From: Alexandre Courbot <[email protected]>

Add the first version of the virtio-media driver.

This driver acts roughly as a V4L2 relay between user-space and the
virtio virtual device on the host, so it is relatively simple, yet
unconventional. It doesn't use VB2 or other frameworks typically used in
a V4L2 driver, and most of its complexity resides in correctly and
efficiently building the virtio descriptor chain to pass to the host,
avoiding copies whenever possible. This is done by
scatterlist_builder.[ch].

This version supports MMAP buffers, while USERPTR buffers can also be
enabled through a driver option. DMABUF support is still pending.

NOTE: This depends on the VIRTIO ID being added in this patch:
https://lore.kernel.org/all/[email protected]

Signed-off-by: Alexandre Courbot <[email protected]>
Co-developed-by: Brian Daniels <[email protected]>
Signed-off-by: Brian Daniels <[email protected]>
---
Guest Setup

Tests were ran on a Debian 12 guest running with crosvm. The guest image
was created with:

$ virt-builder debian-12 --root-password password:""

Build crosvm and launch the guest starting at the "Crosvm" section on
this page: 
https://github.com/chromeos/virtio-media/blob/main/TRY_IT_OUT.md#crosvm

NOTE: Before running v4l2-compliance in the guest, you need to install
v4l-utils and ffmpeg:

$ apt update && apt install v4l-utils ffmpeg

---
Compliance Testing

This was tested using v4l2-compliance. Since virtio-media serves as
a proxy to host devices for the guest VMs, we expect the guest
compliance test to essentially match the host compliance test for the
same device.

NOTE: v4l2-compliance changes its test behavior depending on the driver
name. In the guest, the driver name for virtio-media proxied-devices is
always "virtio-media", even if the actual host device has a driver name
of e.g. "uvcvideo". To ensure the test is consistent between the host
and the guest, I created a patch for the v4l2-compliance tool that
allows you to override the driver name. All test results that follow use
this patch:
https://lore.kernel.org/r/[email protected]/

All tests used a Logitech USB Webcam C925e.

As tested on the host:

$ v4l2-compliance -d1 -s

v4l2-compliance 1.33.0-5471, 64 bits, 64-bit time_t
v4l2-compliance SHA: 9f2d3ea879ff 2026-05-28 14:45:11

Compliance test for uvcvideo device /dev/video1:

Driver Info:
        Driver name      : uvcvideo
        Card type        : Logitech Webcam C925e
        Bus info         : usb-0000:04:00.1-3
        Driver version   : 6.18.14
        Capabilities     : 0x84a00001
                Video Capture
                Metadata Capture
                Streaming
                Extended Pix Format
                Device Capabilities
        Device Caps      : 0x04200001
                Video Capture
                Streaming
                Extended Pix Format
Media Driver Info:
        Driver name      : uvcvideo
        Model            : Logitech Webcam C925e
        Serial           : 686F371F
        Bus info         : usb-0000:04:00.1-3
        Media version    : 6.18.14
        Hardware revision: 0x00000016 (22)
        Driver version   : 6.18.14
Interface Info:
        ID               : 0x03000002
        Type             : V4L Video
Entity Info:
        ID               : 0x00000001 (1)
        Name             : Logitech Webcam C925e
        Function         : V4L2 I/O
        Flags            : default
        Pad 0x01000007   : 0: Sink
          Link 0x0200001f: from remote pad 0x100000a of entity 'Processing 3' 
(Video Pixel Formatter): Data, Enabled, Immutable

Required ioctls:
        test MC information (see 'Media Driver Info' above): OK
        test VIDIOC_QUERYCAP: OK
        test invalid ioctls: OK

Allow for multiple opens:
        test second /dev/video1 open: OK
        test VIDIOC_QUERYCAP: OK
        test VIDIOC_G/S_PRIORITY: OK
        test for unlimited opens: OK

Debug ioctls:
        test VIDIOC_DBG_G/S_REGISTER: OK (Not Supported)
        test VIDIOC_LOG_STATUS: OK (Not Supported)

Input ioctls:
        test VIDIOC_G/S_TUNER/ENUM_FREQ_BANDS: OK (Not Supported)
        test VIDIOC_G/S_FREQUENCY: OK (Not Supported)
        test VIDIOC_S_HW_FREQ_SEEK: OK (Not Supported)
        test VIDIOC_ENUMAUDIO: OK (Not Supported)
        test VIDIOC_G/S/ENUMINPUT: OK
        test VIDIOC_G/S_AUDIO: OK (Not Supported)
        Inputs: 1 Audio Inputs: 0 Tuners: 0

Output ioctls:
        test VIDIOC_G/S_MODULATOR: OK (Not Supported)
        test VIDIOC_G/S_FREQUENCY: OK (Not Supported)
        test VIDIOC_ENUMAUDOUT: OK (Not Supported)
        test VIDIOC_G/S/ENUMOUTPUT: OK (Not Supported)
        test VIDIOC_G/S_AUDOUT: OK (Not Supported)
        Outputs: 0 Audio Outputs: 0 Modulators: 0

Input/Output configuration ioctls:
        test VIDIOC_ENUM/G/S/QUERY_STD: OK (Not Supported)
        test VIDIOC_ENUM/G/S/QUERY_DV_TIMINGS: OK (Not Supported)
        test VIDIOC_DV_TIMINGS_CAP: OK (Not Supported)
        test VIDIOC_G/S_EDID: OK (Not Supported)

Control ioctls (Input 0):
        test VIDIOC_QUERY_EXT_CTRL/QUERYMENU: OK
        test VIDIOC_QUERYCTRL: OK
        test VIDIOC_G/S_CTRL: OK
                fail: v4l2-test-controls.cpp(983): ret != EINVAL (got 13)
        test VIDIOC_G/S/TRY_EXT_CTRLS: FAIL
        test VIDIOC_(UN)SUBSCRIBE_EVENT/DQEVENT: OK
        test VIDIOC_G/S_JPEGCOMP: OK (Not Supported)
        Standard Controls: 19 Private Controls: 0

