KVM: x86: reset edge sense circuit of i8259 on init

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>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
index b6a73537e1efd2270a00d52612342ed168081b55..81cf4fa4a2bea8f35eeb8a68c30bdb3b18564271 100644 (file)
--- 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;