13-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-04-11KVM: SEV: sync FPU and AVX state at LAUNCH_UPDATE_VMSA timePaolo Bonzini
SEV-ES allows passing custom contents for x87, SSE and AVX state into the VMSA. Allow userspace to do that with the usual KVM_SET_XSAVE API and only mark FPU contents as confidential after it has been copied and encrypted into the VMSA. Since the XSAVE state for AVX is the first, it does not need the compacted-state handling of get_xsave_addr(). However, there are other parts of XSAVE state in the VMSA that currently are not handled, and the validation logic of get_xsave_addr() is pointless to duplicate in KVM, so move get_xsave_addr() to public FPU API; it is really just a facility to operate on XSAVE state and does not expose any internal details of arch/x86/kernel/fpu. Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-ID: <20240404121327.3107131-12-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-04-11KVM: SEV: define VM types for SEV and SEV-ESPaolo Bonzini
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-ID: <20240404121327.3107131-11-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-04-11KVM: SEV: introduce to_kvm_sev_infoPaolo Bonzini
Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-ID: <20240404121327.3107131-10-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-04-11KVM: SEV: store VMSA features in kvm_sev_infoPaolo Bonzini
Right now, the set of features that are stored in the VMSA upon initialization is fixed and depends on the module parameters for kvm-amd.ko. However, the hypervisor cannot really change it at will because the feature word has to match between the hypervisor and whatever computes a measurement of the VMSA for attestation purposes. Add a field to kvm_sev_info that holds the set of features to be stored in the VMSA; and query it instead of referring to the module parameters. Because KVM_SEV_INIT and KVM_SEV_ES_INIT accept no parameters, this does not yet introduce any functional change, but it paves the way for an API that allows customization of the features per-VM. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20240209183743.22030-6-pbonzini@redhat.com> Reviewed-by: Michael Roth <michael.roth@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-ID: <20240404121327.3107131-7-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-04-11KVM: SEV: publish supported VMSA featuresPaolo Bonzini
Compute the set of features to be stored in the VMSA when KVM is initialized; move it from there into kvm_sev_info when SEV is initialized, and then into the initial VMSA. The new variable can then be used to return the set of supported features to userspace, via the KVM_GET_DEVICE_ATTR ioctl. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com> Message-ID: <20240404121327.3107131-6-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-04-11KVM: SVM: Compile sev.c if and only if CONFIG_KVM_AMD_SEV=yPaolo Bonzini
Stop compiling sev.c when CONFIG_KVM_AMD_SEV=n, as the number of #ifdefs in sev.c is getting ridiculous, and having #ifdefs inside of SEV helpers is quite confusing. To minimize #ifdefs in code flows, #ifdef away only the kvm_x86_ops hooks and the #VMGEXIT handler. Stubs are also restricted to functions that check sev_enabled and to the destruction functions sev_free_cpu() and sev_vm_destroy(), where the style of their callers is to leave checks to the callers. Most call sites instead rely on dead code elimination to take care of functions that are guarded with sev_guest() or sev_es_guest(). Signed-off-by: Sean Christopherson <seanjc@google.com> Co-developed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-ID: <20240404121327.3107131-3-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-04-11KVM: SVM: Invert handling of SEV and SEV_ES feature flagsSean Christopherson
Leave SEV and SEV_ES '0' in kvm_cpu_caps by default, and instead set them in sev_set_cpu_caps() if SEV and SEV-ES support are fully enabled. Aside from the fact that sev_set_cpu_caps() is wildly misleading when it *clears* capabilities, this will allow compiling out sev.c without falsely advertising SEV/SEV-ES support in KVM_GET_SUPPORTED_CPUID. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Michael Roth <michael.roth@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-ID: <20240404121327.3107131-2-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-04-09KVM: SVM: Create a stack frame in __svm_sev_es_vcpu_run()Sean Christopherson
Now that KVM uses the host save area to context switch RBP, i.e. preserves RBP for the entirety of __svm_sev_es_vcpu_run(), create a stack frame using the standared FRAME_{BEGIN,END} macros. Note, __svm_sev_es_vcpu_run() is subtly not a leaf function as it can call into ibpb_feature() via UNTRAIN_RET_VM. Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20240223204233.3337324-8-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-04-09KVM: SVM: Save/restore args across SEV-ES VMRUN via host save areaSean Christopherson