Format ioctls (Input 0):
        test VIDIOC_ENUM_FMT/FRAMESIZES/FRAMEINTERVALS: OK
        test VIDIOC_G/S_PARM: OK
        test VIDIOC_G_FBUF: OK (Not Supported)
        test VIDIOC_G_FMT: OK
        test VIDIOC_TRY_FMT: OK
        test VIDIOC_S_FMT: OK
        test VIDIOC_G_SLICED_VBI_CAP: OK (Not Supported)
        test Cropping: OK (Not Supported)
        test Composing: OK (Not Supported)
        test Scaling: OK (Not Supported)

Codec ioctls (Input 0):
        test VIDIOC_(TRY_)ENCODER_CMD: OK (Not Supported)
        test VIDIOC_G_ENC_INDEX: OK (Not Supported)
        test VIDIOC_(TRY_)DECODER_CMD: OK (Not Supported)

Buffer ioctls (Input 0):
        test VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF: OK
        test CREATE_BUFS maximum buffers: OK
        test VIDIOC_REMOVE_BUFS: OK
        test VIDIOC_EXPBUF: OK
        test Requests: OK (Not Supported)
        test blocking wait: OK

Test input 0:

Streaming ioctls:
        test read/write: OK (Not Supported)

        Video Capture: Frame #000
        Video Capture: Frame #001
        Video Capture: Frame #002
        Video Capture: Frame #003
        Video Capture: Frame #004
        Video Capture: Frame #005
        Video Capture: Frame #006
        Video Capture: Frame #007
        Video Capture: Frame #008
        Video Capture: Frame #009
        Video Capture: Frame #010
        Video Capture: Frame #011
        Video Capture: Frame #012
        Video Capture: Frame #013
        Video Capture: Frame #014
        Video Capture: Frame #015
        Video Capture: Frame #016
        Video Capture: Frame #017
        Video Capture: Frame #018
        Video Capture: Frame #019
        Video Capture: Frame #020
        Video Capture: Frame #021
        Video Capture: Frame #022
        Video Capture: Frame #023
        Video Capture: Frame #024
        Video Capture: Frame #025
        Video Capture: Frame #026
        Video Capture: Frame #027
        Video Capture: Frame #028
        Video Capture: Frame #029
        Video Capture: Frame #030
        Video Capture: Frame #031
        Video Capture: Frame #032
        Video Capture: Frame #033
        Video Capture: Frame #034
        Video Capture: Frame #035
        Video Capture: Frame #036
        Video Capture: Frame #037
        Video Capture: Frame #038
        Video Capture: Frame #039
        Video Capture: Frame #040
        Video Capture: Frame #041
        Video Capture: Frame #042
        Video Capture: Frame #043
        Video Capture: Frame #044
        Video Capture: Frame #045
        Video Capture: Frame #046
        Video Capture: Frame #047
        Video Capture: Frame #048
        Video Capture: Frame #049
        Video Capture: Frame #050
        Video Capture: Frame #051
        Video Capture: Frame #052
        Video Capture: Frame #053
        Video Capture: Frame #054
        Video Capture: Frame #055
        Video Capture: Frame #056
        Video Capture: Frame #057
        Video Capture: Frame #058
        Video Capture: Frame #059

        test MMAP (no poll, REQBUFS): OK

        Video Capture: Frame #000 (select)
        Video Capture: Frame #001 (select)
        Video Capture: Frame #002 (select)
        Video Capture: Frame #003 (select)
        Video Capture: Frame #004 (select)
        Video Capture: Frame #005 (select)
        Video Capture: Frame #006 (select)
        Video Capture: Frame #007 (select)
        Video Capture: Frame #008 (select)
        Video Capture: Frame #009 (select)
        Video Capture: Frame #010 (select)
        Video Capture: Frame #011 (select)
        Video Capture: Frame #012 (select)
        Video Capture: Frame #013 (select)
        Video Capture: Frame #014 (select)
        Video Capture: Frame #015 (select)
        Video Capture: Frame #016 (select)
        Video Capture: Frame #017 (select)
        Video Capture: Frame #018 (select)
        Video Capture: Frame #019 (select)
        Video Capture: Frame #020 (select)
        Video Capture: Frame #021 (select)
        Video Capture: Frame #022 (select)
        Video Capture: Frame #023 (select)
        Video Capture: Frame #024 (select)
        Video Capture: Frame #025 (select)
        Video Capture: Frame #026 (select)
        Video Capture: Frame #027 (select)
        Video Capture: Frame #028 (select)
        Video Capture: Frame #029 (select)
        Video Capture: Frame #030 (select)
        Video Capture: Frame #031 (select)
        Video Capture: Frame #032 (select)
        Video Capture: Frame #033 (select)
        Video Capture: Frame #034 (select)
        Video Capture: Frame #035 (select)
        Video Capture: Frame #036 (select)
        Video Capture: Frame #037 (select)
        Video Capture: Frame #038 (select)
        Video Capture: Frame #039 (select)
        Video Capture: Frame #040 (select)
        Video Capture: Frame #041 (select)
        Video Capture: Frame #042 (select)
        Video Capture: Frame #043 (select)
        Video Capture: Frame #044 (select)
        Video Capture: Frame #045 (select)
        Video Capture: Frame #046 (select)
        Video Capture: Frame #047 (select)
        Video Capture: Frame #048 (select)
        Video Capture: Frame #049 (select)
        Video Capture: Frame #050 (select)
        Video Capture: Frame #051 (select)
        Video Capture: Frame #052 (select)
        Video Capture: Frame #053 (select)
        Video Capture: Frame #054 (select)
        Video Capture: Frame #055 (select)
        Video Capture: Frame #056 (select)
        Video Capture: Frame #057 (select)
        Video Capture: Frame #058 (select)
        Video Capture: Frame #059 (select)

