#include "vhost-net.h"
#include "virtio-net.h"
-/*
- * Device linked list structure for configuration.
- */
-struct virtio_net_config_ll {
- struct virtio_net dev; /* Virtio device.*/
- struct virtio_net_config_ll *next; /* Next dev on linked list.*/
-};
+#define MAX_VHOST_DEVICE 1024
+static struct virtio_net *vhost_devices[MAX_VHOST_DEVICE];
/* device ops to add/remove device to/from data core. */
struct virtio_net_device_ops const *notify_ops;
-/* root address of the linked list of managed virtio devices */
-static struct virtio_net_config_ll *ll_root;
#define VHOST_USER_F_PROTOCOL_FEATURES 30
#define VHOST_SUPPORTED_FEATURES ((1ULL << VIRTIO_NET_F_MRG_RXBUF) | \
(1ULL << VIRTIO_NET_F_CTRL_VQ) | \
(1ULL << VIRTIO_NET_F_CTRL_RX) | \
- (1ULL << VIRTIO_NET_F_MQ) | \
+ (1ULL << VIRTIO_NET_F_GUEST_ANNOUNCE) | \
+ (VHOST_SUPPORTS_MQ) | \
+ (1ULL << VIRTIO_F_VERSION_1) | \
(1ULL << VHOST_F_LOG_ALL) | \
- (1ULL << VHOST_USER_F_PROTOCOL_FEATURES))
+ (1ULL << VHOST_USER_F_PROTOCOL_FEATURES) | \
+ (1ULL << VIRTIO_NET_F_HOST_TSO4) | \
+ (1ULL << VIRTIO_NET_F_HOST_TSO6) | \
+ (1ULL << VIRTIO_NET_F_CSUM) | \
+ (1ULL << VIRTIO_NET_F_GUEST_CSUM) | \
+ (1ULL << VIRTIO_NET_F_GUEST_TSO4) | \
+ (1ULL << VIRTIO_NET_F_GUEST_TSO6))
+
static uint64_t VHOST_FEATURES = VHOST_SUPPORTED_FEATURES;
}
-/*
- * Retrieves an entry from the devices configuration linked list.
- */
-static struct virtio_net_config_ll *
-get_config_ll_entry(struct vhost_device_ctx ctx)
-{
- struct virtio_net_config_ll *ll_dev = ll_root;
-
- /* Loop through linked list until the device_fh is found. */
- while (ll_dev != NULL) {
- if (ll_dev->dev.device_fh == ctx.fh)
- return ll_dev;
- ll_dev = ll_dev->next;
- }
-
- return NULL;
-}
-
-/*
- * Searches the configuration core linked list and
- * retrieves the device if it exists.
- */
struct virtio_net *
get_device(struct vhost_device_ctx ctx)
{
- struct virtio_net_config_ll *ll_dev;
-
- ll_dev = get_config_ll_entry(ctx);
-
- if (ll_dev)
- return &ll_dev->dev;
-
- RTE_LOG(ERR, VHOST_CONFIG,
- "(%"PRIu64") Device not found in linked list.\n", ctx.fh);
- return NULL;
-}
+ struct virtio_net *dev = vhost_devices[ctx.fh];
-/*
- * Add entry containing a device to the device configuration linked list.
- */
-static void
-add_config_ll_entry(struct virtio_net_config_ll *new_ll_dev)
-{
- struct virtio_net_config_ll *ll_dev = ll_root;
-
- /* If ll_dev == NULL then this is the first device so go to else */
- if (ll_dev) {
- /* If the 1st device_fh != 0 then we insert our device here. */
- if (ll_dev->dev.device_fh != 0) {
- new_ll_dev->dev.device_fh = 0;
- new_ll_dev->next = ll_dev;
- ll_root = new_ll_dev;
- } else {
- /*
- * Increment through the ll until we find un unused
- * device_fh. Insert the device at that entry.
