[RFC PATCH V2 2/2] vhost: device IOTLB API

From: Jason Wang
Date: Thu Mar 24 2016 - 22:34:54 EST

This patch tries to implement an device IOTLB for vhost. This could be
used with for co-operation with userspace(qemu) implementation of DMA
remapping.

The idea is simple. When vhost meets an IOTLB miss, it will request
the assistance of userspace to do the translation, this is done
through:

- Fill the translation request in a preset userspace address (This
address is set through ioctl VHOST_SET_IOTLB_REQUEST_ENTRY).
- Notify userspace through eventfd (This eventfd was set through ioctl
VHOST_SET_IOTLB_FD).
- device IOTLB were started and stopped through VHOST_RUN_IOTLB ioctl

When userspace finishes the translation, it will update the vhost
IOTLB through VHOST_UPDATE_IOTLB ioctl. Userspace is also in charge of
snooping the IOTLB invalidation of IOMMU IOTLB and use
VHOST_UPDATE_IOTLB to invalidate the possible entry in vhost.

Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
drivers/vhost/net.c | 6 +-
drivers/vhost/vhost.c | 301 +++++++++++++++++++++++++++++++++++++++------
drivers/vhost/vhost.h | 17 ++-
fs/eventfd.c | 3 +-
include/uapi/linux/vhost.h | 35 ++++++
5 files changed, 320 insertions(+), 42 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 481db96..7cbdeed 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -334,7 +334,7 @@ static void handle_tx(struct vhost_net *net)
head = vhost_get_vq_desc(vq, vq->iov,
ARRAY_SIZE(vq->iov),
&out, &in,
- NULL, NULL);
+ NULL, NULL, VHOST_ACCESS_RO);
/* On error, stop handling until the next kick. */
if (unlikely(head < 0))
break;
@@ -470,7 +470,7 @@ static int get_rx_bufs(struct vhost_virtqueue *vq,
}
r = vhost_get_vq_desc(vq, vq->iov + seg,
ARRAY_SIZE(vq->iov) - seg, &out,
- &in, log, log_num);
+ &in, log, log_num, VHOST_ACCESS_WO);
if (unlikely(r < 0))
goto err;

@@ -1083,7 +1083,7 @@ static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
r = vhost_dev_ioctl(&n->dev, ioctl, argp);
if (r == -ENOIOCTLCMD)
r = vhost_vring_ioctl(&n->dev, ioctl, argp);
- else
+ else if (ioctl != VHOST_UPDATE_IOTLB)
vhost_net_flush(n);
mutex_unlock(&n->dev.mutex);
return r;
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 32c35a9..1dd43e8 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -280,6 +280,10 @@ static void vhost_vq_reset(struct vhost_dev *dev,
vq->call_ctx = NULL;
vq->call = NULL;
vq->log_ctx = NULL;
+ vq->iotlb_call = NULL;
+ vq->iotlb_call_ctx = NULL;
+ vq->iotlb_request = NULL;
+ vq->pending_request.flags.type = VHOST_IOTLB_INVALIDATE;
vq->umem = NULL;
vq->is_le = virtio_legacy_is_little_endian();
vhost_vq_reset_user_be(vq);
@@ -387,8 +391,10 @@ void vhost_dev_init(struct vhost_dev *dev,
dev->log_ctx = NULL;
dev->log_file = NULL;
dev->umem = NULL;
+ dev->iotlb = NULL;
dev->mm = NULL;
spin_lock_init(&dev->work_lock);
+ spin_lock_init(&dev->iotlb_lock);
INIT_LIST_HEAD(&dev->work_list);
dev->worker = NULL;

@@ -537,6 +543,15 @@ void vhost_dev_stop(struct vhost_dev *dev)
}
EXPORT_SYMBOL_GPL(vhost_dev_stop);