        test MMAP (select, REQBUFS): OK

        Video Capture: Frame #000 (epoll)
        Video Capture: Frame #001 (epoll)
        Video Capture: Frame #002 (epoll)
        Video Capture: Frame #003 (epoll)
        Video Capture: Frame #004 (epoll)
        Video Capture: Frame #005 (epoll)
        Video Capture: Frame #006 (epoll)
        Video Capture: Frame #007 (epoll)
        Video Capture: Frame #008 (epoll)
        Video Capture: Frame #009 (epoll)
        Video Capture: Frame #010 (epoll)
        Video Capture: Frame #011 (epoll)
        Video Capture: Frame #012 (epoll)
        Video Capture: Frame #013 (epoll)
        Video Capture: Frame #014 (epoll)
        Video Capture: Frame #015 (epoll)
        Video Capture: Frame #016 (epoll)
        Video Capture: Frame #017 (epoll)
        Video Capture: Frame #018 (epoll)
        Video Capture: Frame #019 (epoll)
        Video Capture: Frame #020 (epoll)
        Video Capture: Frame #021 (epoll)
        Video Capture: Frame #022 (epoll)
        Video Capture: Frame #023 (epoll)
        Video Capture: Frame #024 (epoll)
        Video Capture: Frame #025 (epoll)
        Video Capture: Frame #026 (epoll)
        Video Capture: Frame #027 (epoll)
        Video Capture: Frame #028 (epoll)
        Video Capture: Frame #029 (epoll)
        Video Capture: Frame #030 (epoll)
        Video Capture: Frame #031 (epoll)
        Video Capture: Frame #032 (epoll)
        Video Capture: Frame #033 (epoll)
        Video Capture: Frame #034 (epoll)
        Video Capture: Frame #035 (epoll)
        Video Capture: Frame #036 (epoll)
        Video Capture: Frame #037 (epoll)
        Video Capture: Frame #038 (epoll)
        Video Capture: Frame #039 (epoll)
        Video Capture: Frame #040 (epoll)
        Video Capture: Frame #041 (epoll)
        Video Capture: Frame #042 (epoll)
        Video Capture: Frame #043 (epoll)
        Video Capture: Frame #044 (epoll)
        Video Capture: Frame #045 (epoll)
        Video Capture: Frame #046 (epoll)
        Video Capture: Frame #047 (epoll)
        Video Capture: Frame #048 (epoll)
        Video Capture: Frame #049 (epoll)
        Video Capture: Frame #050 (epoll)
        Video Capture: Frame #051 (epoll)
        Video Capture: Frame #052 (epoll)
        Video Capture: Frame #053 (epoll)
        Video Capture: Frame #054 (epoll)
        Video Capture: Frame #055 (epoll)
        Video Capture: Frame #056 (epoll)
        Video Capture: Frame #057 (epoll)
        Video Capture: Frame #058 (epoll)
        Video Capture: Frame #059 (epoll)

        test MMAP (epoll, REQBUFS): OK

        Video Capture: Frame #000
        Video Capture: Frame #001
        Video Capture: Frame #002
        Video Capture: Frame #003
        Video Capture: Frame #004
        Video Capture: Frame #005
        Video Capture: Frame #006
        Video Capture: Frame #007
        Video Capture: Frame #008
        Video Capture: Frame #009
        Video Capture: Frame #010
        Video Capture: Frame #011
        Video Capture: Frame #012
        Video Capture: Frame #013
        Video Capture: Frame #014
        Video Capture: Frame #015
        Video Capture: Frame #016
        Video Capture: Frame #017
        Video Capture: Frame #018
        Video Capture: Frame #019
        Video Capture: Frame #020
        Video Capture: Frame #021
        Video Capture: Frame #022
        Video Capture: Frame #023
        Video Capture: Frame #024
        Video Capture: Frame #025
        Video Capture: Frame #026
        Video Capture: Frame #027
        Video Capture: Frame #028
        Video Capture: Frame #029
        Video Capture: Frame #030
        Video Capture: Frame #031
        Video Capture: Frame #032
        Video Capture: Frame #033
        Video Capture: Frame #034
        Video Capture: Frame #035
        Video Capture: Frame #036
        Video Capture: Frame #037
        Video Capture: Frame #038
        Video Capture: Frame #039
        Video Capture: Frame #040
        Video Capture: Frame #041
        Video Capture: Frame #042
        Video Capture: Frame #043
        Video Capture: Frame #044
        Video Capture: Frame #045
        Video Capture: Frame #046
        Video Capture: Frame #047
        Video Capture: Frame #048
        Video Capture: Frame #049
        Video Capture: Frame #050
        Video Capture: Frame #051
        Video Capture: Frame #052
        Video Capture: Frame #053
        Video Capture: Frame #054
        Video Capture: Frame #055
        Video Capture: Frame #056
        Video Capture: Frame #057
        Video Capture: Frame #058
        Video Capture: Frame #059

        test MMAP (no poll, CREATE_BUFS): OK

        Video Capture: Frame #000 (select)
        Video Capture: Frame #001 (select)
        Video Capture: Frame #002 (select)
        Video Capture: Frame #003 (select)
        Video Capture: Frame #004 (select)
        Video Capture: Frame #005 (select)
        Video Capture: Frame #006 (select)
        Video Capture: Frame #007 (select)
        Video Capture: Frame #008 (select)
        Video Capture: Frame #009 (select)
        Video Capture: Frame #010 (select)
        Video Capture: Frame #011 (select)
        Video Capture: Frame #012 (select)
        Video Capture: Frame #013 (select)
        Video Capture: Frame #014 (select)
        Video Capture: Frame #015 (select)
        Video Capture: Frame #016 (select)
        Video Capture: Frame #017 (select)
        Video Capture: Frame #018 (select)
        Video Capture: Frame #019 (select)
        Video Capture: Frame #020 (select)
        Video Capture: Frame #021 (select)
        Video Capture: Frame #022 (select)
        Video Capture: Frame #023 (select)
        Video Capture: Frame #024 (select)
        Video Capture: Frame #025 (select)
        Video Capture: Frame #026 (select)
        Video Capture: Frame #027 (select)
        Video Capture: Frame #028 (select)
        Video Capture: Frame #029 (select)
        Video Capture: Frame #030 (select)
        Video Capture: Frame #031 (select)
        Video Capture: Frame #032 (select)
        Video Capture: Frame #033 (select)
        Video Capture: Frame #034 (select)
        Video Capture: Frame #035 (select)
        Video Capture: Frame #036 (select)
        Video Capture: Frame #037 (select)
        Video Capture: Frame #038 (select)
        Video Capture: Frame #039 (select)
        Video Capture: Frame #040 (select)
        Video Capture: Frame #041 (select)
        Video Capture: Frame #042 (select)
        Video Capture: Frame #043 (select)
        Video Capture: Frame #044 (select)
        Video Capture: Frame #045 (select)
        Video Capture: Frame #046 (select)
        Video Capture: Frame #047 (select)
        Video Capture: Frame #048 (select)
        Video Capture: Frame #049 (select)
        Video Capture: Frame #050 (select)
        Video Capture: Frame #051 (select)
        Video Capture: Frame #052 (select)
        Video Capture: Frame #053 (select)
        Video Capture: Frame #054 (select)
        Video Capture: Frame #055 (select)
        Video Capture: Frame #056 (select)
        Video Capture: Frame #057 (select)
        Video Capture: Frame #058 (select)
        Video Capture: Frame #059 (select)

