From a59a98d100123030a4145e7efe3b8a001920a9f1 Mon Sep 17 00:00:00 2001
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From: Mark Asselstine <mark.asselstine@windriver.com>
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Date: Tue, 26 Feb 2013 11:43:28 -0500
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Subject: [PATCH] apic: fixup fallthrough to PIC
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Commit 0e21e12bb311c4c1095d0269dc2ef81196ccb60a [Don't route PIC
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interrupts through the local APIC if the local APIC config says so.]
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missed a check to ensure the local APIC is enabled. Since if the local
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APIC is disabled it doesn't matter what the local APIC config says.
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If this check isn't done and the guest has disabled the local APIC the
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guest will receive a general protection fault, similar to what is seen
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here:
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https://lists.gnu.org/archive/html/qemu-devel/2012-12/msg02304.html
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The GPF is caused by an attempt to service interrupt 0xffffffff. This
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comes about since cpu_get_pic_interrupt() calls apic_accept_pic_intr()
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(with the local APIC disabled apic_get_interrupt() returns -1).
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apic_accept_pic_intr() returns 0 and thus the interrupt number which
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is returned from cpu_get_pic_interrupt(), and which is attempted to be
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serviced, is -1.
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Signed-off-by: Mark Asselstine <mark.asselstine@windriver.com>
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Upstream-Status: Submitted [https://lists.gnu.org/archive/html/qemu-devel/2013-04/msg00878.html]
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Signed-off-by: He Zhe <zhe.he@windriver.com>
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---
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hw/intc/apic.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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Index: qemu-6.0.0/hw/intc/apic.c
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===================================================================
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--- qemu-6.0.0.orig/hw/intc/apic.c
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+++ qemu-6.0.0/hw/intc/apic.c
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@@ -606,7 +606,7 @@ int apic_accept_pic_intr(DeviceState *de
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APICCommonState *s = APIC(dev);
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uint32_t lvt0;
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- if (!s)
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+ if (!s || !(s->spurious_vec & APIC_SV_ENABLE))
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return -1;
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lvt0 = s->lvt[APIC_LVT_LINT0];
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