On Tue, Feb 02, 2021 at 11:35:16PM -0800, Vivek Kasireddy wrote:
> This driver "transfers" a dmabuf created on the Guest to the Host.
> A common use-case for such a transfer includes sharing the scanout
> buffer created by a display server or a compositor running in the
> Guest with Qemu UI -- running on the Host.
>
> The "transfer" is accomplished by sharing the PFNs of all the pages
> associated with the dmabuf and having a new dmabuf created on the
> Host that is backed up by the pages mapped from the Guest.
>
> Signed-off-by: Dongwon Kim <dongwon.kim@xxxxxxxxx>
> Signed-off-by: Vivek Kasireddy <vivek.kasireddy@xxxxxxxxx>
> ---
> drivers/virtio/Kconfig | 8 +
> drivers/virtio/Makefile | 1 +
> drivers/virtio/virtio_vdmabuf.c | 1090 +++++++++++++++++++++++++++
> include/linux/virtio_vdmabuf.h | 271 +++++++
> include/uapi/linux/virtio_ids.h | 1 +
> include/uapi/linux/virtio_vdmabuf.h | 99 +++
> 6 files changed, 1470 insertions(+)
> create mode 100644 drivers/virtio/virtio_vdmabuf.c
> create mode 100644 include/linux/virtio_vdmabuf.h
> create mode 100644 include/uapi/linux/virtio_vdmabuf.h
>
> diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
> index 7b41130d3f35..e563c12f711e 100644
> --- a/drivers/virtio/Kconfig
> +++ b/drivers/virtio/Kconfig
> @@ -139,4 +139,12 @@ config VIRTIO_DMA_SHARED_BUFFER
> This option adds a flavor of dma buffers that are backed by
> virtio resources.
>
> +config VIRTIO_VDMABUF
> + bool "Enables Vdmabuf driver in guest os"
> + default n
> + depends on VIRTIO
> + help
> + This driver provides a way to share the dmabufs created in
> + the Guest with the Host.
> +
> endif # VIRTIO_MENU
> diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile
> index 591e6f72aa54..b4bb0738009c 100644
> --- a/drivers/virtio/Makefile
> +++ b/drivers/virtio/Makefile
> @@ -9,3 +9,4 @@ obj-$(CONFIG_VIRTIO_INPUT) += virtio_input.o
> obj-$(CONFIG_VIRTIO_VDPA) += virtio_vdpa.o
> obj-$(CONFIG_VIRTIO_MEM) += virtio_mem.o
> obj-$(CONFIG_VIRTIO_DMA_SHARED_BUFFER) += virtio_dma_buf.o
> +obj-$(CONFIG_VIRTIO_VDMABUF) += virtio_vdmabuf.o
> diff --git a/drivers/virtio/virtio_vdmabuf.c b/drivers/virtio/virtio_vdmabuf.c
> new file mode 100644
> index 000000000000..c28f144eb126
> --- /dev/null
> +++ b/drivers/virtio/virtio_vdmabuf.c
> @@ -0,0 +1,1090 @@
> +// SPDX-License-Identifier: (MIT OR GPL-2.0)
> +
> +/*
> + * Copyright © 2021 Intel Corporation
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + *
> + * Authors:
> + * Dongwon Kim <dongwon.kim@xxxxxxxxx>
> + * Mateusz Polrola <mateusz.polrola@xxxxxxxxx>
> + * Vivek Kasireddy <vivek.kasireddy@xxxxxxxxx>
> + */
> +
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/errno.h>
> +#include <linux/module.h>
> +#include <linux/device.h>
> +#include <linux/uaccess.h>
> +#include <linux/miscdevice.h>
> +#include <linux/delay.h>
> +#include <linux/random.h>
> +#include <linux/poll.h>
> +#include <linux/spinlock.h>
> +#include <linux/dma-buf.h>
> +#include <linux/virtio.h>
> +#include <linux/virtio_ids.h>
> +#include <linux/virtio_config.h>
> +#include <linux/virtio_vdmabuf.h>
> +
> +#define VIRTIO_VDMABUF_MAX_ID INT_MAX
> +#define REFS_PER_PAGE (PAGE_SIZE/sizeof(long))
> +#define NEW_BUF_ID_GEN(vmid, cnt) (((vmid & 0xFFFFFFFF) << 32) | \
> + ((cnt) & 0xFFFFFFFF))
> +
> +/* one global drv object */
> +static struct virtio_vdmabuf_info *drv_info;
> +
> +struct virtio_vdmabuf {
> + /* virtio device structure */
> + struct virtio_device *vdev;
> +
> + /* virtual queue array */
> + struct virtqueue *vqs[VDMABUF_VQ_MAX];
> +
> + /* ID of guest OS */
> + u64 vmid;
> +
> + /* spin lock that needs to be acquired before accessing
> + * virtual queue
> + */
> + spinlock_t vq_lock;
> + struct mutex recv_lock;
> + struct mutex send_lock;
> +
> + struct list_head msg_list;
> +
> + /* workqueue */
> + struct workqueue_struct *wq;
> + struct work_struct recv_work;
> + struct work_struct send_work;
> + struct work_struct send_msg_work;
> +
> + struct virtio_vdmabuf_event_queue *evq;
> +};
> +
> +static virtio_vdmabuf_buf_id_t get_buf_id(struct virtio_vdmabuf *vdmabuf)
> +{
> + virtio_vdmabuf_buf_id_t buf_id = {0, {0, 0} };
> + static int count = 0;
> +
> + count = count < VIRTIO_VDMABUF_MAX_ID ? count + 1 : 0;
> + buf_id.id = NEW_BUF_ID_GEN(vdmabuf->vmid, count);
> +
> + /* random data embedded in the id for security */
> + get_random_bytes(&buf_id.rng_key[0], 8);
> +
> + return buf_id;
> +}
> +
> +/* sharing pages for original DMABUF with Host */
> +static struct virtio_vdmabuf_shared_pages
> +*virtio_vdmabuf_share_buf(struct page **pages, int nents,
> + int first_ofst, int last_len)
> +{
> + struct virtio_vdmabuf_shared_pages *pages_info;
> + int i;
> + int n_l2refs = nents/REFS_PER_PAGE +
> + ((nents % REFS_PER_PAGE) ? 1 : 0);
> +
> + pages_info = kvcalloc(1, sizeof(*pages_info), GFP_KERNEL);
> + if (!pages_info)
> + return NULL;
> +
> + pages_info->pages = pages;
> + pages_info->nents = nents;
> + pages_info->first_ofst = first_ofst;
> + pages_info->last_len = last_len;
> + pages_info->l3refs = (gpa_t *)__get_free_page(GFP_KERNEL);
> +
> + if (!pages_info->l3refs) {
> + kvfree(pages_info);
> + return NULL;
> + }
> +
> + pages_info->l2refs = (gpa_t **)__get_free_pages(GFP_KERNEL,
> + get_order(n_l2refs * PAGE_SIZE));
