Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.19 094/105] KVM: lapic: Busy wait for timer to expire when using hv_timer | Date | Mon, 20 May 2019 14:14:40 +0200 |
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From: Sean Christopherson <sean.j.christopherson@intel.com>
commit ee66e453db13d4837a0dcf9d43efa7a88603161b upstream.
...now that VMX's preemption timer, i.e. the hv_timer, also adjusts its programmed time based on lapic_timer_advance_ns. Without the delay, a guest can see a timer interrupt arrive before the requested time when KVM is using the hv_timer to emulate the guest's interrupt.
Fixes: c5ce8235cffa0 ("KVM: VMX: Optimize tscdeadline timer latency") Cc: <stable@vger.kernel.org> Cc: Wanpeng Li <wanpengli@tencent.com> Reviewed-by: Liran Alon <liran.alon@oracle.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/x86/kvm/lapic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -1449,7 +1449,7 @@ static void apic_timer_expired(struct kv if (swait_active(q)) swake_up_one(q); - if (apic_lvtt_tscdeadline(apic)) + if (apic_lvtt_tscdeadline(apic) || ktimer->hv_timer_in_use) ktimer->expired_tscdeadline = ktimer->tscdeadline; }
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