summaryrefslogtreecommitdiff
path: root/arch/x86
diff options
context:
space:
mode:
authorPaolo Bonzini <pbonzini@redhat.com>2016-02-08 14:51:40 +0100
committerPaolo Bonzini <pbonzini@redhat.com>2016-02-16 18:48:34 +0100
commit78db6a5037965429c04d708281f35a6e5562d31b (patch)
tree69df8a7348f8d7c2377a5b8acd3c9a46c156a14f /arch/x86
parent4941b8cb3746f09bb102f7a5d64d878e96a0c6cd (diff)
KVM: x86: rewrite handling of scaled TSC for kvmclock
This is the same as before: kvm_scale_tsc(tgt_tsc_khz) = tgt_tsc_khz * ratio = tgt_tsc_khz * user_tsc_khz / tsc_khz (see set_tsc_khz) = user_tsc_khz (see kvm_guest_time_update) = vcpu->arch.virtual_tsc_khz (see kvm_set_tsc_khz) However, computing it through kvm_scale_tsc will make it possible to include the NTP correction in tgt_tsc_khz. Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kvm/x86.c15
1 files changed, 8 insertions, 7 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 16bbe6df679b..01d22b37556c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1713,7 +1713,7 @@ 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, tgt_tsc_khz;
+ unsigned long flags, tgt_tsc_khz;
struct kvm_vcpu_arch *vcpu = &v->arch;
struct kvm_arch *ka = &v->kvm->arch;
s64 kernel_ns;
@@ -1739,8 +1739,8 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
/* Keep irq disabled to prevent changes to the clock */
local_irq_save(flags);
- this_tsc_khz = __this_cpu_read(cpu_tsc_khz);
- if (unlikely(this_tsc_khz == 0)) {
+ tgt_tsc_khz = __this_cpu_read(cpu_tsc_khz);
+ if (unlikely(tgt_tsc_khz == 0)) {
local_irq_restore(flags);
kvm_make_request(KVM_REQ_CLOCK_UPDATE, v);
return 1;
@@ -1775,13 +1775,14 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
if (!vcpu->pv_time_enabled)
return 0;
- if (unlikely(vcpu->hw_tsc_khz != this_tsc_khz)) {
- tgt_tsc_khz = kvm_has_tsc_control ?
- vcpu->virtual_tsc_khz : this_tsc_khz;
+ if (kvm_has_tsc_control)
+ tgt_tsc_khz = kvm_scale_tsc(v, tgt_tsc_khz);
+
+ if (unlikely(vcpu->hw_tsc_khz != tgt_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;
+ vcpu->hw_tsc_khz = tgt_tsc_khz;
}
/* With all the info we got, fill in the values */