        test MMAP (select, CREATE_BUFS): OK

        Video Capture: Frame #000 (epoll)
        Video Capture: Frame #001 (epoll)
        Video Capture: Frame #002 (epoll)
        Video Capture: Frame #003 (epoll)
        Video Capture: Frame #004 (epoll)
        Video Capture: Frame #005 (epoll)
        Video Capture: Frame #006 (epoll)
        Video Capture: Frame #007 (epoll)
        Video Capture: Frame #008 (epoll)
        Video Capture: Frame #009 (epoll)
        Video Capture: Frame #010 (epoll)
        Video Capture: Frame #011 (epoll)
        Video Capture: Frame #012 (epoll)
        Video Capture: Frame #013 (epoll)
        Video Capture: Frame #014 (epoll)
        Video Capture: Frame #015 (epoll)
        Video Capture: Frame #016 (epoll)
        Video Capture: Frame #017 (epoll)
        Video Capture: Frame #018 (epoll)
        Video Capture: Frame #019 (epoll)
        Video Capture: Frame #020 (epoll)
        Video Capture: Frame #021 (epoll)
        Video Capture: Frame #022 (epoll)
        Video Capture: Frame #023 (epoll)
        Video Capture: Frame #024 (epoll)
        Video Capture: Frame #025 (epoll)
        Video Capture: Frame #026 (epoll)
        Video Capture: Frame #027 (epoll)
        Video Capture: Frame #028 (epoll)
        Video Capture: Frame #029 (epoll)
        Video Capture: Frame #030 (epoll)
        Video Capture: Frame #031 (epoll)
        Video Capture: Frame #032 (epoll)
        Video Capture: Frame #033 (epoll)
        Video Capture: Frame #034 (epoll)
        Video Capture: Frame #035 (epoll)
        Video Capture: Frame #036 (epoll)
        Video Capture: Frame #037 (epoll)
        Video Capture: Frame #038 (epoll)
        Video Capture: Frame #039 (epoll)
        Video Capture: Frame #040 (epoll)
        Video Capture: Frame #041 (epoll)
        Video Capture: Frame #042 (epoll)
        Video Capture: Frame #043 (epoll)
        Video Capture: Frame #044 (epoll)
        Video Capture: Frame #045 (epoll)
        Video Capture: Frame #046 (epoll)
        Video Capture: Frame #047 (epoll)
        Video Capture: Frame #048 (epoll)
        Video Capture: Frame #049 (epoll)
        Video Capture: Frame #050 (epoll)
        Video Capture: Frame #051 (epoll)
        Video Capture: Frame #052 (epoll)
        Video Capture: Frame #053 (epoll)
        Video Capture: Frame #054 (epoll)
        Video Capture: Frame #055 (epoll)
        Video Capture: Frame #056 (epoll)
        Video Capture: Frame #057 (epoll)
        Video Capture: Frame #058 (epoll)
        Video Capture: Frame #059 (epoll)

        test MMAP (epoll, CREATE_BUFS): OK

        Video Capture: Frame #000
        Video Capture: Frame #001
        Video Capture: Frame #002
        Video Capture: Frame #003
        Video Capture: Frame #004
        Video Capture: Frame #005
        Video Capture: Frame #006
        Video Capture: Frame #007
        Video Capture: Frame #008
        Video Capture: Frame #009
        Video Capture: Frame #010
        Video Capture: Frame #011
        Video Capture: Frame #012
        Video Capture: Frame #013
        Video Capture: Frame #014
        Video Capture: Frame #015
        Video Capture: Frame #016
        Video Capture: Frame #017
        Video Capture: Frame #018
        Video Capture: Frame #019
        Video Capture: Frame #020
        Video Capture: Frame #021
        Video Capture: Frame #022
        Video Capture: Frame #023
        Video Capture: Frame #024
        Video Capture: Frame #025
        Video Capture: Frame #026
        Video Capture: Frame #027
        Video Capture: Frame #028
        Video Capture: Frame #029
        Video Capture: Frame #030
        Video Capture: Frame #031
        Video Capture: Frame #032
        Video Capture: Frame #033
        Video Capture: Frame #034
        Video Capture: Frame #035
        Video Capture: Frame #036
        Video Capture: Frame #037
        Video Capture: Frame #038
        Video Capture: Frame #039
        Video Capture: Frame #040
        Video Capture: Frame #041
        Video Capture: Frame #042
        Video Capture: Frame #043
        Video Capture: Frame #044
        Video Capture: Frame #045
        Video Capture: Frame #046
        Video Capture: Frame #047
        Video Capture: Frame #048
        Video Capture: Frame #049
        Video Capture: Frame #050
        Video Capture: Frame #051
        Video Capture: Frame #052
        Video Capture: Frame #053
        Video Capture: Frame #054
        Video Capture: Frame #055
        Video Capture: Frame #056
        Video Capture: Frame #057
        Video Capture: Frame #058
        Video Capture: Frame #059

