[PATCH] reset edge sense circuit of i8259 on init

[Gleb Natapov <gleb@redhat.com>]

The spec says that during initialization "The edge sense circuit is
reset which means that following initialization an interrupt request
(IR) input must make a low-to-high transition to generate an interrupt",
but currently if edge triggered interrupt is in IRR it is delivered
after i8259 initialization.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
index b6a7353..81cf4fa 100644
--- a/arch/x86/kvm/i8259.c
+++ b/arch/x86/kvm/i8259.c
@@ -307,6 +307,7 @@ static void pic_ioport_write(void *opaque, u32 addr, u32 val)
 		if (val & 0x10) {
 			s->init4 = val & 1;
 			s->last_irr = 0;
+			s->irr &= s->elcr;
 			s->imr = 0;
 			s->priority_add = 0;
 			s->special_mask = 0;
--
			Gleb.