mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-07 11:28:32 +00:00
vhost: switch to use new message format
We use to have message like:
struct vhost_msg {
int type;
union {
struct vhost_iotlb_msg iotlb;
__u8 padding[64];
};
};
Unfortunately, there will be a hole of 32bit in 64bit machine because
of the alignment. This leads a different formats between 32bit API and
64bit API. What's more it will break 32bit program running on 64bit
machine.
So fixing this by introducing a new message type with an explicit
32bit reserved field after type like:
struct vhost_msg_v2 {
__u32 type;
__u32 reserved;
union {
struct vhost_iotlb_msg iotlb;
__u8 padding[64];
};
};
We will have a consistent ABI after switching to use this. To enable
this capability, introduce a new ioctl (VHOST_SET_BAKCEND_FEATURE) for
userspace to enable this feature (VHOST_BACKEND_F_IOTLB_V2).
Fixes: 6b1e6cc785
("vhost: new device IOTLB API")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
9c2e955c48
commit
429711aec2
4 changed files with 111 additions and 19 deletions
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@ -77,6 +77,10 @@ enum {
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(1ULL << VIRTIO_F_IOMMU_PLATFORM)
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};
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enum {
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VHOST_NET_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2)
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};
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enum {
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VHOST_NET_VQ_RX = 0,
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VHOST_NET_VQ_TX = 1,
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@ -1399,6 +1403,21 @@ static long vhost_net_reset_owner(struct vhost_net *n)
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return err;
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}
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static int vhost_net_set_backend_features(struct vhost_net *n, u64 features)
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{
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int i;
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mutex_lock(&n->dev.mutex);
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for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
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mutex_lock(&n->vqs[i].vq.mutex);
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n->vqs[i].vq.acked_backend_features = features;
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mutex_unlock(&n->vqs[i].vq.mutex);
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}
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mutex_unlock(&n->dev.mutex);
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return 0;
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}
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static int vhost_net_set_features(struct vhost_net *n, u64 features)
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{
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size_t vhost_hlen, sock_hlen, hdr_len;
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@ -1489,6 +1508,17 @@ static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
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if (features & ~VHOST_NET_FEATURES)
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return -EOPNOTSUPP;
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return vhost_net_set_features(n, features);
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case VHOST_GET_BACKEND_FEATURES:
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features = VHOST_NET_BACKEND_FEATURES;
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if (copy_to_user(featurep, &features, sizeof(features)))
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return -EFAULT;
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return 0;
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case VHOST_SET_BACKEND_FEATURES:
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if (copy_from_user(&features, featurep, sizeof(features)))
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return -EFAULT;
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if (features & ~VHOST_NET_BACKEND_FEATURES)
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return -EOPNOTSUPP;
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return vhost_net_set_backend_features(n, features);
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case VHOST_RESET_OWNER:
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return vhost_net_reset_owner(n);
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case VHOST_SET_OWNER:
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@ -315,6 +315,7 @@ static void vhost_vq_reset(struct vhost_dev *dev,
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vq->log_addr = -1ull;
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vq->private_data = NULL;
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vq->acked_features = 0;
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vq->acked_backend_features = 0;
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vq->log_base = NULL;
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vq->error_ctx = NULL;
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vq->kick = NULL;
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@ -1027,28 +1028,40 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev,
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ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
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struct iov_iter *from)
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{
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struct vhost_msg_node node;
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unsigned size = sizeof(struct vhost_msg);
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size_t ret;
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int err;
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struct vhost_iotlb_msg msg;
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size_t offset;
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int type, ret;
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if (iov_iter_count(from) < size)
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return 0;
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ret = copy_from_iter(&node.msg, size, from);
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if (ret != size)
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ret = copy_from_iter(&type, sizeof(type), from);
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if (ret != sizeof(type))
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goto done;
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switch (node.msg.type) {
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switch (type) {
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case VHOST_IOTLB_MSG:
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err = vhost_process_iotlb_msg(dev, &node.msg.iotlb);
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if (err)
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ret = err;
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/* There maybe a hole after type for V1 message type,
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* so skip it here.