        test USERPTR (no poll): OK

        Video Capture: Frame #000 (select)
        Video Capture: Frame #001 (select)
        Video Capture: Frame #002 (select)
        Video Capture: Frame #003 (select)
        Video Capture: Frame #004 (select)
        Video Capture: Frame #005 (select)
        Video Capture: Frame #006 (select)
        Video Capture: Frame #007 (select)
        Video Capture: Frame #008 (select)
        Video Capture: Frame #009 (select)
        Video Capture: Frame #010 (select)
        Video Capture: Frame #011 (select)
        Video Capture: Frame #012 (select)
        Video Capture: Frame #013 (select)
        Video Capture: Frame #014 (select)
        Video Capture: Frame #015 (select)
        Video Capture: Frame #016 (select)
        Video Capture: Frame #017 (select)
        Video Capture: Frame #018 (select)
        Video Capture: Frame #019 (select)
        Video Capture: Frame #020 (select)
        Video Capture: Frame #021 (select)
        Video Capture: Frame #022 (select)
        Video Capture: Frame #023 (select)
        Video Capture: Frame #024 (select)
        Video Capture: Frame #025 (select)
        Video Capture: Frame #026 (select)
        Video Capture: Frame #027 (select)
        Video Capture: Frame #028 (select)
        Video Capture: Frame #029 (select)
        Video Capture: Frame #030 (select)
        Video Capture: Frame #031 (select)
        Video Capture: Frame #032 (select)
        Video Capture: Frame #033 (select)
        Video Capture: Frame #034 (select)
        Video Capture: Frame #035 (select)
        Video Capture: Frame #036 (select)
        Video Capture: Frame #037 (select)
        Video Capture: Frame #038 (select)
        Video Capture: Frame #039 (select)
        Video Capture: Frame #040 (select)
        Video Capture: Frame #041 (select)
        Video Capture: Frame #042 (select)
        Video Capture: Frame #043 (select)
        Video Capture: Frame #044 (select)
        Video Capture: Frame #045 (select)
        Video Capture: Frame #046 (select)
        Video Capture: Frame #047 (select)
        Video Capture: Frame #048 (select)
        Video Capture: Frame #049 (select)
        Video Capture: Frame #050 (select)
        Video Capture: Frame #051 (select)
        Video Capture: Frame #052 (select)
        Video Capture: Frame #053 (select)
        Video Capture: Frame #054 (select)
        Video Capture: Frame #055 (select)
        Video Capture: Frame #056 (select)
        Video Capture: Frame #057 (select)
        Video Capture: Frame #058 (select)
        Video Capture: Frame #059 (select)

        test USERPTR (select): OK
        test DMABUF: Cannot test, specify --expbuf-device

Total for uvcvideo device /dev/video1: 58, Succeeded: 57, Failed: 1, Warnings: 0

As tested on the guest:

$ v4l2-compliance -d0 -s --driver-name uvcvideo

v4l2-compliance 1.33.0-5457, 64 bits, 64-bit time_t
v4l2-compliance SHA: e7e240f546f3 2026-05-28 17:06:12

Compliance test for uvcvideo device (overridden from virtio-media) /dev/video0:

Driver Info:
        Driver name      : uvcvideo
        Card type        : Logitech Webcam C925e
        Bus info         : platform:virtio-media
        Driver version   : 7.1.0
        Capabilities     : 0x84200001
                Video Capture
                Streaming
                Extended Pix Format
                Device Capabilities
        Device Caps      : 0x04200001
                Video Capture
                Streaming
                Extended Pix Format

Required ioctls:
        test VIDIOC_QUERYCAP: OK
        test invalid ioctls: OK

Allow for multiple opens:
        test second /dev/video0 open: OK
        test VIDIOC_QUERYCAP: OK
        test VIDIOC_G/S_PRIORITY: OK
        test for unlimited opens: OK

Debug ioctls:
        test VIDIOC_DBG_G/S_REGISTER: OK (Not Supported)
        test VIDIOC_LOG_STATUS: OK (Not Supported)

Input ioctls:
        test VIDIOC_G/S_TUNER/ENUM_FREQ_BANDS: OK (Not Supported)
        test VIDIOC_G/S_FREQUENCY: OK (Not Supported)
        test VIDIOC_S_HW_FREQ_SEEK: OK
        test VIDIOC_ENUMAUDIO: OK (Not Supported)
        test VIDIOC_G/S/ENUMINPUT: OK
        test VIDIOC_G/S_AUDIO: OK (Not Supported)
        Inputs: 1 Audio Inputs: 0 Tuners: 0

Output ioctls:
        test VIDIOC_G/S_MODULATOR: OK (Not Supported)
        test VIDIOC_G/S_FREQUENCY: OK (Not Supported)
        test VIDIOC_ENUMAUDOUT: OK (Not Supported)
        test VIDIOC_G/S/ENUMOUTPUT: OK (Not Supported)
        test VIDIOC_G/S_AUDOUT: OK (Not Supported)
        Outputs: 0 Audio Outputs: 0 Modulators: 0

Input/Output configuration ioctls:
        test VIDIOC_ENUM/G/S/QUERY_STD: OK (Not Supported)
        test VIDIOC_ENUM/G/S/QUERY_DV_TIMINGS: OK (Not Supported)
        test VIDIOC_DV_TIMINGS_CAP: OK (Not Supported)
        test VIDIOC_G/S_EDID: OK (Not Supported)

Control ioctls (Input 0):
        test VIDIOC_QUERY_EXT_CTRL/QUERYMENU: OK
        test VIDIOC_QUERYCTRL: OK
        test VIDIOC_G/S_CTRL: OK
                fail: v4l2-test-controls.cpp(981): ret (got 22)
        test VIDIOC_G/S/TRY_EXT_CTRLS: FAIL
        test VIDIOC_(UN)SUBSCRIBE_EVENT/DQEVENT: OK
        test VIDIOC_G/S_JPEGCOMP: OK (Not Supported)
        Standard Controls: 19 Private Controls: 0

Format ioctls (Input 0):
        test VIDIOC_ENUM_FMT/FRAMESIZES/FRAMEINTERVALS: OK
        test VIDIOC_G/S_PARM: OK
        test VIDIOC_G_FBUF: OK (Not Supported)
        test VIDIOC_G_FMT: OK
        test VIDIOC_TRY_FMT: OK
        test VIDIOC_S_FMT: OK
        test VIDIOC_G_SLICED_VBI_CAP: OK (Not Supported)
        test Cropping: OK (Not Supported)
        test Composing: OK (Not Supported)
        test Scaling: OK (Not Supported)