- */
- while ((ll_dev->next != NULL) &&
- (ll_dev->dev.device_fh ==
- (ll_dev->next->dev.device_fh - 1)))
- ll_dev = ll_dev->next;
-
- new_ll_dev->dev.device_fh = ll_dev->dev.device_fh + 1;
- new_ll_dev->next = ll_dev->next;
- ll_dev->next = new_ll_dev;
- }
- } else {
- ll_root = new_ll_dev;
- ll_root->dev.device_fh = 0;
+ if (unlikely(!dev)) {
+ RTE_LOG(ERR, VHOST_CONFIG,
+ "(%"PRIu64") device not found.\n", ctx.fh);
}
+ return dev;
}
static void
-cleanup_vq(struct vhost_virtqueue *vq)
+cleanup_vq(struct vhost_virtqueue *vq, int destroy)
{
- if (vq->callfd >= 0)
+ if ((vq->callfd >= 0) && (destroy != 0))
close(vq->callfd);
if (vq->kickfd >= 0)
close(vq->kickfd);
* free any memory owned by a device.
*/
static void
-cleanup_device(struct virtio_net *dev)
+cleanup_device(struct virtio_net *dev, int destroy)
{
uint32_t i;
- /* Unmap QEMU memory file if mapped. */
- if (dev->mem) {
- munmap((void *)(uintptr_t)dev->mem->mapped_address,
- (size_t)dev->mem->mapped_size);
- free(dev->mem);
- }
+ vhost_backend_cleanup(dev);
for (i = 0; i < dev->virt_qp_nb; i++) {
- cleanup_vq(dev->virtqueue[i * VIRTIO_QNUM + VIRTIO_RXQ]);
- cleanup_vq(dev->virtqueue[i * VIRTIO_QNUM + VIRTIO_TXQ]);
+ cleanup_vq(dev->virtqueue[i * VIRTIO_QNUM + VIRTIO_RXQ], destroy);
+ cleanup_vq(dev->virtqueue[i * VIRTIO_QNUM + VIRTIO_TXQ], destroy);
}
}
* Release virtqueues and device memory.
*/
static void
-free_device(struct virtio_net_config_ll *ll_dev)
+free_device(struct virtio_net *dev)
{
uint32_t i;
- for (i = 0; i < ll_dev->dev.virt_qp_nb; i++)
- rte_free(ll_dev->dev.virtqueue[i * VIRTIO_QNUM]);
+ for (i = 0; i < dev->virt_qp_nb; i++)
+ rte_free(dev->virtqueue[i * VIRTIO_QNUM]);
- rte_free(ll_dev);
-}
-
-/*
- * Remove an entry from the device configuration linked list.
- */
-static struct virtio_net_config_ll *
-rm_config_ll_entry(struct virtio_net_config_ll *ll_dev,
- struct virtio_net_config_ll *ll_dev_last)
-{
- /* First remove the device and then clean it up. */
- if (ll_dev == ll_root) {
- ll_root = ll_dev->next;
- cleanup_device(&ll_dev->dev);
- free_device(ll_dev);
- return ll_root;
- } else {
- if (likely(ll_dev_last != NULL)) {
- ll_dev_last->next = ll_dev->next;
- cleanup_device(&ll_dev->dev);
- free_device(ll_dev);
- return ll_dev_last->next;
- } else {
- cleanup_device(&ll_dev->dev);
- free_device(ll_dev);
- RTE_LOG(ERR, VHOST_CONFIG,
- "Remove entry from config_ll failed\n");
- return NULL;
- }
- }
+ rte_free(dev);
}
static void
{
memset(vq, 0, sizeof(struct vhost_virtqueue));
- vq->kickfd = -1;
- vq->callfd = -1;
+ vq->kickfd = VIRTIO_UNINITIALIZED_EVENTFD;
+ vq->callfd = VIRTIO_UNINITIALIZED_EVENTFD;
/* Backends are set to -1 indicating an inactive device. */
vq->backend = -1;
init_vring_queue(dev->virtqueue[base_idx + VIRTIO_TXQ], qp_idx);
}
+static void
+reset_vring_queue(struct vhost_virtqueue *vq, int qp_idx)
+{
+ int callfd;
+
+ callfd = vq->callfd;
+ init_vring_queue(vq, qp_idx);
+ vq->callfd = callfd;
+}
+
+static void
+reset_vring_queue_pair(struct virtio_net *dev, uint32_t qp_idx)
+{
+ uint32_t base_idx = qp_idx * VIRTIO_QNUM;
+
+ reset_vring_queue(dev->virtqueue[base_idx + VIRTIO_RXQ], qp_idx);
+ reset_vring_queue(dev->virtqueue[base_idx + VIRTIO_TXQ], qp_idx);
+}
+
static int
alloc_vring_queue_pair(struct virtio_net *dev, uint32_t qp_idx)
{
}
/*
- * Initialise all variables in device structure.
