On Sat, Sep 19, 2026 at 3:52 PM Michael S. Tsirkin <[email protected]> wrote:
>
> On Thu, Sep 17, 2026 at 01:19:17PM -0400, Brian Daniels wrote:
> > From: Alexandre Courbot <[email protected]>
> >
> > This patch adds a minimum viable virtio-media driver that binds to the
> > virtio device and registers a V4L2 device and a video device, but lacks
> > any actual functionality.
> >
> > It adds the UAPI header defining the protocol, internal driver headers,
> > Kconfig and Makefile entries, and MAINTAINERS entry. Many of the structs
> > in the protocol add reserved bits. These are present to ensure 64-bit
> > alignment. They are not intended to be used as reserved expansion for
> > the protocol in the future, so more reserved space is not required.
> >
> > The UAPI header includes videodev2.h, which itself does not currently
> > pass UAPI header validation (CONFIG_UAPI_HEADER_TEST=y). I've added
> > virtio_media.h to the same test exception list.
> >
> > Signed-off-by: Alexandre Courbot <[email protected]>
> > Assisted-by: Antigravity:gemini-3.5-flash
> > Co-developed-by: Brian Daniels <[email protected]>
> > Signed-off-by: Brian Daniels <[email protected]>
> > ---
> > MAINTAINERS | 8 +
> > drivers/media/Kconfig | 13 +
> > drivers/media/Makefile | 2 +
> > drivers/media/virtio/Makefile | 7 +
> > drivers/media/virtio/virtio_media.h | 95 +++++++
> > drivers/media/virtio/virtio_media_driver.c | 146 +++++++++++
> > include/uapi/linux/virtio_media.h | 288 +++++++++++++++++++++
> > usr/include/Makefile | 1 +
> > 8 files changed, 560 insertions(+)
> > create mode 100644 drivers/media/virtio/Makefile
> > create mode 100644 drivers/media/virtio/virtio_media.h
> > create mode 100644 drivers/media/virtio/virtio_media_driver.c
> > create mode 100644 include/uapi/linux/virtio_media.h
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 3a19da74d..d6b1e0b30 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -28886,6 +28886,7 @@ F: Documentation/devicetree/bindings/virtio/
> > F: Documentation/driver-api/virtio/
> > F: drivers/block/virtio_blk.c
> > F: drivers/crypto/virtio/
> > +F: drivers/media/virtio/
> > F: drivers/vdpa/
> > F: drivers/virtio/
> > F: include/linux/vdpa.h
> > @@ -28998,6 +28999,13 @@ S: Maintained
> > F: drivers/iommu/virtio-iommu.c
> > F: include/uapi/linux/virtio_iommu.h
> >
> > +VIRTIO MEDIA DRIVER
> > +M: Brian Daniels <[email protected]>
> > +L: [email protected]
> > +S: Maintained
> > +F: drivers/media/virtio/
> > +F: include/uapi/linux/virtio_media.h
> > +
> > VIRTIO MEM DRIVER
> > M: David Hildenbrand <[email protected]>
> > L: [email protected]
> > diff --git a/drivers/media/Kconfig b/drivers/media/Kconfig
> > index 6abc9302c..ce7d088e7 100644
> > --- a/drivers/media/Kconfig
> > +++ b/drivers/media/Kconfig
> > @@ -136,6 +136,19 @@ config MEDIA_PLATFORM_SUPPORT
> >
> > Say Y when you want to be able to see such devices.
> >
> > +config MEDIA_VIRTIO
> > + tristate "Virtio-media Driver"
> > + depends on VIRTIO && VIDEO_DEV && 64BIT && (X86 || CPU_LITTLE_ENDIAN)
> > + select VIDEOBUF2_CORE
> > + select VIDEOBUF2_MEMOPS
> > + help
> > + Enables the virtio-media driver.
> > +
> > + This driver is used to virtualize media devices such as cameras or
> > + decoders from a host into a guest using the V4L2 protocol.
> > +
> > + If unsure, say N.
