[PULL,2/2] qxl: add migration blocker to avoid pre-save assert

Commit Message

Gerd Hoffmann April 11, 2017, 7:02 a.m. UTC

Cc: [e-mail]
Signed-off-by: Gerd Hoffmann <[e-mail]>
Reviewed-by: Marc-André Lureau <[e-mail]>
Message-id: [e-mail]
---
 hw/display/qxl.h |  1 +
 hw/display/qxl.c | 31 +++++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

Patch

diff --git a/hw/display/qxl.h b/hw/display/qxl.h
index d2d49dd..77e5a36 100644
--- a/hw/display/qxl.h
+++ b/hw/display/qxl.h
@@ -40,6 +40,7 @@  typedef struct PCIQXLDevice {
     uint32_t           cmdlog;
 
     uint32_t           guest_bug;
+    Error              *migration_blocker;
 
     enum qxl_mode      mode;
     uint32_t           cmdflags;
diff --git a/hw/display/qxl.c b/hw/display/qxl.c
index c31b293..9feae78 100644
--- a/hw/display/qxl.c
+++ b/hw/display/qxl.c
@@ -26,6 +26,7 @@ 
 #include "qemu/queue.h"
 #include "qemu/atomic.h"
 #include "sysemu/sysemu.h"
+#include "migration/migration.h"
 #include "trace.h"
 
 #include "qxl.h"
@@ -639,6 +640,30 @@  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:
@@ -1236,6 +1261,12 @@  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();
     }