KVM: Keep track of missed timer irq injections

APIC timer IRQ is set every time when a certain period
expires at host time, but the guest may be descheduled
at that time and thus the irq be overwritten by later fire.
This patch keep track of firing irq numbers and decrease
only when the IRQ is injected to guest or buffered in
APIC.

Signed-off-by: Yaozu (Eddie) Dong <Eddie.Dong@intel.com>
Signed-off-by: Qing He <qing.he@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index c8cd242f36ff..00119ec41669 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -1331,7 +1331,9 @@ static void svm_intr_assist(struct vcpu_svm *svm)
 {
         struct vmcb *vmcb = svm->vmcb;
         int intr_vector = -1;
+        struct kvm_vcpu *vcpu = &svm->vcpu;
 
+        kvm_inject_pending_timer_irqs(vcpu);
         if ((vmcb->control.exit_int_info & SVM_EVTINJ_VALID) &&
             ((vmcb->control.exit_int_info & SVM_EVTINJ_TYPE_MASK) == 0)) {
                 intr_vector = vmcb->control.exit_int_info &
@@ -1344,7 +1346,7 @@ static void svm_intr_assist(struct vcpu_svm *svm)
         if (vmcb->control.int_ctl & V_IRQ_MASK)
                 return;
 
-        if (!kvm_cpu_has_interrupt(&svm->vcpu))
+        if (!kvm_cpu_has_interrupt(vcpu))
                 return;
 
         if (!(vmcb->save.rflags & X86_EFLAGS_IF) ||
@@ -1356,8 +1358,9 @@ static void svm_intr_assist(struct vcpu_svm *svm)
                 return;
         }
         /* Okay, we can deliver the interrupt: grab it and update PIC state. */
-        intr_vector = kvm_cpu_get_interrupt(&svm->vcpu);
+        intr_vector = kvm_cpu_get_interrupt(vcpu);
         svm_inject_irq(svm, intr_vector);
+        kvm_timer_intr_post(vcpu, intr_vector);
 }
 
 static void kvm_reput_irq(struct vcpu_svm *svm)