From 9770404a0061ec46dec6e15c4b07731ce2e2d7bb Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 6 Jul 2016 14:57:24 +0200 Subject: [PATCH] KVM: SVM: fix trashing of MSR_TSC_AUX 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 Fixes: 46896c73c1a4 ("KVM: svm: add support for RDTSCP") Signed-off-by: Paolo Bonzini --- 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..f931d3e33c7f 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -41,6 +41,7 @@ #include #include #include +#include #include #include "trace.h" @@ -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 -- 2.20.1