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>
diff --git a/drivers/kvm/lapic.c b/drivers/kvm/lapic.c
index 2706ec3..01e7696 100644
--- a/drivers/kvm/lapic.c
+++ b/drivers/kvm/lapic.c
@@ -788,6 +788,8 @@
for (i = 0; i < APIC_LVT_NUM; i++)
apic_set_reg(apic, APIC_LVTT + 0x10 * i, APIC_LVT_MASKED);
+ apic_set_reg(apic, APIC_LVT0,
+ SET_APIC_DELIVERY_MODE(0, APIC_MODE_EXTINT));
apic_set_reg(apic, APIC_DFR, 0xffffffffU);
apic_set_reg(apic, APIC_SPIV, 0xff);
@@ -932,6 +934,21 @@
return highest_irr;
}
+int kvm_apic_accept_pic_intr(struct kvm_vcpu *vcpu)
+{
+ u32 lvt0 = apic_get_reg(vcpu->apic, APIC_LVT0);
+ int r = 0;
+
+ if (vcpu->vcpu_id == 0) {
+ if (!apic_hw_enabled(vcpu->apic))
+ r = 1;
+ if ((lvt0 & APIC_LVT_MASKED) == 0 &&
+ GET_APIC_DELIVERY_MODE(lvt0) == APIC_MODE_EXTINT)
+ r = 1;
+ }
+ return r;
+}
+
void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *apic = vcpu->apic;