On 2/20/25 17:28, Sergio Lopez wrote:
> Add VIRTGPU_PARAM_HOST_SHM_PAGE_SIZE as a param that can be read with
> VIRTGPU_GETPARAM by userspace applications running in the guest to
> obtain the host's page size and find out the right alignment to be used
> in shared memory allocations.
>
> Signed-off-by: Sergio Lopez <slp@xxxxxxxxxx>
> ---
> drivers/gpu/drm/virtio/virtgpu_ioctl.c | 5 +++++
> include/uapi/drm/virtgpu_drm.h | 1 +
> 2 files changed, 6 insertions(+)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> index c33c057365f85a2ace536f91655c903036827312..f112b862c2de4d021fb6a54a080f42ad75034227 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> @@ -117,6 +117,11 @@ static int virtio_gpu_getparam_ioctl(struct drm_device *dev, void *data,
> case VIRTGPU_PARAM_EXPLICIT_DEBUG_NAME:
> value = vgdev->has_context_init ? 1 : 0;
> break;
> + case VIRTGPU_PARAM_HOST_SHM_PAGE_SIZE:
> + if (!vgdev->has_host_visible)
> + return -ENOENT;
> + value = vgdev->host_visible_region.page_size;
> + break;
> default:
> return -EINVAL;
> }
> diff --git a/include/uapi/drm/virtgpu_drm.h b/include/uapi/drm/virtgpu_drm.h
> index c2ce71987e9bb816d13a300679336cb756f1cbcf..72db6b3339e0dcaf550acbf5ac4381a6e5c2216d 100644
> --- a/include/uapi/drm/virtgpu_drm.h
> +++ b/include/uapi/drm/virtgpu_drm.h
> @@ -98,6 +98,7 @@ struct drm_virtgpu_execbuffer {
> #define VIRTGPU_PARAM_CONTEXT_INIT 6 /* DRM_VIRTGPU_CONTEXT_INIT */
> #define VIRTGPU_PARAM_SUPPORTED_CAPSET_IDs 7 /* Bitmask of supported capability set ids */
> #define VIRTGPU_PARAM_EXPLICIT_DEBUG_NAME 8 /* Ability to set debug name from userspace */
> +#define VIRTGPU_PARAM_HOST_SHM_PAGE_SIZE 9 /* Host SHM page size, with format PAGE_SIZE >> 12 */
>
> struct drm_virtgpu_getparam {
> __u64 param;
>
Reviewed-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>
--
Best regards,
Dmitry
