qxl: set only off-screen surfaces dirty instead of the whole vram

We used to assure the guest surfaces were saved before migration by
setting the whole vram dirty. This patch sets dirty only the areas
that are actually used in the vram.
Signed-off-by: NYonit Halperin <yhalperi@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

hw/qxl.c

@@ -1007,7 +1007,7 @@ static void qxl_reset_surfaces(PCIQXLDevice *d)
     qxl_spice_destroy_surfaces(d, QXL_SYNC);
 }
 
-/* called from spice server thread context only */
+/* can be also called from spice server thread context */
 void *qxl_phys2virt(PCIQXLDevice *qxl, QXLPHYSICAL pqxl, int group_id)
 {
     uint64_t phys   = le64_to_cpu(pqxl);
@@ -1466,6 +1466,46 @@ static void qxl_hw_text_update(void *opaque, console_ch_t *chardata)
     }
 }
 
+static void qxl_dirty_surfaces(PCIQXLDevice *qxl)
+{
+    intptr_t vram_start;
+    int i;
+
+    if (qxl->mode != QXL_MODE_NATIVE) {
+        return;
+    }
+
+    /* dirty the primary surface */
+    qxl_set_dirty(&qxl->vga.vram, qxl->shadow_rom.draw_area_offset,
+                  qxl->shadow_rom.surface0_area_size);
+
+    vram_start =  (intptr_t)memory_region_get_ram_ptr(&qxl->vram_bar);
+
+    /* dirty the off-screen surfaces */
+    for (i = 0; i < NUM_SURFACES; i++) {
+        QXLSurfaceCmd *cmd;
+        intptr_t surface_offset;
+        int surface_size;
+
+        if (qxl->guest_surfaces.cmds[i] == 0) {
+            continue;
+        }
+
+        cmd = qxl_phys2virt(qxl, qxl->guest_surfaces.cmds[i],
+                            MEMSLOT_GROUP_GUEST);
+        assert(cmd->type == QXL_SURFACE_CMD_CREATE);
+        surface_offset = (intptr_t)qxl_phys2virt(qxl,
+                                                 cmd->u.surface_create.data,
+                                                 MEMSLOT_GROUP_GUEST);
+        surface_offset -= vram_start;
+        surface_size = cmd->u.surface_create.height *
+                       abs(cmd->u.surface_create.stride);
+        dprint(qxl, 3, "%s: dirty surface %d, offset %d, size %d\n", __func__,
+               i, (int)surface_offset, surface_size);
+        qxl_set_dirty(&qxl->vram_bar, surface_offset, surface_size);
+    }
+}
+
 static void qxl_vm_change_state_handler(void *opaque, int running,
                                         RunState state)
 {
@@ -1479,14 +1519,9 @@ static void qxl_vm_change_state_handler(void *opaque, int running,
          * called
          */
          qxl_update_irq(qxl);
-    } else if (qxl->mode == QXL_MODE_NATIVE) {
-        /* dirty all vram (which holds surfaces) and devram (primary surface)
-         * to make sure they are saved */
-        /* FIXME #1: should go out during "live" stage */
-        /* FIXME #2: we only need to save the areas which are actually used */
-        qxl_set_dirty(&qxl->vram_bar, 0, qxl->vram_size);
-        qxl_set_dirty(&qxl->vga.vram, qxl->shadow_rom.draw_area_offset,
-                      qxl->shadow_rom.surface0_area_size);
+    } else {
+        /* make sure surfaces are saved before migration */
+        qxl_dirty_surfaces(qxl);
     }
 }