KVM: x86: Use the correct vcpu's TSC rate to compute time scale

This patch makes KVM use virtual_tsc_khz rather than the host TSC rate
as vcpu's TSC rate to compute the time scale if 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/x86.c b/arch/x86/kvm/x86.c
index 3d008de9cb05e900749d3f83734f6d22ef871c8f..2cb074f5aaedb3362c77f8a30ab5df9fd8c7d406 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1707,7 +1707,7 @@ static void kvm_gen_update_masterclock(struct kvm *kvm)
 
 static int kvm_guest_time_update(struct kvm_vcpu *v)
 {
-       unsigned long flags, this_tsc_khz;
+       unsigned long flags, this_tsc_khz, tgt_tsc_khz;
        struct kvm_vcpu_arch *vcpu = &v->arch;
        struct kvm_arch *ka = &v->kvm->arch;
        s64 kernel_ns;
@@ -1770,7 +1770,9 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
                return 0;
 
        if (unlikely(vcpu->hw_tsc_khz != this_tsc_khz)) {
-               kvm_get_time_scale(NSEC_PER_SEC / 1000, this_tsc_khz,
+               tgt_tsc_khz = kvm_has_tsc_control ?
+                       vcpu->virtual_tsc_khz : this_tsc_khz;
+               kvm_get_time_scale(NSEC_PER_SEC / 1000, tgt_tsc_khz,
                                   &vcpu->hv_clock.tsc_shift,
                                   &vcpu->hv_clock.tsc_to_system_mul);
                vcpu->hw_tsc_khz = this_tsc_khz;