+static void vhost_umem_free(struct vhost_umem *umem,
+ struct vhost_umem_node *node)
+{
+ vhost_umem_interval_tree_remove(node, &umem->umem_tree);
+ list_del(&node->link);
+ kfree(node);
+ umem->numem--;
+}
+
static void vhost_umem_clean(struct vhost_umem *umem)
{
struct vhost_umem_node *node, *tmp;
@@ -544,11 +559,9 @@ static void vhost_umem_clean(struct vhost_umem *umem)
if (!umem)
return;

- list_for_each_entry_safe(node, tmp, &umem->umem_list, link) {
- vhost_umem_interval_tree_remove(node, &umem->umem_tree);
- list_del(&node->link);
- kvfree(node);
- }
+ list_for_each_entry_safe(node, tmp, &umem->umem_list, link)
+ vhost_umem_free(umem, node);
+
kvfree(umem);
}

@@ -580,6 +593,8 @@ void vhost_dev_cleanup(struct vhost_dev *dev, bool locked)
/* No one will access memory at this point */
vhost_umem_clean(dev->umem);
dev->umem = NULL;
+ vhost_umem_clean(dev->iotlb);
+ dev->iotlb = NULL;
WARN_ON(!list_empty(&dev->work_list));
if (dev->worker) {
kthread_stop(dev->worker);
@@ -699,11 +714,61 @@ int vhost_vq_access_ok(struct vhost_virtqueue *vq)
}
EXPORT_SYMBOL_GPL(vhost_vq_access_ok);

+static int vhost_new_umem_range(struct vhost_umem *umem,
+ u64 start, u64 size, u64 end,
+ u64 userspace_addr, int perm)
+{
+ struct vhost_umem_node *tmp, *node = kmalloc(sizeof(*node), GFP_ATOMIC);
+
+ if (!node)
+ return -ENOMEM;
+
+ if (umem->numem == VHOST_IOTLB_SIZE) {
+ tmp = list_last_entry(&umem->umem_list, typeof(*tmp), link);
+ vhost_umem_free(umem, tmp);
+ }
+
+ node->start = start;
+ node->size = size;
+ node->last = end;
+ node->userspace_addr = userspace_addr;
+ node->perm = perm;
+ INIT_LIST_HEAD(&node->link);
+ list_add_tail(&node->link, &umem->umem_list);
+ vhost_umem_interval_tree_insert(node, &umem->umem_tree);
+ umem->numem++;
+
+ return 0;
+}
+
+static void vhost_del_umem_range(struct vhost_umem *umem,
+ u64 start, u64 end)
+{
+ struct vhost_umem_node *node;
+
+ while ((node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
+ start, end)))
+ vhost_umem_free(umem, node);
+}
+
+static struct vhost_umem *vhost_umem_alloc(void)
+{
+ struct vhost_umem *umem = vhost_kvzalloc(sizeof(*umem));
+
+ if (!umem)
+ return NULL;
+
+ umem->umem_tree = RB_ROOT;
+ umem->numem = 0;
+ INIT_LIST_HEAD(&umem->umem_list);
+
+ return umem;
+}
+
static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
{
struct vhost_memory mem, *newmem;
struct vhost_memory_region *region;
- struct vhost_umem_node *node;
struct vhost_umem *newumem, *oldumem;
unsigned long size = offsetof(struct vhost_memory, regions);
int i;
@@ -725,28 +790,23 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
return -EFAULT;
}

- newumem = vhost_kvzalloc(sizeof(*newumem));
+ newumem = vhost_umem_alloc();
if (!newumem) {
kvfree(newmem);
return -ENOMEM;
}