Use the host save area to preserve volatile registers that are used in __svm_sev_es_vcpu_run() to access function parameters after #VMEXIT. Like saving/restoring non-volatile registers, there's no reason not to take advantage of hardware restoring registers on #VMEXIT, as doing so shaves a few instructions and the save area is going to be accessed no matter what. Converting all register save/restore code to use the host save area also make it easier to follow the SEV-ES VMRUN flow in its entirety, as opposed to having a mix of stack-based versus host save area save/restore. Add a parameter to RESTORE_HOST_SPEC_CTRL_BODY so that the SEV-ES path doesn't need to write @spec_ctrl_intercepted to memory just to play nice with the common macro. Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20240223204233.3337324-7-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-04-09KVM: SVM: Save/restore non-volatile GPRs in SEV-ES VMRUN via host save areaSean Christopherson
Use the host save area to save/restore non-volatile (callee-saved) registers in __svm_sev_es_vcpu_run() to take advantage of hardware loading all registers from the save area on #VMEXIT. KVM still needs to save the registers it wants restored, but the loads are handled automatically by hardware. Aside from less assembly code, letting hardware do the restoration means stack frames are preserved for the entirety of __svm_sev_es_vcpu_run(). Opportunistically add a comment to call out why @svm needs to be saved across VMRUN->#VMEXIT, as it's not easy to decipher that from the macro hell. Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Michael Roth <michael.roth@amd.com> Cc: Alexey Kardashevskiy <aik@amd.com> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20240223204233.3337324-6-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-04-09KVM: SVM: Clobber RAX instead of RBX when discarding spec_ctrl_interceptedSean Christopherson
POP @spec_ctrl_intercepted into RAX instead of RBX when discarding it from the stack so that __svm_sev_es_vcpu_run() doesn't modify any non-volatile registers. __svm_sev_es_vcpu_run() doesn't return a value, and RAX is already are clobbered multiple times in the #VMEXIT path. This will allowing using the host save area to save/restore non-volatile registers in __svm_sev_es_vcpu_run(). Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20240223204233.3337324-5-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-04-09KVM: SVM: Drop 32-bit "support" from __svm_sev_es_vcpu_run()Sean Christopherson
Drop 32-bit "support" from __svm_sev_es_vcpu_run(), as SEV/SEV-ES firmly 64-bit only. The "support" was purely the result of bad copy+paste from __svm_vcpu_run(), which in turn was slightly less bad copy+paste from __vmx_vcpu_run(). Opportunistically convert to unadulterated register accesses so that it's easier (but still not easy) to follow which registers hold what arguments, and when. Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20240223204233.3337324-4-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-04-09KVM: SVM: Wrap __svm_sev_es_vcpu_run() with #ifdef CONFIG_KVM_AMD_SEVSean Christopherson
Compile (and link) __svm_sev_es_vcpu_run() if and only if SEV support is actually enabled. This will allow dropping non-existent 32-bit "support" from __svm_sev_es_vcpu_run() without causing undue confusion. Intentionally don't provide a stub (but keep the declaration), as any sane compiler, even with things like KASAN enabled, should eliminate the call to __svm_sev_es_vcpu_run() since sev_es_guest() unconditionally returns "false" if CONFIG_KVM_AMD_SEV=n. Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20240223204233.3337324-3-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-04-09KVM: SVM: Create a stack frame in __svm_vcpu_run() for unwindingSean Christopherson
Unconditionally create a stack frame in __svm_vcpu_run() to play nice with unwinding via frame pointers, at least until the point where RBP is loaded with the guest's value. Don't bother conditioning the code on CONFIG_FRAME_POINTER=y, as RBP needs to be saved and restored anyways (due to it being clobbered with the guest's value); omitting the "MOV RSP, RBP" is not worth the extra #ifdef. Creating a stack frame will allow removing the OBJECT_FILES_NON_STANDARD tag from vmenter.S once __svm_sev_es_vcpu_run() is fixed to not stomp all over RBP for no reason. Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20240223204233.3337324-2-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-04-09KVM: SVM: Remove a useless zeroing of allocated memoryChristophe JAILLET
