Re: [PATCH 3/3] drm/virtio: Implement device_attach

[Christian König <christian.koenig@xxxxxxx>]

Am 07.12.24 um 11:50 schrieb Julia Zhang:
> As vram objects may be imported by other gpu drivers, peer2peer flag
> should be checked in dma_buf_ops->attach(). This reimplement virtio gpu
> dma_buf_ops->attach by adding a device_attach() function for virtio gpu.
> This function will get pci_p2pdma_distance and check attach->peer2peer
> before calling drm_gem_map_attach().
>
> Signed-off-by: Julia Zhang <julia.zhang@xxxxxxx>
I can't judge that virtgpu or XEN code path, but that here looks like it 
should work.
Acked-by: Christian König <christian.koenig@xxxxxxx>

> ---
>   drivers/gpu/drm/virtio/virtgpu_prime.c | 14 +++++++++++++-
>   1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_prime.c 
> b/drivers/gpu/drm/virtio/virtgpu_prime.c
> index 4960620eba02..4f6bce79e10e 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_prime.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_prime.c
> @@ -116,6 +116,18 @@ static int virtgpu_get_p2pdma_distance(struct dma_buf 
> *dma_buf,
>         return 0;
>   }
>   
> +static int virtgpu_gem_device_attach(struct dma_buf *dma_buf,
> +                                    struct dma_buf_attachment *attach)
> +{
> +       int ret = virtgpu_get_p2pdma_distance(dma_buf, attach);
> +       if (ret)
> +               return ret;
> +       if (!attach->peer2peer)
> +               return -EBUSY;
> +
> +       return drm_gem_map_attach(dma_buf, attach);
> +}
> +
>   static const struct virtio_dma_buf_ops virtgpu_dmabuf_ops =  {
>         .ops = {
>                 .cache_sgt_mapping = true,
> @@ -128,7 +140,7 @@ static const struct virtio_dma_buf_ops virtgpu_dmabuf_ops = 
>  {
>                 .vmap = drm_gem_dmabuf_vmap,
>                 .vunmap = drm_gem_dmabuf_vunmap,
>         },
> -       .device_attach = drm_gem_map_attach,
> +       .device_attach = virtgpu_gem_device_attach,
>         .get_uuid = virtgpu_virtio_get_uuid,
>   };
>