diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h index a91fbdf233e4f..ebb3ce63d64da 100644 --- a/include/linux/virtio_vsock.h +++ b/include/linux/virtio_vsock.h @@ -160,6 +160,15 @@ struct virtio_transport { /* Takes ownership of the packet */ int (*send_pkt)(struct sk_buff *skb); + + /* Used in MSG_ZEROCOPY mode. Checks, that provided data + * (number of buffers) could be transmitted with zerocopy + * mode. If this callback is not implemented for the current + * transport - this means that this transport doesn't need + * extra checks and can perform zerocopy transmission by + * default. + */ + bool (*can_msgzerocopy)(int bufs_num); }; ssize_t diff --git a/include/trace/events/vsock_virtio_transport_common.h b/include/trace/events/vsock_virtio_transport_common.h index d0b3f0ea9ba11..f1ebe36787c3d 100644 --- a/include/trace/events/vsock_virtio_transport_common.h +++ b/include/trace/events/vsock_virtio_transport_common.h @@ -43,7 +43,8 @@ TRACE_EVENT(virtio_transport_alloc_pkt, __u32 len, __u16 type, __u16 op, - __u32 flags + __u32 flags, + bool zcopy ), TP_ARGS( src_cid, src_port, @@ -51,7 +52,8 @@ TRACE_EVENT(virtio_transport_alloc_pkt, len, type, op, - flags + flags, + zcopy ), TP_STRUCT__entry( __field(__u32, src_cid) @@ -62,6 +64,7 @@ TRACE_EVENT(virtio_transport_alloc_pkt, __field(__u16, type) __field(__u16, op) __field(__u32, flags) + __field(bool, zcopy) ), TP_fast_assign( __entry->src_cid = src_cid; @@ -72,14 +75,15 @@ TRACE_EVENT(virtio_transport_alloc_pkt, __entry->type = type; __entry->op = op; __entry->flags = flags; + __entry->zcopy = zcopy; ), - TP_printk("%u:%u -> %u:%u len=%u type=%s op=%s flags=%#x", + TP_printk("%u:%u -> %u:%u len=%u type=%s op=%s flags=%#x zcopy=%s", __entry->src_cid, __entry->src_port, __entry->dst_cid, __entry->dst_port, __entry->len, show_type(__entry->type), show_op(__entry->op), - __entry->flags) + __entry->flags, __entry->zcopy ? "true" : "false") ); TRACE_EVENT(virtio_transport_recv_pkt, diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c index 73d7301563491..09ba3128e7593 100644 --- a/net/vmw_vsock/virtio_transport.c +++ b/net/vmw_vsock/virtio_transport.c @@ -455,6 +455,37 @@ static void virtio_vsock_rx_done(struct virtqueue *vq) queue_work(virtio_vsock_workqueue, &vsock->rx_work); } +static bool virtio_transport_can_msgzerocopy(int bufs_num) +{ + struct virtio_vsock *vsock; + bool res = false; + + rcu_read_lock(); + + vsock = rcu_dereference(the_virtio_vsock); + if (vsock) { + struct virtqueue *vq = vsock->vqs[VSOCK_VQ_TX]; + + /* Check that tx queue is large enough to keep whole + * data to send. This is needed, because when there is + * not enough free space in the queue, current skb to + * send will be reinserted to the head of tx list of + * the socket to retry transmission later, so if skb + * is bigger than whole queue, it will be reinserted + * again and again, thus blocking other skbs to be sent. + * Each page of the user provided buffer will be added + * as a single buffer to the tx virtqueue, so compare + * number of pages against maximum capacity of the queue. + */ + if (bufs_num <= vq->num_max) + res = true; + } + + rcu_read_unlock(); + + return res; +} + static bool virtio_transport_seqpacket_allow(u32 remote_cid); static struct virtio_transport virtio_transport = { @@ -504,6 +535,7 @@ static struct virtio_transport virtio_transport = { }, .send_pkt = virtio_transport_send_pkt, + .can_msgzerocopy = virtio_transport_can_msgzerocopy, }; static bool virtio_transport_seqpacket_allow(u32 remote_cid) diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index 3a48e48a99ac9..e22c81435ef7d 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -37,73 +37,99 @@ virtio_transport_get_ops(struct vsock_sock *vsk) return container_of(t, struct virtio_transport, transport); } -/* Returns a new packet on success, otherwise returns NULL. - * - * If NULL is returned, errp is set to a negative errno. - */ -static struct sk_buff * -virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info, - size_t len, - u32 src_cid, - u32 src_port, - u32 dst_cid, - u32 dst_port) -{ - const size_t skb_len = VIRTIO_VSOCK_SKB_HEADROOM + len; - struct virtio_vsock_hdr *hdr; - struct sk_buff *skb; - void *payload; - int err; +static bool virtio_transport_can_zcopy(const struct virtio_transport *t_ops, + struct virtio_vsock_pkt_info *info, + size_t pkt_len) +{ + struct iov_iter *iov_iter; - skb = virtio_vsock_alloc_skb(skb_len, GFP_KERNEL); - if (!skb) - return NULL; + if (!info->msg) + return false; - hdr = virtio_vsock_hdr(skb); - hdr->type = cpu_to_le16(info->type); - hdr->op = cpu_to_le16(info->op); - hdr->src_cid = cpu_to_le64(src_cid); - hdr->dst_cid = cpu_to_le64(dst_cid); - hdr->src_port = cpu_to_le32(src_port); - hdr->dst_port = cpu_to_le32(dst_port); - hdr->flags = cpu_to_le32(info->flags); - hdr->len = cpu_to_le32(len); + iov_iter = &info->msg->msg_iter; - if (info->msg && len > 0) { - payload = skb_put(skb, len); - err = memcpy_from_msg(payload, info->msg, len); - if (err) - goto out; + if (iov_iter->iov_offset) + return false; - if (msg_data_left(info->msg) == 0 && - info->type == VIRTIO_VSOCK_TYPE_SEQPACKET) { - hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM); + /* We can't send whole iov. */ + if (iov_iter->count > pkt_len) + return false; - if (info->msg->msg_flags & MSG_EOR) - hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR); - } + /* Check that transport can send data in zerocopy mode. */ + t_ops = virtio_transport_get_ops(info->vsk); + + if (t_ops->can_msgzerocopy) { + int pages_in_iov = iov_iter_npages(iov_iter, MAX_SKB_FRAGS); + int pages_to_send = min(pages_in_iov, MAX_SKB_FRAGS); + + /* +1 is for packet header. */ + return t_ops->can_msgzerocopy(pages_to_send + 1); } - if (info->reply) - virtio_vsock_skb_set_reply(skb); + return true; +} - trace_virtio_transport_alloc_pkt(src_cid, src_port, - dst_cid, dst_port, - len, - info->type, - info->op, - info->flags); +static int virtio_transport_init_zcopy_skb(struct vsock_sock *vsk, + struct sk_buff *skb, + struct msghdr *msg, + bool zerocopy) +{ + struct ubuf_info *uarg; - if (info->vsk && !skb_set_owner_sk_safe(skb, sk_vsock(info->vsk))) { - WARN_ONCE(1, "failed to allocate skb on vsock socket with sk_refcnt == 0\n"); - goto out; + if (msg->msg_ubuf) { + uarg = msg->msg_ubuf; + net_zcopy_get(uarg); + } else { + struct iov_iter *iter = &msg->msg_iter; + struct ubuf_info_msgzc *uarg_zc; + + uarg = msg_zerocopy_realloc(sk_vsock(vsk), + iter->count, + NULL); + if (!uarg) + return -1; + + uarg_zc = uarg_to_msgzc(uarg); + uarg_zc->zerocopy = zerocopy ? 1 : 0; } - return skb; + skb_zcopy_init(skb, uarg); -out: - kfree_skb(skb); - return NULL; + return 0; +} + +static int virtio_transport_fill_skb(struct sk_buff *skb, + struct virtio_vsock_pkt_info *info, + size_t len, + bool zcopy) +{ + if (zcopy) + return __zerocopy_sg_from_iter(info->msg, NULL, skb, + &info->msg->msg_iter, + len); + + return memcpy_from_msg(skb_put(skb, len), info->msg, len); +} + +static void virtio_transport_init_hdr(struct sk_buff *skb, + struct virtio_vsock_pkt_info *info, + size_t payload_len, + u32 src_cid, + u32 src_port, + u32 dst_cid, + u32 dst_port) +{ + struct virtio_vsock_hdr *hdr; + + hdr = virtio_vsock_hdr(skb); + hdr->type = cpu_to_le16(info->type); + hdr->op = cpu_to_le16(info->op); + hdr->src_cid = cpu_to_le64(src_cid); + hdr->dst_cid = cpu_to_le64(dst_cid); + hdr->src_port = cpu_to_le32(src_port); + hdr->dst_port = cpu_to_le32(dst_port); + hdr->flags = cpu_to_le32(info->flags); + hdr->len = cpu_to_le32(payload_len); } static void virtio_transport_copy_nonlinear_skb(const struct sk_buff *skb, @@ -214,6 +240,82 @@ static u16 virtio_transport_get_type(struct sock *sk) return VIRTIO_VSOCK_TYPE_SEQPACKET; } +/* Returns new sk_buff on success, otherwise returns NULL. */ +static struct sk_buff *virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info, + size_t payload_len, + bool zcopy, + u32 src_cid, + u32 