Commit ee66e453 authored Apr 16, 2019 by Sean Christopherson Committed by Paolo Bonzini Apr 30, 2019

KVM: lapic: Busy wait for timer to expire when using hv_timer

...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: c5ce8235 ("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>

parent 6c6a2ab9

arch/x86/kvm/lapic.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1455,7 +1455,7 @@ 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;
		}

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