From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- drivers/vhost/net.c | 1815 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1815 insertions(+) create mode 100644 drivers/vhost/net.c (limited to 'drivers/vhost/net.c') diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c new file mode 100644 index 000000000..f2ed7167c --- /dev/null +++ b/drivers/vhost/net.c @@ -0,0 +1,1815 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (C) 2009 Red Hat, Inc. + * Author: Michael S. Tsirkin + * + * virtio-net server in host kernel. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include "vhost.h" + +static int experimental_zcopytx = 0; +module_param(experimental_zcopytx, int, 0444); +MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;" + " 1 -Enable; 0 - Disable"); + +/* Max number of bytes transferred before requeueing the job. + * Using this limit prevents one virtqueue from starving others. */ +#define VHOST_NET_WEIGHT 0x80000 + +/* Max number of packets transferred before requeueing the job. + * Using this limit prevents one virtqueue from starving others with small + * pkts. + */ +#define VHOST_NET_PKT_WEIGHT 256 + +/* MAX number of TX used buffers for outstanding zerocopy */ +#define VHOST_MAX_PEND 128 +#define VHOST_GOODCOPY_LEN 256 + +/* + * For transmit, used buffer len is unused; we override it to track buffer + * status internally; used for zerocopy tx only. + */ +/* Lower device DMA failed */ +#define VHOST_DMA_FAILED_LEN ((__force __virtio32)3) +/* Lower device DMA done */ +#define VHOST_DMA_DONE_LEN ((__force __virtio32)2) +/* Lower device DMA in progress */ +#define VHOST_DMA_IN_PROGRESS ((__force __virtio32)1) +/* Buffer unused */ +#define VHOST_DMA_CLEAR_LEN ((__force __virtio32)0) + +#define VHOST_DMA_IS_DONE(len) ((__force u32)(len) >= (__force u32)VHOST_DMA_DONE_LEN) + +enum { + VHOST_NET_FEATURES = VHOST_FEATURES | + (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) | + (1ULL << VIRTIO_NET_F_MRG_RXBUF) | + (1ULL << VIRTIO_F_ACCESS_PLATFORM) | + (1ULL << VIRTIO_F_RING_RESET) +}; + +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, +}; + +struct vhost_net_ubuf_ref { + /* refcount follows semantics similar to kref: + * 0: object is released + * 1: no outstanding ubufs + * >1: outstanding ubufs + */ + atomic_t refcount; + wait_queue_head_t wait; + struct vhost_virtqueue *vq; +}; + +#define VHOST_NET_BATCH 64 +struct vhost_net_buf { + void **queue; + int tail; + int head; +}; + +struct vhost_net_virtqueue { + struct vhost_virtqueue vq; + size_t vhost_hlen; + size_t sock_hlen; + /* vhost zerocopy support fields below: */ + /* last used idx for outstanding DMA zerocopy buffers */ + int upend_idx; + /* For TX, first used idx for DMA done zerocopy buffers + * For RX, number of batched heads + */ + int done_idx; + /* Number of XDP frames batched */ + int batched_xdp; + /* an array of userspace buffers info */ + struct ubuf_info_msgzc *ubuf_info; + /* Reference counting for outstanding ubufs. + * Protected by vq mutex. Writers must also take device mutex. */ + struct vhost_net_ubuf_ref *ubufs; + struct ptr_ring *rx_ring; + struct vhost_net_buf rxq; + /* Batched XDP buffs */ + struct xdp_buff *xdp; +}; + +struct vhost_net { + struct vhost_dev dev; + struct vhost_net_virtqueue vqs[VHOST_NET_VQ_MAX]; + struct vhost_poll poll[VHOST_NET_VQ_MAX]; + /* Number of TX recently submitted. + * Protected by tx vq lock. */ + unsigned tx_packets; + /* Number of times zerocopy TX recently failed. + * Protected by tx vq lock. */ + unsigned tx_zcopy_err; + /* Flush in progress. Protected by tx vq lock. */ + bool tx_flush; + /* Private page frag */ + struct page_frag page_frag; + /* Refcount bias of page frag */ + int refcnt_bias; +}; + +static unsigned vhost_net_zcopy_mask __read_mostly; + +static void *vhost_net_buf_get_ptr(struct vhost_net_buf *rxq) +{ + if (rxq->tail != rxq->head) + return rxq->queue[rxq->head]; + else + return NULL; +} + +static int vhost_net_buf_get_size(struct vhost_net_buf *rxq) +{ + return rxq->tail - rxq->head; +} + +static int vhost_net_buf_is_empty(struct vhost_net_buf *rxq) +{ + return rxq->tail == rxq->head; +} + +static void *vhost_net_buf_consume(struct vhost_net_buf *rxq) +{ + void *ret = vhost_net_buf_get_ptr(rxq); + ++rxq->head; + return ret; +} + +static int vhost_net_buf_produce(struct vhost_net_virtqueue *nvq) +{ + struct vhost_net_buf *rxq = &nvq->rxq; + + rxq->head = 0; + rxq->tail = ptr_ring_consume_batched(nvq->rx_ring, rxq->queue, + VHOST_NET_BATCH); + return rxq->tail; +} + +static void vhost_net_buf_unproduce(struct vhost_net_virtqueue *nvq) +{ + struct vhost_net_buf *rxq = &nvq->rxq; + + if (nvq->rx_ring && !vhost_net_buf_is_empty(rxq)) { + ptr_ring_unconsume(nvq->rx_ring, rxq->queue + rxq->head, + vhost_net_buf_get_size(rxq), + tun_ptr_free); + rxq->head = rxq->tail = 0; + } +} + +static int vhost_net_buf_peek_len(void *ptr) +{ + if (tun_is_xdp_frame(ptr)) { + struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr); + + return xdpf->len; + } + + return __skb_array_len_with_tag(ptr); +} + +static int vhost_net_buf_peek(struct vhost_net_virtqueue *nvq) +{ + struct vhost_net_buf *rxq = &nvq->rxq; + + if (!vhost_net_buf_is_empty(rxq)) + goto out; + + if (!vhost_net_buf_produce(nvq)) + return 0; + +out: + return vhost_net_buf_peek_len(vhost_net_buf_get_ptr(rxq)); +} + +static void vhost_net_buf_init(struct vhost_net_buf *rxq) +{ + rxq->head = rxq->tail = 0; +} + +static void vhost_net_enable_zcopy(int vq) +{ + vhost_net_zcopy_mask |= 0x1 << vq; +} + +static struct vhost_net_ubuf_ref * +vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy) +{ + struct vhost_net_ubuf_ref *ubufs; + /* No zero copy