src_port, + u32 dst_cid, + u32 dst_port) +{ + struct vsock_sock *vsk; + struct sk_buff *skb; + size_t skb_len; + + skb_len = VIRTIO_VSOCK_SKB_HEADROOM; + + if (!zcopy) + skb_len += payload_len; + + skb = virtio_vsock_alloc_skb(skb_len, GFP_KERNEL); + if (!skb) + return NULL; + + virtio_transport_init_hdr(skb, info, payload_len, src_cid, src_port, + dst_cid, dst_port); + + vsk = info->vsk; + + /* If 'vsk' != NULL then payload is always present, so we + * will never call '__zerocopy_sg_from_iter()' below without + * setting skb owner in 'skb_set_owner_w()'. The only case + * when 'vsk' == NULL is VIRTIO_VSOCK_OP_RST control message + * without payload. + */ + WARN_ON_ONCE(!(vsk && (info->msg && payload_len)) && zcopy); + + /* Set owner here, because '__zerocopy_sg_from_iter()' uses + * owner of skb without check to update 'sk_wmem_alloc'. + */ + if (vsk) + skb_set_owner_w(skb, sk_vsock(vsk)); + + if (info->msg && payload_len > 0) { + int err; + + err = virtio_transport_fill_skb(skb, info, payload_len, zcopy); + if (err) + goto out; + + if (msg_data_left(info->msg) == 0 && + info->type == VIRTIO_VSOCK_TYPE_SEQPACKET) { + struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb); + + hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM); + + if (info->msg->msg_flags & MSG_EOR) + hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR); + } + } + + if (info->reply) + virtio_vsock_skb_set_reply(skb); + + trace_virtio_transport_alloc_pkt(src_cid, src_port, + dst_cid, dst_port, + payload_len, + info->type, + info->op, + info->flags, + zcopy); + + return skb; +out: + kfree_skb(skb); + return NULL; +} + /* This function can only be used on connecting/connected sockets, * since a socket assigned to a transport is required. * @@ -222,10 +324,12 @@ static u16 virtio_transport_get_type(struct sock *sk) static int virtio_transport_send_pkt_info(struct vsock_sock *vsk, struct virtio_vsock_pkt_info *info) { + u32 max_skb_len = VIRTIO_VSOCK_MAX_PKT_BUF_SIZE; u32 src_cid, src_port, dst_cid, dst_port; const struct virtio_transport *t_ops; struct virtio_vsock_sock *vvs; u32 pkt_len = info->pkt_len; + bool can_zcopy = false; u32 rest_len; int ret; @@ -254,15 +358,30 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk, if (pkt_len == 0 && info->op == VIRTIO_VSOCK_OP_RW) return pkt_len; + if (info->msg) { + /* If zerocopy is not enabled by 'setsockopt()', we behave as + * there is no MSG_ZEROCOPY flag set. + */ + if (!sock_flag(sk_vsock(vsk), SOCK_ZEROCOPY)) + info->msg->msg_flags &= ~MSG_ZEROCOPY; + + if (info->msg->msg_flags & MSG_ZEROCOPY) + can_zcopy = virtio_transport_can_zcopy(t_ops, info, pkt_len); + + if (can_zcopy) + max_skb_len = min_t(u32, VIRTIO_VSOCK_MAX_PKT_BUF_SIZE, + (MAX_SKB_FRAGS * PAGE_SIZE)); + } + rest_len = pkt_len; do { struct sk_buff *skb; size_t skb_len; - skb_len = min_t(u32, VIRTIO_VSOCK_MAX_PKT_BUF_SIZE, rest_len); + skb_len = min(max_skb_len, rest_len); - skb = virtio_transport_alloc_skb(info, skb_len, + skb = virtio_transport_alloc_skb(info, skb_len, can_zcopy, src_cid, src_port, dst_cid, dst_port); if (!skb) { @@ -270,6 +389,21 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk, break; } + /* We process buffer part by part, allocating skb on + * each iteration. If this is last skb for this buffer + * and MSG_ZEROCOPY mode is in use - we must allocate + * completion for the current syscall. + */ + if (info->msg && info->msg->msg_flags & MSG_ZEROCOPY && + skb_len == rest_len && info->op == VIRTIO_VSOCK_OP_RW) { + if (virtio_transport_init_zcopy_skb(vsk, skb, + info->msg, + can_zcopy)) { + ret = -ENOMEM; + break; + } + } + virtio_transport_inc_tx_pkt(vvs, skb); ret = t_ops->send_pkt(skb); @@ -985,7 +1119,7 @@ static int virtio_transport_reset_no_sock(const struct virtio_transport *t, if (!t) return -ENOTCONN; - reply = virtio_transport_alloc_skb(&info, 0, + reply = virtio_transport_alloc_skb(&info, 0, false, le64_to_cpu(hdr->dst_cid), le32_to_cpu(hdr->dst_port), le64_to_cpu(hdr->src_cid),