> > +
> > config MEDIA_TEST_SUPPORT
> > bool
> > prompt "Test drivers" if MEDIA_SUPPORT_FILTER
> > diff --git a/drivers/media/Makefile b/drivers/media/Makefile
> > index 20fac24e4..357e786cc 100644
> > --- a/drivers/media/Makefile
> > +++ b/drivers/media/Makefile
> > @@ -23,6 +23,8 @@ obj-$(CONFIG_DVB_CORE) += dvb-core/
> > # There are both core and drivers at RC subtree - merge before drivers
> > obj-y += rc/
> >
> > +obj-$(CONFIG_MEDIA_VIRTIO) += virtio/
> > +
> > obj-$(CONFIG_CEC_CORE) += cec/
> >
> > #
> > diff --git a/drivers/media/virtio/Makefile b/drivers/media/virtio/Makefile
> > new file mode 100644
> > index 000000000..09d9834da
> > --- /dev/null
> > +++ b/drivers/media/virtio/Makefile
> > @@ -0,0 +1,7 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +#
> > +# Makefile for the virtio-media device driver.
> > +
> > +virtio-media-objs := virtio_media_driver.o
> > +
> > +obj-$(CONFIG_MEDIA_VIRTIO) += virtio-media.o
> > diff --git a/drivers/media/virtio/virtio_media.h
> > b/drivers/media/virtio/virtio_media.h
> > new file mode 100644
> > index 000000000..7acb2b842
> > --- /dev/null
> > +++ b/drivers/media/virtio/virtio_media.h
> > @@ -0,0 +1,95 @@
> > +/* SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0+ */
> > +
> > +/*
> > + * Virtio-media structures & functions declarations.
> > + *
> > + * Copyright (c) 2024-2026 Google LLC.
> > + */
> > +
> > +#ifndef __VIRTIO_MEDIA_H
> > +#define __VIRTIO_MEDIA_H
> > +
> > +#include <linux/virtio_config.h>
> > +#include <media/v4l2-device.h>
> > +
> > +#include "uapi/linux/virtio_media.h"
> > +
> > +#define DESC_CHAIN_MAX_LEN SG_MAX_SINGLE_ALLOC
> > +
> > +#define VIRTIO_MEDIA_DEFAULT_DRIVER_NAME "virtio-media"
> > +
> > +/**
> > + * struct virtio_media - Virtio-media device.
> > + * @v4l2_dev: v4l2_device for the media device.
> > + * @video_dev: video_device for the media device.
> > + * @virtio_dev: virtio device for the media device.
> > + * @commandq: virtio command queue.
> > + * @eventq: virtio event queue.
> > + * @eventq_work: work to run when events are received on @eventq.
> > + * @mmap_region: region into which MMAP buffers are mapped by the host.
> > + * @event_buffer: buffer for event descriptors.
> > + * @sessions: list of active sessions on the device.
> > + * @sessions_lock: protects @sessions and &struct
> > virtio_media_session.list.
> > + * @events_lock: prevents concurrent processing of events.
> > + * @cmd: union of the device commands ``open`` and ``munmap``. The other
> > + * commands are handled by &struct virtio_media_session
> > + * @resp: union of responses to device commands ``open`` and ``munmap``.
> > The
> > + * other responses are handled by &struct virtio_media_session
> > + * @vlock: serializes access to the command queue.
> > + * @wq: waitqueue for host responses on the command queue.