> +
> + if (!pages_info->l2refs) {
> + free_page((gpa_t)pages_info->l3refs);
> + kvfree(pages_info);
> + return NULL;
> + }
> +
> + /* Share physical address of pages */
> + for (i = 0; i < nents; i++)
> + pages_info->l2refs[i] = (gpa_t *)page_to_phys(pages[i]);
> +
> + for (i = 0; i < n_l2refs; i++)
> + pages_info->l3refs[i] =
> + virt_to_phys((void *)pages_info->l2refs +
> + i * PAGE_SIZE);
> +
> + pages_info->ref = (gpa_t)virt_to_phys(pages_info->l3refs);
> +
> + return pages_info;
> +}
> +
> +/* stop sharing pages */
> +static void
> +virtio_vdmabuf_free_buf(struct virtio_vdmabuf_shared_pages *pages_info)
> +{
> + int n_l2refs = (pages_info->nents/REFS_PER_PAGE +
> + ((pages_info->nents % REFS_PER_PAGE) ? 1 : 0));
> +
> + free_pages((gpa_t)pages_info->l2refs, get_order(n_l2refs * PAGE_SIZE));
> + free_page((gpa_t)pages_info->l3refs);
> +
> + kvfree(pages_info);
> +}
> +
> +static int send_msg_to_host(enum virtio_vdmabuf_cmd cmd, int *op)
> +{
> + struct virtio_vdmabuf *vdmabuf = drv_info->priv;
> + struct virtio_vdmabuf_msg *msg;
> + int i;
> +
> + switch (cmd) {
> + case VIRTIO_VDMABUF_CMD_NEED_VMID:
> + msg = kvcalloc(1, sizeof(struct virtio_vdmabuf_msg),
> + GFP_KERNEL);
> + if (!msg)
> + return -ENOMEM;
> +
> + if (op)
> + for (i = 0; i < 4; i++)
> + msg->op[i] = op[i];
> + break;
> +
> + case VIRTIO_VDMABUF_CMD_EXPORT:
> + msg = kvcalloc(1, sizeof(struct virtio_vdmabuf_msg),
> + GFP_KERNEL);
> + if (!msg)
> + return -ENOMEM;
> +
> + memcpy(&msg->op[0], &op[0], 9 * sizeof(int) + op[9]);
> + break;
> +
> + default:
> + /* no command found */
> + return -EINVAL;
> + }
> +
> + msg->cmd = cmd;
> + list_add_tail(&msg->list, &vdmabuf->msg_list);
> + queue_work(vdmabuf->wq, &vdmabuf->send_msg_work);
> +
> + return 0;
> +}
> +
> +static int add_event_buf_rel(struct virtio_vdmabuf_buf *buf_info)
> +{
> + struct virtio_vdmabuf *vdmabuf = drv_info->priv;
> + struct virtio_vdmabuf_event *e_oldest, *e_new;
> + struct virtio_vdmabuf_event_queue *eq = vdmabuf->evq;
> + unsigned long irqflags;
> +
> + e_new = kvzalloc(sizeof(*e_new), GFP_KERNEL);
> + if (!e_new)
> + return -ENOMEM;
> +
> + e_new->e_data.hdr.buf_id = buf_info->buf_id;
> + e_new->e_data.data = (void *)buf_info->priv;
> + e_new->e_data.hdr.size = buf_info->sz_priv;
> +
> + spin_lock_irqsave(&eq->e_lock, irqflags);
> +
> + /* check current number of events and if it hits the max num (32)
> + * then remove the oldest event in the list
> + */
> + if (eq->pending > 31) {
> + e_oldest = list_first_entry(&eq->e_list,
> + struct virtio_vdmabuf_event, link);
> + list_del(&e_oldest->link);
> + eq->pending--;
> + kvfree(e_oldest);
> + }
> +
> + list_add_tail(&e_new->link, &eq->e_list);
> +
> + eq->pending++;
> +
> + wake_up_interruptible(&eq->e_wait);
> + spin_unlock_irqrestore(&eq->e_lock, irqflags);
> +
> + return 0;
> +}
> +
> +static void virtio_vdmabuf_clear_buf(struct virtio_vdmabuf_buf *exp)
> +{
> + /* Start cleanup of buffer in reverse order to exporting */
> + virtio_vdmabuf_free_buf(exp->pages_info);
> +
> + dma_buf_unmap_attachment(exp->attach, exp->sgt,
> + DMA_BIDIRECTIONAL);
> +
> + if (exp->dma_buf) {
> + dma_buf_detach(exp->dma_buf, exp->attach);
> + /* close connection to dma-buf completely */
> + dma_buf_put(exp->dma_buf);
> + exp->dma_buf = NULL;
> + }
> +}
> +
> +static int remove_buf(struct virtio_vdmabuf *vdmabuf,
> + struct virtio_vdmabuf_buf *exp)
> +{
> + int ret;
> +
> + ret = add_event_buf_rel(exp);
> + if (ret)
> + return ret;
> +
> + virtio_vdmabuf_clear_buf(exp);
> +
> + ret = virtio_vdmabuf_del_buf(drv_info, &exp->buf_id);
> + if (ret)
> + return ret;
> +
> + if (exp->sz_priv > 0 && !exp->priv)
> + kvfree(exp->priv);
> +
> + kvfree(exp);
> + return 0;
> +}
> +
> +static int parse_msg_from_host(struct virtio_vdmabuf *vdmabuf,
> + struct virtio_vdmabuf_msg *msg)
> +{
> + struct virtio_vdmabuf_buf *exp;
> + virtio_vdmabuf_buf_id_t buf_id;
> + int ret;
> +
> + switch (msg->cmd) {
> + case VIRTIO_VDMABUF_CMD_NEED_VMID:
> + vdmabuf->vmid = msg->op[0];
> +
> + break;
> + case VIRTIO_VDMABUF_CMD_DMABUF_REL:
> + memcpy(&buf_id, msg->op, sizeof(buf_id));
> +
> + exp = virtio_vdmabuf_find_buf(drv_info, &buf_id);
> + if (!exp) {
> + dev_err(drv_info->dev, "can't find buffer\n");
> + return -EINVAL;
> + }
> +
> + ret = remove_buf(vdmabuf, exp);
> + if (ret)
> + return ret;
> +
> + break;
> + case VIRTIO_VDMABUF_CMD_EXPORT:
> + break;
> + default:
> + dev_err(drv_info->dev, "empty cmd\n");
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static void virtio_vdmabuf_recv_work(struct work_struct *work)
> +{
> + struct virtio_vdmabuf *vdmabuf =
> + container_of(work, struct virtio_vdmabuf, recv_work);
> + struct virtqueue *vq = vdmabuf->vqs[VDMABUF_VQ_RECV];
> + struct virtio_vdmabuf_msg *msg;
> + int sz;
> +
> + mutex_lock(&vdmabuf->recv_lock);
> +
> + do {
> + virtqueue_disable_cb(vq);
> + for (;;) {
> + msg = virtqueue_get_buf(vq, &sz);
> + if (!msg)
> + break;
> +
> + /* valid size */
> + if (sz == sizeof(struct virtio_vdmabuf_msg)) {
> + if (parse_msg_from_host(vdmabuf, msg))
> + dev_err(drv_info->dev,
> + "msg parse error\n");
> +
> + kvfree(msg);
> + } else {
> + dev_err(drv_info->dev,
> + "received malformed message\n");
> + }
> + }
> + } while (!virtqueue_enable_cb(vq));