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*/
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offset = offsetof(struct vhost_msg, iotlb) - sizeof(int);
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break;
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case VHOST_IOTLB_MSG_V2:
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offset = sizeof(__u32);
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break;
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default:
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ret = -EINVAL;
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break;
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goto done;
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}
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iov_iter_advance(from, offset);
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ret = copy_from_iter(&msg, sizeof(msg), from);
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if (ret != sizeof(msg))
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goto done;
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if (vhost_process_iotlb_msg(dev, &msg)) {
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ret = -EFAULT;
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goto done;
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}
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ret = (type == VHOST_IOTLB_MSG) ? sizeof(struct vhost_msg) :
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sizeof(struct vhost_msg_v2);
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done:
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return ret;
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}
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@ -1107,13 +1120,28 @@ ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
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finish_wait(&dev->wait, &wait);
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if (node) {
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ret = copy_to_iter(&node->msg, size, to);
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struct vhost_iotlb_msg *msg;
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void *start = &node->msg;
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if (ret != size || node->msg.type != VHOST_IOTLB_MISS) {
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switch (node->msg.type) {
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case VHOST_IOTLB_MSG:
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size = sizeof(node->msg);
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msg = &node->msg.iotlb;
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break;
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case VHOST_IOTLB_MSG_V2:
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size = sizeof(node->msg_v2);
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msg = &node->msg_v2.iotlb;
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break;
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default:
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BUG();
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break;
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}
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ret = copy_to_iter(start, size, to);
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if (ret != size || msg->type != VHOST_IOTLB_MISS) {
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kfree(node);
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return ret;
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}
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vhost_enqueue_msg(dev, &dev->pending_list, node);
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}
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@ -1126,12 +1154,19 @@ static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova, int access)
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struct vhost_dev *dev = vq->dev;
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struct vhost_msg_node *node;
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struct vhost_iotlb_msg *msg;
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bool v2 = vhost_backend_has_feature(vq, VHOST_BACKEND_F_IOTLB_MSG_V2);
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node = vhost_new_msg(vq, VHOST_IOTLB_MISS);
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node = vhost_new_msg(vq, v2 ? VHOST_IOTLB_MSG_V2 : VHOST_IOTLB_MSG);
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if (!node)
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return -ENOMEM;
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msg = &node->msg.iotlb;
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if (v2) {
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node->msg_v2.type = VHOST_IOTLB_MSG_V2;
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msg = &node->msg_v2.iotlb;
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} else {
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msg = &node->msg.iotlb;
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}
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msg->type = VHOST_IOTLB_MISS;
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msg->iova = iova;
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msg->perm = access;
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@ -132,6 +132,7 @@ struct vhost_virtqueue {
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struct vhost_umem *iotlb;
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void *private_data;
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u64 acked_features;
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u64 acked_backend_features;
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/* Log write descriptors */
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void __user *log_base;
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struct vhost_log *log;
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};
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struct vhost_msg_node {
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struct vhost_msg msg;
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union {
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struct vhost_msg msg;
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struct vhost_msg_v2 msg_v2;
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};
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struct vhost_virtqueue *vq;
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struct list_head node;
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};
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@ -238,6 +242,11 @@ static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
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return vq->acked_features & (1ULL << bit);
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}
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static inline bool vhost_backend_has_feature(struct vhost_virtqueue *vq, int bit)
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{
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return vq->acked_backend_features & (1ULL << bit);
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}
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#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
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static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
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{
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@ -65,6 +65,7 @@ struct vhost_iotlb_msg {
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};
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#define VHOST_IOTLB_MSG 0x1
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#define VHOST_IOTLB_MSG_V2 0x2
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struct vhost_msg {
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int type;
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};
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};
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struct vhost_msg_v2 {
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__u32 type;
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__u32 reserved;
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union {
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struct vhost_iotlb_msg iotlb;
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__u8 padding[64];
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};
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};
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struct vhost_memory_region {
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__u64 guest_phys_addr;
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__u64 memory_size; /* bytes */
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@ -160,6 +170,14 @@ struct vhost_memory {
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#define VHOST_GET_VRING_BUSYLOOP_TIMEOUT _IOW(VHOST_VIRTIO, 0x24, \
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struct vhost_vring_state)
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/* Set or get vhost backend capability */
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/* Use message type V2 */
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#define VHOST_BACKEND_F_IOTLB_MSG_V2 0x1
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#define VHOST_SET_BACKEND_FEATURES _IOW(VHOST_VIRTIO, 0x25, __u64)
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#define VHOST_GET_BACKEND_FEATURES _IOW(VHOST_VIRTIO, 0x26, __u64)
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/* VHOST_NET specific defines */
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/* Attach virtio net ring to a raw socket, or tap device.
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