> > + */
> > +struct virtio_media {
> > + struct v4l2_device v4l2_dev;
> > + struct video_device video_dev;
> > +
> > + struct virtio_device *virtio_dev;
> > + struct virtqueue *commandq;
> > + struct virtqueue *eventq;
> > + struct work_struct eventq_work;
> > +
> > + struct virtio_shm_region mmap_region;
> > +
> > + void *event_buffer;
> > +
> > + struct list_head sessions;
> > + struct mutex sessions_lock; /* protects sessions list */
> > +
> > + struct mutex events_lock; /* prevents concurrent event processing */
> > +
> > + __dma_from_device_group_begin();
> > + union {
> > + struct virtio_media_cmd_open open;
> > + struct virtio_media_cmd_munmap munmap;
> > + } cmd;
> > +
> > + union {
> > + struct virtio_media_resp_open open;
> > + struct virtio_media_resp_munmap munmap;
> > + } resp;
> > + __dma_from_device_group_end();
> > +
> > + struct mutex vlock; /* serializes command queue access */
> > + wait_queue_head_t wq;
> > +};
> > +
> > +static inline struct virtio_media *
> > +to_virtio_media(struct video_device *video_dev)
> > +{
> > + return container_of(video_dev, struct virtio_media, video_dev);
> > +}
> > +
> > +/* virtio_media_driver.c */
> > +
> > +int virtio_media_send_command(struct virtio_media *vv, struct scatterlist
> > **sgs,
> > + const size_t out_sgs, const size_t in_sgs,
> > + size_t minimum_resp_len, size_t *resp_len);
> > +void virtio_media_process_events(struct virtio_media *vv);
> > +
> > +/* virtio_media_ioctls.c */
> > +
> > +long virtio_media_device_ioctl(struct file *file, unsigned int cmd,
> > + unsigned long arg);
> > +extern const struct v4l2_ioctl_ops virtio_media_ioctl_ops;
> > +
> > +#endif // __VIRTIO_MEDIA_H
> > +
> > diff --git a/drivers/media/virtio/virtio_media_driver.c
> > b/drivers/media/virtio/virtio_media_driver.c
> > new file mode 100644
> > index 000000000..25f2ceaa6
> > --- /dev/null
> > +++ b/drivers/media/virtio/virtio_media_driver.c
> > @@ -0,0 +1,146 @@
> > +// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0+
> > +
> > +/*
> > + * Virtio-media driver.
> > + *
> > + * Copyright (c) 2024-2026 Google LLC.
> > + */
> > +
> > +#include <linux/device.h>
> > +#include <linux/dev_printk.h>
> > +#include <linux/mutex.h>
> > +#include <linux/types.h>
> > +#include <linux/module.h>
> > +#include <linux/virtio.h>
> > +#include <linux/virtio_config.h>
> > +#include <linux/virtio_ids.h>
> > +
> > +#include <media/v4l2-dev.h>
> > +#include <media/v4l2-device.h>
> > +
> > +#include "uapi/linux/virtio_media.h"
> > +#include "virtio_media.h"
> > +
> > +static void commandq_callback(struct virtqueue *vq)
> > +{
> > +}
> > +
> > +static void eventq_callback(struct virtqueue *vq)
> > +{
> > +}
> > +
> > +static const struct v4l2_file_operations virtio_media_fops = {
> > + .owner = THIS_MODULE,
> > + .open = v4l2_fh_open,
> > + .release = v4l2_fh_release,
> > +};
> > +
> > +static int virtio_media_probe(struct virtio_device *virtio_dev)
> > +{
> > + struct device *dev = &virtio_dev->dev;
> > + struct virtqueue *vqs[2];
> > + static struct virtqueue_info vq_info[2] = {
> > + {
> > + .name = "command",
> > + .callback = commandq_callback,
> > + },
> > + {
> > + .name = "event",
> > + .callback = eventq_callback,
> > + },
> > + };
> > + struct virtio_media *vv;
> > + struct video_device *vd;
> > + int ret;
> > +
> > + vv = devm_kzalloc(dev, sizeof(*vv), GFP_KERNEL);
> > + if (!vv)
> > + return -ENOMEM;
> > +
> > + INIT_LIST_HEAD(&vv->sessions);
> > + mutex_init(&vv->sessions_lock);
> > + mutex_init(&vv->events_lock);
> > + mutex_init(&vv->vlock);
> > +
> > + vv->virtio_dev = virtio_dev;
> > + virtio_dev->priv = vv;
> > +
> > + init_waitqueue_head(&vv->wq);
> > +
> > + ret = v4l2_device_register(dev, &vv->v4l2_dev);
> > + if (ret)
> > + return ret;
> > +
> > + ret = virtio_find_vqs(virtio_dev, 2, vqs, vq_info, NULL);
> > + if (ret)
> > + goto err_find_vqs;
> > +
> > + vv->commandq = vqs[0];
> > + vv->eventq = vqs[1];
> > +
> > + vd = &vv->video_dev;
> > + vd->v4l2_dev = &vv->v4l2_dev;
> > + vd->vfl_type = VFL_TYPE_VIDEO;
> > + vd->fops = &virtio_media_fops;
> > + vd->release = video_device_release_empty;
> > + strscpy(vd->name, "virtio-media", sizeof(vd->name));
> > +
> > + video_set_drvdata(vd, vv);
> > +
> > + vd->device_caps = virtio_cread32(virtio_dev, 0);
>
> please use offsetof device_caps not hard coded "0".