> +
> + mutex_unlock(&vdmabuf->recv_lock);
> +}
> +
> +static void virtio_vdmabuf_fill_recv_msg(struct virtio_vdmabuf *vdmabuf)
> +{
> + struct virtqueue *vq = vdmabuf->vqs[VDMABUF_VQ_RECV];
> + struct scatterlist sg;
> + struct virtio_vdmabuf_msg *msg;
> + int ret;
> +
> + msg = kvzalloc(sizeof(*msg), GFP_KERNEL);
> + if (!msg)
> + return;
> +
> + sg_init_one(&sg, msg, sizeof(struct virtio_vdmabuf_msg));
> + ret = virtqueue_add_inbuf(vq, &sg, 1, msg, GFP_KERNEL);
> + if (ret)
> + return;
> +
> + virtqueue_kick(vq);
> +}
> +
> +static void virtio_vdmabuf_send_msg_work(struct work_struct *work)
> +{
> + struct virtio_vdmabuf *vdmabuf =
> + container_of(work, struct virtio_vdmabuf, send_msg_work);
> + struct virtqueue *vq = vdmabuf->vqs[VDMABUF_VQ_SEND];
> + struct scatterlist sg;
> + struct virtio_vdmabuf_msg *msg;
> + bool added = false;
> + int ret;
> +
> + mutex_lock(&vdmabuf->send_lock);
> +
> + for (;;) {
> + if (list_empty(&vdmabuf->msg_list))
> + break;
> +
> + virtio_vdmabuf_fill_recv_msg(vdmabuf);
> +
> + msg = list_first_entry(&vdmabuf->msg_list,
> + struct virtio_vdmabuf_msg, list);
> + list_del_init(&msg->list);
> +
> + sg_init_one(&sg, msg, sizeof(struct virtio_vdmabuf_msg));
> + ret = virtqueue_add_outbuf(vq, &sg, 1, msg, GFP_KERNEL);
> + if (ret < 0) {
> + dev_err(drv_info->dev,
> + "failed to add msg to vq\n");
> + break;
> + }
> +
> + added = true;
> + }
> +
> + if (added)
> + virtqueue_kick(vq);
> +
> + mutex_unlock(&vdmabuf->send_lock);
> +}
> +
> +static void virtio_vdmabuf_send_work(struct work_struct *work)
> +{
> + struct virtio_vdmabuf *vdmabuf =
> + container_of(work, struct virtio_vdmabuf, send_work);
> + struct virtqueue *vq = vdmabuf->vqs[VDMABUF_VQ_SEND];
> + struct virtio_vdmabuf_msg *msg;
> + unsigned int sz;
> + bool added = false;
> +
> + mutex_lock(&vdmabuf->send_lock);
> +
> + do {
> + virtqueue_disable_cb(vq);
> +
> + for (;;) {
> + msg = virtqueue_get_buf(vq, &sz);
> + if (!msg)
> + break;
> +
> + if (parse_msg_from_host(vdmabuf, msg))
> + dev_err(drv_info->dev,
> + "msg parse error\n");
> +
> + kvfree(msg);
> + added = true;
> + }
> + } while (!virtqueue_enable_cb(vq));
> +
> + mutex_unlock(&vdmabuf->send_lock);
> +
> + if (added)
> + queue_work(vdmabuf->wq, &vdmabuf->send_msg_work);
> +}
> +
> +static void virtio_vdmabuf_recv_cb(struct virtqueue *vq)
> +{
> + struct virtio_vdmabuf *vdmabuf = vq->vdev->priv;
> +
> + if (!vdmabuf)
> + return;
> +
> + queue_work(vdmabuf->wq, &vdmabuf->recv_work);
> +}
> +
> +static void virtio_vdmabuf_send_cb(struct virtqueue *vq)
> +{
> + struct virtio_vdmabuf *vdmabuf = vq->vdev->priv;
> +
> + if (!vdmabuf)
> + return;
> +
> + queue_work(vdmabuf->wq, &vdmabuf->send_work);
> +}
> +
> +static int remove_all_bufs(struct virtio_vdmabuf *vdmabuf)
> +{
> + struct virtio_vdmabuf_buf *found;
> + struct hlist_node *tmp;
> + int bkt;
> + int ret;
> +
> + hash_for_each_safe(drv_info->buf_list, bkt, tmp, found, node) {
> + ret = remove_buf(vdmabuf, found);
> + if (ret)
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int virtio_vdmabuf_open(struct inode *inode, struct file *filp)
> +{
> + int ret;
> +
> + if (!drv_info) {
> + pr_err("virtio vdmabuf driver is not ready\n");
> + return -EINVAL;
> + }
> +
> + ret = send_msg_to_host(VIRTIO_VDMABUF_CMD_NEED_VMID, 0);
> + if (ret < 0)
> + dev_err(drv_info->dev, "fail to receive vmid\n");
> +
> + filp->private_data = drv_info->priv;
> +
> + return 0;
> +}
> +
> +static int virtio_vdmabuf_release(struct inode *inode, struct file *filp)
> +{
> + return 0;
> +}
> +
> +/* Notify Host about the new vdmabuf */
> +static int export_notify(struct virtio_vdmabuf_buf *exp, struct page **pages)
> +{
> + int *op;
> + int ret;
> +
> + op = kvcalloc(1, sizeof(int) * 65, GFP_KERNEL);
> + if (!op)
> + return -ENOMEM;
> +
> + memcpy(op, &exp->buf_id, sizeof(exp->buf_id));
> +
> + /* if new pages are to be shared */
> + if (pages) {
> + op[4] = exp->pages_info->nents;
> + op[5] = exp->pages_info->first_ofst;
> + op[6] = exp->pages_info->last_len;
> +
> + memcpy(&op[7], &exp->pages_info->ref, sizeof(gpa_t));
> + }
> +
> + op[9] = exp->sz_priv;
> +
> + /* driver/application specific private info */
> + memcpy(&op[10], exp->priv, op[9]);
> +
> + ret = send_msg_to_host(VIRTIO_VDMABUF_CMD_EXPORT, op);
> +
> + kvfree(op);
> + return ret;
> +}
> +
> +/* return total number of pages referenced by a sgt
> + * for pre-calculation of # of pages behind a given sgt
> + */
> +static int num_pgs(struct sg_table *sgt)
> +{
> + struct scatterlist *sgl;
> + int len, i;
> + /* at least one page */
> + int n_pgs = 1;
> +
> + sgl = sgt->sgl;
> +
> + len = sgl->length - PAGE_SIZE + sgl->offset;
> +
> + /* round-up */
> + n_pgs += ((len + PAGE_SIZE - 1)/PAGE_SIZE);
> +
> + for (i = 1; i < sgt->nents; i++) {
> + sgl = sg_next(sgl);
> +
> + /* round-up */
> + n_pgs += ((sgl->length + PAGE_SIZE - 1) /
> + PAGE_SIZE); /* round-up */
> + }
> +
> + return n_pgs;
> +}
> +
> +/* extract pages referenced by sgt */
> +static struct page **extr_pgs(struct sg_table *sgt, int *nents, int *last_len)
Nack, this doesn't work on dma-buf. And it'll blow up at runtime when you
enable the very recently merged CONFIG_DMABUF_DEBUG (would be good to test
with that, just to make sure).