backend? Nothing to count. */ + if (!zcopy) + return NULL; + ubufs = kmalloc(sizeof(*ubufs), GFP_KERNEL); + if (!ubufs) + return ERR_PTR(-ENOMEM); + atomic_set(&ubufs->refcount, 1); + init_waitqueue_head(&ubufs->wait); + ubufs->vq = vq; + return ubufs; +} + +static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs) +{ + int r = atomic_sub_return(1, &ubufs->refcount); + if (unlikely(!r)) + wake_up(&ubufs->wait); + return r; +} + +static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs) +{ + vhost_net_ubuf_put(ubufs); + wait_event(ubufs->wait, !atomic_read(&ubufs->refcount)); +} + +static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs) +{ + vhost_net_ubuf_put_and_wait(ubufs); + kfree(ubufs); +} + +static void vhost_net_clear_ubuf_info(struct vhost_net *n) +{ + int i; + + for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { + kfree(n->vqs[i].ubuf_info); + n->vqs[i].ubuf_info = NULL; + } +} + +static int vhost_net_set_ubuf_info(struct vhost_net *n) +{ + bool zcopy; + int i; + + for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { + zcopy = vhost_net_zcopy_mask & (0x1 << i); + if (!zcopy) + continue; + n->vqs[i].ubuf_info = + kmalloc_array(UIO_MAXIOV, + sizeof(*n->vqs[i].ubuf_info), + GFP_KERNEL); + if (!n->vqs[i].ubuf_info) + goto err; + } + return 0; + +err: + vhost_net_clear_ubuf_info(n); + return -ENOMEM; +} + +static void vhost_net_vq_reset(struct vhost_net *n) +{ + int i; + + vhost_net_clear_ubuf_info(n); + + for (i = 0; i < VHOST_NET_VQ_MAX; i++) { + n->vqs[i].done_idx = 0; + n->vqs[i].upend_idx = 0; + n->vqs[i].ubufs = NULL; + n->vqs[i].vhost_hlen = 0; + n->vqs[i].sock_hlen = 0; + vhost_net_buf_init(&n->vqs[i].rxq); + } + +} + +static void vhost_net_tx_packet(struct vhost_net *net) +{ + ++net->tx_packets; + if (net->tx_packets < 1024) + return; + net->tx_packets = 0; + net->tx_zcopy_err = 0; +} + +static void vhost_net_tx_err(struct vhost_net *net) +{ + ++net->tx_zcopy_err; +} + +static bool vhost_net_tx_select_zcopy(struct vhost_net *net) +{ + /* TX flush waits for outstanding DMAs to be done. + * Don't start new DMAs. + */ + return !net->tx_flush && + net->tx_packets / 64 >= net->tx_zcopy_err; +} + +static bool vhost_sock_zcopy(struct socket *sock) +{ + return unlikely(experimental_zcopytx) && + sock_flag(sock->sk, SOCK_ZEROCOPY); +} + +static bool vhost_sock_xdp(struct socket *sock) +{ + return sock_flag(sock->sk, SOCK_XDP); +} + +/* In case of DMA done not in order in lower device driver for some reason. + * upend_idx is used to track end of used idx, done_idx is used to track head + * of used idx. Once lower device DMA done contiguously, we will signal KVM + * guest used idx. + */ +static void vhost_zerocopy_signal_used(struct vhost_net *net, + struct vhost_virtqueue *vq) +{ + struct vhost_net_virtqueue *nvq = + container_of(vq, struct vhost_net_virtqueue, vq); + int i, add; + int j = 0; + + for (i = nvq->done_idx; i != nvq->upend_idx; i = (i + 1) % UIO_MAXIOV) { + if (vq->heads[i].len == VHOST_DMA_FAILED_LEN) + vhost_net_tx_err(net); + if (VHOST_DMA_IS_DONE(vq->heads[i].len)) { + vq->heads[i].len = VHOST_DMA_CLEAR_LEN; + ++j; + } else + break; + } + while (j) { + add = min(UIO_MAXIOV - nvq->done_idx, j); + vhost_add_used_and_signal_n(vq->dev, vq, + &vq->heads[nvq->done_idx], add); + nvq->done_idx = (nvq->done_idx + add) % UIO_MAXIOV; + j -= add; + } +} + +static void vhost_zerocopy_callback(struct sk_buff *skb, + struct ubuf_info *ubuf_base, bool success) +{ + struct ubuf_info_msgzc *ubuf = uarg_to_msgzc(ubuf_base); + struct vhost_net_ubuf_ref *ubufs = ubuf->ctx; + struct vhost_virtqueue *vq = ubufs->vq; + int cnt; + + rcu_read_lock_bh(); + + /* set len to mark this desc buffers done DMA */ + vq->heads[ubuf->desc].len = success ? + VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN; + cnt = vhost_net_ubuf_put(ubufs); + + /* + * Trigger polling thread if guest stopped submitting new buffers: + * in this case, the refcount after decrement will eventually reach 1. + * We also trigger polling periodically after each 16 packets + * (the value 16 here is more or less arbitrary, it's tuned to trigger + * less than 10% of times). + */ + if (cnt <= 1 || !(cnt % 16)) + vhost_poll_queue(&vq->poll); + + rcu_read_unlock_bh(); +} + +static inline unsigned long busy_clock(void) +{ + return local_clock() >> 10; +} + +static bool vhost_can_busy_poll(unsigned long endtime) +{ + return likely(!need_resched() && !time_after(busy_clock(), endtime) && + !signal_pending(current)); +} + +static void vhost_net_disable_vq(struct vhost_net *n, + struct vhost_virtqueue *vq) +{ + struct vhost_net_virtqueue *nvq = + container_of(vq, struct vhost_net_virtqueue, vq); + struct vhost_poll *poll = n->poll + (nvq - n->vqs); + if (!vhost_vq_get_backend(vq)) + return; + vhost_poll_stop(poll); +} + +static int vhost_net_enable_vq(struct vhost_net *n, + struct vhost_virtqueue *vq) +{ + struct vhost_net_virtqueue *nvq = + container_of(vq, struct vhost_net_virtqueue, vq); + struct vhost_poll *poll = n->poll + (nvq - n->vqs); + struct socket *sock; + + sock = vhost_vq_get_backend(vq); + if (!sock) + return 0; + + return vhost_poll_start(poll, sock->file); +} + +static void vhost_net_signal_used(struct vhost_net_virtqueue *nvq) +{ + struct vhost_virtqueue *vq = &nvq->vq; + struct vhost_dev *dev = vq->dev; + + if (!nvq->done_idx) + return; + + vhost_add_used_and_signal_n(dev, vq, vq->heads, nvq->done_idx); + nvq->done_idx = 0; +} + +static void vhost_tx_batch(struct vhost_net *net, + struct vhost_net_virtqueue *nvq, + struct socket *sock, + struct msghdr *msghdr) +{ + struct tun_msg_ctl ctl = { + .type = TUN_MSG_PTR, + .num = nvq->batched_xdp, + .ptr = nvq->xdp, + }; + int i, err; + + if (nvq->batched_xdp == 0) + goto signal_used; + + msghdr->msg_control = &ctl; + msghdr->msg_controllen = sizeof(ctl); + err = sock->ops->sendmsg(sock, msghdr, 0); + if (unlikely(err < 0)) { + vq_err(&nvq->vq, "Fail to batch sending packets\n"); + + /* free pages owned by XDP; since this is an unlikely error path, + * keep it simple and avoid more complex bulk update for the + * used pages + */ + for (i = 0; i < nvq->batched_xdp; ++i) + put_page(virt_to_head_page(nvq->xdp[i].data)); + nvq->batched_xdp = 0; + nvq->done_idx = 0; + return; + } + +signal_used: + vhost_net_signal_used(nvq); + nvq->batched_xdp = 0; +} + +static int sock_has_rx_data(struct socket *sock) +{ + if (unlikely(!sock)) + return 0; + + if (sock->ops->peek_len) + return sock->ops->peek_len(sock); + + return skb_queue_empty(&sock->sk->sk_receive_queue); +} + +static void vhost_net_busy_poll_try_queue(struct vhost_net *net, + struct vhost_virtqueue *vq) +{ + if (!vhost_vq_avail_empty(&net->dev, vq)) { + vhost_poll_queue(&vq->poll); + } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { + vhost_disable_notify(&net->dev, vq); + vhost_poll_queue(&vq->poll); + } +} + +static void vhost_net_busy_poll(struct vhost_net *net, + struct vhost_virtqueue *rvq, + struct vhost_virtqueue *tvq, + bool *busyloop_intr, + bool poll_rx) +{ + unsigned long busyloop_timeout; + unsigned long endtime; + struct socket *sock; + struct vhost_virtqueue *vq = poll_rx ? tvq : rvq; + + /* Try to hold the vq mutex of the paired virtqueue. We can't + * use mutex_lock() here since we could not guarantee a + * consistenet lock ordering. + */ + if (!mutex_trylock(&vq->mutex)) + return; + + vhost_disable_notify(&net->dev, vq); + sock = vhost_vq_get_backend(rvq); + + busyloop_timeout = poll_rx ? rvq->busyloop_timeout: + tvq->busyloop_timeout; + + preempt_disable(); + endtime = busy_clock() + busyloop_timeout; + + while (vhost_can_busy_poll(endtime)) { + if (vhost_vq_has_work(vq)) { + *busyloop_intr = true; + break; + } + + if ((sock_has_rx_data(sock) && + !vhost_vq_avail_empty(&net->dev, rvq)) || + !vhost_vq_avail_empty(&net->dev, tvq)) + break; + + cpu_relax(); + } + + preempt_enable(); + + if (poll_rx || sock_has_rx_data(sock)) + vhost_net_busy_poll_try_queue(net, vq); + else if (!poll_rx) /* On tx here, sock has no rx data. */ + vhost_enable_notify(&net->dev, rvq); + + mutex_unlock(&vq->mutex); +} + +static int vhost_net_tx_get_vq_desc(struct vhost_net *net, + struct vhost_net_virtqueue *tnvq, + unsigned int *out_num, unsigned int *in_num, + struct msghdr *msghdr, bool *busyloop_intr) +{ + struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX]; + struct vhost_virtqueue *rvq = &rnvq->vq; + struct vhost_virtqueue *tvq = &tnvq->vq; + + int r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov), + out_num, in_num, NULL, NULL); + + if (r == tvq->num && tvq->busyloop_timeout) { + /* Flush batched packets first */ + if (!vhost_sock_zcopy(vhost_vq_get_backend(tvq))) + vhost_tx_batch(net, tnvq, + vhost_vq_get_backend(tvq), + msghdr); + + vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, false); + + r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov), + out_num, in_num, NULL, NULL); + } + + return r; +} + +static bool vhost_exceeds_maxpend(struct vhost_net *net) +{ + struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; + struct vhost_virtqueue *vq = &nvq->vq; + + return (nvq->upend_idx + UIO_MAXIOV - nvq->done_idx) % UIO_MAXIOV > + min_t(unsigned int, VHOST_MAX_PEND, vq->num >> 2); +} + +static size_t init_iov_iter(struct vhost_virtqueue *vq, struct iov_iter *iter, + size_t hdr_size, int out) +{ + /* Skip header. TODO: support TSO. */ + size_t len = iov_length(vq->iov, out); + + iov_iter_init(iter, ITER_SOURCE, vq->iov, out, len); + iov_iter_advance(iter, hdr_size); + + return iov_iter_count(iter); +} + +static int get_tx_bufs(struct vhost_net *net, + struct vhost_net_virtqueue *nvq, + struct msghdr *msg, + unsigned int *out, unsigned int *in, + size_t *len, bool *busyloop_intr) +{ + struct vhost_virtqueue *vq = &nvq->vq; + int ret; + + ret = vhost_net_tx_get_vq_desc(net, nvq, out, in, msg, busyloop_intr); + + if (ret < 0 || ret == vq->num) + return ret; + + if (*in) { + vq_err(vq, "Unexpected descriptor format for TX: out %d, int %d\n", + *out, *in); + return -EFAULT; + } + + /* Sanity check */ + *len = init_iov_iter(vq, &msg->msg_iter, nvq->vhost_hlen, *out); + if (*len == 0) { + vq_err(vq, "Unexpected header len for TX: %zd expected %zd\n", + *len, nvq->vhost_hlen); + return -EFAULT; + } + + return ret; +} + +static bool tx_can_batch(struct vhost_virtqueue *vq, size_t total_len) +{ + return total_len < VHOST_NET_WEIGHT && + !vhost_vq_avail_empty(vq->dev, vq); +} + +static bool vhost_net_page_frag_refill(struct vhost_net *net, unsigned int sz, + struct page_frag *pfrag, gfp_t gfp) +{ + if (pfrag->page) { + if (pfrag->offset + sz <= pfrag->size) + return true; + __page_frag_cache_drain(pfrag->page, net->refcnt_bias); + } + + pfrag->offset = 0; + net->refcnt_bias = 0; + if (SKB_FRAG_PAGE_ORDER) { + /* Avoid direct reclaim but allow kswapd to wake */ + pfrag->page = alloc_pages((gfp & ~__GFP_DIRECT_RECLAIM) | + __GFP_COMP | __GFP_NOWARN | + __GFP_NORETRY, + SKB_FRAG_PAGE_ORDER); + if (likely(pfrag->page)) { + pfrag->size = PAGE_SIZE << SKB_FRAG_PAGE_ORDER; + goto done; + } + } + pfrag->page = alloc_page(gfp); + if (likely(pfrag->page)) { + pfrag->size = PAGE_SIZE; + goto done; + } + return false; + +done: + net->refcnt_bias = USHRT_MAX; + page_ref_add(pfrag->page, USHRT_MAX - 1); + return true; +} + +#define VHOST_NET_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD) + +static