>
> Also, the spec says:
>
>
> struct virtio_media_config {
> le32 device_caps;
> le32 device_type;
> le8 card[32];
> };
>
>
> you (and v4l) should define them as le32 and use virtio_cread_le.
Albert left similar comments, I'll be sure to do this in the next
revision, thanks!
>
>
> > + if (vd->device_caps & (V4L2_CAP_VIDEO_M2M |
> > V4L2_CAP_VIDEO_M2M_MPLANE))
> > + vd->vfl_dir = VFL_DIR_M2M;
> > + else if (vd->device_caps &
> > + (V4L2_CAP_VIDEO_OUTPUT | V4L2_CAP_VIDEO_OUTPUT_MPLANE))
> > + vd->vfl_dir = VFL_DIR_TX;
> > + else
> > + vd->vfl_dir = VFL_DIR_RX;
> > +
> > + ret = video_register_device(vd, virtio_cread32(virtio_dev, 4), 0);
> > + if (ret)
> > + goto err_register_device;
> > +
> > + virtio_device_ready(virtio_dev);
> > +
> > + return 0;
> > +
> > +err_register_device:
> > + virtio_dev->config->del_vqs(virtio_dev);
> > +err_find_vqs:
> > + v4l2_device_unregister(&vv->v4l2_dev);
> > + return ret;
> > +}
> > +
> > +static void virtio_media_remove(struct virtio_device *virtio_dev)
> > +{
> > + struct virtio_media *vv = virtio_dev->priv;
> > +
> > + virtio_reset_device(virtio_dev);
> > + v4l2_device_unregister(&vv->v4l2_dev);
> > + virtio_dev->config->del_vqs(virtio_dev);
> > + video_unregister_device(&vv->video_dev);
> > +}
> > +
> > +static struct virtio_device_id id_table[] = {
> > + { VIRTIO_ID_MEDIA, VIRTIO_DEV_ANY_ID },
> > + { 0 },
> > +};
> > +
> > +static unsigned int features[] = {};
> > +
> > +static struct virtio_driver virtio_media_driver = {
> > + .feature_table = features,
> > + .feature_table_size = ARRAY_SIZE(features),
> > + .driver.name = VIRTIO_MEDIA_DEFAULT_DRIVER_NAME,
> > + .driver.owner = THIS_MODULE,
> > + .id_table = id_table,
> > + .probe = virtio_media_probe,
> > + .remove = virtio_media_remove,
> > +};
> > +
> > +module_virtio_driver(virtio_media_driver);
> > +
> > +MODULE_DEVICE_TABLE(virtio, id_table);
> > +MODULE_DESCRIPTION("virtio media driver");
> > +MODULE_AUTHOR("Alexandre Courbot <[email protected]>");
> > +MODULE_LICENSE("Dual BSD/GPL");
> > diff --git a/include/uapi/linux/virtio_media.h
> > b/include/uapi/linux/virtio_media.h
> > new file mode 100644
> > index 000000000..ac3d75c75
> > --- /dev/null
> > +++ b/include/uapi/linux/virtio_media.h
> > @@ -0,0 +1,288 @@
> > +/* SPDX-License-Identifier: ((GPL-2.0+ WITH Linux-syscall-note) OR
> > BSD-3-Clause) */
> > +
> > +/*
> > + * Definitions of virtio-media protocol structures.
> > + *
> > + * Copyright (c) 2024-2026 Google LLC.
> > + */
> > +
> > +#ifndef _UAPI__LINUX_VIRTIO_MEDIA_H
> > +#define _UAPI__LINUX_VIRTIO_MEDIA_H
> > +
> > +#include <linux/types.h>
> > +#include <linux/videodev2.h>
> > +
> > +/*
> > + * Virtio protocol definition.