+ * Reset some variables in device structure, while keeping few
+ * others untouched, such as device_fh, ifname, virt_qp_nb: they
+ * should be same unless the device is removed.
*/
static void
-init_device(struct virtio_net *dev)
+reset_device(struct virtio_net *dev)
{
- int vq_offset;
uint32_t i;
- /*
- * Virtqueues have already been malloced so
- * we don't want to set them to NULL.
- */
- vq_offset = offsetof(struct virtio_net, virtqueue);
- memset(dev, 0, vq_offset);
+ dev->features = 0;
+ dev->protocol_features = 0;
+ dev->flags = 0;
for (i = 0; i < dev->virt_qp_nb; i++)
- init_vring_queue_pair(dev, i);
+ reset_vring_queue_pair(dev, i);
}
/*
* initialised and a new entry is added to the device configuration linked
* list.
*/
-static int
-new_device(struct vhost_device_ctx ctx)
+int
+vhost_new_device(struct vhost_device_ctx ctx)
{
- struct virtio_net_config_ll *new_ll_dev;
+ struct virtio_net *dev;
+ int i;
- /* Setup device and virtqueues. */
- new_ll_dev = rte_malloc(NULL, sizeof(struct virtio_net_config_ll), 0);
- if (new_ll_dev == NULL) {
+ dev = rte_zmalloc(NULL, sizeof(struct virtio_net), 0);
+ if (dev == NULL) {
RTE_LOG(ERR, VHOST_CONFIG,
"(%"PRIu64") Failed to allocate memory for dev.\n",
ctx.fh);
return -1;
}
- /* Initialise device and virtqueues. */
- init_device(&new_ll_dev->dev);
-
- new_ll_dev->next = NULL;
+ for (i = 0; i < MAX_VHOST_DEVICE; i++) {
+ if (vhost_devices[i] == NULL)
+ break;
+ }
+ if (i == MAX_VHOST_DEVICE) {
+ RTE_LOG(ERR, VHOST_CONFIG,
+ "Failed to find a free slot for new device.\n");
+ return -1;
+ }
- /* Add entry to device configuration linked list. */
- add_config_ll_entry(new_ll_dev);
+ vhost_devices[i] = dev;
+ dev->device_fh = i;
- return new_ll_dev->dev.device_fh;
+ return i;
}
/*
* Function is called from the CUSE release function. This function will
* cleanup the device and remove it from device configuration linked list.
*/
-static void
-destroy_device(struct vhost_device_ctx ctx)
-{
- struct virtio_net_config_ll *ll_dev_cur_ctx, *ll_dev_last = NULL;
- struct virtio_net_config_ll *ll_dev_cur = ll_root;
-
- /* Find the linked list entry for the device to be removed. */
- ll_dev_cur_ctx = get_config_ll_entry(ctx);
- while (ll_dev_cur != NULL) {
- /*
- * If the device is found or
- * a device that doesn't exist is found then it is removed.
- */
- if (ll_dev_cur == ll_dev_cur_ctx) {
- /*
- * If the device is running on a data core then call
- * the function to remove it from the data core.
- */
- if ((ll_dev_cur->dev.flags & VIRTIO_DEV_RUNNING))
- notify_ops->destroy_device(&(ll_dev_cur->dev));
- ll_dev_cur = rm_config_ll_entry(ll_dev_cur,
- ll_dev_last);
- } else {
- ll_dev_last = ll_dev_cur;
- ll_dev_cur = ll_dev_cur->next;
- }
- }
+void
+vhost_destroy_device(struct vhost_device_ctx ctx)
+{
+ struct virtio_net *dev = get_device(ctx);
+
+ if (dev == NULL)
+ return;
+
+ if (dev->flags & VIRTIO_DEV_RUNNING)
+ notify_ops->destroy_device(dev);
+
+ cleanup_device(dev, 1);
+ free_device(dev);
+
+ vhost_devices[ctx.fh] = NULL;
}
-static void
-set_ifname(struct vhost_device_ctx ctx,
+void
+vhost_set_ifname(struct vhost_device_ctx ctx,
const char *if_name, unsigned int if_len)
{
struct virtio_net *dev;
sizeof(dev->ifname) : if_len;
strncpy(dev->ifname, if_name, len);
+ dev->ifname[sizeof(dev->ifname) - 1] = '\0';
}
* This function just returns success at the moment unless
* the device hasn't been initialised.
