Re: [PATCH v6 11/11] virtio-gpu: make blob scanout use dmabuf fd

[Akihiko Odaki <akihiko.odaki@xxxxxxxxxx>]

On 2023/12/19 16:53, Huang Rui wrote:
> From: Robert Beckett <bob.beckett@xxxxxxxxxxxxx>
>
> This relies on a virglrenderer change to include the dmabuf fd when
> returning resource info.
>
> Signed-off-by: Robert Beckett <bob.beckett@xxxxxxxxxxxxx>
> Signed-off-by: Huang Rui <ray.huang@xxxxxxx>
> ---
>
> Changes in v6:
> - Add scanout_blob function for virtio-gpu-virgl.
> - Update for new virgl_gpu_resource.
>
>   hw/display/virtio-gpu-virgl.c  | 104 +++++++++++++++++++++++++++++++++
>   hw/display/virtio-gpu.c        |   4 +-
>   include/hw/virtio/virtio-gpu.h |   6 ++
>   3 files changed, 112 insertions(+), 2 deletions(-)
>
> diff --git a/hw/display/virtio-gpu-virgl.c b/hw/display/virtio-gpu-virgl.c
> index c523a6717a..c384225a98 100644
> --- a/hw/display/virtio-gpu-virgl.c
> +++ b/hw/display/virtio-gpu-virgl.c
> @@ -18,6 +18,7 @@
>   #include "hw/virtio/virtio.h"
>   #include "hw/virtio/virtio-gpu.h"
>   #include "hw/virtio/virtio-gpu-bswap.h"
> +#include "hw/virtio/virtio-gpu-pixman.h"
>   
>   #include "ui/egl-helpers.h"
>   
> @@ -726,6 +727,106 @@ static void virgl_cmd_resource_unmap_blob(VirtIOGPU *g,
>       object_unparent(OBJECT(mr));
>   }
>   
> +static void virgl_cmd_set_scanout_blob(VirtIOGPU *g,
> +                                       struct virtio_gpu_ctrl_command *cmd)
> +{
> +    struct virgl_gpu_resource *vres;
> +    struct virtio_gpu_framebuffer fb = { 0 };
> +    struct virtio_gpu_set_scanout_blob ss;
> +    struct virgl_renderer_resource_info info;
> +    uint64_t fbend;
> +
> +    VIRTIO_GPU_FILL_CMD(ss);
> +    virtio_gpu_scanout_blob_bswap(&ss);
> +    trace_virtio_gpu_cmd_set_scanout_blob(ss.scanout_id, ss.resource_id,
> +                                          ss.r.width, ss.r.height, ss.r.x,
> +                                          ss.r.y);
> +
> +    if (ss.scanout_id >= g->parent_obj.conf.max_outputs) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "%s: illegal scanout id specified %d",
> +                      __func__, ss.scanout_id);
> +        cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_SCANOUT_ID;
> +        return;
> +    }
> +
> +    if (ss.resource_id == 0) {
> +        virtio_gpu_disable_scanout(g, ss.scanout_id);
> +        return;
> +    }
> +
> +    if (ss.width < 16 ||
> +        ss.height < 16 ||
> +        ss.r.x + ss.r.width > ss.width ||
> +        ss.r.y + ss.r.height > ss.height) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "%s: illegal scanout %d bounds for"
> +                      " resource %d, rect (%d,%d)+%d,%d, fb %d %d\n",
> +                      __func__, ss.scanout_id, ss.resource_id,
> +                      ss.r.x, ss.r.y, ss.r.width, ss.r.height,
> +                      ss.width, ss.height);
> +        cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_PARAMETER;
> +        return;
> +    }
> +
> +    if (!console_has_gl(g->parent_obj.scanout[ss.scanout_id].con)) {
Shouldn't OpenGL always be available for virgl?

> +        qemu_log_mask(LOG_GUEST_ERROR, "%s: unable to scanout blot without 
> GL!\n", __func__);
> +        return;
> +    }
> +
> +    vres = virgl_gpu_find_resource(g, ss.resource_id);
> +    if (!vres) {
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "%s: illegal resource specified %d\n",
> +                      __func__, ss.resource_id);
> +        cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_RESOURCE_ID;
> +        return;
> +    }
> +    if (virgl_renderer_resource_get_info(ss.resource_id, &info)) {
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "%s: illegal virgl resource specified %d\n",
> +                      __func__, ss.resource_id);
> +        cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_RESOURCE_ID;
> +        return;
> +    }
> +    if (!vres->res.dmabuf_fd && info.fd)
> +        vres->res.dmabuf_fd = info.fd;
> +
> +    fb.format = virtio_gpu_get_pixman_format(ss.format);
> +    if (!fb.format) {
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "%s: host couldn't handle guest format %d\n",
> +                      __func__, ss.format);
> +        cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_PARAMETER;
> +        return;
> +    }
> +
> +    fb.bytes_pp = DIV_ROUND_UP(PIXMAN_FORMAT_BPP(fb.format), 8);
> +    fb.width = ss.width;
> +    fb.height = ss.height;
> +    fb.stride = ss.strides[0];
> +    fb.offset = ss.offsets[0] + ss.r.x * fb.bytes_pp + ss.r.y * fb.stride;
> +
> +    fbend = fb.offset;
> +    fbend += fb.stride * (ss.r.height - 1);
> +    fbend += fb.bytes_pp * ss.r.width;
> +    if (fbend > vres->res.blob_size) {
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "%s: fb end out of range\n",
> +                      __func__);
> +        cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_PARAMETER;
> +        return;
> +    }
> +
> +    g->parent_obj.enable = 1;
> +    if (virtio_gpu_update_dmabuf(g, ss.scanout_id, &vres->res,
> +                                 &fb, &ss.r)) {
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "%s: failed to update dmabuf\n", __func__);
> +        cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_PARAMETER;
> +        return;
> +    }
> +    virtio_gpu_update_scanout(g, ss.scanout_id, &vres->res, &ss.r);
> +}
> +
>   #endif /* HAVE_VIRGL_RESOURCE_BLOB */
>   
>   void virtio_gpu_virgl_process_cmd(VirtIOGPU *g,
> @@ -807,6 +908,9 @@ void virtio_gpu_virgl_process_cmd(VirtIOGPU *g,
>       case VIRTIO_GPU_CMD_RESOURCE_UNMAP_BLOB:
>           virgl_cmd_resource_unmap_blob(g, cmd);
>           break;
> +    case VIRTIO_GPU_CMD_SET_SCANOUT_BLOB:
VIRTIO_GPU_CMD_SET_SCANOUT_BLOB support should be added before allowing 
the user to enable the resource blob support.
You should also check if virtio_vdev_has_feature(VIRTIO_DEVICE(g), 
VIRTIO_GPU_F_RESOURCE_BLOB). It also applies to other resource blob 
commands though I failed to note that for the earlier patch.