qxl: fix guest cursor tracking

(1) If the guest cursor command is empty, don't reload it after migration.
(2) Cleaning the guest cursor when it is released by
    the spice server. In addition, explicitly reset the
    cursor in spice upon destroying the primary surface
    (was done by spice-server implicitly). This will prevent
    access to pci memory that was released.

RHBZ: 744518

Signed-off-by: Yonit Halperin <yhalperi@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 12 insertions, 4 deletions

diff --git a/hw/qxl.c b/hw/qxl.c
index 2ca1b04eb0..3a3b3a44ac 100644
--- a/hw/qxl.c
+++ b/hw/qxl.c
@@ -236,6 +236,9 @@ void qxl_spice_reset_image_cache(PCIQXLDevice *qxl)
 void qxl_spice_reset_cursor(PCIQXLDevice *qxl)
 {
     qxl->ssd.worker->reset_cursor(qxl->ssd.worker);
+    qemu_mutex_lock(&qxl->track_lock);
+    qxl->guest_cursor = 0;
+    qemu_mutex_unlock(&qxl->track_lock);
 }
 
 
@@ -400,7 +403,9 @@ static void qxl_track_command(PCIQXLDevice *qxl, struct QXLCommandExt *ext)
     {
         QXLCursorCmd *cmd = qxl_phys2virt(qxl, ext->cmd.data, ext->group_id);
         if (cmd->type == QXL_CURSOR_SET) {
+            qemu_mutex_lock(&qxl->track_lock);
             qxl->guest_cursor = ext->cmd.data;
+            qemu_mutex_unlock(&qxl->track_lock);
         }
         break;
     }
@@ -1065,6 +1070,7 @@ static int qxl_destroy_primary(PCIQXLDevice *d, qxl_async_io async)
 
     d->mode = QXL_MODE_UNDEFINED;
     qemu_spice_destroy_primary_surface(&d->ssd, 0, async);
+    qxl_spice_reset_cursor(d);
     return 1;
 }
 
@@ -1704,10 +1710,12 @@ static int qxl_post_load(void *opaque, int version)
             cmds[out].group_id = MEMSLOT_GROUP_GUEST;
             out++;
         }
-        cmds[out].cmd.data = d->guest_cursor;
-        cmds[out].cmd.type = QXL_CMD_CURSOR;
-        cmds[out].group_id = MEMSLOT_GROUP_GUEST;
-        out++;
+        if (d->guest_cursor) {
+            cmds[out].cmd.data = d->guest_cursor;
+            cmds[out].cmd.type = QXL_CMD_CURSOR;
+            cmds[out].group_id = MEMSLOT_GROUP_GUEST;
+            out++;
+        }
         qxl_spice_loadvm_commands(d, cmds, out);
         g_free(cmds);