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KVM: fix i8259 reset irq acking
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The irq ack during pic reset has three problems:

- Ignores slave/master PIC, using gsi 0-8 for both.
- Generates an ACK even if the APIC is in control.
- Depends upon IMR being clear, which is broken if the irq was masked
at the time it was generated.

The last one causes the BIOS to hang after the first reboot of
Windows installation, since PIT interrupts stop.

[avi: fix check whether pic interrupts are seen by cpu]

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
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Marcelo Tosatti authored and Avi Kivity committed Oct 15, 2008
1 parent 8ceed34 commit 85428ac
Showing 1 changed file with 11 additions and 5 deletions.
16 changes: 11 additions & 5 deletions arch/x86/kvm/i8259.c
Original file line number Diff line number Diff line change
Expand Up @@ -195,13 +195,19 @@ int kvm_pic_read_irq(struct kvm *kvm)

void kvm_pic_reset(struct kvm_kpic_state *s)
{
int irq;
int irq, irqbase;
struct kvm *kvm = s->pics_state->irq_request_opaque;
struct kvm_vcpu *vcpu0 = kvm->vcpus[0];

for (irq = 0; irq < PIC_NUM_PINS; irq++) {
if (!(s->imr & (1 << irq)) && (s->irr & (1 << irq) ||
s->isr & (1 << irq)))
kvm_notify_acked_irq(kvm, irq);
if (s == &s->pics_state->pics[0])
irqbase = 0;
else
irqbase = 8;

for (irq = 0; irq < PIC_NUM_PINS/2; irq++) {
if (vcpu0 && kvm_apic_accept_pic_intr(vcpu0))
if (s->irr & (1 << irq) || s->isr & (1 << irq))
kvm_notify_acked_irq(kvm, irq+irqbase);
}
s->last_irr = 0;
s->irr = 0;
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