- newumem->umem_tree = RB_ROOT;
- INIT_LIST_HEAD(&newumem->umem_list);
-
for (region = newmem->regions;
region < newmem->regions + mem.nregions;
region++) {
- node = vhost_kvzalloc(sizeof(*node));
- if (!node)
+ if (vhost_new_umem_range(newumem,
+ region->guest_phys_addr,
+ region->memory_size,
+ region->guest_phys_addr +
+ region->memory_size - 1,
+ region->userspace_addr,
+ VHOST_ACCESS_RW))
goto err;
- node->start = region->guest_phys_addr;
- node->size = region->memory_size;
- node->last = node->start + node->size - 1;
- node->userspace_addr = region->userspace_addr;
- INIT_LIST_HEAD(&node->link);
- list_add_tail(&node->link, &newumem->umem_list);
- vhost_umem_interval_tree_insert(node, &newumem->umem_tree);
}

if (!memory_access_ok(d, newumem, 0))
@@ -782,6 +842,7 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp)
struct vhost_vring_state s;
struct vhost_vring_file f;
struct vhost_vring_addr a;
+ struct vhost_vring_iotlb_entry e;
u32 idx;
long r;

@@ -910,6 +971,35 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp)
} else
filep = eventfp;
break;
+ case VHOST_SET_VRING_IOTLB_REQUEST:
+ r = -EFAULT;
+ if (copy_from_user(&e, argp, sizeof e))
+ break;
+ if (!access_ok(VERIFY_WRITE, e.userspace_addr,
+ sizeof(*vq->iotlb_request)))
+ break;
+ r = 0;
+ vq->iotlb_request = (struct vhost_iotlb_entry __user *)e.userspace_addr;
+ break;
+ case VHOST_SET_VRING_IOTLB_CALL:
+ if (copy_from_user(&f, argp, sizeof f)) {
+ r = -EFAULT;
+ break;
+ }
+ eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
+ if (IS_ERR(eventfp)) {
+ r = PTR_ERR(eventfp);
+ break;
+ }
+ if (eventfp != vq->iotlb_call) {
+ filep = vq->iotlb_call;
+ ctx = vq->iotlb_call_ctx;
+ vq->iotlb_call = eventfp;
+ vq->iotlb_call_ctx = eventfp ?
+ eventfd_ctx_fileget(eventfp) : NULL;
+ } else
+ filep = eventfp;
+ break;
case VHOST_SET_VRING_CALL:
if (copy_from_user(&f, argp, sizeof f)) {
r = -EFAULT;
@@ -977,11 +1067,55 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp)
}
EXPORT_SYMBOL_GPL(vhost_vring_ioctl);

+static int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled)
+{
+ struct vhost_umem *niotlb, *oiotlb;
+
+ if (enabled) {
+ niotlb = vhost_umem_alloc();
+ if (!niotlb)
+ return -ENOMEM;
+ } else
+ niotlb = NULL;
+
+ spin_lock(&d->iotlb_lock);
+ oiotlb = d->iotlb;
+ d->iotlb = niotlb;
+ spin_unlock(&d->iotlb_lock);
+
+ vhost_umem_clean(oiotlb);
+
+ return 0;
+}
+
+static void vhost_complete_iotlb_update(struct vhost_dev *d,
+ struct vhost_iotlb_entry *entry)
+{
+ struct vhost_iotlb_entry *req;
+ struct vhost_virtqueue *vq;
+ int i;
+
+
+ for (i = 0; i < d->nvqs; i++) {
+ vq = d->vqs[i];
+ mutex_lock(&vq->mutex);
+ req = &vq->pending_request;
+ if (entry->iova <= req->iova &&
+ entry->iova + entry->size - 1 > req->iova &&
+ req->flags.type == VHOST_IOTLB_MISS) {
+ *req = *entry;
+ vhost_poll_queue(&vq->poll);
+ }
+ mutex_unlock(&vq->mutex);
+ }
+}
+
/* Caller must have device mutex */
long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
{
struct file *eventfp, *filep = NULL;
struct eventfd_ctx *ctx = NULL;
+ struct vhost_iotlb_entry entry;
u64 p;
long r;
int i, fd;
@@ -1050,6 +1184,52 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
if (filep)
fput(filep);
break;
+ case VHOST_RUN_IOTLB:
+ /* FIXME: enable and disabled */
+ vhost_init_device_iotlb(d, true);
+ break;
+ case VHOST_UPDATE_IOTLB:
+ r = copy_from_user(&entry, argp, sizeof(entry));
+ if (r < 0) {
+ r = -EFAULT;
+ goto done;
+ }
+
+ spin_lock(&d->iotlb_lock);
+ if (!d->iotlb) {
+ spin_unlock(&d->iotlb_lock);
+ r = -EFAULT;
+ goto done;
+ }
+ switch (entry.flags.type) {
+ case VHOST_IOTLB_UPDATE:
+ if (entry.flags.valid != VHOST_IOTLB_VALID) {
+ break;
+ }
+ if (vhost_new_umem_range(d->iotlb,
+ entry.iova,
+ entry.size,
+ entry.iova + entry.size - 1,
+ entry.userspace_addr,
+ entry.flags.perm)) {
+ r = -ENOMEM;
+ break;
+ }
+ break;
+ case VHOST_IOTLB_INVALIDATE:
+ vhost_del_umem_range(d->iotlb,
+ entry.iova,
+ entry.iova + entry.size - 1);
+ break;
+ default:
+ r = -EINVAL;
+ }
+ spin_unlock(&d->iotlb_lock);
+
+ if (!r && entry.flags.type != VHOST_IOTLB_INVALIDATE)
+ vhost_complete_iotlb_update(d, &entry);
+
+ break;
default:
r = -ENOIOCTLCMD;
break;
@@ -1197,27 +1377,69 @@ int vhost_init_used(struct vhost_virtqueue *vq)
}
EXPORT_SYMBOL_GPL(vhost_init_used);

