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>

diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
index 4b7b73ce209894442eddd9df2b8f076408389b12..6e77471951e8d5255354b1c8456606c30652a169 100644 (file)
--- 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)