KVM: VMX: Setup TSC scaling ratio when a vcpu is loaded

This patch makes kvm-intel module to load TSC scaling ratio into TSC
multiplier field of VMCS when a vcpu is loaded, so that TSC scaling
ratio can take effect if VMX TSC scaling is enabled.

Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e45b03ed5c52821c5762e6f68def6ccc0e965c45..890295287afa554a745febfc10cf0bae57c41bc0 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2061,6 +2061,12 @@ 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;
        }