KVM: Move IO APIC to its own lock
The allows removal of irq_lock from the injection path.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
index ccc941a..d057c0c 100644
--- a/arch/x86/kvm/i8259.c
+++ b/arch/x86/kvm/i8259.c
@@ -38,7 +38,15 @@
s->isr_ack |= (1 << irq);
if (s != &s->pics_state->pics[0])
irq += 8;
+ /*
+ * We are dropping lock while calling ack notifiers since ack
+ * notifier callbacks for assigned devices call into PIC recursively.
+ * Other interrupt may be delivered to PIC while lock is dropped but
+ * it should be safe since PIC state is already updated at this stage.
+ */
+ spin_unlock(&s->pics_state->lock);
kvm_notify_acked_irq(s->pics_state->kvm, SELECT_PIC(irq), irq);
+ spin_lock(&s->pics_state->lock);
}
void kvm_pic_clear_isr_ack(struct kvm *kvm)
@@ -176,16 +184,18 @@
static inline void pic_intack(struct kvm_kpic_state *s, int irq)
{
s->isr |= 1 << irq;
- if (s->auto_eoi) {
- if (s->rotate_on_auto_eoi)
- s->priority_add = (irq + 1) & 7;
- pic_clear_isr(s, irq);
- }
/*
* We don't clear a level sensitive interrupt here
*/
if (!(s->elcr & (1 << irq)))
s->irr &= ~(1 << irq);
+
+ if (s->auto_eoi) {
+ if (s->rotate_on_auto_eoi)
+ s->priority_add = (irq + 1) & 7;
+ pic_clear_isr(s, irq);
+ }
+
}
int kvm_pic_read_irq(struct kvm *kvm)
@@ -294,9 +304,9 @@
priority = get_priority(s, s->isr);
if (priority != 8) {
irq = (priority + s->priority_add) & 7;
- pic_clear_isr(s, irq);
if (cmd == 5)
s->priority_add = (irq + 1) & 7;
+ pic_clear_isr(s, irq);
pic_update_irq(s->pics_state);
}
break;