> > + */
> > +
> > +/**
> > + * struct virtio_media_cmd_header - Header for all virtio-media commands.
> > + * @cmd: one of VIRTIO_MEDIA_CMD_*.
> > + * @__reserved: must be set to zero by the driver.
> > + *
> > + * This header starts all commands from the driver to the device on the
> > + * commandq.
> > + */
> > +struct virtio_media_cmd_header {
> > + __le32 cmd;
> > + __le32 __reserved;
> > +};
> > +
> > +/**
> > + * struct virtio_media_resp_header - Header for all virtio-media responses.
> > + * @status: 0 if the command was successful, or one of the standard Linux
> > error
> > + * codes as a positive integer.
> > + * @__reserved: must be set to zero by the device.
> > + *
> > + * This header starts all responses from the device to the driver on the
> > + * commandq.
> > + */
> > +struct virtio_media_resp_header {
> > + __le32 status;
> > + __le32 __reserved;
> > +};
> > +
> > +/**
> > + * VIRTIO_MEDIA_CMD_OPEN - Command for creating a new session.
> > + *
> > + * This is the equivalent of calling ``open`` on a V4L2 device node. Upon
> > + * success, a session id is returned which can be used to perform other
> > + * commands on the session, notably ioctls.
> > + */
> > +#define VIRTIO_MEDIA_CMD_OPEN 1
> > +
> > +/**
> > + * struct virtio_media_cmd_open - Driver command for VIRTIO_MEDIA_CMD_OPEN.
> > + * @hdr: header with cmd member set to VIRTIO_MEDIA_CMD_OPEN.
> > + */
> > +struct virtio_media_cmd_open {
> > + struct virtio_media_cmd_header hdr;
> > +};
> > +
> > +/**
> > + * struct virtio_media_resp_open - Device response for
> > VIRTIO_MEDIA_CMD_OPEN.
> > + * @hdr: header containing the status of the command.
> > + * @session_id: if &struct virtio_media_resp_header.status == 0, contains
> > the
> > + * id of the newly created session.
> > + * @__reserved: must be set to zero by the device.
> > + */
> > +struct virtio_media_resp_open {
> > + struct virtio_media_resp_header hdr;
> > + __le32 session_id;
> > + __le32 __reserved;
> > +};
> > +
> > +/**
> > + * VIRTIO_MEDIA_CMD_CLOSE - Command for closing an active session.
> > + *
> > + * This is the equivalent of calling ``close`` on a previously opened V4L2
> > + * session. All resources associated with this session will be freed and
> > the
> > + * session ID shall not be used again after queueing this command.
> > + *
> > + * This command does not require a response from the device.
> > + */
> > +#define VIRTIO_MEDIA_CMD_CLOSE 2
> > +
> > +/**
> > + * struct virtio_media_cmd_close - Driver command for
> > VIRTIO_MEDIA_CMD_CLOSE.
> > + * @hdr: header with cmd member set to VIRTIO_MEDIA_CMD_CLOSE.
> > + * @session_id: id of the session to close.
> > + * @__reserved: must be set to zero by the driver.
> > + */
> > +struct virtio_media_cmd_close {
> > + struct virtio_media_cmd_header hdr;
> > + __le32 session_id;
> > + __le32 __reserved;
> > +};
> > +
> > +/**
> > + * VIRTIO_MEDIA_CMD_IOCTL - Driver command for executing an ioctl.
> > + *
> > + * This command asks the device to run one of the ``VIDIOC_*`` ioctls on
> > the
> > + * active session.
> > + *
> > + * The code of the ioctl is extracted from the VIDIOC_* definitions in
> > + * ``videodev2.h``, and consists of the second argument of the ``_IO*``
> > macro.
> > + *
> > + * Each ioctl has a payload, which is defined by the third argument of the
> > + * ``_IO*`` macro defining it. It can be writable by the driver
> > (``_IOW``), the
> > + * device (``_IOR``), or both (``_IOWR``).
