Re: [Qemu-devel] [PATCH v8 3/4] qxl: add QXL_IO_MONITORS_CONFIG_ASYNC

[Gerd Hoffmann <kraxel@redhat.com>]

  Hi,

Patch looks alot nicer now with a bunch if #ifdefs removed.

One issue left I missed before:

>      case QXL_MODE_COMPAT:
>          /* note: no need to call qxl_create_memslots, qxl_set_mode
> @@ -2065,6 +2124,7 @@ static VMStateDescription qxl_vmstate = {
>          VMSTATE_ARRAY(guest_surfaces.cmds, PCIQXLDevice, NUM_SURFACES, 0,
>                        vmstate_info_uint64, uint64_t),
>          VMSTATE_UINT64(guest_cursor, PCIQXLDevice),
> +        VMSTATE_UINT64(guest_monitors_config, PCIQXLDevice),
>          VMSTATE_END_OF_LIST()
>      },

That breaks migration.

You probably want a subsection here which stuffs guest_monitors_config
into the stream only in case the guest has actually configured it, so
migration between qemu versions with & without monitor config support
keeps working as long as the guest doesn't use the new feature (or it is
disabled via rev=3).

cheers,
  Gerd