+static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova)
+{
+ struct vhost_iotlb_entry *pending = &vq->pending_request;
+ int ret;
+
+ if (!vq->iotlb_call_ctx)
+ return -EOPNOTSUPP;
+
+ if (!vq->iotlb_request)
+ return -EOPNOTSUPP;
+
+ if (pending->flags.type == VHOST_IOTLB_MISS) {
+ return -EEXIST;
+ }
+
+ pending->iova = iova;
+ pending->flags.type = VHOST_IOTLB_MISS;
+
+ ret = __copy_to_user(vq->iotlb_request, pending,
+ sizeof(struct vhost_iotlb_entry));
+ if (ret) {
+ goto err;
+ }
+
+ if (vq->iotlb_call_ctx)
+ eventfd_signal(vq->iotlb_call_ctx, 1);
+err:
+ return ret;
+}
+
static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
- struct iovec iov[], int iov_size)
+ struct iovec iov[], int iov_size, int access)
{
const struct vhost_umem_node *node;
- struct vhost_umem *umem = vq->umem;
+ struct vhost_dev *dev = vq->dev;
+ struct vhost_umem *umem = dev->iotlb ? dev->iotlb : dev->umem;
struct iovec *_iov;
u64 s = 0;
int ret = 0;

+ spin_lock(&dev->iotlb_lock);
+
while ((u64)len > s) {
u64 size;
if (unlikely(ret >= iov_size)) {
ret = -ENOBUFS;
break;
}
+
node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
addr, addr + len - 1);
if (node == NULL || node->start > addr) {
- ret = -EFAULT;
+ if (umem != dev->iotlb) {
+ ret = -EFAULT;
+ break;
+ }
+ ret = -EAGAIN;
+ break;
+ } else if (!(node->perm & access)) {
+ ret = -EPERM;
break;
}
+
_iov = iov + ret;
size = node->size - addr + node->start;
_iov->iov_len = min((u64)len - s, size);
@@ -1228,6 +1450,10 @@ static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
++ret;
}

+ spin_unlock(&dev->iotlb_lock);
+
+ if (ret == -EAGAIN)
+ vhost_iotlb_miss(vq, addr);
return ret;
}

