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authorGleb Natapov <gleb@redhat.com>2009-08-24 11:54:25 +0300
committerAvi Kivity <avi@redhat.com>2009-12-03 09:32:08 +0200
commiteba0226bdfffe262e72b8360e4d0d12070e9a0f0 (patch)
tree93da785e3bba63a9232e529a2572541ef87c0615 /arch/x86/kvm/i8259.c
parent280aa177dcd1edc718d8a92f17f235b783ec6307 (diff)
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>
Diffstat (limited to 'arch/x86/kvm/i8259.c')
-rw-r--r--arch/x86/kvm/i8259.c22
1 files changed, 16 insertions, 6 deletions
diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
index ccc941af4eaf..d057c0cbd245 100644
--- a/arch/x86/kvm/i8259.c
+++ b/arch/x86/kvm/i8259.c
@@ -38,7 +38,15 @@ static void pic_clear_isr(struct kvm_kpic_state *s, int irq)
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 @@ int kvm_pic_set_irq(void *opaque, int irq, int level)
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 @@ static void pic_ioport_write(void *opaque, u32 addr, u32 val)
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;