Remove KVM's unnecessary zeroing of memory when allocating the pages array in sev_pin_memory() via __vmalloc(), as the array is only used to hold kernel pointers. The kmalloc() path for "small" regions doesn't zero the array, and if KVM leaks state and/or accesses uninitialized data, then the kernel has bigger problems. Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Link: https://lore.kernel.org/r/c7619a3d3cbb36463531a7c73ccbde9db587986c.1710004509.git.christophe.jaillet@wanadoo.fr [sean: massage changelog] Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-04-06Merge branch 'linus' into x86/urgent, to pick up dependent commitIngo Molnar
We want to fix: 0e110732473e ("x86/retpoline: Do the necessary fixup to the Zen3/4 srso return thunk for !SRSO") So merge in Linus's latest into x86/urgent to have it available. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2024-04-04x86/CPU/AMD: Track SNP host status with cc_platform_*()Borislav Petkov (AMD)
The host SNP worthiness can determined later, after alternatives have been patched, in snp_rmptable_init() depending on cmdline options like iommu=pt which is incompatible with SNP, for example. Which means that one cannot use X86_FEATURE_SEV_SNP and will need to have a special flag for that control. Use that newly added CC_ATTR_HOST_SEV_SNP in the appropriate places. Move kdump_sev_callback() to its rightful place, while at it. Fixes: 216d106c7ff7 ("x86/sev: Add SEV-SNP host initialization support") Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Tested-by: Srikanth Aithal <sraithal@amd.com> Link: https://lore.kernel.org/r/20240327154317.29909-6-bp@alien8.de
2024-03-18Merge tag 'kvm-x86-svm-6.9' of https://github.com/kvm-x86/linux into HEADPaolo Bonzini
KVM SVM changes for 6.9: - Add support for systems that are configured with SEV and SEV-ES+ enabled, but have all ASIDs assigned to SEV-ES+ guests, which effectively makes SEV unusuable. Cleanup ASID handling to make supporting this scenario less brittle/ugly. - Return -EINVAL instead of -EBUSY if userspace attempts to invoke KVM_SEV{,ES}_INIT on an SEV+ guest. The operation is simply invalid, and not related to resource contention in any way.
2024-03-15Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull kvm updates from Paolo Bonzini: "S390: - Changes to FPU handling came in via the main s390 pull request - Only deliver to the guest the SCLP events that userspace has requested - More virtual vs physical address fixes (only a cleanup since virtual and physical address spaces are currently the same) - Fix selftests undefined behavior x86: - Fix a restriction that the guest can't program a PMU event whose encoding matches an architectural event that isn't included in the guest CPUID. 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 event *in general*. It might support it, and it might support it using the same encoding that made it into the architectural PMU spec - Fix a variety of bugs in KVM's emulation of RDPMC (more details on individual commits) and add a selftest to verify KVM correctly emulates RDMPC, counter availability, and a variety of other PMC-related behaviors that depend on guest CPUID and therefore are easier to validate with selftests than with custom guests (aka kvm-unit-tests) - Zero out PMU state on AMD if the virtual PMU is disabled, it does not cause any bug but it wastes time in various cases where KVM would check if a PMC event needs to be synthesized - Optimize triggering of emulated events, with a nice ~10% performance improvement in VM-Exit microbenchmarks when a vPMU is exposed to the guest - Tighten the check for "PMI in guest" to reduce false positives if an NMI arrives in the host while KVM is handling an IRQ VM-Exit - Fix a bug where KVM would report stale/bogus exit qualification information when exiting to userspace with an internal error exit code - Add a VMX flag in /proc/cpuinfo to report 5-level EPT support - Rework TDP MMU root unload, free, and alloc to run with mmu_lock held for read, e.g. to avoid serializing vCPUs when userspace deletes a memslot - Tear down TDP MMU page tables at 4KiB granularity (used to be 1GiB). KVM doesn't support yielding in the middle of processing a zap, and 1GiB granularity resulted in multi-millisecond lags that are quite impolite for CONFIG_PREEMPT kernels - Allocate write-tracking metadata on-demand to avoid the memory overhead when a kernel is built with i915 virtualization support but the workloads use neither shadow paging nor i915 virtualization - Explicitly initialize a variety of on-stack variables in the emulator that triggered KMSAN false positives - Fix the debugregs ABI for 32-bit KVM - Rework the "force immediate exit" code so that vendor code ultimately decides how and when to force the exit, which allowed