Codec ioctls (Input 0):
        test VIDIOC_(TRY_)ENCODER_CMD: OK (Not Supported)
        test VIDIOC_G_ENC_INDEX: OK (Not Supported)
        test VIDIOC_(TRY_)DECODER_CMD: OK (Not Supported)

Buffer ioctls (Input 0):
        test VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF: OK
        test CREATE_BUFS maximum buffers: OK
        test VIDIOC_REMOVE_BUFS: OK
        test VIDIOC_EXPBUF: OK (Not Supported)
        test Requests: OK (Not Supported)
        test blocking wait: OK

Test input 0:

Streaming ioctls:
        test read/write: OK (Not Supported)

        Video Capture: Frame #000
        Video Capture: Frame #001
        Video Capture: Frame #002
        Video Capture: Frame #003
        Video Capture: Frame #004
        Video Capture: Frame #005
        Video Capture: Frame #006
        Video Capture: Frame #007
        Video Capture: Frame #008
        Video Capture: Frame #009
        Video Capture: Frame #010
        Video Capture: Frame #011
        Video Capture: Frame #012
        Video Capture: Frame #013
        Video Capture: Frame #014
        Video Capture: Frame #015
        Video Capture: Frame #016
        Video Capture: Frame #017
        Video Capture: Frame #018
        Video Capture: Frame #019
        Video Capture: Frame #020
        Video Capture: Frame #021
        Video Capture: Frame #022
        Video Capture: Frame #023
        Video Capture: Frame #024
        Video Capture: Frame #025
        Video Capture: Frame #026
        Video Capture: Frame #027
        Video Capture: Frame #028
        Video Capture: Frame #029
        Video Capture: Frame #030
        Video Capture: Frame #031
        Video Capture: Frame #032
        Video Capture: Frame #033
        Video Capture: Frame #034
        Video Capture: Frame #035
        Video Capture: Frame #036
        Video Capture: Frame #037
        Video Capture: Frame #038
        Video Capture: Frame #039
        Video Capture: Frame #040
        Video Capture: Frame #041
        Video Capture: Frame #042
        Video Capture: Frame #043
        Video Capture: Frame #044
        Video Capture: Frame #045
        Video Capture: Frame #046
        Video Capture: Frame #047
        Video Capture: Frame #048
        Video Capture: Frame #049
        Video Capture: Frame #050
        Video Capture: Frame #051
        Video Capture: Frame #052
        Video Capture: Frame #053
        Video Capture: Frame #054
        Video Capture: Frame #055
        Video Capture: Frame #056
        Video Capture: Frame #057
        Video Capture: Frame #058
        Video Capture: Frame #059

        test MMAP (no poll, REQBUFS): OK

        Video Capture: Frame #000 (select)
        Video Capture: Frame #001 (select)
        Video Capture: Frame #002 (select)
        Video Capture: Frame #003 (select)
        Video Capture: Frame #004 (select)
        Video Capture: Frame #005 (select)
        Video Capture: Frame #006 (select)
        Video Capture: Frame #007 (select)
        Video Capture: Frame #008 (select)
        Video Capture: Frame #009 (select)
        Video Capture: Frame #010 (select)
        Video Capture: Frame #011 (select)
        Video Capture: Frame #012 (select)
        Video Capture: Frame #013 (select)
        Video Capture: Frame #014 (select)
        Video Capture: Frame #015 (select)
        Video Capture: Frame #016 (select)
        Video Capture: Frame #017 (select)
        Video Capture: Frame #018 (select)
        Video Capture: Frame #019 (select)
        Video Capture: Frame #020 (select)
        Video Capture: Frame #021 (select)
        Video Capture: Frame #022 (select)
        Video Capture: Frame #023 (select)
        Video Capture: Frame #024 (select)
        Video Capture: Frame #025 (select)
        Video Capture: Frame #026 (select)
        Video Capture: Frame #027 (select)
        Video Capture: Frame #028 (select)
        Video Capture: Frame #029 (select)
        Video Capture: Frame #030 (select)
        Video Capture: Frame #031 (select)
        Video Capture: Frame #032 (select)
        Video Capture: Frame #033 (select)
        Video Capture: Frame #034 (select)
        Video Capture: Frame #035 (select)
        Video Capture: Frame #036 (select)
        Video Capture: Frame #037 (select)
        Video Capture: Frame #038 (select)
        Video Capture: Frame #039 (select)
        Video Capture: Frame #040 (select)
        Video Capture: Frame #041 (select)
        Video Capture: Frame #042 (select)
        Video Capture: Frame #043 (select)
        Video Capture: Frame #044 (select)
        Video Capture: Frame #045 (select)
        Video Capture: Frame #046 (select)
        Video Capture: Frame #047 (select)
        Video Capture: Frame #048 (select)
        Video Capture: Frame #049 (select)
        Video Capture: Frame #050 (select)
        Video Capture: Frame #051 (select)
        Video Capture: Frame #052 (select)
        Video Capture: Frame #053 (select)
        Video Capture: Frame #054 (select)
        Video Capture: Frame #055 (select)
        Video Capture: Frame #056 (select)
        Video Capture: Frame #057 (select)
        Video Capture: Frame #058 (select)
        Video Capture: Frame #059 (select)

