Messages in this thread Patch in this message | | | From | Andrew Jones <> | Subject | [PATCH] x86: kvm: fix unstable_tsc boot | Date | Mon, 24 Feb 2014 16:42:29 +0100 |
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When the tsc is marked unstable on the host it causes global clock updates to be requested each time a vcpu is loaded, nearly halting all progress on guests with a large number of vcpus.
Fix this by only requesting a local clock update unless the vcpu is migrating to another cpu.
Signed-off-by: Andrew Jones <drjones@redhat.com> --- arch/x86/kvm/x86.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 6530019116b0d..ea716a162b4a3 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2781,15 +2781,18 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) vcpu->arch.last_guest_tsc); kvm_x86_ops->write_tsc_offset(vcpu, offset); vcpu->arch.tsc_catchup = 1; + set_bit(KVM_REQ_CLOCK_UPDATE, &vcpu->requests); } + } + + if (unlikely(vcpu->cpu != cpu)) { /* * On a host with synchronized TSC, there is no need to update * kvmclock on vcpu->cpu migration */ if (!vcpu->kvm->arch.use_master_clock || vcpu->cpu == -1) kvm_make_request(KVM_REQ_GLOBAL_CLOCK_UPDATE, vcpu); - if (vcpu->cpu != cpu) - kvm_migrate_timers(vcpu); + kvm_migrate_timers(vcpu); vcpu->cpu = cpu; } -- 1.8.1.4
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