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authorOwen Hofmann <osh@google.com>2016-03-01 13:36:13 -0800
committerPaolo Bonzini <pbonzini@redhat.com>2016-03-02 10:37:32 +0100
commit2680d6da455b636dd006636780c0f235c6561d70 (patch)
tree670ef91dac86f41a879067abd51aa91f8b62a230 /arch
parent0178fd7dcc4451fcb90bec5e91226586962478d2 (diff)
downloadlinux-2680d6da455b636dd006636780c0f235c6561d70.tar.gz
kvm: x86: Update tsc multiplier on change.
vmx.c writes the TSC_MULTIPLIER field in vmx_vcpu_load, but only when a vcpu has migrated physical cpus. Record the last value written and update in vmx_vcpu_load on any change, otherwise a cpu migration must occur for TSC frequency scaling to take effect. Cc: stable@vger.kernel.org Fixes: ff2c3a1803775cc72dc6f624b59554956396b0ee Signed-off-by: Owen Hofmann <osh@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/vmx.c14
1 files changed, 9 insertions, 5 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e2951b6edbbc..0ff453749a90 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -596,6 +596,8 @@ struct vcpu_vmx {
/* Support for PML */
#define PML_ENTITY_NUM 512
struct page *pml_pg;
+
+ u64 current_tsc_ratio;
};
enum segment_cache_field {
@@ -2127,14 +2129,16 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
rdmsrl(MSR_IA32_SYSENTER_ESP, sysenter_esp);
vmcs_writel(HOST_IA32_SYSENTER_ESP, sysenter_esp); /* 22.2.3 */
- /* Setup TSC multiplier */
- if (cpu_has_vmx_tsc_scaling())
- vmcs_write64(TSC_MULTIPLIER,
- vcpu->arch.tsc_scaling_ratio);
-
vmx->loaded_vmcs->cpu = cpu;
}
+ /* Setup TSC multiplier */
+ if (kvm_has_tsc_control &&
+ vmx->current_tsc_ratio != vcpu->arch.tsc_scaling_ratio) {
+ vmx->current_tsc_ratio = vcpu->arch.tsc_scaling_ratio;
+ vmcs_write64(TSC_MULTIPLIER, vmx->current_tsc_ratio);
+ }
+
vmx_vcpu_pi_load(vcpu, cpu);
}