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apic: Resolve potential endless loop around apic_update_irq 

Commit d96e173769 refactored the reinjection of pending PIC interrupts.
However, it missed the potential loop of apic_update_irq ->
apic_deliver_pic_intr -> apic_local_deliver -> apic_set_irq ->
apic_update_irq that /could/ occur if LINT0 is injected as APIC_DM_FIXED
and that vector is currently blocked via TPR.

Resolve this by reinjecting only where it matters: inside
apic_get_interrupt. This function may clear a vector while a
PIC-originated reason still exists.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Jan Kiszka 2012-07-09 16:42:30 +02:00 committed by Avi Kivity
parent a75b3e0f64
commit 3db3659bf6
1 changed files with 7 additions and 3 deletions
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10
hw/apic.c
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@ -363,9 +363,6 @@ static void apic_update_irq(APICCommonState *s)
}
if (apic_irq_pending(s) > 0) {
cpu_interrupt(s->cpu_env, CPU_INTERRUPT_HARD);
} else if (apic_accept_pic_intr(&s->busdev.qdev) &&
pic_get_output(isa_pic)) {
apic_deliver_pic_intr(&s->busdev.qdev, 1);
}
}
@ -560,7 +557,14 @@ int apic_get_interrupt(DeviceState *d)
reset_bit(s->irr, intno);
set_bit(s->isr, intno);
apic_sync_vapic(s, SYNC_TO_VAPIC);
/* re-inject if there is still a pending PIC interrupt */
if (apic_accept_pic_intr(&s->busdev.qdev) && pic_get_output(isa_pic)) {
apic_deliver_pic_intr(&s->busdev.qdev, 1);
}
apic_update_irq(s);
return intno;
}