some optimization for both Intel and AMD - Fix a long-standing bug where kvm_has_noapic_vcpu could be left elevated if vCPU creation ultimately failed, causing extra unnecessary work - Cleanup the logic for checking if the currently loaded vCPU is in-kernel - Harden against underflowing the active mmu_notifier invalidation count, so that "bad" invalidations (usually due to bugs elsehwere in the kernel) are detected earlier and are less likely to hang the kernel x86 Xen emulation: - Overlay pages can now be cached based on host virtual address, instead of guest physical addresses. This removes the need to reconfigure and invalidate the cache if the guest changes the gpa but the underlying host virtual address remains the same - When possible, use a single host TSC value when computing the deadline for Xen timers in order to improve the accuracy of the timer emulation - Inject pending upcall events when the vCPU software-enables its APIC to fix a bug where an upcall can be lost (and to follow Xen's behavior) - Fall back to the slow path instead of warning if "fast" IRQ delivery of Xen events fails, e.g. if the guest has aliased xAPIC IDs RISC-V: - Support exception and interrupt handling in selftests - New self test for RISC-V architectural timer (Sstc extension) - New extension support (Ztso, Zacas) - Support userspace emulation of random number seed CSRs ARM: - Infrastructure for building KVM's trap configuration based on the architectural features (or lack thereof) advertised in the VM's ID registers - Support for mapping vfio-pci BARs as Normal-NC (vaguely similar to x86's WC) at stage-2, improving the performance of interacting with assigned devices that can tolerate it - Conversion of KVM's representation of LPIs to an xarray, utilized to address serialization some of the serialization on the LPI injection path - Support for _architectural_ VHE-only systems, advertised through the absence of FEAT_E2H0 in the CPU's ID register - Miscellaneous cleanups, fixes, and spelling corrections to KVM and selftests LoongArch: - Set reserved bits as zero in CPUCFG - Start SW timer only when vcpu is blocking - Do not restart SW timer when it is expired - Remove unnecessary CSR register saving during enter guest - Misc cleanups and fixes as usual Generic: - Clean up Kconfig by removing CONFIG_HAVE_KVM, which was basically always true on all architectures except MIPS (where Kconfig determines the available depending on CPU capabilities). It is replaced either by an architecture-dependent symbol for MIPS, and IS_ENABLED(CONFIG_KVM) everywhere else - Factor common "select" statements in common code instead of requiring each architecture to specify it - Remove thoroughly obsolete APIs from the uapi headers - Move architecture-dependent stuff to uapi/asm/kvm.h - Always flush the async page fault workqueue when a work item is being removed, especially during vCPU destruction, to ensure that there are no workers running in KVM code when all references to KVM-the-module are gone, i.e. to prevent a very unlikely use-after-free if kvm.ko is unloaded - Grab a reference to the VM's mm_struct in the async #PF worker itself instead of gifting the worker a reference, so that there's no need to remember to *conditionally* clean up after the worker Selftests: - Reduce boilerplate especially when utilize selftest TAP infrastructure - Add basic smoke tests for SEV and SEV-ES, along with a pile of library support for handling private/encrypted/protected memory - Fix benign bugs where tests neglect to close() guest_memfd files" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (246 commits) selftests: kvm: remove meaningless assignments in Makefiles KVM: riscv: selftests: Add Zacas extension to get-reg-list test RISC-V: KVM: Allow Zacas extension for Guest/VM KVM: riscv: selftests: Add Ztso extension to get-reg-list test RISC-V: KVM: Allow Ztso extension for Guest/VM RISC-V: KVM: Forward SEED CSR access to user space KVM: riscv: selftests: Add sstc timer test KVM: riscv: selftests: Change vcpu_has_ext to a common function KVM: riscv: selftests: Add guest helper to get vcpu id KVM: riscv: selftests: Add exception handling support LoongArch: KVM: Remove unnecessary CSR register saving during enter guest LoongArch: KVM: Do not restart SW timer when it is expired LoongArch: KVM: Start SW timer only when vcpu is blocking LoongArch: KVM: Set reserved bits as zero in CPUCFG KVM: selftests: Explicitly close guest_memfd files in some gmem tests KVM: x86/xen: fix recursive deadlock in timer injection KVM: pfncache: simplify locking and make more self-contained KVM: x86/xen: remove WARN_ON_ONCE() with false positives in evtchn delivery KVM: x86/xen: inject vCPU upcall vector when local APIC is enabled KVM: x86/xen: improve accuracy of Xen timers ...