> > + *
> > + * If an ioctl is writable by the driver, it must be followed by a
> > + * driver-writable descriptor containing the payload.
> > + *
> > + * If an ioctl is writable by the device, it must be followed by a
> > + * device-writable descriptor of the size of the payload that the device
> > will
> > + * write into.
> > + *
> > + */
> > +#define VIRTIO_MEDIA_CMD_IOCTL 3
> > +
> > +/**
> > + * struct virtio_media_cmd_ioctl - Driver command for
> > VIRTIO_MEDIA_CMD_IOCTL.
> > + * @hdr: header with cmd member set to VIRTIO_MEDIA_CMD_IOCTL.
> > + * @session_id: id of the session to run the ioctl on.
> > + * @code: code of the ioctl to run.
> > + */
> > +struct virtio_media_cmd_ioctl {
> > + struct virtio_media_cmd_header hdr;
> > + __le32 session_id;
> > + __le32 code;
> > +};
> > +
> > +/**
> > + * struct virtio_media_resp_ioctl - Device response for
> > VIRTIO_MEDIA_CMD_IOCTL.
> > + * @hdr: header containing the status of the ioctl.
> > + */
> > +struct virtio_media_resp_ioctl {
> > + struct virtio_media_resp_header hdr;
> > +};
> > +
> > +/**
> > + * struct virtio_media_sg_entry - Description of part of a scattered guest
> > + * memory.
> > + * @start: start guest address of the memory segment.
> > + * @len: length of this memory segment.
> > + * @__reserved: must be set to zero by the driver.
> > + */
> > +struct virtio_media_sg_entry {
> > + __le64 start;
> > + __le32 len;
> > + __le32 __reserved;
> > +};
> > +
> > +/**
> > + * VIRTIO_MEDIA_MMAP_FLAG_RW - Bit position of the
> > VIRTIO_MEDIA_MMAP_FLAG_RW
> > + * flag.
> > + */
> > +#define VIRTIO_MEDIA_MMAP_FLAG_RW 0
> > +
> > +/**
> > + * VIRTIO_MEDIA_CMD_MMAP - Command for mapping a MMAP buffer into the
> > driver's
> > + * address space.
> > + */
> > +#define VIRTIO_MEDIA_CMD_MMAP 4
> > +
> > +/**
> > + * struct virtio_media_cmd_mmap - Driver command for VIRTIO_MEDIA_CMD_MMAP.
> > + * @hdr: header with cmd member set to VIRTIO_MEDIA_CMD_MMAP.
> > + * @session_id: ID of the session we are mapping for.
> > + * @flags: combination of VIRTIO_MEDIA_MMAP_FLAG_*.
> > + * @offset: mem_offset field of the plane to map, as returned by
> > + * VIDIOC_QUERYBUF.
> > + */
> > +struct virtio_media_cmd_mmap {
> > + struct virtio_media_cmd_header hdr;
> > + __le32 session_id;
> > + __le32 flags;
> > + __le32 offset;
> > +};
> > +
> > +/**
> > + * struct virtio_media_resp_mmap - Device response for
> > VIRTIO_MEDIA_CMD_MMAP.
> > + * @hdr: header containing the status of the command.
> > + * @driver_addr: offset into SHM region 0 of the start of the mapping.
> > + * @len: length of the mapping.
> > + */
> > +struct virtio_media_resp_mmap {
> > + struct virtio_media_resp_header hdr;
> > + __le64 driver_addr;
> > + __le64 len;
> > +};
> > +
> > +/**
> > + * VIRTIO_MEDIA_CMD_MUNMAP - Unmap a MMAP buffer previously mapped using
> > + * VIRTIO_MEDIA_CMD_MMAP.
> > + */
> > +#define VIRTIO_MEDIA_CMD_MUNMAP 5
> > +
> > +/**
> > + * struct virtio_media_cmd_munmap - Driver command for
> > VIRTIO_MEDIA_CMD_MUNMAP.
> > + * @hdr: header with cmd member set to VIRTIO_MEDIA_CMD_MUNMAP.
> > + * @driver_addr: offset into SHM region 0 at which the buffer has been
> > + * previously mapped.
