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| author | Radim Krčmář <rkrcmar@redhat.com> | 2016-07-15 14:38:36 +0200 |
|---|---|---|
| committer | Radim Krčmář <rkrcmar@redhat.com> | 2016-07-16 15:26:54 +0200 |
| commit | 6a907cd0ad31fce30b7a7416576410a7de7c8933 (patch) | |
| tree | edd5c641dc154e14848bc7d284fcd07492decc6e | |
| parent | 2b23c3a6e3eb2fba77eb35fdfa3d71a9aa3f33b7 (diff) | |
| download | linux-6a907cd0ad31fce30b7a7416576410a7de7c8933.tar.bz2 | |
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
| -rw-r--r-- | arch/x86/kvm/svm.c | 8 |
1 files changed, 3 insertions, 5 deletions
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); |