int vhost_net_build_xdp(struct vhost_net_virtqueue *nvq, + struct iov_iter *from) +{ + struct vhost_virtqueue *vq = &nvq->vq; + struct vhost_net *net = container_of(vq->dev, struct vhost_net, + dev); + struct socket *sock = vhost_vq_get_backend(vq); + struct page_frag *alloc_frag = &net->page_frag; + struct virtio_net_hdr *gso; + struct xdp_buff *xdp = &nvq->xdp[nvq->batched_xdp]; + struct tun_xdp_hdr *hdr; + size_t len = iov_iter_count(from); + int headroom = vhost_sock_xdp(sock) ? XDP_PACKET_HEADROOM : 0; + int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); + int pad = SKB_DATA_ALIGN(VHOST_NET_RX_PAD + headroom + nvq->sock_hlen); + int sock_hlen = nvq->sock_hlen; + void *buf; + int copied; + + if (unlikely(len < nvq->sock_hlen)) + return -EFAULT; + + if (SKB_DATA_ALIGN(len + pad) + + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE) + return -ENOSPC; + + buflen += SKB_DATA_ALIGN(len + pad); + alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES); + if (unlikely(!vhost_net_page_frag_refill(net, buflen, + alloc_frag, GFP_KERNEL))) + return -ENOMEM; + + buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset; + copied = copy_page_from_iter(alloc_frag->page, + alloc_frag->offset + + offsetof(struct tun_xdp_hdr, gso), + sock_hlen, from); + if (copied != sock_hlen) + return -EFAULT; + + hdr = buf; + gso = &hdr->gso; + + if ((gso->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && + vhost16_to_cpu(vq, gso->csum_start) + + vhost16_to_cpu(vq, gso->csum_offset) + 2 > + vhost16_to_cpu(vq, gso->hdr_len)) { + gso->hdr_len = cpu_to_vhost16(vq, + vhost16_to_cpu(vq, gso->csum_start) + + vhost16_to_cpu(vq, gso->csum_offset) + 2); + + if (vhost16_to_cpu(vq, gso->hdr_len) > len) + return -EINVAL; + } + + len -= sock_hlen; + copied = copy_page_from_iter(alloc_frag->page, + alloc_frag->offset + pad, + len, from); + if (copied != len) + return -EFAULT; + + xdp_init_buff(xdp, buflen, NULL); + xdp_prepare_buff(xdp, buf, pad, len, true); + hdr->buflen = buflen; + + --net->refcnt_bias; + alloc_frag->offset += buflen; + + ++nvq->batched_xdp; + + return 0; +} + +static void handle_tx_copy(struct vhost_net *net, struct socket *sock) +{ + struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; + struct vhost_virtqueue *vq = &nvq->vq; + unsigned out, in; + int head; + struct msghdr msg = { + .msg_name = NULL, + .msg_namelen = 0, + .msg_control = NULL, + .msg_controllen = 0, + .msg_flags = MSG_DONTWAIT, + }; + size_t len, total_len = 0; + int err; + int sent_pkts = 0; + bool sock_can_batch = (sock->sk->sk_sndbuf == INT_MAX); + + do { + bool busyloop_intr = false; + + if (nvq->done_idx == VHOST_NET_BATCH) + vhost_tx_batch(net, nvq, sock, &msg); + + head = get_tx_bufs(net, nvq, &msg, &out, &in, &len, + &busyloop_intr); + /* On error, stop handling until the next kick. */ + if (unlikely(head < 0)) + break; + /* Nothing new? Wait for eventfd to tell us they refilled. */ + if (head == vq->num) { + if (unlikely(busyloop_intr)) { + vhost_poll_queue(&vq->poll); + } else if (unlikely(vhost_enable_notify(&net->dev, + vq))) { + vhost_disable_notify(&net->dev, vq); + continue; + } + break; + } + + total_len += len; + + /* For simplicity, TX batching is only enabled if + * sndbuf is unlimited. + */ + if (sock_can_batch) { + err = vhost_net_build_xdp(nvq, &msg.msg_iter); + if (!err) { + goto done; + } else if (unlikely(err != -ENOSPC)) { + vhost_tx_batch(net, nvq, sock, &msg); + vhost_discard_vq_desc(vq, 1); + vhost_net_enable_vq(net, vq); + break; + } + + /* We can't build XDP buff, go for single + * packet path but let's flush batched + * packets. + */ + vhost_tx_batch(net, nvq, sock, &msg); + msg.msg_control = NULL; + } else { + if (tx_can_batch(vq, total_len)) + msg.msg_flags |= MSG_MORE; + else + msg.msg_flags &= ~MSG_MORE; + } + + err = sock->ops->sendmsg(sock, &msg, len); + if (unlikely(err < 0)) { + if (err == -EAGAIN || err == -ENOMEM || err == -ENOBUFS) { + vhost_discard_vq_desc(vq, 1); + vhost_net_enable_vq(net, vq); + break; + } + pr_debug("Fail to send packet: err %d", err); + } else if (unlikely(err != len)) + pr_debug("Truncated TX packet: len %d != %zd\n", + err, len); +done: + vq->heads[nvq->done_idx].id = cpu_to_vhost32(vq, head); + vq->heads[nvq->done_idx].len = 0; + ++nvq->done_idx; + } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len))); + + vhost_tx_batch(net, nvq, sock, &msg); +} + +static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock) +{ + struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; + struct vhost_virtqueue *vq = &nvq->vq; + unsigned out, in; + int head; + struct msghdr msg = { + .msg_name = NULL, + .msg_namelen = 0, + .msg_control = NULL, + .msg_controllen = 0, + .msg_flags = MSG_DONTWAIT, + }; + struct tun_msg_ctl ctl; + size_t len, total_len = 0; + int err; + struct vhost_net_ubuf_ref *ubufs; + struct ubuf_info_msgzc *ubuf; + bool zcopy_used; + int sent_pkts = 0; + + do { + bool busyloop_intr; + + /* Release DMAs done buffers first */ + vhost_zerocopy_signal_used(net, vq); + + busyloop_intr = false; + head = get_tx_bufs(net, nvq, &msg, &out, &in, &len, + &busyloop_intr); + /* On error, stop handling until the next kick. */ + if (unlikely(head < 0)) + break; + /* Nothing new? Wait for eventfd to tell us they refilled. */ + if (head == vq->num) { + if (unlikely(busyloop_intr)) { + vhost_poll_queue(&vq->poll); + } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { + vhost_disable_notify(&net->dev, vq); + continue; + } + break; + } + + zcopy_used = len >= VHOST_GOODCOPY_LEN + && !vhost_exceeds_maxpend(net) + && vhost_net_tx_select_zcopy(net); + + /* use msg_control to pass vhost zerocopy ubuf info to skb */ + if (zcopy_used) { + ubuf = nvq->ubuf_info + nvq->upend_idx; + vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, head); + vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS; + ubuf->ctx = nvq->ubufs; + ubuf->desc = nvq->upend_idx; + ubuf->ubuf.callback = vhost_zerocopy_callback; + ubuf->ubuf.flags = SKBFL_ZEROCOPY_FRAG; + refcount_set(&ubuf->ubuf.refcnt, 1); + msg.msg_control = &ctl; + ctl.type = TUN_MSG_UBUF; + ctl.ptr = &ubuf->ubuf; + msg.msg_controllen = sizeof(ctl); + ubufs = nvq->ubufs; + atomic_inc(&ubufs->refcount); + nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV; + } else { + msg.msg_control = NULL; + ubufs = NULL; + } + total_len += len; + if (tx_can_batch(vq, total_len) && + likely(!vhost_exceeds_maxpend(net))) { + msg.msg_flags |= MSG_MORE; + } else { + msg.msg_flags &= ~MSG_MORE; + } + + err = sock->ops->sendmsg(sock, &msg, len); + if (unlikely(err < 0)) { + bool retry = err == -EAGAIN || err == -ENOMEM || err == -ENOBUFS; + + if (zcopy_used) { + if (vq->heads[ubuf->desc].len == VHOST_DMA_IN_PROGRESS) + vhost_net_ubuf_put(ubufs); + if (retry) + nvq->upend_idx = ((unsigned)nvq->upend_idx - 1) + % UIO_MAXIOV; + else + vq->heads[ubuf->desc].len = VHOST_DMA_DONE_LEN; + } + if (retry) { + vhost_discard_vq_desc(vq, 1); + vhost_net_enable_vq(net, vq); + break; + } + pr_debug("Fail to send packet: err %d", err); + } else if (unlikely(err != len)) + pr_debug("Truncated TX packet: " + " len %d != %zd\n", err, len); + if (!zcopy_used) + vhost_add_used_and_signal(&net->dev, vq, head, 0); + else + vhost_zerocopy_signal_used(net, vq); + vhost_net_tx_packet(net); + } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len))); +} + +/* Expects to be always run from workqueue - which acts as + * read-size critical section for our kind of RCU. */ +static void handle_tx(struct vhost_net *net) +{ + struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; + struct vhost_virtqueue *vq = &nvq->vq; + struct socket *sock; + + mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_TX); + sock = vhost_vq_get_backend(vq); + if (!sock) + goto out; + + if (!vq_meta_prefetch(vq)) + goto out; + + vhost_disable_notify(&net->dev, vq); + vhost_net_disable_vq(net, vq); + + if (vhost_sock_zcopy(sock)) + handle_tx_zerocopy(net, sock); + else + handle_tx_copy(net, sock); + +out: + mutex_unlock(&vq->mutex); +} + +static int peek_head_len(struct vhost_net_virtqueue *rvq, struct sock *sk) +{ + struct sk_buff *head; + int len = 0; + unsigned long flags; + + if (rvq->rx_ring) + return vhost_net_buf_peek(rvq); + + spin_lock_irqsave(&sk->sk_receive_queue.lock, flags); + head = skb_peek(&sk->sk_receive_queue); + if (likely(head)) { + len = head->len; + if (skb_vlan_tag_present(head)) + len += VLAN_HLEN; + } + + spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags); + return len; +} + +static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk, + bool *busyloop_intr) +{ + struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX]; + struct vhost_net_virtqueue *tnvq = &net->vqs[VHOST_NET_VQ_TX]; + struct vhost_virtqueue *rvq = &rnvq->vq; + struct vhost_virtqueue *tvq = &tnvq->vq; + int len = peek_head_len(rnvq, sk); + + if (!len && rvq->busyloop_timeout) { + /* Flush batched heads first */ + vhost_net_signal_used(rnvq); + /* Both tx vq and rx socket were polled here */ + vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, true); + + len = peek_head_len(rnvq, sk); + } + + return len; +} + +/* This is a multi-buffer version of vhost_get_desc, that works if + * vq has read descriptors only. + * @vq - the relevant virtqueue + * @datalen - data length we'll be reading + * @iovcount - returned count of io vectors we fill + * @log - vhost log + * @log_num - log offset + * @quota - headcount quota, 1 for big buffer + * returns number of buffer heads allocated, negative on error + */ +static int get_rx_bufs(struct vhost_virtqueue *vq, + struct vring_used_elem *heads, + int datalen, + unsigned *iovcount, + struct vhost_log *log, + unsigned *log_num, + unsigned int quota) +{ + unsigned int out, in; + int seg = 0; + int headcount = 0; + unsigned d; + int r, nlogs = 0; + /* len is always initialized before use since we are always called with + * datalen > 0. + */ + u32 len; + + while (datalen > 0 && headcount < quota) { + if (unlikely(seg >= UIO_MAXIOV)) { + r = -ENOBUFS; + goto err; + } + r = vhost_get_vq_desc(vq, vq->iov + seg, + ARRAY_SIZE(vq->iov) - seg, &out, + &in, log, log_num); + if (unlikely(r < 0)) + goto err; + + d = r; + if (d == vq->num) { + r = 0; + goto err; + } + if (unlikely(out || in <= 0)) { + vq_err(vq, "unexpected descriptor format for RX: " + "out %d, in %d\n", out, in); + r = -EINVAL; + goto err; + } + if (unlikely(log)) { + nlogs += *log_num; + log += *log_num; + } + heads[headcount].id = cpu_to_vhost32(vq, d); + len = iov_length(vq->iov + seg, in); + heads[headcount].len = cpu_to_vhost32(vq, len); + datalen -= len; + ++headcount; + seg += in; + } + heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen); + *iovcount = seg; + if (unlikely(log)) + *log_num = nlogs; + + /* Detect overrun */ + if (unlikely(datalen > 0)) { + r = UIO_MAXIOV + 1; + goto err; + } + return headcount; +err: + vhost_discard_vq_desc(vq, headcount); + return r; +} + +/* Expects to be always run from workqueue - which acts as + * read-size critical section for our kind of RCU. */ +static void handle_rx(struct vhost_net *net) +{ + struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_RX]; + struct vhost_virtqueue *vq = &nvq->vq; + unsigned in, log; + struct vhost_log *vq_log; + struct msghdr msg = { + .msg_name = NULL, + .msg_namelen = 0, + .msg_control = NULL, /* FIXME: get and handle RX aux data. */ + .msg_controllen = 0, + .msg_flags = MSG_DONTWAIT, + }; + struct virtio_net_hdr hdr = { + .flags = 0, + .gso_type = VIRTIO_NET_HDR_GSO_NONE + }; + size_t total_len = 0; + int err, mergeable; + s16 headcount; + size_t vhost_hlen, sock_hlen; + size_t vhost_len, sock_len; + bool busyloop_intr = false; + struct socket *sock; + struct iov_iter fixup; + __virtio16 num_buffers; + int recv_pkts = 0; + + mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_RX); + sock = vhost_vq_get_backend(vq); + if (!sock) + goto out; + + if (!vq_meta_prefetch(vq)) + goto out; + + vhost_disable_notify(&net->dev, vq); + vhost_net_disable_vq(net, vq); + + vhost_hlen = nvq->vhost_hlen; + sock_hlen = nvq->sock_hlen; + + vq_log = unlikely(vhost_has_feature(vq, VHOST_F_LOG_ALL)) ? + vq->log : NULL; + mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF); + + do { + sock_len = vhost_net_rx_peek_head_len(net, sock->sk, + &busyloop_intr); + if (!sock_len) + break; + sock_len += sock_hlen; + vhost_len = sock_len + vhost_hlen; + headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx, + vhost_len, &in, vq_log, &log, + likely(mergeable) ? UIO_MAXIOV : 1); + /* On error, stop handling until the next kick. */ + if (unlikely(headcount < 0)) + goto out; + /* OK, now we need to know about added descriptors. */ + if (!headcount) { + if (unlikely(busyloop_intr)) { + vhost_poll_queue(&vq->poll); + } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { + /* They have slipped one in as we were + * doing that: check again. */ + vhost_disable_notify(&net->dev, vq); + continue; + } + /* Nothing new? Wait for eventfd to tell us + * they refilled. */ + goto out; + } + busyloop_intr = false; + if (nvq->rx_ring) + msg.msg_control = vhost_net_buf_consume(&nvq->rxq); + /* On overrun, truncate and discard */ + if (unlikely(headcount > UIO_MAXIOV)) { + iov_iter_init(&msg.msg_iter, ITER_DEST, vq->iov, 1, 1); + err = sock->ops->recvmsg(sock, &msg, + 1, MSG_DONTWAIT | MSG_TRUNC); + pr_debug("Discarded rx packet: len %zd\n", sock_len); + continue; + } + /* We don't need to be notified again. */ + iov_iter_init(&msg.msg_iter, ITER_DEST, vq->iov, in, vhost_len); + fixup = msg.msg_iter; + if (unlikely((vhost_hlen))) { + /* We will supply the header ourselves + * TODO: support TSO. + */ + iov_iter_advance(&msg.msg_iter, vhost_hlen); + } + err = sock->ops->recvmsg(sock, &msg, + sock_len, MSG_DONTWAIT | MSG_TRUNC); + /* Userspace might have consumed the packet meanwhile: + * it's not supposed to do this usually, but might be hard + * to prevent. Discard data we got (if any) and keep going. */ + if (unlikely(err != sock_len)) { + pr_debug("Discarded rx packet: " + " len %d, expected %zd\n", err, sock_len); + vhost_discard_vq_desc(vq, headcount); + continue; + } + /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */ + if (unlikely(vhost_hlen)) { + if (copy_to_iter(&hdr, sizeof(hdr), + &fixup) != sizeof(hdr)) { + vq_err(vq, "Unable to write vnet_hdr " + "at addr %p\n", vq->iov->iov_base); + goto out; + } + } else { + /* Header came from socket; we'll need to patch + * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF + */ + iov_iter_advance(&fixup, sizeof(hdr)); + } + /* TODO: Should check and handle checksum. */ + + num_buffers = cpu_to_vhost16(vq, headcount); + if (likely(mergeable) && + copy_to_iter(&num_buffers, sizeof num_buffers, + &fixup) != sizeof num_buffers) { + vq_err(vq, "Failed num_buffers write"); + vhost_discard_vq_desc(vq, headcount); + goto out; + } + nvq->done_idx += headcount; + if (nvq->done_idx > VHOST_NET_BATCH) + vhost_net_signal_used(nvq); + if (unlikely(vq_log)) + vhost_log_write(vq, vq_log, log, vhost_len, + vq->iov, in); + total_len += vhost_len; + } while (likely(!vhost_exceeds_weight(vq, ++recv_pkts, total_len))); + + if (unlikely(busyloop_intr)) + vhost_poll_queue(&vq->poll); + else if (!sock_len) + vhost_net_enable_vq(net, vq); +out: + vhost_net_signal_used(nvq); + mutex_unlock(&vq->mutex); +} + +static void handle_tx_kick(struct vhost_work *work) +{ + struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, + poll.work); + struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); + + handle_tx(net); +} + +static void handle_rx_kick(struct vhost_work *work) +{ + struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, + poll.work); + struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); + + handle_rx(net); +} + +static void handle_tx_net(struct vhost_work *work) +{ + struct vhost_net *net = container_of(work, struct vhost_net, + poll[VHOST_NET_VQ_TX].work); + handle_tx(net); +} + +static void handle_rx_net(struct vhost_work *work) +{ + struct vhost_net *net = container_of(work, struct vhost_net, + poll[VHOST_NET_VQ_RX].work); + handle_rx(net); +} + +static int vhost_net_open(struct inode *inode, struct file *f) +{ + struct vhost_net *n; + struct vhost_dev *dev; + struct vhost_virtqueue **vqs; + void **queue; + struct xdp_buff *xdp; + int i; + + n = kvmalloc(sizeof *n, GFP_KERNEL | __GFP_RETRY_MAYFAIL); + if (!n) + return -ENOMEM; + vqs = kmalloc_array(VHOST_NET_VQ_MAX, sizeof(*vqs), GFP_KERNEL); + if (!vqs) { + kvfree(n); + return -ENOMEM; + } + + queue = kmalloc_array(VHOST_NET_BATCH, sizeof(void *), + GFP_KERNEL); + if (!queue) { + kfree(vqs); + kvfree(n); + return -ENOMEM; + } + n->vqs[VHOST_NET_VQ_RX].rxq.queue = queue; + + xdp = kmalloc_array(VHOST_NET_BATCH, sizeof(*xdp), GFP_KERNEL); + if (!xdp) { + kfree(vqs); + kvfree(n); + kfree(queue); + return -ENOMEM; + } + n->vqs[VHOST_NET_VQ_TX].xdp = xdp; + + dev = &n->dev; + vqs[VHOST_NET_VQ_TX] = &n->vqs[VHOST_NET_VQ_TX].vq; + vqs[VHOST_NET_VQ_RX] = &n->vqs[VHOST_NET_VQ_RX].vq; + n->vqs[VHOST_NET_VQ_TX].vq.handle_kick = handle_tx_kick; + n->vqs[VHOST_NET_VQ_RX].vq.handle_kick = handle_rx_kick; + for (i = 0; i < VHOST_NET_VQ_MAX; i++) { + n->vqs[i].ubufs = NULL; + n->vqs[i].ubuf_info = NULL; + n->vqs[i].upend_idx = 0; + n->vqs[i].done_idx = 0; + n->vqs[i].batched_xdp = 0; + n->vqs[i].vhost_hlen = 0; + n->vqs[i].sock_hlen = 0; + n->vqs[i].rx_ring = NULL; + vhost_net_buf_init(&n->vqs[i].rxq); + } + vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX, + UIO_MAXIOV + VHOST_NET_BATCH, + VHOST_NET_PKT_WEIGHT, VHOST_NET_WEIGHT, true, + NULL); + + vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, EPOLLOUT, dev, + vqs[VHOST_NET_VQ_TX]); + vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, EPOLLIN, dev, + vqs[VHOST_NET_VQ_RX]); + + f->private_data = n; + n->page_frag.page = NULL; + n->refcnt_bias = 0; + + return 0; +} + +static struct socket *vhost_net_stop_vq(struct vhost_net *n, + struct vhost_virtqueue *vq) +{ + struct socket *sock; + struct vhost_net_virtqueue *nvq = + container_of(vq, struct vhost_net_virtqueue, vq); + + mutex_lock(&vq->mutex); + sock = vhost_vq_get_backend(vq); + vhost_net_disable_vq(n, vq); + vhost_vq_set_backend(vq, NULL); + vhost_net_buf_unproduce(nvq); + nvq->rx_ring = NULL; + mutex_unlock(&vq->mutex); + return sock; +} + +static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock, + struct socket **rx_sock) +{ + *tx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_TX].vq); + *rx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_RX].vq); +} + +static void vhost_net_flush(struct vhost_net *n) +{ + vhost_dev_flush(&n->dev); + if (n->vqs[VHOST_NET_VQ_TX].ubufs) { + mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); + n->tx_flush = true; + mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); + /* Wait for all lower device DMAs done. */ + vhost_net_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs); + mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); + n->tx_flush = false; + atomic_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1); + mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); + } +} + +static int vhost_net_release(struct inode *inode, struct file *f) +{ + struct vhost_net *n = f->private_data; + struct socket *tx_sock; + struct socket *rx_sock; + + vhost_net_stop(n, &tx_sock, &rx_sock); + vhost_net_flush(n); + vhost_dev_stop(&n->dev); + vhost_dev_cleanup(&n->dev); + vhost_net_vq_reset(n); + if (tx_sock) + sockfd_put(tx_sock); + if (rx_sock) + sockfd_put(rx_sock); + /* Make sure no callbacks are outstanding */ + synchronize_rcu(); + /* We do an extra flush before freeing memory, + * since jobs can re-queue themselves. */ + vhost_net_flush(n); + kfree(n->vqs[VHOST_NET_VQ_RX].rxq.queue); + kfree(n->vqs[VHOST_NET_VQ_TX].xdp); + kfree(n->dev.vqs); + if (n->page_frag.page) + __page_frag_cache_drain(n->page_frag.page, n->refcnt_bias); + kvfree(n); + return 0; +} + +static struct socket *get_raw_socket(int fd) +{ + int r; + struct socket *sock = sockfd_lookup(fd, &r); + + if (!sock) + return ERR_PTR(-ENOTSOCK); + + /* Parameter checking */ + if (sock->sk->sk_type != SOCK_RAW) { + r = -ESOCKTNOSUPPORT; + goto err; + } + + if (sock->sk->sk_family != AF_PACKET) { + r = -EPFNOSUPPORT; + goto err; + } + return sock; +err: + sockfd_put(sock); + return ERR_PTR(r); +} + +static struct ptr_ring *get_tap_ptr_ring(struct file *file) +{ + struct ptr_ring *ring; + ring = tun_get_tx_ring(file); + if (!IS_ERR(ring)) + goto out; + ring = tap_get_ptr_ring(file); + if (!IS_ERR(ring)) + goto out; + ring = NULL; +out: + return ring; +} + +static struct socket *get_tap_socket(int fd) +{ + struct file *file = fget(fd); + struct socket *sock; + + if (!file) + return ERR_PTR(-EBADF); + sock = tun_get_socket(file); + if (!IS_ERR(sock)) + return sock; + sock = tap_get_socket(file); + if (IS_ERR(sock)) + fput(file); + return sock; +} + +static struct socket *get_socket(int fd) +{ + struct socket *sock; + + /* special case to disable backend */ + if (fd == -1) + return NULL; + sock = get_raw_socket(fd); + if (!IS_ERR(sock)) + return sock; + sock = get_tap_socket(fd); + if (!IS_ERR(sock)) + return sock; + return ERR_PTR(-ENOTSOCK); +} + +static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) +{ + struct socket *sock, *oldsock; + struct vhost_virtqueue *vq; + struct vhost_net_virtqueue *nvq; + struct vhost_net_ubuf_ref *ubufs, *oldubufs = NULL; + int r; + + mutex_lock(&n->dev.mutex); + r = vhost_dev_check_owner(&n->dev); + if (r) + goto err; + + if (index >= VHOST_NET_VQ_MAX) { + r = -ENOBUFS; + goto err; + } + vq = &n->vqs[index].vq; + nvq = &n->vqs[index]; + mutex_lock(&vq->mutex); + + if (fd == -1) + vhost_clear_msg(&n->dev); + + /* Verify that ring has been setup correctly. */ + if (!vhost_vq_access_ok(vq)) { + r = -EFAULT; + goto err_vq; + } + sock = get_socket(fd); + if (IS_ERR(sock)) { + r = PTR_ERR(sock); + goto err_vq; + } + + /* start polling new socket */ + oldsock = vhost_vq_get_backend(vq); + if (sock != oldsock) { + ubufs = vhost_net_ubuf_alloc(vq, + sock && vhost_sock_zcopy(sock)); + if (IS_ERR(ubufs)) { + r = PTR_ERR(ubufs); + goto err_ubufs; + } + + vhost_net_disable_vq(n, vq); + vhost_vq_set_backend(vq, sock); + vhost_net_buf_unproduce(nvq); + r = vhost_vq_init_access(vq); + if (r) + goto err_used; + r = vhost_net_enable_vq(n, vq); + if (r) + goto err_used; + if (index == VHOST_NET_VQ_RX) { + if (sock) + nvq->rx_ring = get_tap_ptr_ring(sock->file); + else + nvq->rx_ring = NULL; + } + + oldubufs = nvq->ubufs; + nvq->ubufs = ubufs; + + n->tx_packets = 0; + n->tx_zcopy_err = 0; + n->tx_flush = false; + } + + mutex_unlock(&vq->mutex); + + if (oldubufs) { + vhost_net_ubuf_put_wait_and_free(oldubufs); + mutex_lock(&vq->mutex); + vhost_zerocopy_signal_used(n, vq); + mutex_unlock(&vq->mutex); + } + + if (oldsock) { + vhost_dev_flush(&n->dev); + sockfd_put(oldsock); + } + + mutex_unlock(&n->dev.mutex); + return 0; + +err_used: + vhost_vq_set_backend(vq, oldsock); + vhost_net_enable_vq(n, vq); + if (ubufs) + vhost_net_ubuf_put_wait_and_free(ubufs); +err_ubufs: + if (sock) + sockfd_put(sock); +err_vq: + mutex_unlock(&vq->mutex); +err: + mutex_unlock(&n->dev.mutex); + return r; +} + +static long vhost_net_reset_owner(struct vhost_net *n) +{ + struct socket *tx_sock = NULL; + struct socket *rx_sock = NULL; + long err; + struct vhost_iotlb *umem; + + mutex_lock(&n->dev.mutex); + err = vhost_dev_check_owner(&n->dev); + if (err) + goto done; + umem = vhost_dev_reset_owner_prepare(); + if (!umem) { + err = -ENOMEM; + goto done; + } + vhost_net_stop(n, &tx_sock, &rx_sock); + vhost_net_flush(n); + vhost_dev_stop(&n->dev); + vhost_dev_reset_owner(&n->dev, umem); + vhost_net_vq_reset(n); +done: + mutex_unlock(&n->dev.mutex); + if (tx_sock) + sockfd_put(tx_sock); + if (rx_sock) + sockfd_put(rx_sock); + return err; +} + +static int vhost_net_set_features(struct vhost_net *n, u64 features) +{ + size_t vhost_hlen, sock_hlen, hdr_len; + int i; + + hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) | + (1ULL << VIRTIO_F_VERSION_1))) ? + sizeof(struct virtio_net_hdr_mrg_rxbuf) : + sizeof(struct virtio_net_hdr); + if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) { + /* vhost provides vnet_hdr */ + vhost_hlen = hdr_len; + sock_hlen = 0; + } else { + /* socket provides vnet_hdr */ + vhost_hlen = 0; + sock_hlen = hdr_len; + } + mutex_lock(&n->dev.mutex); + if ((features & (1 << VHOST_F_LOG_ALL)) && + !vhost_log_access_ok(&n->dev)) + goto out_unlock; + + if ((features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) { + if (vhost_init_device_iotlb(&n->dev)) + goto out_unlock; + } + + for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { + mutex_lock(&n->vqs[i].vq.mutex); + n->vqs[i].vq.acked_features = features; + n->vqs[i].vhost_hlen = vhost_hlen; + n->vqs[i].sock_hlen = sock_hlen; + mutex_unlock(&n->vqs[i].vq.mutex); + } + mutex_unlock(&n->dev.mutex); + return 0; + +out_unlock: + mutex_unlock(&n->dev.mutex); + return -EFAULT; +} + +static long vhost_net_set_owner(struct vhost_net *n) +{ + int r; + + mutex_lock(&n->dev.mutex); + if (vhost_dev_has_owner(&n->dev)) { + r = -EBUSY; + goto out; + } + r = vhost_net_set_ubuf_info(n); + if (r) + goto out; + r = vhost_dev_set_owner(&n->dev); + if (r) + vhost_net_clear_ubuf_info(n); + vhost_net_flush(n); +out: + mutex_unlock(&n->dev.mutex); + return r; +} + +static long vhost_net_ioctl(struct file *f, unsigned int ioctl, + unsigned long arg) +{ + struct vhost_net *n = f->private_data; + void __user *argp = (void __user *)arg; + u64 __user *featurep = argp; + struct vhost_vring_file backend; + u64 features; + int r; + + switch (ioctl) { + case VHOST_NET_SET_BACKEND: + if (copy_from_user(&backend, argp, sizeof backend)) + return -EFAULT; + return vhost_net_set_backend(n, backend.index, backend.fd); + case VHOST_GET_FEATURES: + features = VHOST_NET_FEATURES; + if (copy_to_user(featurep, &features, sizeof features)) + return -EFAULT; + return 0; + case VHOST_SET_FEATURES: + if (copy_from_user(&features, featurep, sizeof features)) + return -EFAULT; + 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; + vhost_set_backend_features(&n->dev, features); + return 0; + case VHOST_RESET_OWNER: + return vhost_net_reset_owner(n); + case VHOST_SET_OWNER: + return vhost_net_set_owner(n); + default: + mutex_lock(&n->dev.mutex); + r = vhost_dev_ioctl(&n->dev, ioctl, argp); + if (r == -ENOIOCTLCMD) + r = vhost_vring_ioctl(&n->dev, ioctl, argp); + else + vhost_net_flush(n); + mutex_unlock(&n->dev.mutex); + return r; + } +} + +static ssize_t vhost_net_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) +{ + struct file *file = iocb->ki_filp; + struct vhost_net *n = file->private_data; + struct vhost_dev *dev = &n->dev; + int noblock = file->f_flags & O_NONBLOCK; + + return vhost_chr_read_iter(dev, to, noblock); +} + +static ssize_t vhost_net_chr_write_iter(struct kiocb *iocb, + struct iov_iter *from) +{ + struct file *file = iocb->ki_filp; + struct vhost_net *n = file->private_data; + struct vhost_dev *dev = &n->dev; + + return vhost_chr_write_iter(dev, from); +} + +static __poll_t vhost_net_chr_poll(struct file *file, poll_table *wait) +{ + struct vhost_net *n = file->private_data; + struct vhost_dev *dev = &n->dev; + + return vhost_chr_poll(file, dev, wait); +} + +static const struct file_operations vhost_net_fops = { + .owner = THIS_MODULE, + .release = vhost_net_release, + .read_iter = vhost_net_chr_read_iter, + .write_iter = vhost_net_chr_write_iter, + .poll = vhost_net_chr_poll, + .unlocked_ioctl = vhost_net_ioctl, + .compat_ioctl = compat_ptr_ioctl, + .open = vhost_net_open, + .llseek = noop_llseek, +}; + +static struct miscdevice vhost_net_misc = { + .minor = VHOST_NET_MINOR, + .name = "vhost-net", + .fops = &vhost_net_fops, +}; + +static int __init vhost_net_init(void) +{ + if (experimental_zcopytx) + vhost_net_enable_zcopy(VHOST_NET_VQ_TX); + return misc_register(&vhost_net_misc); +} +module_init(vhost_net_init); + +static void __exit vhost_net_exit(void) +{ + misc_deregister(&vhost_net_misc); +} +module_exit(vhost_net_exit); + +MODULE_VERSION("0.0.1"); +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Michael S. Tsirkin"); +MODULE_DESCRIPTION("Host kernel accelerator for virtio net"); +MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR); +MODULE_ALIAS("devname:vhost-net"); -- cgit v1.2.3