[04/12] IOAPIC timer interrupt redirect.

Commit Message

Chris Lalancette Dec. 1, 2009, 2:36 p.m. UTC

None

Patch

diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 53f3166..fd52949 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -144,6 +144,15 @@  static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
 	}
 }
 
+static int ioapic_dest_multiple_cpus(struct kvm_lapic_irq *irqe)
+{
+	/* physical mode is always directed to 1 cpu */
+	if (irqe->dest_mode == 0 || irqe->dest_id == 0)
+		return 0;
+
+	return hweight_long(irqe->dest_id) != 1;
+}
+
 static int ioapic_deliver(struct kvm_ioapic *ioapic, int irq)
 {
 	union kvm_ioapic_redirect_entry *entry = &ioapic->redirtbl[irq];
@@ -164,8 +173,10 @@  static int ioapic_deliver(struct kvm_ioapic *ioapic, int irq)
 	irqe.shorthand = 0;
 
 #ifdef CONFIG_X86
-	/* Always deliver PIT interrupt to vcpu 0 */
-	if (irq == 0) {
+	/* if this is the PIT interrupt and the dest_id is multiple
+	 * vcpus, re-write to go to vcpu 0
+	 */
+	if (irq == 0 && ioapic_dest_multiple_cpus(&irqe)) {
 		irqe.dest_mode = 0; /* Physical mode. */
 		/* need to read apic_id from apic register since
 		 * it can be rewritten */