Aside from this, for virtio/kvm use-cases we've already merged the udmabuf
driver. Does this not work for your usecase?
Adding Gerd as the subject expert for this area.
Thanks, Daniel
> +{
> + struct scatterlist *sgl;
> + struct page **pages;
> + struct page **temp_pgs;
> + int i, j;
> + int len;
> +
> + *nents = num_pgs(sgt);
> + pages = kvmalloc_array(*nents, sizeof(struct page *), GFP_KERNEL);
> + if (!pages)
> + return NULL;
> +
> + sgl = sgt->sgl;
> +
> + temp_pgs = pages;
> + *temp_pgs++ = sg_page(sgl);
> + len = sgl->length - PAGE_SIZE + sgl->offset;
> +
> + i = 1;
> + while (len > 0) {
> + *temp_pgs++ = nth_page(sg_page(sgl), i++);
> + len -= PAGE_SIZE;
> + }
> +
> + for (i = 1; i < sgt->nents; i++) {
> + sgl = sg_next(sgl);
> + *temp_pgs++ = sg_page(sgl);
> + len = sgl->length - PAGE_SIZE;
> + j = 1;
> +
> + while (len > 0) {
> + *temp_pgs++ = nth_page(sg_page(sgl), j++);
> + len -= PAGE_SIZE;
> + }
> + }
> +
> + *last_len = len + PAGE_SIZE;
> +
> + return pages;
> +}
> +
> +/* ioctl - exporting new vdmabuf
> + *
> + * int dmabuf_fd - File handle of original DMABUF
> + * virtio_vdmabuf_buf_id_t buf_id - returned vdmabuf ID
> + * int sz_priv - size of private data from userspace
> + * char *priv - buffer of user private data
> + *
> + */
> +static int export_ioctl(struct file *filp, void *data)
> +{
> + struct virtio_vdmabuf *vdmabuf = drv_info->priv;
> + struct virtio_vdmabuf_export *attr = data;
> + struct dma_buf *dmabuf;
> + struct dma_buf_attachment *attach;
> + struct sg_table *sgt;
> + struct virtio_vdmabuf_buf *exp;
> + struct page **pages;
> + int nents, last_len;
> + virtio_vdmabuf_buf_id_t buf_id;
> + int ret = 0;
> +
> + if (vdmabuf->vmid <= 0)
> + return -EINVAL;
> +
> + dmabuf = dma_buf_get(attr->fd);
> + if (IS_ERR(dmabuf))
> + return PTR_ERR(dmabuf);
> +
> + mutex_lock(&drv_info->g_mutex);
> +
> + buf_id = get_buf_id(vdmabuf);
> +
> + attach = dma_buf_attach(dmabuf, drv_info->dev);
> + if (IS_ERR(attach)) {
> + ret = PTR_ERR(attach);
> + goto fail_attach;
> + }
> +
> + sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
> + if (IS_ERR(sgt)) {
> + ret = PTR_ERR(sgt);
> + goto fail_map_attachment;
> + }
> +
> + /* allocate a new exp */
> + exp = kvcalloc(1, sizeof(*exp), GFP_KERNEL);
> + if (!exp) {
> + ret = -ENOMEM;
> + goto fail_sgt_info_creation;
> + }
> +
> + /* possible truncation */
> + if (attr->sz_priv > MAX_SIZE_PRIV_DATA)
> + exp->sz_priv = MAX_SIZE_PRIV_DATA;
> + else
> + exp->sz_priv = attr->sz_priv;
> +
> + /* creating buffer for private data */
> + if (exp->sz_priv != 0) {
> + exp->priv = kvcalloc(1, exp->sz_priv, GFP_KERNEL);
> + if (!exp->priv) {
> + ret = -ENOMEM;
> + goto fail_priv_creation;
> + }
> + }
> +
> + exp->buf_id = buf_id;
> + exp->attach = attach;
> + exp->sgt = sgt;
> + exp->dma_buf = dmabuf;
> + exp->valid = 1;
> +
> + if (exp->sz_priv) {
> + /* copy private data to sgt_info */
> + ret = copy_from_user(exp->priv, attr->priv, exp->sz_priv);
> + if (ret) {
> + ret = -EINVAL;
> + goto fail_exp;
> + }
> + }
> +
> + pages = extr_pgs(sgt, &nents, &last_len);
> + if (pages == NULL) {
> + ret = -ENOMEM;
> + goto fail_exp;
> + }
> +
> + exp->pages_info = virtio_vdmabuf_share_buf(pages, nents,
> + sgt->sgl->offset,
> + last_len);
> + if (!exp->pages_info) {
> + ret = -ENOMEM;
> + goto fail_create_pages_info;
> + }
> +
> + attr->buf_id = exp->buf_id;
> + ret = export_notify(exp, pages);
> + if (ret < 0)
> + goto fail_send_request;
> +
> + /* now register it to the export list */
> + virtio_vdmabuf_add_buf(drv_info, exp);
> +
> + exp->filp = filp;
> +
> + mutex_unlock(&drv_info->g_mutex);
> +
> + return ret;
> +
> +/* Clean-up if error occurs */
> +fail_send_request:
> + virtio_vdmabuf_free_buf(exp->pages_info);
> +
> +fail_create_pages_info:
> + kvfree(pages);
> +
> +fail_exp:
> + kvfree(exp->priv);
> +
> +fail_priv_creation:
> + kvfree(exp);
> +
> +fail_sgt_info_creation:
> + dma_buf_unmap_attachment(attach, sgt,
> + DMA_BIDIRECTIONAL);
> +
> +fail_map_attachment:
> + dma_buf_detach(dmabuf, attach);
> +
> +fail_attach:
> + dma_buf_put(dmabuf);
> +
> + mutex_unlock(&drv_info->g_mutex);
> +
> + return ret;
> +}
> +
> +static const struct virtio_vdmabuf_ioctl_desc virtio_vdmabuf_ioctls[] = {
> + VIRTIO_VDMABUF_IOCTL_DEF(VIRTIO_VDMABUF_IOCTL_EXPORT, export_ioctl, 0),
> +};
> +
> +static long virtio_vdmabuf_ioctl(struct file *filp, unsigned int cmd,
> + unsigned long param)
> +{
