diff options
Diffstat (limited to 'drivers/net/xen-netback/rx.c')
| -rw-r--r-- | drivers/net/xen-netback/rx.c | 789 |
1 files changed, 789 insertions, 0 deletions
diff --git a/drivers/net/xen-netback/rx.c b/drivers/net/xen-netback/rx.c new file mode 100644 index 0000000000000..03836aaac1c2e --- /dev/null +++ b/drivers/net/xen-netback/rx.c @@ -0,0 +1,789 @@ +/* + * Copyright (c) 2016 Citrix Systems Inc. + * Copyright (c) 2002-2005, K A Fraser + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation; or, when distributed + * separately from the Linux kernel or incorporated into other + * software packages, subject to the following license: + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this source file (the "Software"), to deal in the Software without + * restriction, including without limitation the rights to use, copy, modify, + * merge, publish, distribute, sublicense, and/or sell copies of the Software, + * and to permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS + * IN THE SOFTWARE. + */ + +#include "common.h" + +#include <linux/kthread.h> + +#include <xen/xen.h> +#include <xen/events.h> + +static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue) +{ + RING_IDX prod, cons; + struct sk_buff *skb; + int needed; + + skb = skb_peek(&queue->rx_queue); + if (!skb) + return false; + + needed = DIV_ROUND_UP(skb->len, XEN_PAGE_SIZE); + if (skb_is_gso(skb)) + needed++; + if (skb->sw_hash) + needed++; + + do { + prod = queue->rx.sring->req_prod; + cons = queue->rx.req_cons; + + if (prod - cons >= needed) + return true; + + queue->rx.sring->req_event = prod + 1; + + /* Make sure event is visible before we check prod + * again. + */ + mb(); + } while (queue->rx.sring->req_prod != prod); + + return false; +} + +void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb) +{ + unsigned long flags; + + spin_lock_irqsave(&queue->rx_queue.lock, flags); + + __skb_queue_tail(&queue->rx_queue, skb); + + queue->rx_queue_len += skb->len; + if (queue->rx_queue_len > queue->rx_queue_max) { + struct net_device *dev = queue->vif->dev; + + netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id)); + } + + spin_unlock_irqrestore(&queue->rx_queue.lock, flags); +} + +static struct sk_buff *xenvif_rx_dequeue(struct xenvif_queue *queue) +{ + struct sk_buff *skb; + + spin_lock_irq(&queue->rx_queue.lock); + + skb = __skb_dequeue(&queue->rx_queue); + if (skb) + queue->rx_queue_len -= skb->len; + + spin_unlock_irq(&queue->rx_queue.lock); + + return skb; +} + +static void xenvif_rx_queue_maybe_wake(struct xenvif_queue *queue) +{ + spin_lock_irq(&queue->rx_queue.lock); + + if (queue->rx_queue_len < queue->rx_queue_max) { + struct net_device *dev = queue->vif->dev; + + netif_tx_wake_queue(netdev_get_tx_queue(dev, queue->id)); + } + + spin_unlock_irq(&queue->rx_queue.lock); +} + +static void xenvif_rx_queue_purge(struct xenvif_queue *queue) +{ + struct sk_buff *skb; + + while ((skb = xenvif_rx_dequeue(queue)) != NULL) + kfree_skb(skb); +} + +static void xenvif_rx_queue_drop_expired(struct xenvif_queue *queue) +{ + struct sk_buff *skb; + + for (;;) { + skb = skb_peek(&queue->rx_queue); + if (!skb) + break; + if (time_before(jiffies, XENVIF_RX_CB(skb)->expires)) + break; + xenvif_rx_dequeue(queue); + kfree_skb(skb); + } +} + +struct