Revert "KVM: SVM: fix trashing of MSR_TSC_AUX" (6a907cd0) · Commits · 戴 / test

This reverts commit . The reverted patch is not needed as only userspace uses RDTSCP and MSR_TSC_AUX is in host_save_user_msrs[] and therefore properly saved in svm_vcpu_load() and restored in svm_vcpu_put() before every switch to userspace. The reverted patch did not allow the kernel to use RDTSCP in the future, because of missed trashing in svm_set_msr() and 64-bit ifdef. This reverts commit . ("KVM: SVM: do not set MSR_TSC_AUX on 32-bit builds") is a build fix for and reverting them separately would only break more bisections. Cc: stable@vger.kernel.org

arch/x86/kvm/svm.c

+3 −5

Original line number	Diff line number	Diff line
		@@ -41,7 +41,6 @@
		#include <asm/desc.h>
		#include <asm/debugreg.h>
		#include <asm/kvm_para.h>
		#include <asm/vgtod.h>

		#include <asm/virtext.h>
		#include "trace.h"
		@@ -1531,6 +1530,9 @@ 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);
		}
		@@ -4472,8 +4474,6 @@ 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();

		@@ -4551,8 +4551,6 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
		);

		#ifdef CONFIG_X86_64
		if (static_cpu_has(X86_FEATURE_RDTSCP))
		wrmsrl(MSR_TSC_AUX, __getcpu());
		wrmsrl(MSR_GS_BASE, svm->host.gs_base);
		#else
		loadsegment(fs, svm->host.fs);

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