KVM: round robin for APIC lowest priority delivery mode
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 01e7696..ca1db38 100644
--- a/drivers/kvm/lapic.c
+++ b/drivers/kvm/lapic.c
@@ -371,12 +371,35 @@
unsigned long bitmap)
{
int vcpu_id;
+ int last;
+ int next;
+ struct kvm_lapic *apic;
- /* TODO for real round robin */
- vcpu_id = fls(bitmap) - 1;
- if (vcpu_id < 0)
- printk(KERN_DEBUG "vcpu not ready for apic_round_robin\n");
- return kvm->vcpus[vcpu_id]->apic;
+ last = kvm->round_robin_prev_vcpu;
+ next = last;
+
+ do {
+ if (++next == KVM_MAX_VCPUS)
+ next = 0;
+ if (kvm->vcpus[next] == NULL || !test_bit(next, &bitmap))
+ continue;
+ apic = kvm->vcpus[next]->apic;
+ if (apic && apic_enabled(apic))
+ break;
+ apic = NULL;
+ } while (next != last);
+ kvm->round_robin_prev_vcpu = next;
+
+ if (!apic) {
+ vcpu_id = ffs(bitmap) - 1;
+ if (vcpu_id < 0) {
+ vcpu_id = 0;
+ printk(KERN_DEBUG "vcpu not ready for apic_round_robin\n");
+ }
+ apic = kvm->vcpus[vcpu_id]->apic;
+ }
+
+ return apic;
}
static void apic_set_eoi(struct kvm_lapic *apic)