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Commit 9770404a authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: SVM: fix trashing of MSR_TSC_AUX 



I don't know what I was thinking when I wrote commit 46896c73 ("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: 46896c73 ("KVM: svm: add support for RDTSCP")
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 30b072ce

arch/x86/kvm/svm.c

+5 −3
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ 
#include <asm/desc.h>

#include <asm/debugreg.h>

#include <asm/kvm_para.h>

#include <asm/vgtod.h>



#include <asm/virtext.h>

#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