KVM: i8259: Make ICW1 conform to spec

ICW is not a full reset, instead it resets a limited number of registers
in the PIC.  Change ICW1 emulation to only reset those registers.

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

1 files changed, 10 insertions, 6 deletions

diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
index 4b7b73ce2098..6e77471951e8 100644
--- a/arch/x86/kvm/i8259.c
+++ b/arch/x86/kvm/i8259.c
@@ -308,13 +308,17 @@ static void pic_ioport_write(void *opaque, u32 addr, u32 val)
         addr &= 1;
         if (addr == 0) {
                 if (val & 0x10) {
-                        kvm_pic_reset(s);       /* init */
-                        /*
-                         * deassert a pending interrupt
-                         */
-                        pic_irq_request(s->pics_state->kvm, 0);
-                        s->init_state = 1;
                         s->init4 = val & 1;
+                        s->last_irr = 0;
+                        s->imr = 0;
+                        s->priority_add = 0;
+                        s->special_mask = 0;
+                        s->read_reg_select = 0;
+                        if (!s->init4) {
+                                s->special_fully_nested_mode = 0;
+                                s->auto_eoi = 0;
+                        }
+                        s->init_state = 1;
                         if (val & 0x02)
                                 printk(KERN_ERR "single mode not supported");
                         if (val & 0x08)