KVM: deliver PIC interrupt only to vcpu0

This patch changes the PIC interrupts delivery. Now it is only delivered
to vcpu0 when either condition is met (on vcpu0):
  1. local APIC is hardware disabled
  2. LVT0 is unmasked and configured to delivery mode ExtInt

It fixes the 2x faster wall clock on x86_64 and SMP i386 Linux guests

Signed-off-by: Eddie (Yaozu) 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, 10 insertions, 5 deletions

diff --git a/drivers/kvm/irq.c b/drivers/kvm/irq.c
index b88e5011558..7628c7ff628 100644
--- a/drivers/kvm/irq.c
+++ b/drivers/kvm/irq.c
@@ -33,8 +33,11 @@ int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
         struct kvm_pic *s;
 
         if (kvm_apic_has_interrupt(v) == -1) {  /* LAPIC */
-                s = pic_irqchip(v->kvm);        /* PIC */
-                return s->output;
+                if (kvm_apic_accept_pic_intr(v)) {
+                        s = pic_irqchip(v->kvm);        /* PIC */
+                        return s->output;
+                } else
+                        return 0;
         }
         return 1;
 }
@@ -50,9 +53,11 @@ int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
 
         vector = kvm_get_apic_interrupt(v);     /* APIC */
         if (vector == -1) {
-                s = pic_irqchip(v->kvm);
-                s->output = 0;          /* PIC */
-                vector = kvm_pic_read_irq(s);
+                if (kvm_apic_accept_pic_intr(v)) {
+                        s = pic_irqchip(v->kvm);
+                        s->output = 0;          /* PIC */
+                        vector = kvm_pic_read_irq(s);
+                }
         }
         return vector;
 }