From 1ba58dbd2dce4e6ccaf3be3ad5c9ecc22565313f Mon Sep 17 00:00:00 2001 From: Mark Asselstine Date: Tue, 26 Feb 2013 11:43:28 -0500 Subject: [PATCH] apic: fixup fallthrough to PIC Commit 0e21e12bb311c4c1095d0269dc2ef81196ccb60a [Don't route PIC interrupts through the local APIC if the local APIC config says so.] missed a check to ensure the local APIC is enabled. Since if the local APIC is disabled it doesn't matter what the local APIC config says. If this check isn't done and the guest has disabled the local APIC the guest will receive a general protection fault, similar to what is seen here: https://lists.gnu.org/archive/html/qemu-devel/2012-12/msg02304.html The GPF is caused by an attempt to service interrupt 0xffffffff. This comes about since cpu_get_pic_interrupt() calls apic_accept_pic_intr() (with the local APIC disabled apic_get_interrupt() returns -1). apic_accept_pic_intr() returns 0 and thus the interrupt number which is returned from cpu_get_pic_interrupt(), and which is attempted to be serviced, is -1. Signed-off-by: Mark Asselstine Upstream-Status: Submitted [https://lists.gnu.org/archive/html/qemu-devel/2013-04/msg00878.html] Signed-off-by: He Zhe --- hw/intc/apic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/intc/apic.c b/hw/intc/apic.c index 4186c57b3..43cd805a9 100644 --- a/hw/intc/apic.c +++ b/hw/intc/apic.c @@ -759,7 +759,7 @@ int apic_accept_pic_intr(DeviceState *dev) APICCommonState *s = APIC(dev); uint32_t lvt0; - if (!s) + if (!s || !(s->spurious_vec & APIC_SV_ENABLE)) return -1; lvt0 = s->lvt[APIC_LVT_LINT0];