Revert "qxl: add migration blocker to avoid pre-save assert"

This reverts commit 86dbcdd.

The pre-save assert is gone now, so the migration blocker
is not needed any more.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20210721093347.338536-3-kraxel@redhat.com>

hw/display/qxl.c

@@ -30,7 +30,6 @@
 #include "qemu/module.h"
 #include "hw/qdev-properties.h"
 #include "sysemu/runstate.h"
-#include "migration/blocker.h"
 #include "migration/vmstate.h"
 #include "trace.h"
 
@@ -666,30 +665,6 @@ static int interface_get_command(QXLInstance *sin, struct QXLCommandExt *ext)
         qxl->guest_primary.commands++;
         qxl_track_command(qxl, ext);
         qxl_log_command(qxl, "cmd", ext);
-        {
-            /*
-             * Windows 8 drivers place qxl commands in the vram
-             * (instead of the ram) bar.  We can't live migrate such a
-             * guest, so add a migration blocker in case we detect
-             * this, to avoid triggering the assert in pre_save().
-             *
-             * https://cgit.freedesktop.org/spice/win32/qxl-wddm-dod/commit/?id=f6e099db39e7d0787f294d5fd0dce328b5210faa
-             */
-            void *msg = qxl_phys2virt(qxl, ext->cmd.data, ext->group_id);
-            if (msg != NULL && (
-                    msg < (void *)qxl->vga.vram_ptr ||
-                    msg > ((void *)qxl->vga.vram_ptr + qxl->vga.vram_size))) {
-                if (!qxl->migration_blocker) {
-                    Error *local_err = NULL;
-                    error_setg(&qxl->migration_blocker,
-                               "qxl: guest bug: command not in ram bar");
-                    migrate_add_blocker(qxl->migration_blocker, &local_err);
-                    if (local_err) {
-                        error_report_err(local_err);
-                    }
-                }
-            }
-        }
         trace_qxl_ring_command_get(qxl->id, qxl_mode_to_string(qxl->mode));
         return true;
     default:
@@ -1283,12 +1258,6 @@ static void qxl_hard_reset(PCIQXLDevice *d, int loadvm)
     qemu_spice_create_host_memslot(&d->ssd);
     qxl_soft_reset(d);
 
-    if (d->migration_blocker) {
-        migrate_del_blocker(d->migration_blocker);
-        error_free(d->migration_blocker);
-        d->migration_blocker = NULL;
-    }
-
     if (startstop) {
         qemu_spice_display_start();
     }

hw/display/qxl.h

@@ -39,7 +39,6 @@ struct PCIQXLDevice {
     uint32_t           cmdlog;
 
     uint32_t           guest_bug;
-    Error              *migration_blocker;
 
     enum qxl_mode      mode;
     uint32_t           cmdflags;