*/
-static int
-set_owner(struct vhost_device_ctx ctx)
+int
+vhost_set_owner(struct vhost_device_ctx ctx)
{
struct virtio_net *dev;
/*
* Called from CUSE IOCTL: VHOST_RESET_OWNER
*/
-static int
-reset_owner(struct vhost_device_ctx ctx)
+int
+vhost_reset_owner(struct vhost_device_ctx ctx)
{
struct virtio_net *dev;
- uint64_t device_fh;
dev = get_device(ctx);
if (dev == NULL)
return -1;
- device_fh = dev->device_fh;
- cleanup_device(dev);
- init_device(dev);
- dev->device_fh = device_fh;
+ if (dev->flags & VIRTIO_DEV_RUNNING)
+ notify_ops->destroy_device(dev);
+
+ cleanup_device(dev, 0);
+ reset_device(dev);
return 0;
}
* Called from CUSE IOCTL: VHOST_GET_FEATURES
* The features that we support are requested.
*/
-static int
-get_features(struct vhost_device_ctx ctx, uint64_t *pu)
+int
+vhost_get_features(struct vhost_device_ctx ctx, uint64_t *pu)
{
struct virtio_net *dev;
* Called from CUSE IOCTL: VHOST_SET_FEATURES
* We receive the negotiated features supported by us and the virtio device.
*/
-static int
-set_features(struct vhost_device_ctx ctx, uint64_t *pu)
+int
+vhost_set_features(struct vhost_device_ctx ctx, uint64_t *pu)
{
struct virtio_net *dev;
uint16_t vhost_hlen;
return -1;
dev->features = *pu;
- if (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF)) {
- LOG_DEBUG(VHOST_CONFIG,
- "(%"PRIu64") Mergeable RX buffers enabled\n",
- dev->device_fh);
+ if (dev->features &
+ ((1 << VIRTIO_NET_F_MRG_RXBUF) | (1ULL << VIRTIO_F_VERSION_1))) {
vhost_hlen = sizeof(struct virtio_net_hdr_mrg_rxbuf);
} else {
- LOG_DEBUG(VHOST_CONFIG,
- "(%"PRIu64") Mergeable RX buffers disabled\n",
- dev->device_fh);
vhost_hlen = sizeof(struct virtio_net_hdr);
}
+ LOG_DEBUG(VHOST_CONFIG,
+ "(%"PRIu64") Mergeable RX buffers %s, virtio 1 %s\n",
+ dev->device_fh,
+ (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF)) ? "on" : "off",
+ (dev->features & (1ULL << VIRTIO_F_VERSION_1)) ? "on" : "off");
for (i = 0; i < dev->virt_qp_nb; i++) {
uint16_t base_idx = i * VIRTIO_QNUM;
* Called from CUSE IOCTL: VHOST_SET_VRING_NUM
* The virtio device sends us the size of the descriptor ring.
*/
-static int
-set_vring_num(struct vhost_device_ctx ctx, struct vhost_vring_state *state)
+int
+vhost_set_vring_num(struct vhost_device_ctx ctx,
+ struct vhost_vring_state *state)
{
struct virtio_net *dev;
numa_realloc(struct virtio_net *dev, int index)
{
int oldnode, newnode;
- struct virtio_net_config_ll *old_ll_dev, *new_ll_dev = NULL;
- struct vhost_virtqueue *old_vq, *new_vq = NULL;
+ struct virtio_net *old_dev;
+ struct vhost_virtqueue *old_vq, *vq;
int ret;
- int realloc_dev = 0, realloc_vq = 0;
- old_ll_dev = (struct virtio_net_config_ll *)dev;
- old_vq = dev->virtqueue[index];
+ /*
+ * vq is allocated on pairs, we should try to do realloc
+ * on first queue of one queue pair only.
