Re: [PATCH 2/3] hw/display: add vhost-user-media device

["Daniel P. Berrangé" <berrange@redhat.com>]

On Tue, Jun 30, 2026 at 01:23:09PM +0200, Albert Esteve wrote:
> Add the QEMU side of the vhost-user-media device, which connects to a
> virtio-media vhost-user backend daemon implementing the V4L2 API over
> the virtio-media protocol.
> 
> The virtio-media device is specified in the VirtIO specification v1.4,
> section 5.22:
>     https://docs.oasis-open.org/virtio/virtio/v1.4/cs01/virtio-v1.4-cs01.html
> 
> Tested with the rust-vmm vhost-device-media backend [1]:
> 
>     cargo run -- -s /path/to/media.sock -d /dev/video0 --backend v4l2-proxy
> 
> Example invocation:
> 
>     qemu-system-x86_64 \
>         -chardev socket,path=/tmp/media.sock,id=media \
>         -device vhost-user-media-pci,chardev=media,id=media
> 
> [1] https://github.com/rust-vmm/vhost-device/pull/944
> 
> Signed-off-by: Albert Esteve <aesteve@redhat.com>
> ---
>  hw/display/Kconfig                   |   5 +
>  hw/display/meson.build               |   3 +
>  hw/display/vhost-user-media-pci.c    |  77 ++++++
>  hw/display/vhost-user-media.c        | 393 +++++++++++++++++++++++++++
>  hw/virtio/virtio.c                   |   3 +-
>  include/hw/virtio/vhost-user-media.h |  47 ++++
>  6 files changed, 527 insertions(+), 1 deletion(-)
>  create mode 100644 hw/display/vhost-user-media-pci.c
>  create mode 100644 hw/display/vhost-user-media.c
>  create mode 100644 include/hw/virtio/vhost-user-media.h
> 
> diff --git a/hw/display/Kconfig b/hw/display/Kconfig
> index b3593fe981..060274b1e6 100644
> --- a/hw/display/Kconfig
> +++ b/hw/display/Kconfig
> @@ -120,6 +120,11 @@ config VHOST_USER_VGA
>      default y
>      depends on VIRTIO_VGA && VHOST_USER_GPU
>  
> +config VHOST_USER_MEDIA
> +    bool
> +    default y
> +    depends on VIRTIO && VHOST_USER
> +
>  config DPCD
>      bool
>      select AUX
> diff --git a/hw/display/meson.build b/hw/display/meson.build
> index ffecedbf70..214c047df6 100644
> --- a/hw/display/meson.build
> +++ b/hw/display/meson.build
> @@ -37,6 +37,9 @@ system_ss.add(when: 'CONFIG_NEXTCUBE', if_true: files('next-fb.c'))
>  system_ss.add(when: 'CONFIG_VGA', if_true: files('vga.c'))
>  system_ss.add(when: 'CONFIG_VIRTIO', if_true: files('virtio-dmabuf.c'))
>  system_ss.add(when: 'CONFIG_DM163', if_true: files('dm163.c'))
> +system_ss.add(when: 'CONFIG_VHOST_USER_MEDIA', if_true: files('vhost-user-media.c'))
> +system_ss.add(when: ['CONFIG_VHOST_USER_MEDIA', 'CONFIG_VIRTIO_PCI' ],
> +  if_true: files('vhost-user-media-pci.c'))
>  
>  stub_ss.add([files('acpi-vga-stub.c'), pixman])
>  if (config_all_devices.has_key('CONFIG_VGA_CIRRUS') or
> diff --git a/hw/display/vhost-user-media-pci.c b/hw/display/vhost-user-media-pci.c
> new file mode 100644
> index 0000000000..ad9e3900a4
> --- /dev/null
> +++ b/hw/display/vhost-user-media-pci.c
> @@ -0,0 +1,77 @@
> +/*
> + * Vhost-user MEDIA virtio device PCI glue
> + *
> + * Copyright Red Hat, Inc. 2024

Have you really been hanging on to this new code for 2 years
before posting ? Should this be 2026 ? 

> + * Authors: Albert Esteve <aesteve@redhat.com>
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */

> diff --git a/hw/display/vhost-user-media.c b/hw/display/vhost-user-media.c
> new file mode 100644
> index 0000000000..5c627437e7
> --- /dev/null
> +++ b/hw/display/vhost-user-media.c
> @@ -0,0 +1,393 @@
> +/*
> + * Vhost-user Media device
> + *
> + * Copyright Red Hat, Inc. 2024

Same Q

> + *
> + * This is the boilerplate for instantiating a vhost-user device
> + * implementing a virtio-media device.
> + *
> + * Authors:
> + *     Albert Esteve <aesteve@redhat.com>
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +

> diff --git a/include/hw/virtio/vhost-user-media.h b/include/hw/virtio/vhost-user-media.h
> new file mode 100644
> index 0000000000..30bdef8ce1
> --- /dev/null
> +++ b/include/hw/virtio/vhost-user-media.h
> @@ -0,0 +1,47 @@
> +/*
> + * vhost-user-media virtio device
> + *
> + * Copyright Red Hat, Inc. 2024

Again


With regards,
Daniel
-- 
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