@@ -1256,7 +1482,7 @@ static int get_indirect(struct vhost_virtqueue *vq,
struct iovec iov[], unsigned int iov_size,
unsigned int *out_num, unsigned int *in_num,
struct vhost_log *log, unsigned int *log_num,
- struct vring_desc *indirect)
+ struct vring_desc *indirect, int access)
{
struct vring_desc desc;
unsigned int i = 0, count, found = 0;
@@ -1274,9 +1500,10 @@ static int get_indirect(struct vhost_virtqueue *vq,
}

ret = translate_desc(vq, vhost64_to_cpu(vq, indirect->addr), len, vq->indirect,
- UIO_MAXIOV);
+ UIO_MAXIOV, access);
if (unlikely(ret < 0)) {
- vq_err(vq, "Translation failure %d in indirect.\n", ret);
+ if (ret != -EAGAIN)
+ vq_err(vq, "Translation failure %d in indirect.\n", ret);
return ret;
}
iov_iter_init(&from, READ, vq->indirect, ret, len);
@@ -1316,10 +1543,11 @@ static int get_indirect(struct vhost_virtqueue *vq,

ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
vhost32_to_cpu(vq, desc.len), iov + iov_count,
- iov_size - iov_count);
+ iov_size - iov_count, access);
if (unlikely(ret < 0)) {
- vq_err(vq, "Translation failure %d indirect idx %d\n",
- ret, i);
+ if (ret != -EAGAIN)
+ vq_err(vq, "Translation failure %d indirect idx %d\n",
+ ret, i);
return ret;
}
/* If this is an input descriptor, increment that count. */
@@ -1355,7 +1583,8 @@ static int get_indirect(struct vhost_virtqueue *vq,
int vhost_get_vq_desc(struct vhost_virtqueue *vq,
struct iovec iov[], unsigned int iov_size,
unsigned int *out_num, unsigned int *in_num,
- struct vhost_log *log, unsigned int *log_num)
+ struct vhost_log *log, unsigned int *log_num,
+ int access)
{
struct vring_desc desc;
unsigned int i, head, found = 0;
@@ -1433,10 +1662,11 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT)) {
ret = get_indirect(vq, iov, iov_size,
out_num, in_num,
- log, log_num, &desc);
+ log, log_num, &desc, access);
if (unlikely(ret < 0)) {
- vq_err(vq, "Failure detected "
- "in indirect descriptor at idx %d\n", i);
+ if (ret != -EAGAIN)
+ vq_err(vq, "Failure detected "
+ "in indirect descriptor at idx %d\n", i);
return ret;
}
continue;
@@ -1444,10 +1674,11 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,

ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
vhost32_to_cpu(vq, desc.len), iov + iov_count,
- iov_size - iov_count);
+ iov_size - iov_count, access);
if (unlikely(ret < 0)) {
- vq_err(vq, "Translation failure %d descriptor idx %d\n",
- ret, i);
+ if (ret != -EAGAIN)
+ vq_err(vq, "Translation failure %d descriptor idx %d\n",
+ ret, i);
return ret;
}
if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE)) {
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 5d64393..4365104 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -62,13 +62,15 @@ struct vhost_umem_node {
__u64 last;
__u64 size;
__u64 userspace_addr;
- __u64 flags_padding;
+ __u32 perm;
+ __u32 flags_padding;
__u64 __subtree_last;
};

struct vhost_umem {
struct rb_root umem_tree;
struct list_head umem_list;
+ int numem;
};

/* The virtqueue structure describes a queue attached to a device. */
@@ -84,9 +86,13 @@ struct vhost_virtqueue {
struct file *kick;
struct file *call;
struct file *error;
+ struct file *iotlb_call;
struct eventfd_ctx *call_ctx;
struct eventfd_ctx *error_ctx;
struct eventfd_ctx *log_ctx;
+ struct eventfd_ctx *iotlb_call_ctx;
+ struct vhost_iotlb_entry __user *iotlb_request;
+ struct vhost_iotlb_entry pending_request;

struct vhost_poll poll;

@@ -135,6 +141,8 @@ struct vhost_virtqueue {
#endif
};

