From 38f114887ca48048a0da736607166a62d5813342 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 16 Apr 2019 13:32:44 -0700 Subject: [PATCH] KVM: lapic: Busy wait for timer to expire when using hv_timer 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: Cc: Wanpeng Li Reviewed-by: Liran Alon Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/lapic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index d2f5aa220355..cba414db14cb 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -1449,7 +1449,7 @@ static void apic_timer_expired(struct kvm_lapic *apic) 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; } -- GitLab