KVM: x86: Clear apic tsc-deadline after deadline
Intel SDM 10.5.4.1 says "When the timer generates an interrupt, it disarms
itself and clears the IA32_TSC_DEADLINE MSR".
This patch clears the MSR upon timer interrupt delivery which delivered on
deadline mode. Since the MSR may be reconfigured while an interrupt is
pending, causing the new value to be overriden, pending timer interrupts are
checked before setting a new deadline.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 08e8a89..666c086 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1352,6 +1352,9 @@
return;
hrtimer_cancel(&apic->lapic_timer.timer);
+ /* Inject here so clearing tscdeadline won't override new value */
+ if (apic_has_pending_timer(vcpu))
+ kvm_inject_apic_timer_irqs(vcpu);
apic->lapic_timer.tscdeadline = data;
start_apic_timer(apic);
}
@@ -1639,6 +1642,8 @@
if (atomic_read(&apic->lapic_timer.pending) > 0) {
kvm_apic_local_deliver(apic, APIC_LVTT);
+ if (apic_lvtt_tscdeadline(apic))
+ apic->lapic_timer.tscdeadline = 0;
atomic_set(&apic->lapic_timer.pending, 0);
}
}