> > + */
> > +struct virtio_media_cmd_munmap {
> > + struct virtio_media_cmd_header hdr;
> > + __le64 driver_addr;
> > +};
> > +
> > +/**
> > + * struct virtio_media_resp_munmap - Device response for
> > + * VIRTIO_MEDIA_CMD_MUNMAP.
> > + * @hdr: header containing the status of the command.
> > + */
> > +struct virtio_media_resp_munmap {
> > + struct virtio_media_resp_header hdr;
> > +};
> > +
> > +/* The values for these events are set by the virtio-media specification.
> > */
> > +#define VIRTIO_MEDIA_EVT_ERROR 0
> > +#define VIRTIO_MEDIA_EVT_DQBUF 1
> > +#define VIRTIO_MEDIA_EVT_EVENT 2
> > +
> > +/**
> > + * struct virtio_media_event_header - Header for events on the eventq.
> > + * @event: one of VIRTIO_MEDIA_EVT_*
> > + * @session_id: ID of the session the event applies to.
> > + */
> > +struct virtio_media_event_header {
> > + __le32 event;
> > + __le32 session_id;
> > +};
> > +
> > +/**
> > + * struct virtio_media_event_error - Unrecoverable device-side error.
> > + * @hdr: header for the event.
> > + * @errno: error code describing the kind of error that occurred.
> > + * @__reserved: must be set to zero by the device.
> > + *
> > + * Upon receiving this event, the session mentioned in the header is
> > considered
> > + * corrupted and closed.
> > + */
> > +struct virtio_media_event_error {
> > + struct virtio_media_event_header hdr;
> > + __le32 errno;
> > + __le32 __reserved;
> > +};
> > +
> > +/* This is set to VIDEO_MAX_PLANES defined in
> > include/uapi/linux/videodev2.h.
> > + * It is renamed here to match the constant that is defined in the
> > virtio-media
> > + * specification.
> > + */
> > +#define VIRTIO_MEDIA_MAX_PLANES VIDEO_MAX_PLANES
> > +
> > +/**
> > + * struct virtio_media_event_dqbuf - Dequeued buffer event.
> > + * @hdr: header for the event.
> > + * @buffer: &struct v4l2_buffer describing the buffer that has been
> > dequeued.
> > + * @planes: plane information for the dequeued buffer.
> > + *
> > + * This event is used to signal that a buffer is not being used anymore by
> > the
> > + * device and is returned to the driver.
> > + */
> > +struct virtio_media_event_dqbuf {
> > + struct virtio_media_event_header hdr;
> > + struct v4l2_buffer buffer;
> > + struct v4l2_plane planes[VIRTIO_MEDIA_MAX_PLANES];
> > +};
> > +
> > +/**
> > + * struct virtio_media_event_event - V4L2 event.
> > + * @hdr: header for the event.
> > + * @event: description of the event that occurred.
> > + *
> > + * This event signals that a V4L2 event has been emitted for a session.
> > + */
> > +struct virtio_media_event_event {
> > + struct virtio_media_event_header hdr;
> > + struct v4l2_event event;
> > +};
> > +
> > +/* Maximum size of an event. We will queue descriptors of this size on the
> > + * eventq.
> > + */
> > +#define VIRTIO_MEDIA_EVENT_MAX_SIZE sizeof(struct virtio_media_event_dqbuf)
> > +
> > +#endif // _UAPI__LINUX_VIRTIO_MEDIA_H
> > diff --git a/usr/include/Makefile b/usr/include/Makefile
> > index ee69dd9d9..df106b5d9 100644
> > --- a/usr/include/Makefile
> > +++ b/usr/include/Makefile
> > @@ -37,6 +37,7 @@ no-header-test += linux/usb/audio.h
> > no-header-test += linux/v4l2-mediabus.h
> > no-header-test += linux/v4l2-subdev.h
> > no-header-test += linux/videodev2.h
> > +no-header-test += linux/virtio_media.h
> > no-header-test += linux/vm_sockets.h
> > no-header-test += sound/asequencer.h
> > no-header-test += sound/asoc.h
> > --
> > 2.55.0.1082.g2b9226bbc0-goog
>
