[patch 145/176] KVM: i8259: initialize isr_ack

From: Greg KH
Date: Tue Feb 15 2011 - 19:51:37 EST


2.6.36-stable review patch. If anyone has any objections, please let us know.

------------------


From: Avi Kivity <avi@xxxxxxxxxx>

commit a0272630bb594b4eac03a79e77957df7dad8eade upstream.

isr_ack is never initialized. So, until the first PIC reset, interrupts
may fail to be injected. This can cause Windows XP to fail to boot, as
reported in the fallout from the fix to
https://bugzilla.kernel.org/show_bug.cgi?id=21962.

Reported-and-tested-by: Nicolas Prochazka <prochazka.nicolas@xxxxxxxxx>
Signed-off-by: Avi Kivity <avi@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
arch/x86/kvm/i8259.c | 2 ++
1 file changed, 2 insertions(+)

--- a/arch/x86/kvm/i8259.c
+++ b/arch/x86/kvm/i8259.c
@@ -570,6 +570,8 @@ struct kvm_pic *kvm_create_pic(struct kv
s->pics[1].elcr_mask = 0xde;
s->pics[0].pics_state = s;
s->pics[1].pics_state = s;
+ s->pics[0].isr_ack = 0xff;
+ s->pics[1].isr_ack = 0xff;

/*
* Initialize PIO device


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