2024-03-11Merge tag 'x86-core-2024-03-11' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull core x86 updates from Ingo Molnar: - The biggest change is the rework of the percpu code, to support the 'Named Address Spaces' GCC feature, by Uros Bizjak: - This allows C code to access GS and FS segment relative memory via variables declared with such attributes, which allows the compiler to better optimize those accesses than the previous inline assembly code. - The series also includes a number of micro-optimizations for various percpu access methods, plus a number of cleanups of %gs accesses in assembly code. - These changes have been exposed to linux-next testing for the last ~5 months, with no known regressions in this area. - Fix/clean up __switch_to()'s broken but accidentally working handling of FPU switching - which also generates better code - Propagate more RIP-relative addressing in assembly code, to generate slightly better code - Rework the CPU mitigations Kconfig space to be less idiosyncratic, to make it easier for distros to follow & maintain these options - Rework the x86 idle code to cure RCU violations and to clean up the logic - Clean up the vDSO Makefile logic - Misc cleanups and fixes * tag 'x86-core-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits) x86/idle: Select idle routine only once x86/idle: Let prefer_mwait_c1_over_halt() return bool x86/idle: Cleanup idle_setup() x86/idle: Clean up idle selection x86/idle: Sanitize X86_BUG_AMD_E400 handling sched/idle: Conditionally handle tick broadcast in default_idle_call() x86: Increase brk randomness entropy for 64-bit systems x86/vdso: Move vDSO to mmap region x86/vdso/kbuild: Group non-standard build attributes and primary object file rules together x86/vdso: Fix rethunk patching for vdso-image-{32,64}.o x86/retpoline: Ensure default return thunk isn't used at runtime x86/vdso: Use CONFIG_COMPAT_32 to specify vdso32 x86/vdso: Use $(addprefix ) instead of $(foreach ) x86/vdso: Simplify obj-y addition x86/vdso: Consolidate targets and clean-files x86/bugs: Rename CONFIG_RETHUNK => CONFIG_MITIGATION_RETHUNK x86/bugs: Rename CONFIG_CPU_SRSO => CONFIG_MITIGATION_SRSO x86/bugs: Rename CONFIG_CPU_IBRS_ENTRY => CONFIG_MITIGATION_IBRS_ENTRY x86/bugs: Rename CONFIG_CPU_UNRET_ENTRY => CONFIG_MITIGATION_UNRET_ENTRY x86/bugs: Rename CONFIG_SLS => CONFIG_MITIGATION_SLS ...