> + const struct virtio_vdmabuf_ioctl_desc *ioctl = NULL;
> + unsigned int nr = _IOC_NR(cmd);
> + int ret;
> + virtio_vdmabuf_ioctl_t func;
> + char *kdata;
> +
> + if (nr >= ARRAY_SIZE(virtio_vdmabuf_ioctls)) {
> + dev_err(drv_info->dev, "invalid ioctl\n");
> + return -EINVAL;
> + }
> +
> + ioctl = &virtio_vdmabuf_ioctls[nr];
> +
> + func = ioctl->func;
> +
> + if (unlikely(!func)) {
> + dev_err(drv_info->dev, "no function\n");
> + return -EINVAL;
> + }
> +
> + kdata = kvmalloc(_IOC_SIZE(cmd), GFP_KERNEL);
> + if (!kdata)
> + return -ENOMEM;
> +
> + if (copy_from_user(kdata, (void __user *)param,
> + _IOC_SIZE(cmd)) != 0) {
> + dev_err(drv_info->dev,
> + "failed to copy from user arguments\n");
> + ret = -EFAULT;
> + goto ioctl_error;
> + }
> +
> + ret = func(filp, kdata);
> +
> + if (copy_to_user((void __user *)param, kdata,
> + _IOC_SIZE(cmd)) != 0) {
> + dev_err(drv_info->dev,
> + "failed to copy to user arguments\n");
> + ret = -EFAULT;
> + goto ioctl_error;
> + }
> +
> +ioctl_error:
> + kvfree(kdata);
> + return ret;
> +}
> +
> +static unsigned int virtio_vdmabuf_event_poll(struct file *filp,
> + struct poll_table_struct *wait)
> +{
> + struct virtio_vdmabuf *vdmabuf = filp->private_data;
> +
> + poll_wait(filp, &vdmabuf->evq->e_wait, wait);
> +
> + if (!list_empty(&vdmabuf->evq->e_list))
> + return POLLIN | POLLRDNORM;
> +
> + return 0;
> +}
> +
> +static ssize_t virtio_vdmabuf_event_read(struct file *filp, char __user *buf,
> + size_t cnt, loff_t *ofst)
> +{
> + struct virtio_vdmabuf *vdmabuf = filp->private_data;
> + int ret;
> +
> + /* make sure user buffer can be written */
> + if (!access_ok(buf, sizeof (*buf))) {
> + dev_err(drv_info->dev, "user buffer can't be written.\n");
> + return -EINVAL;
> + }
> +
> + ret = mutex_lock_interruptible(&vdmabuf->evq->e_readlock);
> + if (ret)
> + return ret;
> +
> + for (;;) {
> + struct virtio_vdmabuf_event *e = NULL;
> +
> + spin_lock_irq(&vdmabuf->evq->e_lock);
> + if (!list_empty(&vdmabuf->evq->e_list)) {
> + e = list_first_entry(&vdmabuf->evq->e_list,
> + struct virtio_vdmabuf_event, link);
> + list_del(&e->link);
> + }
> + spin_unlock_irq(&vdmabuf->evq->e_lock);
> +
> + if (!e) {
> + if (ret)
> + break;
> +
> + if (filp->f_flags & O_NONBLOCK) {
> + ret = -EAGAIN;
> + break;
> + }
> +
> + mutex_unlock(&vdmabuf->evq->e_readlock);
> + ret = wait_event_interruptible(vdmabuf->evq->e_wait,
> + !list_empty(&vdmabuf->evq->e_list));
> +
> + if (ret == 0)
> + ret = mutex_lock_interruptible(
> + &vdmabuf->evq->e_readlock);
> +
> + if (ret)
> + return ret;
> + } else {
> + unsigned int len = (sizeof(e->e_data.hdr) +
> + e->e_data.hdr.size);
> +
> + if (len > cnt - ret) {
> +put_back_event:
> + spin_lock_irq(&vdmabuf->evq->e_lock);
> + list_add(&e->link, &vdmabuf->evq->e_list);
> + spin_unlock_irq(&vdmabuf->evq->e_lock);
> + break;
> + }
> +
> + if (copy_to_user(buf + ret, &e->e_data.hdr,
> + sizeof(e->e_data.hdr))) {
> + if (ret == 0)
> + ret = -EFAULT;
> +
> + goto put_back_event;
> + }
> +
> + ret += sizeof(e->e_data.hdr);
> +
> + if (copy_to_user(buf + ret, e->e_data.data,
> + e->e_data.hdr.size)) {
> + /* error while copying void *data */
> +
> + struct virtio_vdmabuf_e_hdr dummy_hdr = {0};
> +
> + ret -= sizeof(e->e_data.hdr);
> +
> + /* nullifying hdr of the event in user buffer */
> + if (copy_to_user(buf + ret, &dummy_hdr,
> + sizeof(dummy_hdr)))
> + dev_err(drv_info->dev,
> + "fail to nullify invalid hdr\n");
> +
> + ret = -EFAULT;
> +
> + goto put_back_event;
> + }
> +
> + ret += e->e_data.hdr.size;
> + vdmabuf->evq->pending--;
> + kvfree(e);
> + }
> + }
> +
> + mutex_unlock(&vdmabuf->evq->e_readlock);
> +
> + return ret;
> +}
> +
> +static const struct file_operations virtio_vdmabuf_fops = {
> + .owner = THIS_MODULE,
> + .open = virtio_vdmabuf_open,
> + .release = virtio_vdmabuf_release,
> + .read = virtio_vdmabuf_event_read,
> + .poll = virtio_vdmabuf_event_poll,
> + .unlocked_ioctl = virtio_vdmabuf_ioctl,
> +};
> +
> +static struct miscdevice virtio_vdmabuf_miscdev = {
> + .minor = MISC_DYNAMIC_MINOR,
> + .name = "virtio-vdmabuf",
> + .fops = &virtio_vdmabuf_fops,
> +};
> +
> +static int virtio_vdmabuf_probe(struct virtio_device *vdev)
> +{
> + vq_callback_t *cbs[] = {
> + virtio_vdmabuf_recv_cb,
> + virtio_vdmabuf_send_cb,
> + };
> + static const char *const names[] = {
> + "recv",
> + "send",
> + };
> + struct virtio_vdmabuf *vdmabuf;
> + int ret = 0;
> +
> + if (!drv_info)
> + return -EINVAL;
> +