netrx_pending_operations { + unsigned int copy_prod, copy_cons; + unsigned int meta_prod, meta_cons; + struct gnttab_copy *copy; + struct xenvif_rx_meta *meta; + int copy_off; + grant_ref_t copy_gref; +}; + +static struct xenvif_rx_meta *get_next_rx_buffer( + struct xenvif_queue *queue, + struct netrx_pending_operations *npo) +{ + struct xenvif_rx_meta *meta; + struct xen_netif_rx_request req; + + RING_COPY_REQUEST(&queue->rx, queue->rx.req_cons++, &req); + + meta = npo->meta + npo->meta_prod++; + meta->gso_type = XEN_NETIF_GSO_TYPE_NONE; + meta->gso_size = 0; + meta->size = 0; + meta->id = req.id; + + npo->copy_off = 0; + npo->copy_gref = req.gref; + + return meta; +} + +struct gop_frag_copy { + struct xenvif_queue *queue; + struct netrx_pending_operations *npo; + struct xenvif_rx_meta *meta; + int head; + int gso_type; + int protocol; + int hash_present; + + struct page *page; +}; + +static void xenvif_setup_copy_gop(unsigned long gfn, + unsigned int offset, + unsigned int *len, + struct gop_frag_copy *info) +{ + struct gnttab_copy *copy_gop; + struct xen_page_foreign *foreign; + /* Convenient aliases */ + struct xenvif_queue *queue = info->queue; + struct netrx_pending_operations *npo = info->npo; + struct page *page = info->page; + + WARN_ON(npo->copy_off > MAX_BUFFER_OFFSET); + + if (npo->copy_off == MAX_BUFFER_OFFSET) + info->meta = get_next_rx_buffer(queue, npo); + + if (npo->copy_off + *len > MAX_BUFFER_OFFSET) + *len = MAX_BUFFER_OFFSET - npo->copy_off; + + copy_gop = npo->copy + npo->copy_prod++; + copy_gop->flags = GNTCOPY_dest_gref; + copy_gop->len = *len; + + foreign = xen_page_foreign(page); + if (foreign) { + copy_gop->source.domid = foreign->domid; + copy_gop->source.u.ref = foreign->gref; + copy_gop->flags |= GNTCOPY_source_gref; + } else { + copy_gop->source.domid = DOMID_SELF; + copy_gop->source.u.gmfn = gfn; + } + copy_gop->source.offset = offset; + + copy_gop->dest.domid = queue->vif->domid; + copy_gop->dest.offset = npo->copy_off; + copy_gop->dest.u.ref = npo->copy_gref; + + npo->copy_off += *len; + info->meta->size += *len; + + if (!info->head) + return; + + /* Leave a gap for the GSO descriptor. */ + if ((1 << info->gso_type) & queue->vif->gso_mask) + queue->rx.req_cons++; + + /* Leave a gap for the hash extra segment. */ + if (info->hash_present) + queue->rx.req_cons++; + + info->head = 0; /* There must be something in this buffer now */ +} + +static void xenvif_gop_frag_copy_grant(unsigned long gfn, + unsigned int offset, + unsigned int len, + void *data) +{ + unsigned int bytes; + + while (len) { + bytes = len; + xenvif_setup_copy_gop(gfn, offset, &bytes, data); + offset += bytes; + len -= bytes; + } +} + +/* Set up the grant operations for this fragment. If it's a flipping + * interface, we also set up the unmap request from here. + */ +static void xenvif_gop_frag_copy(struct xenvif_queue *queue, + struct sk_buff *skb, + struct netrx_pending_operations *npo, + struct page *page, unsigned long size, + unsigned long offset, int *head) +{ + struct gop_frag_copy info = { + .queue = queue, + .npo = npo, + .head = *head, + .gso_type = XEN_NETIF_GSO_TYPE_NONE, + /* xenvif_set_skb_hash() will have either set a s/w + * hash or cleared the hash depending on + * whether the the frontend