From: Radim Krčmář <rkrcmar@redhat.com>
Date: Fri, 15 Jul 2016 12:38:36 +0000 (+0200)
Subject: Revert "KVM: SVM: fix trashing of MSR_TSC_AUX"
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=6a907cd0ad31fce30b7a7416576410a7de7c8933;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

Revert "KVM: SVM: fix trashing of MSR_TSC_AUX"

This reverts commit 9770404a0061ec46dec6e15c4b07731ce2e2d7bb.

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 2b23c3a6e3eb2fba77eb35fdfa3d71a9aa3f33b7.

2b23c3a6e3eb ("KVM: SVM: do not set MSR_TSC_AUX on 32-bit builds") is a
build fix for 9770404a0061 and reverting them separately would only
break more bisections.

Cc: stable@vger.kernel.org
---

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 05c08b69cee7..16ef31b87452 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -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);