atapi: make change media detection for guests easier

If you have a guest with a media in the optical drive and you change
it, the windows guest cannot properly recognize this media change.

Windows needs to detect sense "NOT_READY with ASC_MEDIUM_NOT_PRESENT"
before we send sense "UNIT_ATTENTION with ASC_MEDIUM_MAY_HAVE_CHANGED".
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

hw/ide/atapi.c

@@ -1124,12 +1124,17 @@ void ide_atapi_cmd(IDEState *s)
      * GET_EVENT_STATUS_NOTIFICATION to detect such tray open/close
      * states rely on this behavior.
      */
-    if (!s->tray_open && bdrv_is_inserted(s->bs) && s->cdrom_changed) {
-        ide_atapi_cmd_error(s, NOT_READY, ASC_MEDIUM_NOT_PRESENT);
+    if (!(atapi_cmd_table[s->io_buffer[0]].flags & ALLOW_UA) &&
+        !s->tray_open && bdrv_is_inserted(s->bs) && s->cdrom_changed) {
+
+        if (s->cdrom_changed == 1) {
+            ide_atapi_cmd_error(s, NOT_READY, ASC_MEDIUM_NOT_PRESENT);
+            s->cdrom_changed = 2;
+        } else {
+            ide_atapi_cmd_error(s, UNIT_ATTENTION, ASC_MEDIUM_MAY_HAVE_CHANGED);
+            s->cdrom_changed = 0;
+        }
 
-        s->cdrom_changed = 0;
-        s->sense_key = UNIT_ATTENTION;
-        s->asc = ASC_MEDIUM_MAY_HAVE_CHANGED;
         return;
     }
 

hw/ide/core.c

@@ -2160,12 +2160,6 @@ static int ide_drive_post_load(void *opaque, int version_id)
 {
     IDEState *s = opaque;
 
-    if (version_id < 3) {
-        if (s->sense_key == UNIT_ATTENTION &&
-            s->asc == ASC_MEDIUM_MAY_HAVE_CHANGED) {
-            s->cdrom_changed = 1;
-        }
-    }
     if (s->identify_set) {
         bdrv_set_enable_write_cache(s->bs, !!(s->identify_data[85] & (1 << 5)));
     }