wants a hash for this skb. + */ + .hash_present = skb->sw_hash, + }; + unsigned long bytes; + + if (skb_is_gso(skb)) { + if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) + info.gso_type = XEN_NETIF_GSO_TYPE_TCPV4; + else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) + info.gso_type = XEN_NETIF_GSO_TYPE_TCPV6; + } + + /* Data must not cross a page boundary. */ + WARN_ON(size + offset > (PAGE_SIZE << compound_order(page))); + + info.meta = npo->meta + npo->meta_prod - 1; + + /* Skip unused frames from start of page */ + page += offset >> PAGE_SHIFT; + offset &= ~PAGE_MASK; + + while (size > 0) { + WARN_ON(offset >= PAGE_SIZE); + + bytes = PAGE_SIZE - offset; + if (bytes > size) + bytes = size; + + info.page = page; + gnttab_foreach_grant_in_range(page, offset, bytes, + xenvif_gop_frag_copy_grant, + &info); + size -= bytes; + offset = 0; + + /* Next page */ + if (size) { + WARN_ON(!PageCompound(page)); + page++; + } + } + + *head = info.head; +} + +/* Prepare an SKB to be transmitted to the frontend. + * + * This function is responsible for allocating grant operations, meta + * structures, etc. + * + * It returns the number of meta structures consumed. The number of + * ring slots used is always equal to the number of meta slots used + * plus the number of GSO descriptors used. Currently, we use either + * zero GSO descriptors (for non-GSO packets) or one descriptor (for + * frontend-side LRO). + */ +static int xenvif_gop_skb(struct sk_buff *skb, + struct netrx_pending_operations *npo, + struct xenvif_queue *queue) +{ + struct xenvif *vif = netdev_priv(skb->dev); + int nr_frags = skb_shinfo(skb)->nr_frags; + int i; + struct xen_netif_rx_request req; + struct xenvif_rx_meta *meta; + unsigned char *data; + int head = 1; + int old_meta_prod; + int gso_type; + + old_meta_prod = npo->meta_prod; + + gso_type = XEN_NETIF_GSO_TYPE_NONE; + if (skb_is_gso(skb)) { + if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) + gso_type = XEN_NETIF_GSO_TYPE_TCPV4; + else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) + gso_type = XEN_NETIF_GSO_TYPE_TCPV6; + } + + /* Set up a GSO prefix descriptor, if necessary */ + if ((1 << gso_type) & vif->gso_prefix_mask) { + RING_COPY_REQUEST(&queue->rx, queue->rx.req_cons++, &req); + meta = npo->meta + npo->meta_prod++; + meta->gso_type = gso_type; + meta->gso_size = skb_shinfo(skb)->gso_size; + meta->size = 0; + meta->id = req.id; + } + + RING_COPY_REQUEST(&queue->rx, queue->rx.req_cons++, &req); + meta = npo->meta + npo->meta_prod++; + + if ((1 << gso_type) & vif->gso_mask) { + meta->gso_type = gso_type; + meta->gso_size = skb_shinfo(skb)->gso_size; + } else { + meta->gso_type = XEN_NETIF_GSO_TYPE_NONE; + meta->gso_size = 0; + } + + meta->size = 0; + meta->id = req.id; + npo->copy_off = 0; + npo->copy_gref = req.gref; + + data = skb->data; + while (data < skb_tail_pointer(skb)) { + unsigned int offset = offset_in_page(data); + unsigned int len = PAGE_SIZE - offset; + + if (data + len > skb_tail_pointer(skb)) + len = skb_tail_pointer(skb) - data; + + xenvif_gop_frag_copy(queue, skb, npo, + virt_to_page(data), len, offset, &head); + data += len; + } + + for (i = 0; i < nr_frags; i++) { + xenvif_gop_frag_copy(queue, skb, npo, + skb_frag_page(&skb_shinfo(skb)->frags[i]), + skb_frag_size(&skb_shinfo(skb)->frags[i]), + skb_shinfo(skb)->frags[i].page_offset, + &head); + } + + return npo->meta_prod - old_meta_prod; +} + +/* This is a twin to xenvif_gop_skb. Assume that xenvif_gop_skb was + * used to set up the operations on the top of + * netrx_pending_operations, which have since been done. Check that + * they didn't give any errors and advance over them. + */ +static int xenvif_check_gop(struct xenvif *vif, int nr_meta_slots, + struct netrx_pending_operations *npo) +{ + struct gnttab_copy *copy_op; + int status = XEN_NETIF_RSP_OKAY; + int i; + + for (i = 0; i < nr_meta_slots; i++) { + copy_op = npo->copy + npo->copy_cons++; + if (copy_op->status != GNTST_okay) { + netdev_dbg(vif->dev, + "Bad status %d from copy to DOM%d.\n", + copy_op->status, vif->domid); + status = XEN_NETIF_RSP_ERROR; + } + } + + return status; +} + +static struct xen_netif_rx_response *make_rx_response( + struct xenvif_queue *queue, u16 id, s8 st, u16 offset, u16 size, + u16 flags) +{ + RING_IDX i = queue->rx.rsp_prod_pvt; + struct xen_netif_rx_response *resp; + + resp = RING_GET_RESPONSE(&queue->rx, i); + resp->offset = offset; + resp->flags = flags; + resp->id = id; + resp->status = (s16)size; + if (st < 0) + resp->status = (s16)st; + + queue->rx.rsp_prod_pvt = ++i; + + return resp; +} + +static void xenvif_add_frag_responses(struct xenvif_queue *queue, + int status, + struct xenvif_rx_meta *meta, + int nr_meta_slots) +{ + int i; + unsigned long offset; + + /* No fragments used */ + if (nr_meta_slots <= 1) + return; + + nr_meta_slots--; + + for (i = 0; i < nr_meta_slots; i++) { + int flags; + + if (i == nr_meta_slots - 1) + flags = 0; + else + flags = XEN_NETRXF_more_data; + + offset = 0; + make_rx_response(queue, meta[i].id, status, offset, + meta[i].size, flags); + } +} + +static void xenvif_rx_action(struct xenvif_queue *queue) +{ + struct xenvif *vif = queue->vif; + s8 status; + u16 flags; + struct xen_netif_rx_response *resp; + struct sk_buff_head rxq; + struct sk_buff *skb; + LIST_HEAD(notify); + int ret; + unsigned long offset; + bool need_to_notify = false; + + struct netrx_pending_operations npo = { + .copy = queue->grant_copy_op, + .meta = queue->meta, + }; + + skb_queue_head_init(&rxq); + + while (xenvif_rx_ring_slots_available(queue) && + (skb = xenvif_rx_dequeue(queue)) != NULL) { + queue->last_rx_time = jiffies; + + XENVIF_RX_CB(skb)->meta_slots_used = + xenvif_gop_skb(skb, &npo, queue); + + __skb_queue_tail(&rxq, skb); + } + + WARN_ON(npo.meta_prod > ARRAY_SIZE(queue->meta)); + + if (!npo.copy_prod) + goto done; + + WARN_ON(npo.copy_prod > MAX_GRANT_COPY_OPS); + gnttab_batch_copy(queue->grant_copy_op, npo.copy_prod); + + while ((skb = __skb_dequeue(&rxq)) != NULL) { + struct xen_netif_extra_info *extra = NULL; + + if ((1 << queue->meta[npo.meta_cons].gso_type) & + vif->gso_prefix_mask) { + resp = RING_GET_RESPONSE(&queue->rx, + queue->rx.rsp_prod_pvt++); + + resp->flags = XEN_NETRXF_gso_prefix | + XEN_NETRXF_more_data; + + resp->offset = queue->meta[npo.meta_cons].gso_size; + resp->id = queue->meta[npo.meta_cons].id; + resp->status = XENVIF_RX_CB(skb)->meta_slots_used; + + npo.meta_cons++; + XENVIF_RX_CB(skb)->meta_slots_used--; + } + + queue->stats.tx_bytes += skb->len; + queue->stats.tx_packets++; + + status = xenvif_check_gop(vif, + XENVIF_RX_CB(skb)->meta_slots_used, + &npo); + + if (XENVIF_RX_CB(skb)->meta_slots_used == 1) + flags = 0; + else + flags = XEN_NETRXF_more_data; + + if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */ + flags |= XEN_NETRXF_csum_blank | + XEN_NETRXF_data_validated; + else if (skb->ip_summed == CHECKSUM_UNNECESSARY) + /* remote but checksummed. */ + flags |= XEN_NETRXF_data_validated; + + offset = 0; + resp = make_rx_response(queue, queue->meta[npo.meta_cons].id, + status, offset, + queue->meta[npo.meta_cons].size, + flags); + + if ((1 << queue->meta[npo.meta_cons].gso_type) & + vif->gso_mask) { + extra = (struct xen_netif_extra_info *) + RING_GET_RESPONSE(&queue->rx, + queue->rx.rsp_prod_pvt++); + + resp->flags |= XEN_NETRXF_extra_info; + + extra->u.gso.type = queue->meta[npo.meta_cons].gso_type; + extra->u.gso.size = queue->meta[npo.meta_cons].gso_size; + extra->u.gso.pad = 0; + extra->u.gso.features = 0; + + extra->type = XEN_NETIF_EXTRA_TYPE_GSO; + extra->flags = 0; + } + + if (skb->sw_hash) { + /* Since the skb got here via xenvif_select_queue() + * we know that the hash has been re-calculated + * according to a configuration set by the frontend + * and therefore we know that it is legitimate to + * pass it to the frontend. + */ + if (resp->flags & XEN_NETRXF_extra_info) + extra->flags |= XEN_NETIF_EXTRA_FLAG_MORE; + else + resp->flags |= XEN_NETRXF_extra_info; + + extra = (struct xen_netif_extra_info *) + RING_GET_RESPONSE(&queue->rx, + queue->rx.rsp_prod_pvt++); + + extra->u.hash.algorithm = + XEN_NETIF_CTRL_HASH_ALGORITHM_TOEPLITZ; + + if (skb->l4_hash) + extra->u.hash.type = + skb->protocol == htons(ETH_P_IP) ? + _XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP : + _XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP; + else + extra->u.hash.type = + skb->protocol == htons(ETH_P_IP) ? + _XEN_NETIF_CTRL_HASH_TYPE_IPV4 : + _XEN_NETIF_CTRL_HASH_TYPE_IPV6; + + *(uint32_t *)extra->u.hash.value = + skb_get_hash_raw(skb); + + extra->type = XEN_NETIF_EXTRA_TYPE_HASH; + extra->flags = 0; + } + + xenvif_add_frag_responses(queue, status, + queue->meta + npo.meta_cons + 1, + XENVIF_RX_CB(skb)->meta_slots_used); + + RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->rx, ret); + + need_to_notify |= !!ret; + + npo.meta_cons += XENVIF_RX_CB(skb)->meta_slots_used; + dev_kfree_skb(skb); + } + +done: + if (need_to_notify) + notify_remote_via_irq(queue->rx_irq); +} + +static bool xenvif_rx_queue_stalled(struct xenvif_queue *queue) +{ + RING_IDX prod, cons; + + prod = queue->rx.sring->req_prod; + cons = queue->rx.req_cons; + + return !queue->stalled && + prod - cons < 1 && + time_after(jiffies, + queue->last_rx_time + queue->vif->stall_timeout); +} + +static bool xenvif_rx_queue_ready(struct xenvif_queue *queue) +{ + RING_IDX prod, cons; + + prod = queue->rx.sring->req_prod; + cons = queue->rx.req_cons; + + return queue->stalled && prod - cons >= 1; +} + +static bool xenvif_have_rx_work(struct xenvif_queue *queue) +{ + return xenvif_rx_ring_slots_available(queue) || + (queue->vif->stall_timeout && + (xenvif_rx_queue_stalled(queue) || + xenvif_rx_queue_ready(queue))) || + kthread_should_stop() || + queue->vif->disabled; +} + +static long xenvif_rx_queue_timeout(struct xenvif_queue *queue) +{ + struct sk_buff *skb; + long timeout; + + skb = skb_peek(&queue->rx_queue); + if (!skb) + return MAX_SCHEDULE_TIMEOUT; + + timeout = XENVIF_RX_CB(skb)->expires - jiffies; + return timeout < 0 ? 