> + vdmabuf = drv_info->priv;
> +
> + if (!vdmabuf)
> + return -EINVAL;
> +
> + vdmabuf->vdev = vdev;
> + vdev->priv = vdmabuf;
> +
> + /* initialize spinlock for synchronizing virtqueue accesses */
> + spin_lock_init(&vdmabuf->vq_lock);
> +
> + ret = virtio_find_vqs(vdmabuf->vdev, VDMABUF_VQ_MAX, vdmabuf->vqs,
> + cbs, names, NULL);
> + if (ret) {
> + dev_err(drv_info->dev, "Cannot find any vqs\n");
> + return ret;
> + }
> +
> + INIT_LIST_HEAD(&vdmabuf->msg_list);
> + INIT_WORK(&vdmabuf->recv_work, virtio_vdmabuf_recv_work);
> + INIT_WORK(&vdmabuf->send_work, virtio_vdmabuf_send_work);
> + INIT_WORK(&vdmabuf->send_msg_work, virtio_vdmabuf_send_msg_work);
> +
> + return ret;
> +}
> +
> +static void virtio_vdmabuf_remove(struct virtio_device *vdev)
> +{
> + struct virtio_vdmabuf *vdmabuf;
> +
> + if (!drv_info)
> + return;
> +
> + vdmabuf = drv_info->priv;
> + flush_work(&vdmabuf->recv_work);
> + flush_work(&vdmabuf->send_work);
> + flush_work(&vdmabuf->send_msg_work);
> +
> + vdev->config->reset(vdev);
> + vdev->config->del_vqs(vdev);
> +}
> +
> +static struct virtio_device_id id_table[] = {
> + { VIRTIO_ID_VDMABUF, VIRTIO_DEV_ANY_ID },
> + { 0 },
> +};
> +
> +static struct virtio_driver virtio_vdmabuf_vdev_drv = {
> + .driver.name = KBUILD_MODNAME,
> + .driver.owner = THIS_MODULE,
> + .id_table = id_table,
> + .probe = virtio_vdmabuf_probe,
> + .remove = virtio_vdmabuf_remove,
> +};
> +
> +static int __init virtio_vdmabuf_init(void)
> +{
> + struct virtio_vdmabuf *vdmabuf;
> + int ret = 0;
> +
> + drv_info = NULL;
> +
> + ret = misc_register(&virtio_vdmabuf_miscdev);
> + if (ret) {
> + pr_err("virtio-vdmabuf misc driver can't be registered\n");
> + return ret;
> + }
> +
> + ret = dma_set_mask_and_coherent(virtio_vdmabuf_miscdev.this_device,
> + DMA_BIT_MASK(64));
> + if (ret < 0) {
> + misc_deregister(&virtio_vdmabuf_miscdev);
> + return -EINVAL;
> + }
> +
> + drv_info = kvcalloc(1, sizeof(*drv_info), GFP_KERNEL);
> + if (!drv_info) {
> + misc_deregister(&virtio_vdmabuf_miscdev);
> + return -ENOMEM;
> + }
> +
> + vdmabuf = kvcalloc(1, sizeof(*vdmabuf), GFP_KERNEL);
> + if (!vdmabuf) {
> + kvfree(drv_info);
> + misc_deregister(&virtio_vdmabuf_miscdev);
> + return -ENOMEM;
> + }
> +
> + vdmabuf->evq = kvcalloc(1, sizeof(*(vdmabuf->evq)), GFP_KERNEL);
> + if (!vdmabuf->evq) {
> + kvfree(drv_info);
> + kvfree(vdmabuf);
> + misc_deregister(&virtio_vdmabuf_miscdev);
> + return -ENOMEM;
> + }
> +
> + drv_info->priv = (void *)vdmabuf;
> + drv_info->dev = virtio_vdmabuf_miscdev.this_device;
> +
> + mutex_init(&drv_info->g_mutex);
> +
> + mutex_init(&vdmabuf->evq->e_readlock);
> + spin_lock_init(&vdmabuf->evq->e_lock);
> +
> + INIT_LIST_HEAD(&vdmabuf->evq->e_list);
> + init_waitqueue_head(&vdmabuf->evq->e_wait);
> + hash_init(drv_info->buf_list);
> +
> + vdmabuf->evq->pending = 0;
> + vdmabuf->wq = create_workqueue("virtio_vdmabuf_wq");
> +
> + ret = register_virtio_driver(&virtio_vdmabuf_vdev_drv);
> + if (ret) {
> + dev_err(drv_info->dev, "vdmabuf driver can't be registered\n");
> + misc_deregister(&virtio_vdmabuf_miscdev);
> + kvfree(vdmabuf);
> + kvfree(drv_info);
> + return -EFAULT;
> + }
> +
> + return 0;
> +}
> +
> +static void __exit virtio_vdmabuf_deinit(void)
> +{
> + struct virtio_vdmabuf *vdmabuf = drv_info->priv;
> + struct virtio_vdmabuf_event *e, *et;
> + unsigned long irqflags;
> +
> + misc_deregister(&virtio_vdmabuf_miscdev);
> + unregister_virtio_driver(&virtio_vdmabuf_vdev_drv);
> +
> + if (vdmabuf->wq)
> + destroy_workqueue(vdmabuf->wq);
> +
> + spin_lock_irqsave(&vdmabuf->evq->e_lock, irqflags);
> +
> + list_for_each_entry_safe(e, et, &vdmabuf->evq->e_list,
> + link) {
> + list_del(&e->link);
> + kvfree(e);
> + vdmabuf->evq->pending--;
> + }
> +
> + spin_unlock_irqrestore(&vdmabuf->evq->e_lock, irqflags);
> +
> + /* freeing all exported buffers */
> + remove_all_bufs(vdmabuf);
> +
> + kvfree(vdmabuf->evq);
> + kvfree(vdmabuf);
> + kvfree(drv_info);
> +}
> +
> +module_init(virtio_vdmabuf_init);
> +module_exit(virtio_vdmabuf_deinit);
> +
> +MODULE_DEVICE_TABLE(virtio, virtio_vdmabuf_id_table);
> +MODULE_DESCRIPTION("Virtio Vdmabuf frontend driver");
> +MODULE_LICENSE("GPL and additional rights");
> diff --git a/include/linux/virtio_vdmabuf.h b/include/linux/virtio_vdmabuf.h
> new file mode 100644
> index 000000000000..9500bf4a54ac
> --- /dev/null
> +++ b/include/linux/virtio_vdmabuf.h
> @@ -0,0 +1,271 @@
> +/* SPDX-License-Identifier: (MIT OR GPL-2.0) */
> +
> +/*
> + * Copyright © 2021 Intel Corporation
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + *
> + */
> +
> +#ifndef _LINUX_VIRTIO_VDMABUF_H
> +#define _LINUX_VIRTIO_VDMABUF_H
> +
> +#include <uapi/linux/virtio_vdmabuf.h>
> +#include <linux/hashtable.h>
> +#include <linux/kvm_types.h>
> +
> +struct virtio_vdmabuf_shared_pages {
> + /* cross-VM ref addr for the buffer */
> + gpa_t ref;
> +
> + /* page array */
> + struct page **pages;
> + gpa_t **l2refs;
> + gpa_t *l3refs;
> +
> + /* data offset in the first page
> + * and data length in the last page
> + */
> + int first_ofst;
> + int last_len;
> +
> + /* number of shared pages */
> + int nents;
> +};
> +
> +struct virtio_vdmabuf_buf {
> + virtio_vdmabuf_buf_id_t buf_id;
> +
> + struct dma_buf_attachment *attach;
> + struct dma_buf *dma_buf;
> + struct sg_table *sgt;
> + struct virtio_vdmabuf_shared_pages *pages_info;
> + int vmid;
> +
> + /* validity of the buffer */
> + bool valid;
> +
> + /* set if the buffer is imported via import_ioctl */
> + bool imported;
> +
> + /* size of private */
> + size_t sz_priv;
> + /* private data associated with the exported buffer */
> + void *priv;
> +
> + struct file *filp;
> + struct hlist_node node;
> +};
> +
> +struct virtio_vdmabuf_event {
> + struct virtio_vdmabuf_e_data e_data;
> + struct list_head link;
> +};
> +
> +struct virtio_vdmabuf_event_queue {
> + wait_queue_head_t e_wait;
> + struct list_head e_list;
> +
> + spinlock_t e_lock;
> + struct mutex e_readlock;
> +
> + /* # of pending events */
> + int pending;
> +};
> +
> +/* driver information */
> +struct virtio_vdmabuf_info {
> + struct device *dev;
> +
> + struct list_head head_vdmabuf_list;
> + struct list_head kvm_instances;
> +
> + DECLARE_HASHTABLE(buf_list, 7);
> +
> + void *priv;
> + struct mutex g_mutex;
> + struct notifier_block kvm_notifier;
> +};
> +
> +/* IOCTL definitions
> + */
> +typedef int (*virtio_vdmabuf_ioctl_t)(struct file *filp, void *data);
> +
> +struct virtio_vdmabuf_ioctl_desc {
> + unsigned int cmd;
> + int flags;
> + virtio_vdmabuf_ioctl_t func;
> + const char *name;
> +};
> +
> +#define VIRTIO_VDMABUF_IOCTL_DEF(ioctl, _func, _flags) \
> + [_IOC_NR(ioctl)] = { \
> + .cmd = ioctl, \
> + .func = _func, \
> + .flags = _flags, \
> + .name = #ioctl \
> +}
> +
> +#define VIRTIO_VDMABUF_VMID(buf_id) ((((buf_id).id) >> 32) & 0xFFFFFFFF)
> +
> +/* Messages between Host and Guest */
> +
> +/* List of commands from Guest to Host:
> + *
> + * ------------------------------------------------------------------
> + * A. NEED_VMID
> + *
> + * guest asks the host to provide its vmid
> + *
> + * req:
> + *
> + * cmd: VIRTIO_VDMABUF_NEED_VMID
> + *
> + * ack:
> + *
> + * cmd: same as req
> + * op[0] : vmid of guest
> + *
> + * ------------------------------------------------------------------
> + * B. EXPORT
> + *
> + * export dmabuf to host
> + *
> + * req:
> + *
> + * cmd: VIRTIO_VDMABUF_CMD_EXPORT
> + * op0~op3 : HDMABUF ID
> + * op4 : number of pages to be shared
> + * op5 : offset of data in the first page
> + * op6 : length of data in the last page
> + * op7 : upper 32 bit of top-level ref of shared buf
> + * op8 : lower 32 bit of top-level ref of shared buf
> + * op9 : size of private data
> + * op10 ~ op64: User private date associated with the buffer
> + * (e.g. graphic buffer's meta info)
> + *
> + * ------------------------------------------------------------------
> + *
> + * List of commands from Host to Guest
> + *
> + * ------------------------------------------------------------------
> + * A. RELEASE
> + *
> + * notifying guest that the shared buffer is released by an importer
> + *
> + * req:
> + *
> + * cmd: VIRTIO_VDMABUF_CMD_DMABUF_REL
> + * op0~op3 : VDMABUF ID
> + *
> + * ------------------------------------------------------------------
> + */
> +
> +/* msg structures */
> +struct virtio_vdmabuf_msg {
> + struct list_head list;
> + unsigned int cmd;
> + unsigned int op[64];
> +};
> +
> +enum {
> + VDMABUF_VQ_RECV = 0,
> + VDMABUF_VQ_SEND = 1,
> + VDMABUF_VQ_MAX = 2,
> +};
> +
> +enum virtio_vdmabuf_cmd {
> + VIRTIO_VDMABUF_CMD_NEED_VMID,
> + VIRTIO_VDMABUF_CMD_EXPORT = 0x10,
> + VIRTIO_VDMABUF_CMD_DMABUF_REL
> +};
> +
> +enum virtio_vdmabuf_ops {
> + VIRTIO_VDMABUF_HDMABUF_ID_ID = 0,
> + VIRTIO_VDMABUF_HDMABUF_ID_RNG_KEY0,
> + VIRTIO_VDMABUF_HDMABUF_ID_RNG_KEY1,
> + VIRTIO_VDMABUF_NUM_PAGES_SHARED = 4,
> + VIRTIO_VDMABUF_FIRST_PAGE_DATA_OFFSET,
