Re: [PATCH 2/2] Revert "qxl: add migration blocker to avoid pre-save assert"

[Markus Armbruster]

Gerd Hoffmann <kraxel@redhat.com> writes:

> This reverts commit 86dbcdd9c7590d06db89ca256c5eaf0b4aba8858.
>
> The pre-save assert is gone now, so the migration blocker
> is not needed any more.
>
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  hw/display/qxl.h |  1 -
>  hw/display/qxl.c | 31 -------------------------------
>  2 files changed, 32 deletions(-)
>
> diff --git a/hw/display/qxl.h b/hw/display/qxl.h
> index 379d3304abc1..30d21f4d0bdc 100644
> --- a/hw/display/qxl.h
> +++ b/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;
> diff --git a/hw/display/qxl.c b/hw/display/qxl.c
> index 3867b94fe236..43482d4364ba 100644
> --- a/hw/display/qxl.c
> +++ b/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:

Conflicts with my "[PATCH 09/16] migration: Unify failure check for
migrate_add_blocker()".  Easy to resolve: your patch goes first, I drop
the hunk from mine.

> @@ -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();
>      }