0 : timeout; +} + +/* Wait until the guest Rx thread has work. + * + * The timeout needs to be adjusted based on the current head of the + * queue (and not just the head at the beginning). In particular, if + * the queue is initially empty an infinite timeout is used and this + * needs to be reduced when a skb is queued. + * + * This cannot be done with wait_event_timeout() because it only + * calculates the timeout once. + */ +static void xenvif_wait_for_rx_work(struct xenvif_queue *queue) +{ + DEFINE_WAIT(wait); + + if (xenvif_have_rx_work(queue)) + return; + + for (;;) { + long ret; + + prepare_to_wait(&queue->wq, &wait, TASK_INTERRUPTIBLE); + if (xenvif_have_rx_work(queue)) + break; + ret = schedule_timeout(xenvif_rx_queue_timeout(queue)); + if (!ret) + break; + } + finish_wait(&queue->wq, &wait); +} + +static void xenvif_queue_carrier_off(struct xenvif_queue *queue) +{ + struct xenvif *vif = queue->vif; + + queue->stalled = true; + + /* At least one queue has stalled? Disable the carrier. */ + spin_lock(&vif->lock); + if (vif->stalled_queues++ == 0) { + netdev_info(vif->dev, "Guest Rx stalled"); + netif_carrier_off(vif->dev); + } + spin_unlock(&vif->lock); +} + +static void xenvif_queue_carrier_on(struct xenvif_queue *queue) +{ + struct xenvif *vif = queue->vif; + + queue->last_rx_time = jiffies; /* Reset Rx stall detection. */ + queue->stalled = false; + + /* All queues are ready? Enable the carrier. */ + spin_lock(&vif->lock); + if (--vif->stalled_queues == 0) { + netdev_info(vif->dev, "Guest Rx ready"); + netif_carrier_on(vif->dev); + } + spin_unlock(&vif->lock); +} + +int xenvif_kthread_guest_rx(void *data) +{ + struct xenvif_queue *queue = data; + struct xenvif *vif = queue->vif; + + if (!vif->stall_timeout) + xenvif_queue_carrier_on(queue); + + for (;;) { + xenvif_wait_for_rx_work(queue); + + if (kthread_should_stop()) + break; + + /* This frontend is found to be rogue, disable it in + * kthread context. Currently this is only set when + * netback finds out frontend sends malformed packet, + * but we cannot disable the interface in softirq + * context so we defer it here, if this thread is + * associated with queue 0. + */ + if (unlikely(vif->disabled && queue->id == 0)) { + xenvif_carrier_off(vif); + break; + } + + if (!skb_queue_empty(&queue->rx_queue)) + xenvif_rx_action(queue); + + /* If the guest hasn't provided any Rx slots for a + * while it's probably not responsive, drop the + * carrier so packets are dropped earlier. + */ + if (vif->stall_timeout) { + if (xenvif_rx_queue_stalled(queue)) + xenvif_queue_carrier_off(queue); + else if (xenvif_rx_queue_ready(queue)) + xenvif_queue_carrier_on(queue); + } + + /* Queued packets may have foreign pages from other + * domains. These cannot be queued indefinitely as + * this would starve guests of grant refs and transmit + * slots. + */ + xenvif_rx_queue_drop_expired(queue); + + xenvif_rx_queue_maybe_wake(queue); + + cond_resched(); + } + + /* Bin any remaining skbs */ + xenvif_rx_queue_purge(queue); + + return 0; +} |