From 3db3659bf60094657e1465cc809acb09551816ee Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Mon, 9 Jul 2012 16:42:30 +0200 Subject: [PATCH] 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 Signed-off-by: Avi Kivity --- hw/apic.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/hw/apic.c b/hw/apic.c index 60552df..e65a35f 100644 --- a/hw/apic.c +++ b/hw/apic.c @@ -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; } -- 2.7.4