From: Alexandre Courbot <[email protected]> Introduce the scatterlist builder and synchronous V4L2 ioctl forwarding via VIRTIO_MEDIA_CMD_IOCTL.
The scatterlist builder constructs virtio descriptor chains for ioctl commands and responses, mapping 1:1 kernel memory and vmalloc buffers directly into scatterlists when possible while falling back to a per-session shadow buffer otherwise. Use this infrastructure to implement VIDIOC_QUERYCAP from the virtio configuration space along with fixed-size read, write, and read-write V4L2 ioctls covering format negotiation, frame sizes and intervals, control and menu queries, inputs and outputs, audio, selection, video standards, tuners, and DV timings. Signed-off-by: Alexandre Courbot <[email protected]> Assisted-by: LLM Co-developed-by: Brian Daniels <[email protected]> Signed-off-by: Brian Daniels <[email protected]> --- drivers/media/virtio/Makefile | 2 +- drivers/media/virtio/scatterlist_builder.c | 222 ++++++++ drivers/media/virtio/scatterlist_builder.h | 90 +++ drivers/media/virtio/session.h | 28 +- drivers/media/virtio/virtio_media.h | 9 + drivers/media/virtio/virtio_media_driver.c | 24 +- drivers/media/virtio/virtio_media_ioctls.c | 606 +++++++++++++++++++++ include/uapi/linux/virtio_media.h | 43 ++ 8 files changed, 1020 insertions(+), 4 deletions(-) create mode 100644 drivers/media/virtio/scatterlist_builder.c create mode 100644 drivers/media/virtio/scatterlist_builder.h create mode 100644 drivers/media/virtio/virtio_media_ioctls.c diff --git a/drivers/media/virtio/Makefile b/drivers/media/virtio/Makefile index 09d9834da..f1bc8a3ce 100644 --- a/drivers/media/virtio/Makefile +++ b/drivers/media/virtio/Makefile @@ -2,6 +2,6 @@ # # Makefile for the virtio-media device driver. -virtio-media-objs := virtio_media_driver.o +virtio-media-objs := scatterlist_builder.o virtio_media_ioctls.o virtio_media_driver.o obj-$(CONFIG_MEDIA_VIRTIO) += virtio-media.o diff --git a/drivers/media/virtio/scatterlist_builder.c b/drivers/media/virtio/scatterlist_builder.c new file mode 100644 index 000000000..ae8ffee82 --- /dev/null +++ b/drivers/media/virtio/scatterlist_builder.c @@ -0,0 +1,222 @@ +// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0+ + +/* + * Scatterlist builder helpers for virtio-media. + * + * Copyright (c) 2024-2026 Google LLC. + */ + +#include <linux/moduleparam.h> +#include <linux/scatterlist.h> +#include <linux/videodev2.h> +#include <media/videobuf2-memops.h> + +#include "uapi/linux/virtio_media.h" +#include "scatterlist_builder.h" +#include "session.h" + +/* + * If set to %true, then the driver will always copy the data passed to the + * host into the shadow buffer (instead of trying to map the source memory into + * the SG table directly when possible). + */ +static bool always_use_shadow_buffer; +module_param(always_use_shadow_buffer, bool, 0660); + +/* Convert a V4L2 IOCTL into the IOCTL code we can give to the host */ +#define VIRTIO_MEDIA_IOCTL_CODE(IOCTL) (((IOCTL) >> _IOC_NRSHIFT) & _IOC_NRMASK) + +/** + * scatterlist_builder_add_descriptor() - Add a descriptor to the chain. + * @builder: builder to use. + * @desc_index: index of the descriptor to add. + * + * Returns %-ENOSPC if @builder->sgs is already full. + */ +int scatterlist_builder_add_descriptor(struct scatterlist_builder *builder, + size_t desc_index) +{ + if (builder->cur_sg >= builder->num_sgs) + return -ENOSPC; + builder->sgs[builder->cur_sg++] = &builder->descs[desc_index]; + + return 0; +} + +/** + * scatterlist_builder_add_data() - Append arbitrary data to the descriptor + * chain. + * @builder: builder to use. + * @data: pointer to the data to add to the descriptor chain. + * @len: length of the data to add. + * + * @data will either be directly referenced, or copied into the shadow buffer + * to be referenced from there. + */ +int scatterlist_builder_add_data(struct scatterlist_builder *builder, + void *data, size_t len) +{ + const size_t cur_desc = builder->cur_desc; + + if (len == 0) + return 0; + + if (builder->cur_desc >= builder->num_descs) + return -ENOSPC; + + if (!always_use_shadow_buffer && virt_addr_valid(data) && + virt_addr_valid(data + len)) { + /* + * If "data" is in the 1:1 physical memory mapping then we can + * use a single SG entry and avoid copying. + */ + struct page *page = virt_to_page(data); + size_t offset = (((size_t)data) & ~PAGE_MASK); + struct scatterlist *next_desc = + &builder->descs[builder->cur_desc]; + + memset(next_desc, 0, sizeof(*next_desc)); + sg_set_page(next_desc, page, len, offset); + builder->cur_desc++; + } else if (!always_use_shadow_buffer && is_vmalloc_addr(data)) { + bool prev_pfn_valid = false; + unsigned long prev_pfn = 0; + + /* + * If "data" has been vmalloc'ed, we need at most one entry per + * memory page but can avoid copying. + */ + while (len > 0) { + struct page *page = vmalloc_to_page(data); + unsigned long cur_pfn = page_to_pfn(page); + /* All pages but the first will start at offset 0. */ + unsigned long offset = + (((unsigned long)data) & ~PAGE_MASK); + size_t len_in_page = min(PAGE_SIZE - offset, len); + struct scatterlist *next_desc = + &builder->descs[builder->cur_desc]; + + if (builder->cur_desc >= builder->num_descs) + return -ENOSPC; + + /* Optimize contiguous pages */ + if (prev_pfn_valid && (cur_pfn == prev_pfn + 1)) { + (next_desc - 1)->length += len_in_page; + } else { + memset(next_desc, 0, sizeof(*next_desc)); + sg_set_page(next_desc, page, len_in_page, + offset); + builder->cur_desc++; + } + data += len_in_page; + len -= len_in_page; + prev_pfn = cur_pfn; + prev_pfn_valid = true; + } + } else { + /* + * As a last resort, copy into the shadow buffer and reference + * it with a single SG entry. Calling + * scatterlist_builder_retrieve_data() will be necessary to copy + * the data written by the device back into @data. + */ + void *shadow_buffer = + builder->shadow_buffer + builder->shadow_buffer_pos; + struct page *page = virt_to_page(shadow_buffer); + unsigned long offset = + (((unsigned long)shadow_buffer) & ~PAGE_MASK); + struct scatterlist *next_desc = + &builder->descs[builder->cur_desc]; + + if (len > + builder->shadow_buffer_size - builder->shadow_buffer_pos) + return -ENOSPC; + + memcpy(shadow_buffer, data, len); + memset(next_desc, 0, sizeof(*next_desc)); + sg_set_page(next_desc, page, len, offset); + builder->cur_desc++; + builder->shadow_buffer_pos += len; + } + + sg_mark_end(&builder->descs[builder->cur_desc - 1]); + return scatterlist_builder_add_descriptor(builder, cur_desc); +} + +/** + * scatterlist_builder_retrieve_data() - Retrieve a response written by the + * device on the shadow buffer. + * @builder: builder to use. + * @sg_index: index of the descriptor to read from. + * @data: destination for the shadowed data. + * + * If the shadow buffer is pointed to by the descriptor at index @sg_index of + * the chain, then ``sg->length`` bytes are copied back from it into @data. + * Otherwise nothing is done since the device has written into @data directly. + * + * @data must have originally been added by scatterlist_builder_add_data() as + * the same size as passed to scatterlist_builder_add_data() will be copied + * back. + */ +int scatterlist_builder_retrieve_data(struct scatterlist_builder *builder, + size_t sg_index, void *data) +{ + void *shadow_buf = builder->shadow_buffer; + struct scatterlist *sg; + void *kaddr; + + /* We can only retrieve from the range of sgs currently set. */ + if (sg_index >= builder->cur_sg) + return -ERANGE; + + sg = builder->sgs[sg_index]; + kaddr = pfn_to_kaddr(page_to_pfn(sg_page(sg))) + sg->offset; + + if (kaddr >= shadow_buf && + kaddr < shadow_buf + builder->shadow_buffer_size) { + if (kaddr + sg->length > + shadow_buf + builder->shadow_buffer_size) + return -EINVAL; + + memcpy(data, kaddr, sg->length); + } + + return 0; +} + +/** + * scatterlist_builder_add_ioctl_cmd() - Add an ioctl command to the descriptor + * chain. + * @builder: builder to use. + * @session: session on behalf of which the ioctl command is added. + * @ioctl_code: code of the ioctl to add (i.e. ``VIDIOC_*``). + */ +int scatterlist_builder_add_ioctl_cmd(struct scatterlist_builder *builder, + struct virtio_media_session *session, + u32 ioctl_code) +{ + struct virtio_media_cmd_ioctl *cmd_ioctl = &session->cmd.ioctl; + + cmd_ioctl->hdr.cmd = VIRTIO_MEDIA_CMD_IOCTL; + cmd_ioctl->hdr.__reserved = 0; + cmd_ioctl->session_id = session->id; + cmd_ioctl->code = VIRTIO_MEDIA_IOCTL_CODE(ioctl_code); + + return scatterlist_builder_add_data(builder, cmd_ioctl, + sizeof(*cmd_ioctl)); +} + +/** + * scatterlist_builder_add_ioctl_resp() - Add storage to receive an ioctl + * response to the descriptor chain. + * @builder: builder to use. + * @session: session on behalf of which the ioctl response is added. + */ +int scatterlist_builder_add_ioctl_resp(struct scatterlist_builder *builder, + struct virtio_media_session *session) +{ + struct virtio_media_resp_ioctl *resp_ioctl = &session->resp.ioctl; + + return scatterlist_builder_add_data(builder, resp_ioctl, + sizeof(*resp_ioctl)); +} diff --git a/drivers/media/virtio/scatterlist_builder.h b/drivers/media/virtio/scatterlist_builder.h new file mode 100644 index 000000000..044ea409a --- /dev/null +++ b/drivers/media/virtio/scatterlist_builder.h @@ -0,0 +1,90 @@ +/* SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0+ */ + +/* + * Scatterlist builder helpers for virtio-media. + * + * Copyright (c) 2024-2026 Google LLC. + */ + +#ifndef __VIRTIO_MEDIA_SCATTERLIST_BUILDER_H +#define __VIRTIO_MEDIA_SCATTERLIST_BUILDER_H + +#include <linux/scatterlist.h> + +#include "session.h" + +/** + * struct scatterlist_builder - helper to build a scatterlist from data. + * @descs: pool of descriptors to use. + * @num_descs: number of entries in descs. + * @cur_desc: next descriptor to be used in @descs. + * @shadow_buffer: pointer to a shadow buffer where elements that cannot be + * mapped directly into the scatterlist get copied. + * @shadow_buffer_size: size of @shadow_buffer. + * @shadow_buffer_pos: current position in @shadow_buffer. + * @sgs: descriptor chain to eventually pass to virtio functions. + * @num_sgs: total number of entries in @sgs. + * @cur_sg: next entry in @sgs to be used. + * + * Virtio passes data from the driver to the device (through e.g. + * virtqueue_add_sgs()) via a scatterlist that the device interprets as a + * linear view over scattered driver memory. + * + * In virtio-media, the payload of ioctls from user-space can for the most part + * be passed as-is, or after slight modification, which makes it tempting to + * just forward the ioctl payload received from user-space as-is instead of + * doing another copy into a dedicated buffer. This structure helps with this. + * + * virtio-media descriptor chains are typically made of the following parts: + * + * Device-readable: + * - A command structure, i.e. ``virtio_media_cmd_*``, + * - An ioctl payload (one of the regular ioctl parameters), + * - (optionally) arrays of &struct virtio_media_sg_entry describing the + * content of buffers in guest memory. + * + * Device-writable: + * - A response structure, i.e. ``virtio_media_resp_*``, + * - An ioctl payload, that the device will write to. + * + * This structure helps laying out the descriptor chain into its @sgs member in + * an optimal way, by building a scatterlist adapted to the originating memory + * of the data we want to pass to the device while avoiding copies when + * possible. + * + * It is made of a pool of &struct scatterlist (@descs) that is used to + * build the final descriptor chain @sgs, and a @shadow_buffer where data that + * cannot (or should not) be mapped directly by the host can be temporarily + * copied. + */ +struct scatterlist_builder { + struct scatterlist *descs; + size_t num_descs; + size_t cur_desc; + + void *shadow_buffer; + size_t shadow_buffer_size; + size_t shadow_buffer_pos; + + struct scatterlist **sgs; + size_t num_sgs; + size_t cur_sg; +}; + +int scatterlist_builder_add_descriptor(struct scatterlist_builder *builder, + size_t desc_index); + +int scatterlist_builder_add_data(struct scatterlist_builder *builder, + void *data, size_t len); + +int scatterlist_builder_retrieve_data(struct scatterlist_builder *builder, + size_t sg_index, void *data); + +int scatterlist_builder_add_ioctl_cmd(struct scatterlist_builder *builder, + struct virtio_media_session *session, + u32 ioctl_code); + +int scatterlist_builder_add_ioctl_resp(struct scatterlist_builder *builder, + struct virtio_media_session *session); + +#endif // __VIRTIO_MEDIA_SCATTERLIST_BUILDER_H diff --git a/drivers/media/virtio/session.h b/drivers/media/virtio/session.h index 4ade7fb9c..6fe7ff5ae 100644 --- a/drivers/media/virtio/session.h +++ b/drivers/media/virtio/session.h @@ -9,17 +9,32 @@ #ifndef __VIRTIO_MEDIA_SESSION_H #define __VIRTIO_MEDIA_SESSION_H +#include <linux/scatterlist.h> #include <media/v4l2-fh.h> #include "uapi/linux/virtio_media.h" +/* + * Size of the per-session virtio shadow and event buffers. 16K should be + * enough to contain everything we need. + */ +#define VIRTIO_SHADOW_BUF_SIZE 0x4000 + /** * struct virtio_media_session - A session on a virtio_media device. * @fh: file handler for the session. * @file: file pointer associated with the session's file handler. * @id: session ID used to communicate with the device. - * @cmd: union of session-level commands. A session can have one command - * currently running. + * @cmd: union of session commands ``close`` and ``ioctl``. A session can have + * one command currently running. The rest of the commands are handled by + * &struct virtio_media. + * @resp: union of responses to session commands. A session can wait on one + * command only. The rest of the responses are handled by + * &struct virtio_media. + * @shadow_buf: shadow buffer where data to be added to the descriptor chain can + * be staged before being sent to the device. + * @command_sgs: SG table gathering descriptors for a given command and its + * response. * @list: link into the list of sessions for the device. */ struct virtio_media_session { @@ -30,9 +45,18 @@ struct virtio_media_session { __dma_from_device_group_begin(); union { struct virtio_media_cmd_close close; + struct virtio_media_cmd_ioctl ioctl; } cmd; + + union { + struct virtio_media_resp_ioctl ioctl; + } resp; __dma_from_device_group_end(); + void *shadow_buf; + + struct sg_table command_sgs; + struct list_head list; }; diff --git a/drivers/media/virtio/virtio_media.h b/drivers/media/virtio/virtio_media.h index 68299377a..a120c1014 100644 --- a/drivers/media/virtio/virtio_media.h +++ b/drivers/media/virtio/virtio_media.h @@ -14,6 +14,8 @@ #include "uapi/linux/virtio_media.h" +#define DESC_CHAIN_MAX_LEN SG_MAX_SINGLE_ALLOC + #define VIRTIO_MEDIA_DEFAULT_DRIVER_NAME "virtio-media" /** @@ -66,5 +68,12 @@ to_virtio_media(struct video_device *video_dev) 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); + +/* 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 index 10073d863..2f2e95077 100644 --- a/drivers/media/virtio/virtio_media_driver.c +++ b/drivers/media/virtio/virtio_media_driver.c @@ -37,10 +37,20 @@ static struct virtio_media_session * virtio_media_session_alloc(struct virtio_media *vv, struct file *file) { struct virtio_media_session *session; + int ret; session = kzalloc_obj(*session, GFP_KERNEL); if (!session) - return ERR_PTR(-ENOMEM); + goto err_session; + + session->shadow_buf = kzalloc(VIRTIO_SHADOW_BUF_SIZE, GFP_KERNEL); + if (!session->shadow_buf) + goto err_shadow_buf; + + ret = sg_alloc_table(&session->command_sgs, DESC_CHAIN_MAX_LEN, + GFP_KERNEL); + if (ret) + goto err_payload_sgs; // The caller is expected to set the ID once the host assigns a value. session->id = 0; @@ -50,6 +60,13 @@ virtio_media_session_alloc(struct virtio_media *vv, struct file *file) virtio_media_session_fh_add(session, file); return session; + +err_payload_sgs: + kfree(session->shadow_buf); +err_shadow_buf: + kfree(session); +err_session: + return ERR_PTR(-ENOMEM); } /** @@ -77,6 +94,9 @@ static void virtio_media_session_free(struct virtio_media_session *session) virtio_media_session_fh_del(session); v4l2_fh_exit(&session->fh); + sg_free_table(&session->command_sgs); + + kfree(session->shadow_buf); kfree(session); } @@ -342,6 +362,7 @@ static const struct v4l2_file_operations virtio_media_fops = { .owner = THIS_MODULE, .open = virtio_media_device_open, .release = virtio_media_device_close, + .unlocked_ioctl = virtio_media_device_ioctl, }; static void virtio_media_release(struct v4l2_device *v4l2_dev) @@ -394,6 +415,7 @@ static int virtio_media_probe(struct virtio_device *virtio_dev) vd = &vv->video_dev; vd->v4l2_dev = &vv->v4l2_dev; + vd->ioctl_ops = &virtio_media_ioctl_ops; vd->fops = &virtio_media_fops; vd->release = video_device_release_empty; strscpy(vd->name, "virtio-media", sizeof(vd->name)); diff --git a/drivers/media/virtio/virtio_media_ioctls.c b/drivers/media/virtio/virtio_media_ioctls.c new file mode 100644 index 000000000..656ecea8a --- /dev/null +++ b/drivers/media/virtio/virtio_media_ioctls.c @@ -0,0 +1,606 @@ +// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0+ + +/* + * Ioctl implementations for the virtio-media driver. + * + * Copyright (c) 2024-2026 Google LLC. + */ + +#include <linux/mutex.h> +#include <linux/videodev2.h> +#include <linux/virtio_config.h> +#include <media/v4l2-ioctl.h> + +#include "scatterlist_builder.h" +#include "virtio_media.h" + +/** + * virtio_media_send_r_ioctl() - Send a read-only ioctl to the device. + * @fh: file handler of the session doing the ioctl. + * @ioctl: ``VIDIOC_*`` ioctl code. + * @ioctl_data: pointer to the ioctl payload. + * @ioctl_data_len: length in bytes of the ioctl payload. + * + * Send an ioctl that has no driver payload, but expects a response from the + * host (i.e. an ioctl specified with ``_IOR``). + */ +static int virtio_media_send_r_ioctl(struct v4l2_fh *fh, u32 ioctl, + void *ioctl_data, size_t ioctl_data_len) +{ + struct video_device *video_dev = fh->vdev; + struct virtio_media *vv = to_virtio_media(video_dev); + struct virtio_media_session *session = fh_to_session(fh); + struct scatterlist *sgs[3]; + struct scatterlist_builder builder = { + .descs = session->command_sgs.sgl, + .num_descs = DESC_CHAIN_MAX_LEN, + .cur_desc = 0, + .shadow_buffer = session->shadow_buf, + .shadow_buffer_size = VIRTIO_SHADOW_BUF_SIZE, + .shadow_buffer_pos = 0, + .sgs = sgs, + .num_sgs = ARRAY_SIZE(sgs), + .cur_sg = 0, + }; + + /* Command descriptor */ + int ret = scatterlist_builder_add_ioctl_cmd(&builder, session, ioctl); + + if (ret) + return ret; + + /* Response descriptor */ + ret = scatterlist_builder_add_ioctl_resp(&builder, session); + if (ret) + return ret; + + /* Response payload */ + ret = scatterlist_builder_add_data(&builder, ioctl_data, + ioctl_data_len); + if (ret) { + v4l2_err(&vv->v4l2_dev, + "failed to prepare command descriptor chain\n"); + return ret; + } + + ret = virtio_media_send_command(vv, sgs, 1, 2, + sizeof(struct virtio_media_resp_ioctl) + + ioctl_data_len, NULL); + if (ret < 0) + return ret; + + ret = scatterlist_builder_retrieve_data(&builder, 2, ioctl_data); + if (ret) { + v4l2_err(&vv->v4l2_dev, + "failed to retrieve response descriptor chain\n"); + return ret; + } + + return 0; +} + +/** + * virtio_media_send_w_ioctl() - Send a write-only ioctl to the device. + * @fh: file handler of the session doing the ioctl. + * @ioctl: ``VIDIOC_*`` ioctl code. + * @ioctl_data: pointer to the ioctl payload. + * @ioctl_data_len: length in bytes of the ioctl payload. + * + * Send an ioctl that does not expect a reply beyond an error status (i.e. an + * ioctl specified with ``_IOW``) to the host. + */ +static int virtio_media_send_w_ioctl(struct v4l2_fh *fh, u32 ioctl, + const void *ioctl_data, + size_t ioctl_data_len) +{ + struct video_device *video_dev = fh->vdev; + struct virtio_media *vv = to_virtio_media(video_dev); + struct virtio_media_session *session = fh_to_session(fh); + struct scatterlist *sgs[3]; + struct scatterlist_builder builder = { + .descs = session->command_sgs.sgl, + .num_descs = DESC_CHAIN_MAX_LEN, + .cur_desc = 0, + .shadow_buffer = session->shadow_buf, + .shadow_buffer_size = VIRTIO_SHADOW_BUF_SIZE, + .shadow_buffer_pos = 0, + .sgs = sgs, + .num_sgs = ARRAY_SIZE(sgs), + .cur_sg = 0, + }; + + /* Command descriptor */ + int ret = scatterlist_builder_add_ioctl_cmd(&builder, session, ioctl); + + if (ret) + return ret; + + /* Command payload */ + ret = scatterlist_builder_add_data(&builder, (void *)ioctl_data, + ioctl_data_len); + if (ret) { + v4l2_err(&vv->v4l2_dev, + "failed to prepare command descriptor chain\n"); + return ret; + } + + /* Response descriptor */ + ret = scatterlist_builder_add_ioctl_resp(&builder, session); + if (ret) + return ret; + + ret = virtio_media_send_command(vv, sgs, 2, 1, + sizeof(struct virtio_media_resp_ioctl), + NULL); + if (ret < 0) + return ret; + + return 0; +} + +/** + * virtio_media_send_wr_ioctl() - Send a read-write ioctl to the device. + * @fh: file handler of the session doing the ioctl. + * @ioctl: ``VIDIOC_*`` ioctl code. + * @ioctl_data: pointer to the ioctl payload. + * @ioctl_data_len: length in bytes of the ioctl payload. + * @minimum_resp_payload: minimum expected length of the response's payload. + * + * Sends an ioctl that expects a response of exactly the same size as the + * input (i.e. an ioctl specified with ``_IOWR``) to the host. + * + * This corresponds to what most V4L2 ioctls do. For instance + * ``VIDIOC_ENUM_FMT`` takes a partially-initialized &struct v4l2_fmtdesc + * and returns its filled version. + */ +static int virtio_media_send_wr_ioctl(struct v4l2_fh *fh, u32 ioctl, + void *ioctl_data, size_t ioctl_data_len, + size_t minimum_resp_payload) +{ + struct video_device *video_dev = fh->vdev; + struct virtio_media *vv = to_virtio_media(video_dev); + struct virtio_media_session *session = fh_to_session(fh); + struct scatterlist *sgs[4]; + struct scatterlist_builder builder = { + .descs = session->command_sgs.sgl, + .num_descs = DESC_CHAIN_MAX_LEN, + .cur_desc = 0, + .shadow_buffer = session->shadow_buf, + .shadow_buffer_size = VIRTIO_SHADOW_BUF_SIZE, + .shadow_buffer_pos = 0, + .sgs = sgs, + .num_sgs = ARRAY_SIZE(sgs), + .cur_sg = 0, + }; + + /* Command descriptor */ + int ret = scatterlist_builder_add_ioctl_cmd(&builder, session, ioctl); + + if (ret) + return ret; + + /* Command payload */ + ret = scatterlist_builder_add_data(&builder, ioctl_data, + ioctl_data_len); + if (ret) { + v4l2_err(&vv->v4l2_dev, + "failed to prepare command descriptor chain\n"); + return ret; + } + + /* Response descriptor */ + ret = scatterlist_builder_add_ioctl_resp(&builder, session); + if (ret) + return ret; + + /* Response payload, same as command */ + ret = scatterlist_builder_add_descriptor(&builder, 1); + if (ret) + return ret; + + ret = virtio_media_send_command(vv, sgs, 2, 2, + sizeof(struct virtio_media_resp_ioctl) + + minimum_resp_payload, + NULL); + if (ret < 0) + return