diff options
author | Jason Wang <jasowang@redhat.com> | 2018-08-06 06:17:47 +0300 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2018-08-06 20:41:04 +0300 |
commit | 429711aec282c4b5fe5bbd7b2f0bbbff4110ffb2 (patch) | |
tree | 81c65e5a1a91dac774b07eb5b233d677b4c05064 /drivers | |
parent | 9c2e955c48363a6a000a684aa49be7f4ac1120ad (diff) | |
download | linux-429711aec282c4b5fe5bbd7b2f0bbbff4110ffb2.tar.xz |
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: 6b1e6cc7855b ("vhost: new device IOTLB API")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/vhost/net.c | 30 | ||||
-rw-r--r-- | drivers/vhost/vhost.c | 71 | ||||
-rw-r--r-- | drivers/vhost/vhost.h | 11 |
3 files changed, 93 insertions, 19 deletions
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 367d8023b54d..4e656f89cb22 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -78,6 +78,10 @@ enum { }; enum { + VHOST_NET_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2) +}; + +enum { VHOST_NET_VQ_RX = 0, VHOST_NET_VQ_TX = 1, VHOST_NET_VQ_MAX = 2, @@ -1399,6 +1403,21 @@ done: return err; } +static int vhost_net_set_backend_features(struct vhost_net *n, u64 features) +{ + int i; + + mutex_lock(&n->dev.mutex); + for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { + mutex_lock(&n->vqs[i].vq.mutex); + n->vqs[i].vq.acked_backend_features = features; + mutex_unlock(&n->vqs[i].vq.mutex); + } + mutex_unlock(&n->dev.mutex); + + return 0; +} + static int vhost_net_set_features(struct vhost_net *n, u64 features) { size_t vhost_hlen, sock_hlen, hdr_len; @@ -1489,6 +1508,17 @@ static long vhost_net_ioctl(struct file *f, unsigned int ioctl, if (features & ~VHOST_NET_FEATURES) return -EOPNOTSUPP; return vhost_net_set_features(n, features); + case VHOST_GET_BACKEND_FEATURES: + features = VHOST_NET_BACKEND_FEATURES; + if (copy_to_user(featurep, &features, sizeof(features))) + return -EFAULT; + return 0; + case VHOST_SET_BACKEND_FEATURES: + if (copy_from_user(&features, featurep, sizeof(features))) + return -EFAULT; + if (features & ~VHOST_NET_BACKEND_FEATURES) + return -EOPNOTSUPP; + return vhost_net_set_backend_features(n, features); case VHOST_RESET_OWNER: return vhost_net_reset_owner(n); case VHOST_SET_OWNER: diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index a502f1af4a21..6f6c42d5e4be 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -315,6 +315,7 @@ static void vhost_vq_reset(struct vhost_dev *dev, vq->log_addr = -1ull; vq->private_data = NULL; vq->acked_features = 0; + vq->acked_backend_features = 0; vq->log_base = NULL; vq->error_ctx = NULL; vq->kick = NULL; @@ -1027,28 +1028,40 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev, ssize_t vhost_chr_write_iter(struct vhost_dev *dev, struct iov_iter *from) { - struct vhost_msg_node node; - unsigned size = sizeof(struct vhost_msg); - size_t ret; - int err; + struct vhost_iotlb_msg msg; + size_t offset; + int type, ret; - if (iov_iter_count(from) < size) - return 0; - ret = copy_from_iter(&node.msg, size, from); - if (ret != size) + ret = copy_from_iter(&type, sizeof(type), from); + if (ret != sizeof(type)) goto done; - switch (node.msg.type) { + switch (type) { case VHOST_IOTLB_MSG: - err = vhost_process_iotlb_msg(dev, &node.msg.iotlb); - if (err) - ret = err; + /* There maybe a hole after type for V1 message type, + * so skip it here. + */ + offset = offsetof(struct vhost_msg, iotlb) - sizeof(int); + break; + case VHOST_IOTLB_MSG_V2: + offset = sizeof(__u32); break; default: ret = -EINVAL; - break; + goto done; + } + + iov_iter_advance(from, offset); + ret = copy_from_iter(&msg, sizeof(msg), from); + if (ret != sizeof(msg)) + goto done; + if (vhost_process_iotlb_msg(dev, &msg)) { + ret = -EFAULT; + goto done; } + ret = (type == VHOST_IOTLB_MSG) ? sizeof(struct vhost_msg) : + sizeof(struct vhost_msg_v2); done: return ret; } @@ -1107,13 +1120,28 @@ ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to, finish_wait(&dev->wait, &wait); if (node) { - ret = copy_to_iter(&node->msg, size, to); + struct vhost_iotlb_msg *msg; + void *start = &node->msg; + + switch (node->msg.type) { + case VHOST_IOTLB_MSG: + size = sizeof(node->msg); + msg = &node->msg.iotlb; + break; + case VHOST_IOTLB_MSG_V2: + size = sizeof(node->msg_v2); + msg = &node->msg_v2.iotlb; + break; + default: + BUG(); + break; + } - if (ret != size || node->msg.type != VHOST_IOTLB_MISS) { + ret = copy_to_iter(start, size, to); + if (ret != size || msg->type != VHOST_IOTLB_MISS) { kfree(node); return ret; } - vhost_enqueue_msg(dev, &dev->pending_list, node); } @@ -1126,12 +1154,19 @@ static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova, int access) struct vhost_dev *dev = vq->dev; struct vhost_msg_node *node; struct vhost_iotlb_msg *msg; + bool v2 = vhost_backend_has_feature(vq, VHOST_BACKEND_F_IOTLB_MSG_V2); - node = vhost_new_msg(vq, VHOST_IOTLB_MISS); + node = vhost_new_msg(vq, v2 ? VHOST_IOTLB_MSG_V2 : VHOST_IOTLB_MSG); if (!node) return -ENOMEM; - msg = &node->msg.iotlb; + if (v2) { + node->msg_v2.type = VHOST_IOTLB_MSG_V2; + msg = &node->msg_v2.iotlb; + } else { + msg = &node->msg.iotlb; + } + msg->type = VHOST_IOTLB_MISS; msg->iova = iova; msg->perm = access; diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index 6c844b90a168..466ef7542291 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -132,6 +132,7 @@ struct vhost_virtqueue { struct vhost_umem *iotlb; void *private_data; u64 acked_features; + u64 acked_backend_features; /* Log write descriptors */ void __user *log_base; struct vhost_log *log; @@ -147,7 +148,10 @@ struct vhost_virtqueue { }; struct vhost_msg_node { - struct vhost_msg msg; + union { + struct vhost_msg msg; + struct vhost_msg_v2 msg_v2; + }; struct vhost_virtqueue *vq; struct list_head node; }; @@ -238,6 +242,11 @@ static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit) return vq->acked_features & (1ULL << bit); } +static inline bool vhost_backend_has_feature(struct vhost_virtqueue *vq, int bit) +{ + return vq->acked_backend_features & (1ULL << bit); +} + #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq) { |