Messages in this thread Patch in this message | | | From | Paolo Bonzini <> | Subject | [PATCH] KVM: SVM: fix trashing of MSR_TSC_AUX | Date | Wed, 6 Jul 2016 15:43:16 +0200 |
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I don't know what I was thinking when I wrote commit 46896c73c1a4 ("KVM: svm: add support for RDTSCP", 2015-11-12); I missed write_rdtscp_aux which obviously uses MSR_TSC_AUX.
Therefore we do need to save/restore MSR_TSC_AUX in svm_vcpu_run.
Cc: stable@vger.kernel.org Cc: Borislav Petkov <bp@alien8.de> Fixes: 46896c73c1a4 ("KVM: svm: add support for RDTSCP") Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- arch/x86/kvm/svm.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 16ef31b87452..44f6368f8b45 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -43,6 +43,7 @@ #include <asm/kvm_para.h> #include <asm/virtext.h> +#include <asm/vgtod.h> #include "trace.h" #define __ex(x) __kvm_handle_fault_on_reboot(x) @@ -1530,9 +1531,6 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu) wrmsrl(MSR_AMD64_TSC_RATIO, tsc_ratio); } } - /* This assumes that the kernel never uses MSR_TSC_AUX */ - if (static_cpu_has(X86_FEATURE_RDTSCP)) - wrmsrl(MSR_TSC_AUX, svm->tsc_aux); avic_vcpu_load(vcpu, cpu); } @@ -4474,6 +4472,8 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu) svm->vmcb->save.cr2 = vcpu->arch.cr2; clgi(); + if (static_cpu_has(X86_FEATURE_RDTSCP)) + wrmsrl(MSR_TSC_AUX, svm->tsc_aux); local_irq_enable(); @@ -4550,6 +4550,8 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu) #endif ); + if (static_cpu_has(X86_FEATURE_RDTSCP)) + wrmsrl(MSR_TSC_AUX, __getcpu()); #ifdef CONFIG_X86_64 wrmsrl(MSR_GS_BASE, svm->host.gs_base); #else -- 1.8.3.1
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