+#define VHOST_IOTLB_SIZE 2048
+
struct vhost_dev {
struct mm_struct *mm;
struct mutex mutex;
@@ -146,6 +154,8 @@ struct vhost_dev {
struct list_head work_list;
struct task_struct *worker;
struct vhost_umem *umem;
+ struct vhost_umem *iotlb;
+ spinlock_t iotlb_lock;
};

void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, int nvqs);
@@ -164,7 +174,8 @@ int vhost_log_access_ok(struct vhost_dev *);
int vhost_get_vq_desc(struct vhost_virtqueue *,
struct iovec iov[], unsigned int iov_count,
unsigned int *out_num, unsigned int *in_num,
- struct vhost_log *log, unsigned int *log_num);
+ struct vhost_log *log, unsigned int *log_num,
+ int access);
void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);

int vhost_init_used(struct vhost_virtqueue *);
@@ -183,7 +194,7 @@ int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
unsigned int log_num, u64 len);

#define vq_err(vq, fmt, ...) do { \
- pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \
+ printk(pr_fmt(fmt), ##__VA_ARGS__); \
if ((vq)->error_ctx) \
eventfd_signal((vq)->error_ctx, 1);\
} while (0)
diff --git a/fs/eventfd.c b/fs/eventfd.c
index 8d0c0df..5c0a22f 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -59,8 +59,9 @@ __u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n)
if (ULLONG_MAX - ctx->count < n)
n = ULLONG_MAX - ctx->count;
ctx->count += n;
- if (waitqueue_active(&ctx->wqh))
+ if (waitqueue_active(&ctx->wqh)) {
wake_up_locked_poll(&ctx->wqh, POLLIN);
+ }
spin_unlock_irqrestore(&ctx->wqh.lock, flags);

return n;
diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
index ab373191..5c35ab4 100644
--- a/include/uapi/linux/vhost.h
+++ b/include/uapi/linux/vhost.h
@@ -47,6 +47,32 @@ struct vhost_vring_addr {
__u64 log_guest_addr;
};

+struct vhost_iotlb_entry {
+ __u64 iova;
+ __u64 size;
+ __u64 userspace_addr;
+ struct {
+#define VHOST_ACCESS_RO 0x1
+#define VHOST_ACCESS_WO 0x2
+#define VHOST_ACCESS_RW 0x3
+ __u8 perm;
+#define VHOST_IOTLB_MISS 1
+#define VHOST_IOTLB_UPDATE 2
+#define VHOST_IOTLB_INVALIDATE 3
+ __u8 type;
+#define VHOST_IOTLB_INVALID 0x1
+#define VHOST_IOTLB_VALID 0x2
+ __u8 valid;
+ __u8 u8_padding;
+ __u32 padding;
+ } flags;
+};
+
+struct vhost_vring_iotlb_entry {
+ unsigned int index;
+ __u64 userspace_addr;
+};
+
struct vhost_memory_region {
__u64 guest_phys_addr;
__u64 memory_size; /* bytes */
@@ -127,6 +153,15 @@ struct vhost_memory {
/* Set eventfd to signal an error */
#define VHOST_SET_VRING_ERR _IOW(VHOST_VIRTIO, 0x22, struct vhost_vring_file)

+/* IOTLB */
+/* Specify an eventfd file descriptor to signle on IOTLB miss */
+#define VHOST_SET_VRING_IOTLB_CALL _IOW(VHOST_VIRTIO, 0x23, struct \
+ vhost_vring_file)
+#define VHOST_SET_VRING_IOTLB_REQUEST _IOW(VHOST_VIRTIO, 0x25, struct \
+ vhost_vring_iotlb_entry)
+#define VHOST_UPDATE_IOTLB _IOW(VHOST_VIRTIO, 0x24, struct vhost_iotlb_entry)
+#define VHOST_RUN_IOTLB _IOW(VHOST_VIRTIO, 0x26, int)
+
/* VHOST_NET specific defines */

/* Attach virtio net ring to a raw socket, or tap device.
--
2.5.0