Re: [Qemu-devel] [PATCH] qxl: create slots on post_load in any state (fix RHBZ 740547)

[Alon Levy]

On Mon, Oct 17, 2011 at 12:24:20PM +0200, Alon Levy wrote:
> If we migrate when the device is not in a native state the guest
> still believes the slots are created, and will cause operations
> that reference the slots, causing a "panic: virtual address out of range"
> on the first of them. Easy to see by migrating in vga mode (with
> a driver loaded, for instance windows cmd window in full screen mode)
> and then exiting vga mode back to native mode will cause said panic.
> 

Self NACK, doesn't work with compat mode. We don't save delta in
migration.

> Fixed by doing the slot recreation unconditionally at post_load
> 
> Signed-off-by: Alon Levy <address@hidden>
> ---
>  hw/qxl.c |   14 ++++++++------
>  1 files changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/hw/qxl.c b/hw/qxl.c
> index 03848ed..4e9f39f 100644
> --- a/hw/qxl.c
> +++ b/hw/qxl.c
> @@ -1684,6 +1684,14 @@ static int qxl_post_load(void *opaque, int version)
>          qxl_mode_to_string(d->mode));
>      newmode = d->mode;
>      d->mode = QXL_MODE_UNDEFINED;
> +    for (i = 0; i < NUM_MEMSLOTS; i++) {
> +        if (!d->guest_slots[i].active) {
> +            continue;
> +        }
> +        dprint(d, 1, "%s: restoring guest slot %d delta %"PRIu64"\n",
> +               __func__, i, d->guest_slots[i].delta);
> +        qxl_add_memslot(d, i, d->guest_slots[i].delta, QXL_SYNC);
> +    }
>      switch (newmode) {
>      case QXL_MODE_UNDEFINED:
>          break;
> @@ -1691,12 +1699,6 @@ static int qxl_post_load(void *opaque, int version)
>          qxl_enter_vga_mode(d);
>          break;
>      case QXL_MODE_NATIVE:
> -        for (i = 0; i < NUM_MEMSLOTS; i++) {
> -            if (!d->guest_slots[i].active) {
> -                continue;
> -            }
> -            qxl_add_memslot(d, i, 0, QXL_SYNC);
> -        }
>          qxl_create_guest_primary(d, 1, QXL_SYNC);
>  
>          /* replay surface-create and cursor-set commands */
> -- 
> 1.7.6.4
> 
>