> + VIRTIO_VDMABUF_LAST_PAGE_DATA_LENGTH,
> + VIRTIO_VDMABUF_REF_ADDR_UPPER_32BIT,
> + VIRTIO_VDMABUF_REF_ADDR_LOWER_32BIT,
> + VIRTIO_VDMABUF_PRIVATE_DATA_SIZE,
> + VIRTIO_VDMABUF_PRIVATE_DATA_START
> +};
> +
> +/* adding exported/imported vdmabuf info to hash */
> +static inline int
> +virtio_vdmabuf_add_buf(struct virtio_vdmabuf_info *info,
> + struct virtio_vdmabuf_buf *new)
> +{
> + hash_add(info->buf_list, &new->node, new->buf_id.id);
> + return 0;
> +}
> +
> +/* comparing two vdmabuf IDs */
> +static inline bool
> +is_same_buf(virtio_vdmabuf_buf_id_t a,
> + virtio_vdmabuf_buf_id_t b)
> +{
> + int i;
> +
> + if (a.id != b.id)
> + return 1;
> +
> + /* compare keys */
> + for (i = 0; i < 2; i++) {
> + if (a.rng_key[i] != b.rng_key[i])
> + return false;
> + }
> +
> + return true;
> +}
> +
> +/* find buf for given vdmabuf ID */
> +static inline struct virtio_vdmabuf_buf
> +*virtio_vdmabuf_find_buf(struct virtio_vdmabuf_info *info,
> + virtio_vdmabuf_buf_id_t *buf_id)
> +{
> + struct virtio_vdmabuf_buf *found;
> +
> + hash_for_each_possible(info->buf_list, found, node, buf_id->id)
> + if (is_same_buf(found->buf_id, *buf_id))
> + return found;
> +
> + return NULL;
> +}
> +
> +/* delete buf from hash */
> +static inline int
> +virtio_vdmabuf_del_buf(struct virtio_vdmabuf_info *info,
> + virtio_vdmabuf_buf_id_t *buf_id)
> +{
> + struct virtio_vdmabuf_buf *found;
> +
> + found = virtio_vdmabuf_find_buf(info, buf_id);
> + if (!found)
> + return -ENOENT;
> +
> + hash_del(&found->node);
> +
> + return 0;
> +}
> +
> +#endif
> diff --git a/include/uapi/linux/virtio_ids.h b/include/uapi/linux/virtio_ids.h
> index bc1c0621f5ed..39c94637ddee 100644
> --- a/include/uapi/linux/virtio_ids.h
> +++ b/include/uapi/linux/virtio_ids.h
> @@ -54,5 +54,6 @@
> #define VIRTIO_ID_FS 26 /* virtio filesystem */
> #define VIRTIO_ID_PMEM 27 /* virtio pmem */
> #define VIRTIO_ID_MAC80211_HWSIM 29 /* virtio mac80211-hwsim */
> +#define VIRTIO_ID_VDMABUF 40 /* virtio vdmabuf */
>
> #endif /* _LINUX_VIRTIO_IDS_H */
> diff --git a/include/uapi/linux/virtio_vdmabuf.h b/include/uapi/linux/virtio_vdmabuf.h
> new file mode 100644
> index 000000000000..7bddaa04ddd6
> --- /dev/null
> +++ b/include/uapi/linux/virtio_vdmabuf.h
> @@ -0,0 +1,99 @@
> +// SPDX-License-Identifier: (MIT OR GPL-2.0)
> +
> +/*
> + * Copyright © 2021 Intel Corporation
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + *
> + */
> +
> +#ifndef _UAPI_LINUX_VIRTIO_VDMABUF_H
> +#define _UAPI_LINUX_VIRTIO_VDMABUF_H
> +
> +#define MAX_SIZE_PRIV_DATA 192
> +
> +typedef struct {
> + __u64 id;
> + /* 8B long Random number */
> + int rng_key[2];
> +} virtio_vdmabuf_buf_id_t;
> +
> +struct virtio_vdmabuf_e_hdr {
> + /* buf_id of new buf */
> + virtio_vdmabuf_buf_id_t buf_id;
> + /* size of private data */
> + int size;
> +};
> +
> +struct virtio_vdmabuf_e_data {
> + struct virtio_vdmabuf_e_hdr hdr;
> + /* ptr to private data */
> + void __user *data;
> +};
> +
> +#define VIRTIO_VDMABUF_IOCTL_IMPORT \
> +_IOC(_IOC_NONE, 'G', 2, sizeof(struct virtio_vdmabuf_import))
> +#define VIRTIO_VDMABUF_IOCTL_RELEASE \
> +_IOC(_IOC_NONE, 'G', 3, sizeof(struct virtio_vdmabuf_import))
> +struct virtio_vdmabuf_import {
> + /* IN parameters */
> + /* ahdb buf id to be imported */
> + virtio_vdmabuf_buf_id_t buf_id;
> + /* flags */
> + int flags;
> + /* OUT parameters */
> + /* exported dma buf fd */
> + int fd;
> +};
> +
> +#define VIRTIO_VDMABUF_IOCTL_EXPORT \
> +_IOC(_IOC_NONE, 'G', 4, sizeof(struct virtio_vdmabuf_export))
> +struct virtio_vdmabuf_export {
> + /* IN parameters */
> + /* DMA buf fd to be exported */
> + int fd;
> + /* exported dma buf id */
> + virtio_vdmabuf_buf_id_t buf_id;
> + int sz_priv;
> + char *priv;
> +};
> +
> +#define VIRTIO_VDMABUF_IOCTL_QUERY \
> +_IOC(_IOC_NONE, 'G', 5, sizeof(struct virtio_vdmabuf_query))
> +struct virtio_vdmabuf_query {
> + /* in parameters */
> + /* id of buf to be queried */
> + virtio_vdmabuf_buf_id_t buf_id;
> + /* item to be queried */
> + int item;
> + /* OUT parameters */
> + /* Value of queried item */
> + unsigned long info;
> +};
> +
> +/* DMABUF query */
> +enum virtio_vdmabuf_query_cmd {
> + VIRTIO_VDMABUF_QUERY_SIZE = 0x10,
> + VIRTIO_VDMABUF_QUERY_BUSY,
> + VIRTIO_VDMABUF_QUERY_PRIV_INFO_SIZE,
> + VIRTIO_VDMABUF_QUERY_PRIV_INFO,
> +};
> +
> +#endif
> --
> 2.26.2
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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