2024-03-11Merge tag 'x86_sev_for_v6.9_rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 SEV updates from Borislav Petkov: - Add the x86 part of the SEV-SNP host support. This will allow the kernel to be used as a KVM hypervisor capable of running SNP (Secure Nested Paging) guests. Roughly speaking, SEV-SNP is the ultimate goal of the AMD confidential computing side, providing the most comprehensive confidential computing environment up to date. This is the x86 part and there is a KVM part which did not get ready in time for the merge window so latter will be forthcoming in the next cycle. - Rework the early code's position-dependent SEV variable references in order to allow building the kernel with clang and -fPIE/-fPIC and -mcmodel=kernel - The usual set of fixes, cleanups and improvements all over the place * tag 'x86_sev_for_v6.9_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits) x86/sev: Disable KMSAN for memory encryption TUs x86/sev: Dump SEV_STATUS crypto: ccp - Have it depend on AMD_IOMMU iommu/amd: Fix failure return from snp_lookup_rmpentry() x86/sev: Fix position dependent variable references in startup code crypto: ccp: Make snp_range_list static x86/Kconfig: Remove CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT Documentation: virt: Fix up pre-formatted text block for SEV ioctls crypto: ccp: Add the SNP_SET_CONFIG command crypto: ccp: Add the SNP_COMMIT command crypto: ccp: Add the SNP_PLATFORM_STATUS command x86/cpufeatures: Enable/unmask SEV-SNP CPU feature KVM: SEV: Make AVIC backing, VMSA and VMCB memory allocation SNP safe crypto: ccp: Add panic notifier for SEV/SNP firmware shutdown on kdump iommu/amd: Clean up RMP entries for IOMMU pages during SNP shutdown crypto: ccp: Handle legacy SEV commands when SNP is enabled crypto: ccp: Handle non-volatile INIT_EX data when SNP is enabled crypto: ccp: Handle the legacy TMR allocation when SNP is enabled x86/sev: Introduce an SNP leaked pages list crypto: ccp: Provide an API to issue SEV and SNP commands ...
2024-03-11Merge tag 'kvm-x86-pmu-6.9' of https://github.com/kvm-x86/linux into HEADPaolo Bonzini
KVM x86 PMU changes for 6.9: - Fix several bugs where KVM speciously prevents the guest from utilizing fixed counters and architectural event encodings based on whether or not guest CPUID reports support for the _architectural_ encoding. - Fix a variety of bugs in KVM's emulation of RDPMC, e.g. for "fast" reads, priority of VMX interception vs #GP, PMC types in architectural PMUs, etc. - Add a selftest to verify KVM correctly emulates RDMPC, counter availability, and a variety of other PMC-related behaviors that depend on guest CPUID, i.e. are difficult to validate via KVM-Unit-Tests. - Zero out PMU metadata on AMD if the virtual PMU is disabled to avoid wasting cycles, e.g. when checking if a PMC event needs to be synthesized when skipping an instruction. - Optimize triggering of emulated events, e.g. for "count instructions" events when skipping an instruction, which yields a ~10% performance improvement in VM-Exit microbenchmarks when a vPMU is exposed to the guest. - Tighten the check for "PMI in guest" to reduce false positives if an NMI arrives in the host while KVM is handling an IRQ VM-Exit.
2024-03-11Merge tag 'kvm-x86-misc-6.9' of https://github.com/kvm-x86/linux into HEADPaolo Bonzini
KVM x86 misc changes for 6.9: - Explicitly initialize a variety of on-stack variables in the emulator that triggered KMSAN false positives (though in fairness in KMSAN, it's comically difficult to see that the uninitialized memory is never truly consumed). - Fix the deubgregs ABI for 32-bit KVM, and clean up code related to reading DR6 and DR7. - Rework the "force immediate exit" code so that vendor code ultimately decides how and when to force the exit. This allows VMX to further optimize handling preemption timer exits, and allows SVM to avoid sending a duplicate IPI (SVM also has a need to force an exit). - Fix a long-standing bug where kvm_has_noapic_vcpu could be left elevated if vCPU creation ultimately failed, and add WARN to guard against similar bugs. - Provide a dedicated arch hook for checking if a different vCPU was in-kernel (for directed yield), and simplify the logic for checking if the currently loaded vCPU is in-kernel. - Misc cleanups and fixes.
