KVM: i8259: initialize isr_ack

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@gmail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
index 4b7b73ce209894442eddd9df2b8f076408389b12..9f163e61283c7eba3ec30b203de82751a1f701bc 100644 (file)
--- a/arch/x86/kvm/i8259.c
+++ b/arch/x86/kvm/i8259.c
@@ -570,6 +570,8 @@ struct kvm_pic *kvm_create_pic(struct kvm *kvm)
        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