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KVM: VMX: Use a scaled host TSC for guest readings of MSR_IA32_TSC

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This patch makes kvm-intel to return a scaled host TSC plus the TSC
offset when handling guest readings to MSR_IA32_TSC.

Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Haozhong Zhang 2015-10-20 15:39:11 +08:00 committed by Paolo Bonzini
parent ff2c3a1803
commit be7b263ea9
1 changed files with 5 additions and 4 deletions
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9
arch/x86/kvm/vmx.c
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@ -2371,15 +2371,16 @@ static void setup_msrs(struct vcpu_vmx *vmx)
/*
* reads and returns guest's timestamp counter "register"
* guest_tsc = host_tsc + tsc_offset -- 21.3
* guest_tsc = (host_tsc * tsc multiplier) >> 48 + tsc_offset
* -- Intel TSC Scaling for Virtualization White Paper, sec 1.3
*/
static u64 guest_read_tsc(void)
static u64 guest_read_tsc(struct kvm_vcpu *vcpu)
{
u64 host_tsc, tsc_offset;
host_tsc = rdtsc();
tsc_offset = vmcs_read64(TSC_OFFSET);
return host_tsc + tsc_offset;
return kvm_scale_tsc(vcpu, host_tsc) + tsc_offset;
}
/*
@ -2771,7 +2772,7 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case MSR_EFER:
return kvm_get_msr_common(vcpu, msr_info);
case MSR_IA32_TSC:
msr_info->data = guest_read_tsc();
msr_info->data = guest_read_tsc(vcpu);
break;
case MSR_IA32_SYSENTER_CS:
msr_info->data = vmcs_read32(GUEST_SYSENTER_CS);