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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: c5ce8235cf ("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>
hifive-unleashed-5.2
Sean Christopherson 2019-04-16 13:32:44 -07:00 committed by Paolo Bonzini
parent 6c6a2ab962
commit ee66e453db
1 changed files with 1 additions and 1 deletions
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2
arch/x86/kvm/lapic.c
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@ -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;
}