Andrew Jones 7e44e4495a x86: kvm: rate-limit global clock updates ... When we update a vcpu's local clock it may pick up an NTP correction. We can't wait an indeterminate amount of time for other vcpus to pick up that correction, so commit 0061d53daf introduced a global clock update. However, we can't request a global clock update on every vcpu load either (which is what happens if the tsc is marked as unstable). The solution is to rate-limit the global clock updates. Marcelo calculated that we should delay the global clock updates no more than 0.1s as follows: Assume an NTP correction c is applied to one vcpu, but not the other, then in n seconds the delta of the vcpu system_timestamps will be c * n. If we assume a correction of 500ppm (worst-case), then the two vcpus will diverge 50us in 0.1s, which is a considerable amount. Signed-off-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>		2014-03-04 11:50:47 +01:00
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asm	x86: kvm: rate-limit global clock updates	2014-03-04 11:50:47 +01:00
uapi/asm	KVM: x86: Intel MPX vmx and msr handle	2014-02-24 12:14:00 +01:00