[Devel] [PATCH 11/16] KVM: VMX: Setup TSC scaling ratio when a vcpu is loaded

[Roman Kagan]

From: Haozhong Zhang <haozhong.zhang at intel.com>

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 at intel.com>
Signed-off-by: Paolo Bonzini <pbonzini at redhat.com>
(cherry-picked from commit ff2c3a1803775cc72dc6f624b59554956396b0ee)
Signed-off-by: Denis Plotnikov <dplotnikov at virtuozzo.com>
Signed-off-by: Roman Kagan <rkagan at virtuozzo.com>
---
 arch/x86/kvm/vmx.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index ab8a678..265bc0e 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1883,6 +1883,12 @@ 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;
 	}
 }
-- 
2.7.4