+ */
+ if (index % VIRTIO_QNUM != 0)
+ return dev;
+
+ old_dev = dev;
+ vq = old_vq = dev->virtqueue[index];
- ret = get_mempolicy(&newnode, NULL, 0, old_vq->desc,
- MPOL_F_NODE | MPOL_F_ADDR);
- ret = ret | get_mempolicy(&oldnode, NULL, 0, old_ll_dev,
- MPOL_F_NODE | MPOL_F_ADDR);
+ ret = get_mempolicy(&newnode, NULL, 0, old_vq->desc,
+ MPOL_F_NODE | MPOL_F_ADDR);
+
+ /* check if we need to reallocate vq */
+ ret |= get_mempolicy(&oldnode, NULL, 0, old_vq,
+ MPOL_F_NODE | MPOL_F_ADDR);
if (ret) {
RTE_LOG(ERR, VHOST_CONFIG,
- "Unable to get vring desc or dev numa information.\n");
+ "Unable to get vq numa information.\n");
return dev;
}
- if (oldnode != newnode)
- realloc_dev = 1;
+ if (oldnode != newnode) {
+ RTE_LOG(INFO, VHOST_CONFIG,
+ "reallocate vq from %d to %d node\n", oldnode, newnode);
+ vq = rte_malloc_socket(NULL, sizeof(*vq) * VIRTIO_QNUM, 0,
+ newnode);
+ if (!vq)
+ return dev;
+
+ memcpy(vq, old_vq, sizeof(*vq) * VIRTIO_QNUM);
+ rte_free(old_vq);
+ }
- ret = get_mempolicy(&oldnode, NULL, 0, old_vq,
- MPOL_F_NODE | MPOL_F_ADDR);
+ /* check if we need to reallocate dev */
+ ret = get_mempolicy(&oldnode, NULL, 0, old_dev,
+ MPOL_F_NODE | MPOL_F_ADDR);
if (ret) {
RTE_LOG(ERR, VHOST_CONFIG,
- "Unable to get vq numa information.\n");
- return dev;
+ "Unable to get dev numa information.\n");
+ goto out;
}
- if (oldnode != newnode)
- realloc_vq = 1;
-
- if (realloc_dev == 0 && realloc_vq == 0)
- return dev;
-
- if (realloc_dev)
- new_ll_dev = rte_malloc_socket(NULL,
- sizeof(struct virtio_net_config_ll), 0, newnode);
- if (realloc_vq)
- new_vq = rte_malloc_socket(NULL,
- sizeof(struct vhost_virtqueue), 0, newnode);
- if (!new_ll_dev && !new_vq)
- return dev;
-
- if (realloc_vq)
- memcpy(new_vq, old_vq, sizeof(*new_vq));
- if (realloc_dev)
- memcpy(new_ll_dev, old_ll_dev, sizeof(*new_ll_dev));
- (new_ll_dev ? new_ll_dev : old_ll_dev)->dev.virtqueue[index] =
- new_vq ? new_vq : old_vq;
- if (realloc_vq)
- rte_free(old_vq);
- if (realloc_dev) {
- if (ll_root == old_ll_dev)
- ll_root = new_ll_dev;
- else {
- struct virtio_net_config_ll *prev = ll_root;
- while (prev->next != old_ll_dev)
- prev = prev->next;
- prev->next = new_ll_dev;
- new_ll_dev->next = old_ll_dev->next;
+ if (oldnode != newnode) {
+ RTE_LOG(INFO, VHOST_CONFIG,
+ "reallocate dev from %d to %d node\n",
+ oldnode, newnode);
+ dev = rte_malloc_socket(NULL, sizeof(*dev), 0, newnode);
+ if (!dev) {
+ dev = old_dev;
+ goto out;
}
- rte_free(old_ll_dev);
+
+ memcpy(dev, old_dev, sizeof(*dev));
+ rte_free(old_dev);
}
- return realloc_dev ? &new_ll_dev->dev : dev;
+out:
+ dev->virtqueue[index] = vq;
+ dev->virtqueue[index + 1] = vq + 1;
+ vhost_devices[dev->device_fh] = dev;
+
+ return dev;
}
#else
static struct virtio_net*
* The virtio device sends us the desc, used and avail ring addresses.
* This function then converts these to our address space.