2024-03-09SEV: disable SEV-ES DebugSwap by defaultPaolo Bonzini
The DebugSwap feature of SEV-ES provides a way for confidential guests to use data breakpoints. However, because the status of the DebugSwap feature is recorded in the VMSA, enabling it by default invalidates the attestation signatures. In 6.10 we will introduce a new API to create SEV VMs that will allow enabling DebugSwap based on what the user tells KVM to do. Contextually, we will change the legacy KVM_SEV_ES_INIT API to never enable DebugSwap. For compatibility with kernels that pre-date the introduction of DebugSwap, as well as with those where KVM_SEV_ES_INIT will never enable it, do not enable the feature by default. If anybody wants to use it, for now they can enable the sev_es_debug_swap_enabled module parameter, but this will result in a warning. Fixes: d1f85fbe836e ("KVM: SEV: Enable data breakpoints in SEV-ES") Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-02-23KVM: SVM: Flush pages under kvm->lock to fix UAF in svm_register_enc_region()Sean Christopherson
Do the cache flush of converted pages in svm_register_enc_region() before dropping kvm->lock to fix use-after-free issues where region and/or its array of pages could be freed by a different task, e.g. if userspace has __unregister_enc_region_locked() already queued up for the region. Note, the "obvious" alternative of using local variables doesn't fully resolve the bug, as region->pages is also dynamically allocated. I.e. the region structure itself would be fine, but region->pages could be freed. Flushing multiple pages under kvm->lock is unfortunate, but the entire flow is a rare slow path, and the manual flush is only needed on CPUs that lack coherency for encrypted memory. Fixes: 19a23da53932 ("Fix unsynchronized access to sev members through svm_register_enc_region") Reported-by: Gabe Kirkpatrick <gkirkpatrick@google.com> Cc: Josh Eads <josheads@google.com> Cc: Peter Gonda <pgonda@google.com> Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20240217013430.2079561-1-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-02-22KVM: x86: Fully defer to vendor code to decide how to force immediate exitSean Christopherson
Now that vmx->req_immediate_exit is used only in the scope of vmx_vcpu_run(), use force_immediate_exit to detect that KVM should usurp the VMX preemption to force a VM-Exit and let vendor code fully handle forcing a VM-Exit. Opportunsitically drop __kvm_request_immediate_exit() and just have vendor code call smp_send_reschedule() directly. SVM already does this when injecting an event while also trying to single-step an IRET, i.e. it's not exactly secret knowledge that KVM uses a reschedule IPI to force an exit. Link: https://lore.kernel.org/r/20240110012705.506918-7-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-02-22KVM: x86: Move handling of is_guest_mode() into fastpath exit handlersSean Christopherson
Let the fastpath code decide which exits can/can't be handled in the fastpath when L2 is active, e.g. when KVM generates a VMX preemption timer exit to forcefully regain control, there is no "work" to be done and so such exits can be handled in the fastpath regardless of whether L1 or L2 is active. Moving the is_guest_mode() check into the fastpath code also makes it easier to see that L2 isn't allowed to use the fastpath in most cases, e.g. it's not immediately obvious why handle_fastpath_preemption_timer() is called from the fastpath and the normal path. Link: https://lore.kernel.org/r/20240110012705.506918-5-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-02-22KVM: x86: Plumb "force_immediate_exit" into kvm_entry() tracepointSean Christopherson
Annotate the kvm_entry() tracepoint with "immediate exit" when KVM is forcing a VM-Exit immediately after VM-Enter, e.g. when KVM wants to inject an event but needs to first complete some other operation. Knowing that KVM is (or isn't) forcing an exit is useful information when debugging issues related to event injection. Suggested-by: Maxim Levitsky <mlevitsk@redhat.com> Link: https://lore.kernel.org/r/20240110012705.506918-2-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-02-22KVM: x86: Make kvm_get_dr() return a value, not use an out parameterSean Christopherson
Convert kvm_get_dr()'s output parameter to a return value, and clean up most of the mess that was created by forcing callers to provide a pointer. No functional change intended. Acked-by: Mathias Krause <minipli@grsecurity.net> Reviewed-by: Mathias Krause <minipli@grsecurity.net> Link: https://lore.kernel.org/r/20240209220752.388160-2-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-02-14Merge branch 'x86/bugs' into x86/core, to pick up pending changes before ↵Ingo Molnar
dependent patches Merge in pending alternatives patching infrastructure changes, before applying more patches. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2024-02-09work around gcc bugs with 'asm goto' with outputsLinus Torvalds