        test MMAP (select, REQBUFS): OK

        Video Capture: Frame #000 (epoll)
        Video Capture: Frame #001 (epoll)
        Video Capture: Frame #002 (epoll)
        Video Capture: Frame #003 (epoll)
        Video Capture: Frame #004 (epoll)
        Video Capture: Frame #005 (epoll)
        Video Capture: Frame #006 (epoll)
        Video Capture: Frame #007 (epoll)
        Video Capture: Frame #008 (epoll)
        Video Capture: Frame #009 (epoll)
        Video Capture: Frame #010 (epoll)
        Video Capture: Frame #011 (epoll)
        Video Capture: Frame #012 (epoll)
        Video Capture: Frame #013 (epoll)
        Video Capture: Frame #014 (epoll)
        Video Capture: Frame #015 (epoll)
        Video Capture: Frame #016 (epoll)
        Video Capture: Frame #017 (epoll)
        Video Capture: Frame #018 (epoll)
        Video Capture: Frame #019 (epoll)
        Video Capture: Frame #020 (epoll)
        Video Capture: Frame #021 (epoll)
        Video Capture: Frame #022 (epoll)
        Video Capture: Frame #023 (epoll)
        Video Capture: Frame #024 (epoll)
        Video Capture: Frame #025 (epoll)
        Video Capture: Frame #026 (epoll)
        Video Capture: Frame #027 (epoll)
        Video Capture: Frame #028 (epoll)
        Video Capture: Frame #029 (epoll)
        Video Capture: Frame #030 (epoll)
        Video Capture: Frame #031 (epoll)
        Video Capture: Frame #032 (epoll)
        Video Capture: Frame #033 (epoll)
        Video Capture: Frame #034 (epoll)
        Video Capture: Frame #035 (epoll)
        Video Capture: Frame #036 (epoll)
        Video Capture: Frame #037 (epoll)
        Video Capture: Frame #038 (epoll)
        Video Capture: Frame #039 (epoll)
        Video Capture: Frame #040 (epoll)
        Video Capture: Frame #041 (epoll)
        Video Capture: Frame #042 (epoll)
        Video Capture: Frame #043 (epoll)
        Video Capture: Frame #044 (epoll)
        Video Capture: Frame #045 (epoll)
        Video Capture: Frame #046 (epoll)
        Video Capture: Frame #047 (epoll)
        Video Capture: Frame #048 (epoll)
        Video Capture: Frame #049 (epoll)
        Video Capture: Frame #050 (epoll)
        Video Capture: Frame #051 (epoll)
        Video Capture: Frame #052 (epoll)
        Video Capture: Frame #053 (epoll)
        Video Capture: Frame #054 (epoll)
        Video Capture: Frame #055 (epoll)
        Video Capture: Frame #056 (epoll)
        Video Capture: Frame #057 (epoll)
        Video Capture: Frame #058 (epoll)
        Video Capture: Frame #059 (epoll)

        test MMAP (epoll, REQBUFS): OK

        Video Capture: Frame #000
        Video Capture: Frame #001
        Video Capture: Frame #002
        Video Capture: Frame #003
        Video Capture: Frame #004
        Video Capture: Frame #005
        Video Capture: Frame #006
        Video Capture: Frame #007
        Video Capture: Frame #008
        Video Capture: Frame #009
        Video Capture: Frame #010
        Video Capture: Frame #011
        Video Capture: Frame #012
        Video Capture: Frame #013
        Video Capture: Frame #014
        Video Capture: Frame #015
        Video Capture: Frame #016
        Video Capture: Frame #017
        Video Capture: Frame #018
        Video Capture: Frame #019
        Video Capture: Frame #020
        Video Capture: Frame #021
        Video Capture: Frame #022
        Video Capture: Frame #023
        Video Capture: Frame #024
        Video Capture: Frame #025
        Video Capture: Frame #026
        Video Capture: Frame #027
        Video Capture: Frame #028
        Video Capture: Frame #029
        Video Capture: Frame #030
        Video Capture: Frame #031
        Video Capture: Frame #032
        Video Capture: Frame #033
        Video Capture: Frame #034
        Video Capture: Frame #035
        Video Capture: Frame #036
        Video Capture: Frame #037
        Video Capture: Frame #038
        Video Capture: Frame #039
        Video Capture: Frame #040
        Video Capture: Frame #041
        Video Capture: Frame #042
        Video Capture: Frame #043
        Video Capture: Frame #044
        Video Capture: Frame #045
        Video Capture: Frame #046
        Video Capture: Frame #047
        Video Capture: Frame #048
        Video Capture: Frame #049
        Video Capture: Frame #050
        Video Capture: Frame #051
        Video Capture: Frame #052
        Video Capture: Frame #053
        Video Capture: Frame #054
        Video Capture: Frame #055
        Video Capture: Frame #056
        Video Capture: Frame #057
        Video Capture: Frame #058
        Video Capture: Frame #059

        test MMAP (no poll, CREATE_BUFS): OK

        Video Capture: Frame #000 (select)
        Video Capture: Frame #001 (select)
        Video Capture: Frame #002 (select)
        Video Capture: Frame #003 (select)
        Video Capture: Frame #004 (select)
        Video Capture: Frame #005 (select)
        Video Capture: Frame #006 (select)
        Video Capture: Frame #007 (select)
        Video Capture: Frame #008 (select)
        Video Capture: Frame #009 (select)
        Video Capture: Frame #010 (select)
        Video Capture: Frame #011 (select)
        Video Capture: Frame #012 (select)
        Video Capture: Frame #013 (select)
        Video Capture: Frame #014 (select)
        Video Capture: Frame #015 (select)
        Video Capture: Frame #016 (select)
        Video Capture: Frame #017 (select)
        Video Capture: Frame #018 (select)
        Video Capture: Frame #019 (select)
        Video Capture: Frame #020 (select)
        Video Capture: Frame #021 (select)
        Video Capture: Frame #022 (select)
        Video Capture: Frame #023 (select)
        Video Capture: Frame #024 (select)
        Video Capture: Frame #025 (select)
        Video Capture: Frame #026 (select)
        Video Capture: Frame #027 (select)
        Video Capture: Frame #028 (select)
        Video Capture: Frame #029 (select)
        Video Capture: Frame #030 (select)
        Video Capture: Frame #031 (select)
        Video Capture: Frame #032 (select)
        Video Capture: Frame #033 (select)
        Video Capture: Frame #034 (select)
        Video Capture: Frame #035 (select)
        Video Capture: Frame #036 (select)
        Video Capture: Frame #037 (select)
        Video Capture: Frame #038 (select)
        Video Capture: Frame #039 (select)
        Video Capture: Frame #040 (select)
        Video Capture: Frame #041 (select)
        Video Capture: Frame #042 (select)
        Video Capture: Frame #043 (select)
        Video Capture: Frame #044 (select)
        Video Capture: Frame #045 (select)
        Video Capture: Frame #046 (select)
        Video Capture: Frame #047 (select)
        Video Capture: Frame #048 (select)
        Video Capture: Frame #049 (select)
        Video Capture: Frame #050 (select)
        Video Capture: Frame #051 (select)
        Video Capture: Frame #052 (select)
        Video Capture: Frame #053 (select)
        Video Capture: Frame #054 (select)
        Video Capture: Frame #055 (select)
        Video Capture: Frame #056 (select)
        Video Capture: Frame #057 (select)
        Video Capture: Frame #058 (select)
        Video Capture: Frame #059 (select)

