Re: [PATCH v5 4/4] virtio-gpu: advertise VIRTIO_GPU_F_BLOB_ALIGNMENT

["Alex Bennée" <alex.bennee@linaro.org>]

Lucas Amaral <lucaaamaral@gmail.com> writes:

> Set blob_alignment to the host page size so the guest kernel can
> align blob BAR offsets accordingly, avoiding alignment mismatches
> with the VMM's memory mapping API (e.g., hv_vm_map on macOS).
>
> Guest-side kernel support (drm_mm alignment) is pending upstream
> Linux merge.
>
> Signed-off-by: Lucas Amaral <lucaaamaral@gmail.com>
> ---
>  hw/display/virtio-gpu.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/hw/display/virtio-gpu.c b/hw/display/virtio-gpu.c
> index de7a86a7..44ae5034 100644
> --- a/hw/display/virtio-gpu.c
> +++ b/hw/display/virtio-gpu.c
> @@ -1532,6 +1532,14 @@ void virtio_gpu_device_realize(DeviceState *qdev, Error **errp)
>  #endif
>      }
>  
> +    /*
> +     * TODO: guest-side F_BLOB_ALIGNMENT support pending upstream Linux merge
> +     * (Sergio Lopez's patches, Nov 2025). Until merged, the guest won't
> +     * negotiate this feature. The host advertises it per OASIS virtio spec.
> +     */
> +    g->parent_obj.virtio_config.blob_alignment =
> +        cpu_to_le32(qemu_real_host_page_size());
> +

Is it merged yet?

>      if (!virtio_gpu_base_device_realize(qdev,
>                                          virtio_gpu_handle_ctrl_cb,
>                                          virtio_gpu_handle_cursor_cb,

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro