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....@intel.com>
Signed-off-by: Vivek Kasireddy <vivek.kasire...@intel.com>
---
drivers/virtio/Kconfig | 8 +
drivers/virtio/Makefile | 1 +
drivers/virtio/virtio_vdmabuf.c | 973 ++++++++++++++++++++++++++++
include/linux/virtio_vdmabuf.h | 271 ++++++++
include/uapi/linux/virtio_ids.h | 1 +
include/uapi/linux/virtio_vdmabuf.h | 99 +++
6 files changed, 1353 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..e377114c2a2b
--- /dev/null
+++ b/drivers/virtio/virtio_vdmabuf.c
@@ -0,0 +1,973 @@
+// 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....@intel.com>
+ * Mateusz Polrola <mateusz.polr...@gmail.com>
+ * Vivek Kasireddy <vivek.kasire...@intel.com>
+ *
+ */
+
+#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 *vq;
+
+ /* ID of guest OS */
+ u64 vmid;
+
+ /* spin lock that needs to be acquired before accessing
+ * virtual queue
+ */
+ spinlock_t vq_lock;
+ struct mutex rx_lock;
+
+ /* workqueue */
+ struct workqueue_struct *wq;
+ struct work_struct rx_work;
+ struct virtio_vdmabuf_event_queue *evq;
+};
+
+static virtio_vdmabuf_buf_id_t get_buf_id(void)
+{
+ struct virtio_vdmabuf *vdmabuf = drv_info->priv;
+ 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;
+ struct scatterlist sg;
+ unsigned long flags;
+ int i, tx_size, ret = 0;
+
+ 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];
+
+ tx_size = sizeof(struct virtio_vdmabuf_msg);
+ 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]);
+ tx_size = sizeof(struct virtio_vdmabuf_msg);
+ break;
+
+ default:
+ /* no command found */
+ return -EINVAL;
+ }
+
+ msg->cmd = cmd;
+ sg_init_one(&sg, msg, tx_size);
+
+ spin_lock_irqsave(&vdmabuf->vq_lock, flags);
+
+ ret = virtqueue_add_inbuf(vdmabuf->vq, &sg, 1, msg, GFP_KERNEL);
+ if (ret)
+ goto err;
+
+ ret = virtqueue_kick(vdmabuf->vq);
+err:
+ spin_unlock_irqrestore(&vdmabuf->vq_lock, flags);
+
+ return ret;
+}
+
+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;
+
+ /* empty message not allowed and ignored */
+ if (!msg->cmd) {
+ dev_err(drv_info->dev, "empty cmd\n");
+ return -EINVAL;
+ }
+
+ 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;
+ }
+
+ switch (msg->cmd) {
+ case VIRTIO_VDMABUF_CMD_DMABUF_REL:
+ ret = remove_buf(vdmabuf, exp);
+ if (ret)
+ return ret;
+
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static void virtio_vdmabuf_rx_work(struct work_struct *work)
+{
+ struct virtio_vdmabuf *vdmabuf = drv_info->priv;
+ struct virtqueue *vq = vdmabuf->vq;
+ struct virtio_vdmabuf_msg *msg;
+ int sz;
+
+ mutex_lock(&vdmabuf->rx_lock);
+
+ do {
+ virtqueue_disable_cb(vq);
+ msg = virtqueue_get_buf(vq, &sz);
+ if (!msg)
+ break;
+
+ /* valid size */
+ if (sz == sizeof(struct virtio_vdmabuf_msg)) {
+ if (msg->cmd == VIRTIO_VDMABUF_CMD_NEED_VMID) {
+ vdmabuf->vmid = msg->op[0];
+ } else {
+ if (parse_msg_from_host(vdmabuf, msg))
+ dev_err(drv_info->dev,
+ "msg parse error\n");
+ }
+ } else {
+ dev_err(drv_info->dev,
+ "received malformed message\n");
+ }
+ } while (!virtqueue_enable_cb(vq));
+
+ mutex_unlock(&vdmabuf->rx_lock);
+}
+
+static void rx_event(struct virtqueue *vq)
+{
+ struct virtio_vdmabuf *vdmabuf = drv_info->priv;
+
+ queue_work(vdmabuf->wq, &vdmabuf->rx_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)
+{
+ if (!drv_info) {
+ pr_err("virtio vdmabuf driver is not ready\n");
+ return -EINVAL;
+ }
+
+ 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(long));
+ }
+
+ 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)
+{
+ 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_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;
+
+ 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();
+
+ 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_vdev_probe(struct virtio_device *vdev)
+{
+ vq_callback_t *cb[] = {rx_event};
+ static const char * const name[] = {"virtio_vdmabuf_virtqueue"};
+ 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, 1, &vdmabuf->vq, cb,
+ name, NULL);
+ if (ret) {
+ dev_err(drv_info->dev, "Cannot find any vqs\n");
+ return ret;
+ }
+
+ INIT_WORK(&vdmabuf->rx_work, virtio_vdmabuf_rx_work);
+
+ return ret;
+}
+
+static void virtio_vdmabuf_vdev_remove(struct virtio_device *vdev)
+{
+ struct virtio_vdmabuf *vdmabuf;
+
+ if (!drv_info)
+ return;
+
+ vdmabuf = drv_info->priv;
+ flush_work(&vdmabuf->rx_work);
+
+ vdev->config->reset(vdev);
+ vdev->config->del_vqs(vdev);
+}
+
+static void virtio_vdmabuf_vdev_scan(struct virtio_device *vdev)
+{
+ int ret;
+
+ /* Send VIRTIO_VDMABUF_CMD_NEED_VMID request to know vmid
+ */
+ ret = send_msg_to_host(VIRTIO_VDMABUF_CMD_NEED_VMID, 0);
+ if (ret < 0)
+ dev_err(drv_info->dev, "fail to receive vmid\n");
+
+ return;
+}
+
+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_vdev_probe,
+ .remove = virtio_vdmabuf_vdev_remove,
+ .scan = virtio_vdmabuf_vdev_scan,
+};
+
+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;
+ }
+
+ dma_coerce_mask_and_coherent(virtio_vdmabuf_miscdev.this_device,
+ DMA_BIT_MASK(64));
+
+ 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;
+ }
+
+ 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);
+ 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..3b15024230c0
--- /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;
+};
+
+/* 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 {
+ unsigned int req_id;
+ unsigned int stat;
+ unsigned int cmd;
+ unsigned int op[64];
+};
+
+struct virtio_vdmabuf_txmsg {
+ struct virtio_vdmabuf_msg msg;
+ void __user *msg_ptr;
+ int head;
+};
+
+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,
+ 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..f1ea1c2f5cbf 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 30 /* 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
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