We've had issues with gcc and 'asm goto' before, and we created a 'asm_volatile_goto()' macro for that in the past: see commits 3f0116c3238a ("compiler/gcc4: Add quirk for 'asm goto' miscompilation bug") and a9f180345f53 ("compiler/gcc4: Make quirk for asm_volatile_goto() unconditional"). Then, much later, we ended up removing the workaround in commit 43c249ea0b1e ("compiler-gcc.h: remove ancient workaround for gcc PR 58670") because we no longer supported building the kernel with the affected gcc versions, but we left the macro uses around. Now, Sean Christopherson reports a new version of a very similar problem, which is fixed by re-applying that ancient workaround. But the problem in question is limited to only the 'asm goto with outputs' cases, so instead of re-introducing the old workaround as-is, let's rename and limit the workaround to just that much less common case. It looks like there are at least two separate issues that all hit in this area: (a) some versions of gcc don't mark the asm goto as 'volatile' when it has outputs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98619 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110420 which is easy to work around by just adding the 'volatile' by hand. (b) Internal compiler errors: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110422 which are worked around by adding the extra empty 'asm' as a barrier, as in the original workaround. but the problem Sean sees may be a third thing since it involves bad code generation (not an ICE) even with the manually added 'volatile'. but the same old workaround works for this case, even if this feels a bit like voodoo programming and may only be hiding the issue. Reported-and-tested-by: Sean Christopherson <seanjc@google.com> Link: https://lore.kernel.org/all/20240208220604.140859-1-seanjc@google.com/ Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Uros Bizjak <ubizjak@gmail.com> Cc: Jakub Jelinek <jakub@redhat.com> Cc: Andrew Pinski <quic_apinski@quicinc.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-02-06KVM: SVM: Return -EINVAL instead of -EBUSY on attempt to re-init SEV/SEV-ESSean Christopherson
Return -EINVAL instead of -EBUSY if userspace attempts KVM_SEV{,ES}_INIT on a VM that already has SEV active. Returning -EBUSY is nonsencial as it's impossible to deactivate SEV without destroying the VM, i.e. the VM isn't "busy" in any sane sense of the word, and the odds of any userspace wanting exactly -EBUSY on a userspace bug are minuscule. Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20240131235609.4161407-5-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-02-06KVM: SVM: Add support for allowing zero SEV ASIDsAshish Kalra
Some BIOSes allow the end user to set the minimum SEV ASID value (CPUID 0x8000001F_EDX) to be greater than the maximum number of encrypted guests, or maximum SEV ASID value (CPUID 0x8000001F_ECX) in order to dedicate all the SEV ASIDs to SEV-ES or SEV-SNP. The SEV support, as coded, does not handle the case where the minimum SEV ASID value can be greater than the maximum SEV ASID value. As a result, the following confusing message is issued: [ 30.715724] kvm_amd: SEV enabled (ASIDs 1007 - 1006) Fix the support to properly handle this case. Fixes: 916391a2d1dc ("KVM: SVM: Add support for SEV-ES capability in KVM") Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com> Cc: stable@vger.kernel.org Acked-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20240104190520.62510-1-Ashish.Kalra@amd.com Link: https://lore.kernel.org/r/20240131235609.4161407-4-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-02-06KVM: SVM: Use unsigned integers when dealing with ASIDsSean Christopherson
Convert all local ASID variables and parameters throughout the SEV code from signed integers to unsigned integers. As ASIDs are fundamentally unsigned values, and the global min/max variables are appropriately unsigned integers, too. Functionally, this is a glorified nop as KVM guarantees min_sev_asid is non-zero, and no CPU supports -1u as the _only_ asid, i.e. the signed vs. unsigned goof won't cause problems in practice. Opportunistically use sev_get_asid() in sev_flush_encrypted_page() instead of open coding an equivalent. Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20240131235609.4161407-3-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-02-06KVM: SVM: Set sev->asid in sev_asid_new() instead of overloading the returnSean Christopherson
Explicitly set sev->asid in sev_asid_new() when a new ASID is successfully allocated, and return '0' to indicate success instead of overloading the return value to multiplex the ASID with error codes. There is exactly one caller of sev_asid_new(), and sev_asid_free() already consumes sev->asid, i.e. returning the ASID isn't necessary for flexibility, nor does it provide symmetry between related APIs. Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20240131235609.4161407-2-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-09 12:27:34 +0000