*/
-static int
-set_vring_addr(struct vhost_device_ctx ctx, struct vhost_vring_addr *addr)
+int
+vhost_set_vring_addr(struct vhost_device_ctx ctx, struct vhost_vring_addr *addr)
{
struct virtio_net *dev;
struct vhost_virtqueue *vq;
dev = get_device(ctx);
- if (dev == NULL)
+ if ((dev == NULL) || (dev->mem == NULL))
return -1;
/* addr->index refers to the queue index. The txq 1, rxq is 0. */
return -1;
}
+ vq->log_guest_addr = addr->log_guest_addr;
+
LOG_DEBUG(VHOST_CONFIG, "(%"PRIu64") mapped address desc: %p\n",
dev->device_fh, vq->desc);
LOG_DEBUG(VHOST_CONFIG, "(%"PRIu64") mapped address avail: %p\n",
dev->device_fh, vq->avail);
LOG_DEBUG(VHOST_CONFIG, "(%"PRIu64") mapped address used: %p\n",
dev->device_fh, vq->used);
+ LOG_DEBUG(VHOST_CONFIG, "(%"PRIu64") log_guest_addr: %"PRIx64"\n",
+ dev->device_fh, vq->log_guest_addr);
return 0;
}
* Called from CUSE IOCTL: VHOST_SET_VRING_BASE
* The virtio device sends us the available ring last used index.
*/
-static int
-set_vring_base(struct vhost_device_ctx ctx, struct vhost_vring_state *state)
+int
+vhost_set_vring_base(struct vhost_device_ctx ctx,
+ struct vhost_vring_state *state)
{
struct virtio_net *dev;
* Called from CUSE IOCTL: VHOST_GET_VRING_BASE
* We send the virtio device our available ring last used index.
*/
-static int
-get_vring_base(struct vhost_device_ctx ctx, uint32_t index,
+int
+vhost_get_vring_base(struct vhost_device_ctx ctx, uint32_t index,
struct vhost_vring_state *state)
{
struct virtio_net *dev;
* The virtio device sends an eventfd to interrupt the guest. This fd gets
* copied into our process space.
*/
-static int
-set_vring_call(struct vhost_device_ctx ctx, struct vhost_vring_file *file)
+int
+vhost_set_vring_call(struct vhost_device_ctx ctx, struct vhost_vring_file *file)
{
struct virtio_net *dev;
struct vhost_virtqueue *vq;
* The virtio device sends an eventfd that it can use to notify us.
* This fd gets copied into our process space.
*/
-static int
-set_vring_kick(struct vhost_device_ctx ctx, struct vhost_vring_file *file)
+int
+vhost_set_vring_kick(struct vhost_device_ctx ctx, struct vhost_vring_file *file)
{
struct virtio_net *dev;
struct vhost_virtqueue *vq;
* At that point we remove the device from the data core.
* The device will still exist in the device configuration linked list.
*/
-static int
-set_backend(struct vhost_device_ctx ctx, struct vhost_vring_file *file)
+int
+vhost_set_backend(struct vhost_device_ctx ctx, struct vhost_vring_file *file)
{
struct virtio_net *dev;
return 0;
}
-/*
- * Function pointers are set for the device operations to allow CUSE to call
- * functions when an IOCTL, device_add or device_release is received.
- */
-static const struct vhost_net_device_ops vhost_device_ops = {
- .new_device = new_device,
- .destroy_device = destroy_device,
-
- .set_ifname = set_ifname,
-
- .get_features = get_features,
- .set_features = set_features,
-
- .set_vring_num = set_vring_num,
- .set_vring_addr = set_vring_addr,
- .set_vring_base = set_vring_base,
- .get_vring_base = get_vring_base,
-
- .set_vring_kick = set_vring_kick,
- .set_vring_call = set_vring_call,
-
- .set_backend = set_backend,
-
- .set_owner = set_owner,
- .reset_owner = reset_owner,
-};
-
-/*
- * Called by main to setup callbacks when registering CUSE device.
- */
-struct vhost_net_device_ops const *
-get_virtio_net_callbacks(void)
-{
- return &vhost_device_ops;
-}
-
int rte_vhost_enable_guest_notification(struct virtio_net *dev,
uint16_t queue_id, int enable)
{
return -1;
}
- dev->virtqueue[queue_id]->used->flags =
- enable ? 0 : VRING_USED_F_NO_NOTIFY;
+ dev->virtqueue[queue_id]->used->flags = VRING_USED_F_NO_NOTIFY;
return 0;
}