ret; + + ret = scatterlist_builder_retrieve_data(&builder, 3, ioctl_data); + if (ret) { + v4l2_err(&vv->v4l2_dev, + "failed to retrieve response descriptor chain\n"); + return ret; + } + + return 0; +} + +/* + * Macros suitable for defining ioctls with a constant size payload. + */ + +#define SIMPLE_WR_IOCTL(name, ioctl, payload_t) \ + static int virtio_media_##name(struct file *file, void *fh, \ + payload_t *payload) \ + { \ + struct v4l2_fh *vfh = file_to_v4l2_fh(file); \ + return virtio_media_send_wr_ioctl(vfh, ioctl, payload,\ + sizeof(*payload), \ + sizeof(*payload)); \ + } +#define SIMPLE_R_IOCTL(name, ioctl, payload_t) \ + static int virtio_media_##name(struct file *file, void *fh, \ + payload_t *payload) \ + { \ + struct v4l2_fh *vfh = file_to_v4l2_fh(file); \ + return virtio_media_send_r_ioctl(vfh, ioctl, payload,\ + sizeof(*payload)); \ + } +#define SIMPLE_W_IOCTL(name, ioctl, payload_t) \ + static int virtio_media_##name(struct file *file, void *fh, \ + payload_t *payload) \ + { \ + struct v4l2_fh *vfh = file_to_v4l2_fh(file); \ + return virtio_media_send_w_ioctl(vfh, ioctl, payload,\ + sizeof(*payload)); \ + } + +/* + * V4L2 ioctl handlers. + * + * Most of these functions just forward the ioctl to the host, for these we can + * use one of the SIMPLE_*_IOCTL macros. Exceptions that have their own + * standalone function follow. + */ + +SIMPLE_WR_IOCTL(enum_fmt, VIDIOC_ENUM_FMT, struct v4l2_fmtdesc) +SIMPLE_WR_IOCTL(g_fmt, VIDIOC_G_FMT, struct v4l2_format) +SIMPLE_WR_IOCTL(s_fmt, VIDIOC_S_FMT, struct v4l2_format) +SIMPLE_WR_IOCTL(try_fmt, VIDIOC_TRY_FMT, struct v4l2_format) +SIMPLE_WR_IOCTL(enum_framesizes, VIDIOC_ENUM_FRAMESIZES, + struct v4l2_frmsizeenum) +SIMPLE_WR_IOCTL(enum_frameintervals, VIDIOC_ENUM_FRAMEINTERVALS, + struct v4l2_frmivalenum) +SIMPLE_WR_IOCTL(query_ext_ctrl, VIDIOC_QUERY_EXT_CTRL, + struct v4l2_query_ext_ctrl) +SIMPLE_WR_IOCTL(s_dv_timings, VIDIOC_S_DV_TIMINGS, struct v4l2_dv_timings) +SIMPLE_WR_IOCTL(g_dv_timings, VIDIOC_G_DV_TIMINGS, struct v4l2_dv_timings) +SIMPLE_R_IOCTL(query_dv_timings, VIDIOC_QUERY_DV_TIMINGS, + struct v4l2_dv_timings) +SIMPLE_WR_IOCTL(enum_dv_timings, VIDIOC_ENUM_DV_TIMINGS, + struct v4l2_enum_dv_timings) +SIMPLE_WR_IOCTL(dv_timings_cap, VIDIOC_DV_TIMINGS_CAP, + struct v4l2_dv_timings_cap) +SIMPLE_WR_IOCTL(enuminput, VIDIOC_ENUMINPUT, struct v4l2_input) +SIMPLE_WR_IOCTL(querymenu, VIDIOC_QUERYMENU, struct v4l2_querymenu) +SIMPLE_WR_IOCTL(enumoutput, VIDIOC_ENUMOUTPUT, struct v4l2_output) +SIMPLE_WR_IOCTL(enumaudio, VIDIOC_ENUMAUDIO, struct v4l2_audio) +SIMPLE_R_IOCTL(g_audio, VIDIOC_G_AUDIO, struct v4l2_audio) +SIMPLE_W_IOCTL(s_audio, VIDIOC_S_AUDIO, const struct v4l2_audio) +SIMPLE_WR_IOCTL(enumaudout, VIDIOC_ENUMAUDOUT, struct v4l2_audioout) +SIMPLE_R_IOCTL(g_audout, VIDIOC_G_AUDOUT, struct v4l2_audioout) +SIMPLE_W_IOCTL(s_audout, VIDIOC_S_AUDOUT, const struct v4l2_audioout) +SIMPLE_WR_IOCTL(g_modulator, VIDIOC_G_MODULATOR, struct v4l2_modulator) +SIMPLE_W_IOCTL(s_modulator, VIDIOC_S_MODULATOR, const struct v4l2_modulator) +SIMPLE_WR_IOCTL(g_selection, VIDIOC_G_SELECTION, struct v4l2_selection) +SIMPLE_WR_IOCTL(s_selection, VIDIOC_S_SELECTION, struct v4l2_selection) +SIMPLE_R_IOCTL(g_enc_index, VIDIOC_G_ENC_INDEX, struct v4l2_enc_idx) +SIMPLE_WR_IOCTL(encoder_cmd, VIDIOC_ENCODER_CMD, struct v4l2_encoder_cmd) +SIMPLE_WR_IOCTL(try_encoder_cmd, VIDIOC_TRY_ENCODER_CMD, + struct v4l2_encoder_cmd) +SIMPLE_WR_IOCTL(try_decoder_cmd, VIDIOC_TRY_DECODER_CMD, + struct v4l2_decoder_cmd) +SIMPLE_WR_IOCTL(g_parm, VIDIOC_G_PARM, struct v4l2_streamparm) +SIMPLE_WR_IOCTL(s_parm, VIDIOC_S_PARM, struct v4l2_streamparm) +SIMPLE_R_IOCTL(g_std, VIDIOC_G_STD, v4l2_std_id) +SIMPLE_R_IOCTL(querystd, VIDIOC_QUERYSTD, v4l2_std_id) +SIMPLE_WR_IOCTL(enumstd, VIDIOC_ENUMSTD, struct v4l2_standard) +SIMPLE_WR_IOCTL(g_tuner, VIDIOC_G_TUNER, struct v4l2_tuner) +SIMPLE_W_IOCTL(s_tuner, VIDIOC_S_TUNER, const struct v4l2_tuner) +SIMPLE_WR_IOCTL(g_frequency, VIDIOC_G_FREQUENCY, struct v4l2_frequency) +SIMPLE_W_IOCTL(s_frequency, VIDIOC_S_FREQUENCY, const struct v4l2_frequency) +SIMPLE_WR_IOCTL(enum_freq_bands, VIDIOC_ENUM_FREQ_BANDS, + struct v4l2_frequency_band) +SIMPLE_WR_IOCTL(g_sliced_vbi_cap, VIDIOC_G_SLICED_VBI_CAP, + struct v4l2_sliced_vbi_cap) +SIMPLE_W_IOCTL(s_hw_freq_seek, VIDIOC_S_HW_FREQ_SEEK, + const struct v4l2_hw_freq_seek) + +/* + * QUERYCAP is handled by reading the configuration area. + */ + +static int virtio_media_querycap(struct file *file, void *fh, + struct v4l2_capability *cap) +{ + struct video_device *video_dev = video_devdata(file); + struct virtio_media *vv = to_virtio_media(video_dev); + + strscpy(cap->bus_info, "platform:virtio-media"); + strscpy(cap->driver, VIRTIO_MEDIA_DEFAULT_DRIVER_NAME); + + virtio_cread_bytes(vv->virtio_dev, 8, cap->card, sizeof(cap->card)); + + cap->capabilities = video_dev->device_caps | V4L2_CAP_DEVICE_CAPS; + cap->device_caps = video_dev->device_caps; + + return 0; +} + +/* + * s/g_input/output work with an unsigned int - recast this to a u32 so the + * size is unambiguous. + */ + +static int virtio_media_g_input(struct file *file, void *fh, unsigned int *i) +{ + u32 input; + + int ret = virtio_media_send_wr_ioctl(file_to_v4l2_fh(file), + VIDIOC_G_INPUT, &input, + sizeof(input), sizeof(input)); + if (ret) + return ret; + + *i = input; + + return 0; +} + +static int virtio_media_s_input(struct file *file, void *fh, unsigned int i) +{ + u32 input = i; + + return virtio_media_send_wr_ioctl(file_to_v4l2_fh(file), + VIDIOC_S_INPUT, &input, + sizeof(input), sizeof(input)); +} + +static int virtio_media_g_output(struct file *file, void *fh, unsigned int *o) +{ + u32 output; + + int ret = virtio_media_send_wr_ioctl(file_to_v4l2_fh(file), + VIDIOC_G_OUTPUT, &output, + sizeof(output), sizeof(output)); + if (ret) + return ret; + + *o = output; + + return 0; +} + +static int virtio_media_s_output(struct file *file, void *fh, unsigned int o) +{ + u32 output = o; + + return virtio_media_send_wr_ioctl(file_to_v4l2_fh(file), + VIDIOC_S_OUTPUT, &output, + sizeof(output), sizeof(output)); +} + +/* + * s_std doesn't work with a pointer, so we cannot use SIMPLE_W_IOCTL. + */ + +static int virtio_media_s_std(struct file *file, void *fh, v4l2_std_id s) +{ + int ret = virtio_media_send_w_ioctl(file_to_v4l2_fh(file), VIDIOC_S_STD, + &s, sizeof(s)); + if (ret) + return ret; + + return 0; +} + +const struct v4l2_ioctl_ops virtio_media_ioctl_ops = { + /* VIDIOC_QUERYCAP handler */ + .vidioc_querycap = virtio_media_querycap, + + /* VIDIOC_ENUM_FMT handlers */ + .vidioc_enum_fmt_vid_cap = virtio_media_enum_fmt, + .vidioc_enum_fmt_vid_overlay = virtio_media_enum_fmt, + .vidioc_enum_fmt_vid_out = virtio_media_enum_fmt, + .vidioc_enum_fmt_sdr_cap = virtio_media_enum_fmt, + .vidioc_enum_fmt_sdr_out = virtio_media_enum_fmt, + .vidioc_enum_fmt_meta_cap = virtio_media_enum_fmt, + .vidioc_enum_fmt_meta_out = virtio_media_enum_fmt, + + /* VIDIOC_G_FMT handlers */ + .vidioc_g_fmt_vid_cap = virtio_media_g_fmt, + .vidioc_g_fmt_vid_overlay = virtio_media_g_fmt, + .vidioc_g_fmt_vid_out = virtio_media_g_fmt, + .vidioc_g_fmt_vid_out_overlay = virtio_media_g_fmt, + .vidioc_g_fmt_vbi_cap = virtio_media_g_fmt, + .vidioc_g_fmt_vbi_out = virtio_media_g_fmt, + .vidioc_g_fmt_sliced_vbi_cap = virtio_media_g_fmt, + .vidioc_g_fmt_sliced_vbi_out = virtio_media_g_fmt, + .vidioc_g_fmt_vid_cap_mplane = virtio_media_g_fmt, + .vidioc_g_fmt_vid_out_mplane = virtio_media_g_fmt, + .vidioc_g_fmt_sdr_cap = virtio_media_g_fmt, + .vidioc_g_fmt_sdr_out = virtio_media_g_fmt, + .vidioc_g_fmt_meta_cap = virtio_media_g_fmt, + .vidioc_g_fmt_meta_out = virtio_media_g_fmt, + + /* VIDIOC_S_FMT handlers */ + .vidioc_s_fmt_vid_cap = virtio_media_s_fmt, + .vidioc_s_fmt_vid_overlay = virtio_media_s_fmt, + .vidioc_s_fmt_vid_out = virtio_media_s_fmt, + .vidioc_s_fmt_vid_out_overlay = virtio_media_s_fmt, + .vidioc_s_fmt_vbi_cap = virtio_media_s_fmt, + .vidioc_s_fmt_vbi_out = virtio_media_s_fmt, + .vidioc_s_fmt_sliced_vbi_cap = virtio_media_s_fmt, + .vidioc_s_fmt_sliced_vbi_out = virtio_media_s_fmt, + .vidioc_s_fmt_vid_cap_mplane = virtio_media_s_fmt, + .vidioc_s_fmt_vid_out_mplane = virtio_media_s_fmt, + .vidioc_s_fmt_sdr_cap = virtio_media_s_fmt, + .vidioc_s_fmt_sdr_out = virtio_media_s_fmt, + .vidioc_s_fmt_meta_cap = virtio_media_s_fmt, + .vidioc_s_fmt_meta_out = virtio_media_s_fmt, + + /* VIDIOC_TRY_FMT handlers */ + .vidioc_try_fmt_vid_cap = virtio_media_try_fmt, + .vidioc_try_fmt_vid_overlay = virtio_media_try_fmt, + .vidioc_try_fmt_vid_out = virtio_media_try_fmt, + .vidioc_try_fmt_vid_out_overlay = virtio_media_try_fmt, + .vidioc_try_fmt_vbi_cap = virtio_media_try_fmt, + .vidioc_try_fmt_vbi_out = virtio_media_try_fmt, + .vidioc_try_fmt_sliced_vbi_cap = virtio_media_try_fmt, + .vidioc_try_fmt_sliced_vbi_out = virtio_media_try_fmt, + .vidioc_try_fmt_vid_cap_mplane = virtio_media_try_fmt, + .vidioc_try_fmt_vid_out_mplane = virtio_media_try_fmt, + .vidioc_try_fmt_sdr_cap = virtio_media_try_fmt, + .vidioc_try_fmt_sdr_out = virtio_media_try_fmt, + .vidioc_try_fmt_meta_cap = virtio_media_try_fmt, + .vidioc_try_fmt_meta_out = virtio_media_try_fmt, + + /* Standard handling */ + .vidioc_g_std = virtio_media_g_std, + .vidioc_s_std = virtio_media_s_std, + .vidioc_querystd = virtio_media_querystd, + + /* Input handling */ + .vidioc_enum_input = virtio_media_enuminput, + .vidioc_g_input = virtio_media_g_input, + .vidioc_s_input = virtio_media_s_input, + + /* Output handling */ + .vidioc_enum_output = virtio_media_enumoutput, + .vidioc_g_output = virtio_media_g_output, + .vidioc_s_output = virtio_media_s_output, + + /* Control handling */ + .vidioc_query_ext_ctrl = virtio_media_query_ext_ctrl, + .vidioc_querymenu = virtio_media_querymenu, + + /* Audio ioctls */ + .vidioc_enumaudio = virtio_media_enumaudio, + .vidioc_g_audio = virtio_media_g_audio, + .vidioc_s_audio = virtio_media_s_audio, + + /* Audio out ioctls */ + .vidioc_enumaudout = virtio_media_enumaudout, + .vidioc_g_audout = virtio_media_g_audout, + .vidioc_s_audout = virtio_media_s_audout, + .vidioc_g_modulator = virtio_media_g_modulator, + .vidioc_s_modulator = virtio_media_s_modulator, + + /* Crop ioctls */ + /* + * Not directly an ioctl (part of VIDIOC_CROPCAP), so no need to + * implement. + */ + .vidioc_g_pixelaspect = NULL, + .vidioc_g_selection = virtio_media_g_selection, + .vidioc_s_selection = virtio_media_s_selection, + + /* Compression ioctls */ + /* Deprecated in V4L2. */ + .vidioc_g_jpegcomp = NULL, + /* Deprecated in V4L2. */ + .vidioc_s_jpegcomp = NULL, + .vidioc_g_enc_index = virtio_media_g_enc_index, + .vidioc_encoder_cmd = virtio_media_encoder_cmd, + .vidioc_try_encoder_cmd = virtio_media_try_encoder_cmd, + .vidioc_try_decoder_cmd = virtio_media_try_decoder_cmd, + + /* Stream type-dependent parameter ioctls */ + .vidioc_g_parm = virtio_media_g_parm, + .vidioc_s_parm = virtio_media_s_parm, + + /* Tuner ioctls */ + .vidioc_g_tuner = virtio_media_g_tuner, + .vidioc_s_tuner = virtio_media_s_tuner, + .vidioc_g_frequency = virtio_media_g_frequency, + .vidioc_s_frequency = virtio_media_s_frequency, + .vidioc_enum_freq_bands = virtio_media_enum_freq_bands, + + /* Sliced VBI cap */ + .vidioc_g_sliced_vbi_cap = virtio_media_g_sliced_vbi_cap, + + /* Log status ioctl */ + /* Guest-only operation */ + .vidioc_log_status = NULL, + + .vidioc_s_hw_freq_seek = virtio_media_s_hw_freq_seek, + + .vidioc_enum_framesizes = virtio_media_enum_framesizes, + .vidioc_enum_frameintervals = virtio_media_enum_frameintervals, + + /* DV Timings IOCTLs */ + .vidioc_s_dv_timings = virtio_media_s_dv_timings, + .vidioc_g_dv_timings = virtio_media_g_dv_timings, + .vidioc_query_dv_timings = virtio_media_query_dv_timings, + .vidioc_enum_dv_timings = virtio_media_enum_dv_timings, + .vidioc_dv_timings_cap = virtio_media_dv_timings_cap, + .vidioc_g_edid = NULL, + .vidioc_s_edid = NULL, + + /* For other private ioctls */ + .vidioc_default = NULL, +}; + +long virtio_media_device_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct video_device *video_dev = video_devdata(file); + struct virtio_media *vv = to_virtio_media(video_dev); + struct v4l2_fh *vfh = NULL; + struct v4l2_standard standard; + v4l2_std_id std_id = 0; + int ret; + + if (test_bit(V4L2_FL_USES_V4L2_FH, &video_dev->flags)) + vfh = file_to_v4l2_fh(file); + + mutex_lock(&vv->vlock); + + /* + * We need to handle a few ioctls manually because their results + * rely on vfd->tvnorms, which is normally updated by the driver + * as S_INPUT is called. Since we want to just pass these ioctls + * through, we have to hijack them from here. + */ + switch (cmd) { + case VIDIOC_S_STD: + ret = copy_from_user(&std_id, (void __user *)arg, + sizeof(std_id)); + if (ret) { + ret = -EFAULT; + break; + } + ret = virtio_media_s_std(file, vfh, std_id); + break; + case VIDIOC_ENUMSTD: + ret = copy_from_user(&standard, (void __user *)arg, + sizeof(standard)); + if (ret) { + ret = -EFAULT; + break; + } + ret = virtio_media_enumstd(file, vfh, &standard); + if (ret) + break; + ret = copy_to_user((void __user *)arg, &standard, + sizeof(standard)); + if (ret) + ret = -EFAULT; + break; + case VIDIOC_QUERYSTD: + ret = virtio_media_querystd(file, vfh, &std_id); + if (ret) + break; + ret = copy_to_user((void __user *)arg, &std_id, sizeof(std_id)); + if (ret) + ret = -EFAULT; + break; + default: + ret = video_ioctl2(file, cmd, arg); + break; + } + + mutex_unlock(&vv->vlock); + + return ret; +} diff --git a/include/uapi/linux/virtio_media.h b/include/uapi/linux/virtio_media.h index ad05d7421..c1e68d47c 100644 --- a/include/uapi/linux/virtio_media.h +++ b/include/uapi/linux/virtio_media.h @@ -115,4 +115,47 @@ struct virtio_media_cmd_close { __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; +}; + #endif // _UAPI__LINUX_VIRTIO_MEDIA_H -- 2.56.0.317.g454f8302e1-goog
