[PATCH 080/104] KVM: round robin for APIC lowest priority delivery mode

Avi Kivity
2007-09-17T08:32:02Z

From: He, Qing <qing.he-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>

Signed-off-by: Qing He <qing.he-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
---
drivers/kvm/kvm.h | 1 +
drivers/kvm/lapic.c | 33 ++++++++++++++++++++++++++++-----
2 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index f8fe87d..dbb929d 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -413,6 +413,7 @@ struct kvm {
struct kvm_io_bus pio_bus;
struct kvm_pic *vpic;
struct kvm_ioapic *vioapic;
+ int round_robin_prev_vcpu;
};

static inline struct kvm_pic *pic_irqchip(struct kvm *kvm)
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 @@ struct kvm_lapic *kvm_apic_round_robin(struct kvm *kvm, u8 vector,
unsigned long bitmap)
{
int vcpu_id;
+ int last;
+ int next;
+ struct kvm_lapic *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;
+ }

- /* 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;
+ return apic;
}

static void apic_set_eoi(struct kvm_lapic *apic)