diff options
| author | Babu Moger <babu.moger@amd.com> | 2022-04-19 15:54:44 -0500 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-04-29 12:49:15 -0400 |
| commit | 296d5a17e793956f7b914336422043c939263409 (patch) | |
| tree | e6dae9614be53367fac2eec0fe49eaaa5ceb13da | |
| parent | f30903394eb62316dddea8801b357f5cec4df187 (diff) | |
KVM: SEV-ES: Use V_TSC_AUX if available instead of RDTSC/MSR_TSC_AUX intercepts
The TSC_AUX virtualization feature allows AMD SEV-ES guests to securely use
TSC_AUX (auxiliary time stamp counter data) in the RDTSCP and RDPID
instructions. The TSC_AUX value is set using the WRMSR instruction to the
TSC_AUX MSR (0xC0000103). It is read by the RDMSR, RDTSCP and RDPID
instructions. If the read/write of the TSC_AUX MSR is intercepted, then
RDTSCP and RDPID must also be intercepted when TSC_AUX virtualization
is present. However, the RDPID instruction can't be intercepted. This means
that when TSC_AUX virtualization is present, RDTSCP and TSC_AUX MSR
read/write must not be intercepted for SEV-ES (or SEV-SNP) guests.
Signed-off-by: Babu Moger <babu.moger@amd.com>
Message-Id: <165040164424.1399644.13833277687385156344.stgit@bmoger-ubuntu>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/x86/include/asm/cpufeatures.h | 2 | ||||
| -rw-r--r-- | arch/x86/kvm/svm/sev.c | 8 | ||||
| -rw-r--r-- | arch/x86/kvm/svm/svm.c | 1 | ||||
| -rw-r--r-- | arch/x86/kvm/svm/svm.h | 2 |
4 files changed, 11 insertions, 2 deletions
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index 1bc66a17a95a..1d6826eac3e6 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -405,7 +405,7 @@ #define X86_FEATURE_SEV (19*32+ 1) /* AMD Secure Encrypted Virtualization */ #define X86_FEATURE_VM_PAGE_FLUSH (19*32+ 2) /* "" VM Page Flush MSR is supported */ #define X86_FEATURE_SEV_ES (19*32+ 3) /* AMD Secure Encrypted Virtualization - Encrypted State */ -#define X86_FEATURE_V_TSC_AUX (19*32+ 9) /* Virtual TSC_AUX */ +#define X86_FEATURE_V_TSC_AUX (19*32+ 9) /* "" Virtual TSC_AUX */ #define X86_FEATURE_SME_COHERENT (19*32+10) /* "" AMD hardware-enforced cache coherency */ /* diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 9ce162119b23..b67ce873d5d2 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -2926,6 +2926,14 @@ void sev_es_init_vmcb(struct vcpu_svm *svm) set_msr_interception(vcpu, svm->msrpm, MSR_IA32_LASTBRANCHTOIP, 1, 1); set_msr_interception(vcpu, svm->msrpm, MSR_IA32_LASTINTFROMIP, 1, 1); set_msr_interception(vcpu, svm->msrpm, MSR_IA32_LASTINTTOIP, 1, 1); + + if (boot_cpu_has(X86_FEATURE_V_TSC_AUX) && + (guest_cpuid_has(&svm->vcpu, X86_FEATURE_RDTSCP) || + guest_cpuid_has(&svm->vcpu, X86_FEATURE_RDPID))) { + set_msr_interception(vcpu, svm->msrpm, MSR_TSC_AUX, 1, 1); + if (guest_cpuid_has(&svm->vcpu, X86_FEATURE_RDTSCP)) + svm_clr_intercept(svm, INTERCEPT_RDTSCP); + } } void sev_es_vcpu_reset(struct vcpu_svm *svm) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 22bbd69495ad..b83af9ecf85a 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -99,6 +99,7 @@ static const struct svm_direct_access_msrs { { .index = MSR_EFER, .always = false }, { .index = MSR_IA32_CR_PAT, .always = false }, { .index = MSR_AMD64_SEV_ES_GHCB, .always = true }, + { .index = MSR_TSC_AUX, .always = false }, { .index = MSR_INVALID, .always = false }, }; diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index e246793cbeae..32220a1b0ea2 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -29,7 +29,7 @@ #define IOPM_SIZE PAGE_SIZE * 3 #define MSRPM_SIZE PAGE_SIZE * 2 -#define MAX_DIRECT_ACCESS_MSRS 20 +#define MAX_DIRECT_ACCESS_MSRS 21 #define MSRPM_OFFSETS 16 extern u32 msrpm_offsets[MSRPM_OFFSETS] __read_mostly; extern bool npt_enabled; |