[Xen-changelog] [qemu-upstream-unstable] pckbd: set bits 2-3-6-7 of the output port by default

[patchbot@xxxxxxx]

commit 49725cdf045e3bb7b6f5ae5d6c1331fdcc034d64
Author:     Paolo Bonzini <pbonzini@xxxxxxxxxx>
AuthorDate: Mon Dec 22 08:55:19 2014 +0100
Commit:     Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
CommitDate: Sun Feb 22 18:06:17 2015 -0600

    pckbd: set bits 2-3-6-7 of the output port by default
    
    OSes typically write 0xdd/0xdf to turn the A20 line off and on.  This
    has bits 2-3-6-7 on, so that the output port subsection is migrated.
    Change the reset value and migration default to include those four
    bits, thus avoiding that the subsection is migrated.
    
    This strictly speaking changes guest ABI, but the long time during which
    we have not migrated the value means that the guests really do not care
    much; so the change is for all machine types.
    
    Reported-by: Igor Mammedov <imammedo@xxxxxxxxxx>
    Cc: qemu-stable@xxxxxxxxxx
    Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
    (cherry picked from commit d13c0404092eb46e548754a47a808da1bb8d4fd0)
    Signed-off-by: Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
---
 hw/input/pckbd.c |   10 ++++++++--
 1 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/hw/input/pckbd.c b/hw/input/pckbd.c
index 2b0cd3d..9b9a7d7 100644
--- a/hw/input/pckbd.c
+++ b/hw/input/pckbd.c
@@ -101,6 +101,12 @@
 #define KBD_OUT_OBF             0x10    /* Keyboard output buffer full */
 #define KBD_OUT_MOUSE_OBF       0x20    /* Mouse output buffer full */
 
+/* OSes typically write 0xdd/0xdf to turn the A20 line off and on.
+ * We make the default value of the outport include these four bits,
+ * so that the subsection is rarely necessary.
+ */
+#define KBD_OUT_ONES            0xcc
+
 /* Mouse Commands */
 #define AUX_SET_SCALE11                0xE6    /* Set 1:1 scaling */
 #define AUX_SET_SCALE21                0xE7    /* Set 2:1 scaling */
@@ -367,13 +373,13 @@ static void kbd_reset(void *opaque)
 
     s->mode = KBD_MODE_KBD_INT | KBD_MODE_MOUSE_INT;
     s->status = KBD_STAT_CMD | KBD_STAT_UNLOCKED;
-    s->outport = KBD_OUT_RESET | KBD_OUT_A20;
+    s->outport = KBD_OUT_RESET | KBD_OUT_A20 | KBD_OUT_ONES;
     s->outport_present = false;
 }
 
 static uint8_t kbd_outport_default(KBDState *s)
 {
-    return KBD_OUT_RESET | KBD_OUT_A20
+    return KBD_OUT_RESET | KBD_OUT_A20 | KBD_OUT_ONES
            | (s->status & KBD_STAT_OBF ? KBD_OUT_OBF : 0)
            | (s->status & KBD_STAT_MOUSE_OBF ? KBD_OUT_MOUSE_OBF : 0);
 }
--
generated by git-patchbot for /home/xen/git/qemu-upstream-unstable.git

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