        test MMAP (select, CREATE_BUFS): OK

        Video Capture: Frame #000 (epoll)
        Video Capture: Frame #001 (epoll)
        Video Capture: Frame #002 (epoll)
        Video Capture: Frame #003 (epoll)
        Video Capture: Frame #004 (epoll)
        Video Capture: Frame #005 (epoll)
        Video Capture: Frame #006 (epoll)
        Video Capture: Frame #007 (epoll)
        Video Capture: Frame #008 (epoll)
        Video Capture: Frame #009 (epoll)
        Video Capture: Frame #010 (epoll)
        Video Capture: Frame #011 (epoll)
        Video Capture: Frame #012 (epoll)
        Video Capture: Frame #013 (epoll)
        Video Capture: Frame #014 (epoll)
        Video Capture: Frame #015 (epoll)
        Video Capture: Frame #016 (epoll)
        Video Capture: Frame #017 (epoll)
        Video Capture: Frame #018 (epoll)
        Video Capture: Frame #019 (epoll)
        Video Capture: Frame #020 (epoll)
        Video Capture: Frame #021 (epoll)
        Video Capture: Frame #022 (epoll)
        Video Capture: Frame #023 (epoll)
        Video Capture: Frame #024 (epoll)
        Video Capture: Frame #025 (epoll)
        Video Capture: Frame #026 (epoll)
        Video Capture: Frame #027 (epoll)
        Video Capture: Frame #028 (epoll)
        Video Capture: Frame #029 (epoll)
        Video Capture: Frame #030 (epoll)
        Video Capture: Frame #031 (epoll)
        Video Capture: Frame #032 (epoll)
        Video Capture: Frame #033 (epoll)
        Video Capture: Frame #034 (epoll)
        Video Capture: Frame #035 (epoll)
        Video Capture: Frame #036 (epoll)
        Video Capture: Frame #037 (epoll)
        Video Capture: Frame #038 (epoll)
        Video Capture: Frame #039 (epoll)
        Video Capture: Frame #040 (epoll)
        Video Capture: Frame #041 (epoll)
        Video Capture: Frame #042 (epoll)
        Video Capture: Frame #043 (epoll)
        Video Capture: Frame #044 (epoll)
        Video Capture: Frame #045 (epoll)
        Video Capture: Frame #046 (epoll)
        Video Capture: Frame #047 (epoll)
        Video Capture: Frame #048 (epoll)
        Video Capture: Frame #049 (epoll)
        Video Capture: Frame #050 (epoll)
        Video Capture: Frame #051 (epoll)
        Video Capture: Frame #052 (epoll)
        Video Capture: Frame #053 (epoll)
        Video Capture: Frame #054 (epoll)
        Video Capture: Frame #055 (epoll)
        Video Capture: Frame #056 (epoll)
        Video Capture: Frame #057 (epoll)
        Video Capture: Frame #058 (epoll)
        Video Capture: Frame #059 (epoll)

        test MMAP (epoll, CREATE_BUFS): OK
        test USERPTR (no poll): OK (Not Supported)
        test USERPTR (select): OK (Not Supported)
        test DMABUF (no poll): OK (Not Supported)
        test DMABUF (select): OK (Not Supported)

Total for uvcvideo device /dev/video0: 59, Succeeded: 58, Failed: 1, Warnings: 0

---
Changes in v4:
- Rebased on top of v7.1-rc1
- Replace usages of filep->private_data with file_to_v4l2_fh()
  throughout the driver
- Link to v3: 
https://lore.kernel.org/r/[email protected]

Changes in v3:
- Rebased on top of v6.15-rc1 and removes obsolete control callbacks.
- Link to v2: 
https://lore.kernel.org/r/[email protected]

Changes in v2:
- Fixed kernel test robot and media CI warnings (ignored a few false
  positives).
- Changed in-driver email address to personal one since my Google one
  will soon become invalid.
- Link to v1: 
https://lore.kernel.org/r/[email protected]

Brian Daniels (8):
  media: virtio: Add protocol
  media: virtio: Add virtio-media driver structs and function
    declarations
  media: virtio: Add virtio-media session related structures
  media: virtio: Add scatterlist_builder
  media: virtio: Add virtio_media_ioctls
  media: virtio: Add virtio_media_driver
  media: virtio: Add virtio-media to the build system
  media: virtio: Add MAINTAINERS entry

 MAINTAINERS                                |    6 +
 drivers/media/Kconfig                      |   13 +
 drivers/media/Makefile                     |    2 +
 drivers/media/virtio/Makefile              |    8 +
 drivers/media/virtio/protocol.h            |  287 +++++
 drivers/media/virtio/scatterlist_builder.c |  574 +++++++++
 drivers/media/virtio/scatterlist_builder.h |  112 ++
 drivers/media/virtio/session.h             |  130 ++
 drivers/media/virtio/virtio_media.h        |   95 ++
 drivers/media/virtio/virtio_media_driver.c |  959 ++++++++++++++
 drivers/media/virtio/virtio_media_ioctls.c | 1338 ++++++++++++++++++++
 11 files changed, 3524 insertions(+)
 create mode 100644 drivers/media/virtio/Makefile
 create mode 100644 drivers/media/virtio/protocol.h
 create mode 100644 drivers/media/virtio/scatterlist_builder.c
 create mode 100644 drivers/media/virtio/scatterlist_builder.h
 create mode 100644 drivers/media/virtio/session.h
 create mode 100644 drivers/media/virtio/virtio_media.h
 create mode 100644 drivers/media/virtio/virtio_media_driver.c
 create mode 100644 drivers/media/virtio/virtio_media_ioctls.c


base-commit: 06cb687a5132fcffe624c0070576ab852ac6b568
-- 
2.55.0.rc0.799.gd6f94ed593-goog


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