On Tue, Aug 15, 2023 at 4:20 PM Thomas Huth <th...@redhat.com> wrote:
>
> Using "-device virtio-gpu,blob=true" currently does not work on big
> endian hosts (like s390x). The guest kernel prints an error message
> like:
>
> [drm:virtio_gpu_dequeue_ctrl_func [virtio_gpu]] *ERROR* response 0x1200
> (command 0x10c)
>
> and the display stays black. When running QEMU with "-d guest_errors",
> it shows an error message like this:
>
> virtio_gpu_create_mapping_iov: nr_entries is too big (83886080 > 16384)
>
> which indicates that this value has not been properly byte-swapped.
> And indeed, the virtio_gpu_create_blob_bswap() function (that should
> swap the fields in the related structure) fails to swap some of the
> entries. After correctly swapping all missing values here, too, the
> virtio-gpu device is now also working with blob=true on s390x hosts.
>
> Fixes: e0933d91b1 ("virtio-gpu: Add virtio_gpu_resource_create_blob")
> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2230469
> Signed-off-by: Thomas Huth <th...@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lur...@redhat.com>
> ---
> include/hw/virtio/virtio-gpu-bswap.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/include/hw/virtio/virtio-gpu-bswap.h
> b/include/hw/virtio/virtio-gpu-bswap.h
> index 9124108485..637a0585d0 100644
> --- a/include/hw/virtio/virtio-gpu-bswap.h
> +++ b/include/hw/virtio/virtio-gpu-bswap.h
> @@ -63,7 +63,10 @@ virtio_gpu_create_blob_bswap(struct
> virtio_gpu_resource_create_blob *cblob)
> {
> virtio_gpu_ctrl_hdr_bswap(&cblob->hdr);
> le32_to_cpus(&cblob->resource_id);
> + le32_to_cpus(&cblob->blob_mem);
> le32_to_cpus(&cblob->blob_flags);
> + le32_to_cpus(&cblob->nr_entries);
> + le64_to_cpus(&cblob->blob_id);
> le64_to_cpus(&cblob->size);
> }
>
> --
> 2.39.3
>
