| /* |
| * 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> |
| |
| /* |
| * Update the needed ring page slots for the first SKB queued. |
| * Note that any call sequence outside the RX thread calling this function |
| * needs to wake up the RX thread via a call of xenvif_kick_thread() |
| * afterwards in order to avoid a race with putting the thread to sleep. |
| */ |
| static void xenvif_update_needed_slots(struct xenvif_queue *queue, |
| const struct sk_buff *skb) |
| { |
| unsigned int needed = 0; |
| |
| if (skb) { |
| needed = DIV_ROUND_UP(skb->len, XEN_PAGE_SIZE); |
| if (skb_is_gso(skb)) |
| needed++; |
| if (skb->sw_hash) |
| needed++; |
| } |
| |
| WRITE_ONCE(queue->rx_slots_needed, needed); |
| } |
| |
| static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue) |
| { |
| RING_IDX prod, cons; |
| unsigned int needed; |
| |
| needed = READ_ONCE(queue->rx_slots_needed); |
| if (!needed) |
| return false; |
| |
| 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); |
| |
| 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)); |
| kfree_skb(skb); |
| queue->vif->dev->stats.rx_dropped++; |
| } else { |
| if (skb_queue_empty(&queue->rx_queue)) |
| xenvif_update_needed_slots(queue, skb); |
| |
| __skb_queue_tail(&queue->rx_queue, skb); |
| |
| queue->rx_queue_len += skb->len; |
| } |
| |
| 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) { |
| xenvif_update_needed_slots(queue, skb_peek(&queue->rx_queue)); |
| |
| queue->rx_queue_len -= skb->len; |
| if (queue->rx_queue_len < queue->rx_queue_max) { |
| struct netdev_queue *txq; |
| |
| txq = netdev_get_tx_queue(queue->vif->dev, queue->id); |
| netif_tx_wake_queue(txq); |
| } |
| } |
| |
| spin_unlock_irq(&queue->rx_queue.lock); |
| |
| return skb; |
| } |
| |
| 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); |
| queue->vif->dev->stats.rx_dropped++; |
| } |
| } |
| |
| static void xenvif_rx_copy_flush(struct xenvif_queue *queue) |
| { |
| unsigned int i; |
| int notify; |
| |
| gnttab_batch_copy(queue->rx_copy.op, queue->rx_copy.num); |
| |
| for (i = 0; i < queue->rx_copy.num; i++) { |
| struct gnttab_copy *op; |
| |
| op = &queue->rx_copy.op[i]; |
| |
| /* If the copy failed, overwrite the status field in |
| * the corresponding response. |
| */ |
| if (unlikely(op->status != GNTST_okay)) { |
| struct xen_netif_rx_response *rsp; |
| |
| rsp = RING_GET_RESPONSE(&queue->rx, |
| queue->rx_copy.idx[i]); |
| rsp->status = op->status; |
| } |
| } |
| |
| queue->rx_copy.num = 0; |
| |
| /* Push responses for all completed packets. */ |
| RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->rx, notify); |
| if (notify) |
| notify_remote_via_irq(queue->rx_irq); |
| |
| __skb_queue_purge(queue->rx_copy.completed); |
| } |
| |
| static void xenvif_rx_copy_add(struct xenvif_queue *queue, |
| struct xen_netif_rx_request *req, |
| unsigned int offset, void *data, size_t len) |
| { |
| struct gnttab_copy *op; |
| struct page *page; |
| struct xen_page_foreign *foreign; |
| |
| if (queue->rx_copy.num == COPY_BATCH_SIZE) |
| xenvif_rx_copy_flush(queue); |
| |
| op = &queue->rx_copy.op[queue->rx_copy.num]; |
| |
| page = virt_to_page(data); |
| |
| op->flags = GNTCOPY_dest_gref; |
| |
| foreign = xen_page_foreign(page); |
| if (foreign) { |
| op->source.domid = foreign->domid; |
| op->source.u.ref = foreign->gref; |
| op->flags |= GNTCOPY_source_gref; |
| } else { |
| op->source.u.gmfn = virt_to_gfn(data); |
| op->source.domid = DOMID_SELF; |
| } |
| |
| op->source.offset = xen_offset_in_page(data); |
| op->dest.u.ref = req->gref; |
| op->dest.domid = queue->vif->domid; |
| op->dest.offset = offset; |
| op->len = len; |
| |
| queue->rx_copy.idx[queue->rx_copy.num] = queue->rx.req_cons; |
| queue->rx_copy.num++; |
| } |
| |
| static unsigned int xenvif_gso_type(struct sk_buff *skb) |
| { |
| if (skb_is_gso(skb)) { |
| if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) |
| return XEN_NETIF_GSO_TYPE_TCPV4; |
| else |
| return XEN_NETIF_GSO_TYPE_TCPV6; |
| } |
| return XEN_NETIF_GSO_TYPE_NONE; |
| } |
| |
| struct xenvif_pkt_state { |
| struct sk_buff *skb; |
| size_t remaining_len; |
| struct sk_buff *frag_iter; |
| int frag; /* frag == -1 => frag_iter->head */ |
| unsigned int frag_offset; |
| struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1]; |
| unsigned int extra_count; |
| unsigned int slot; |
| }; |
| |
| static void xenvif_rx_next_skb(struct xenvif_queue *queue, |
| struct xenvif_pkt_state *pkt) |
| { |
| struct sk_buff *skb; |
| unsigned int gso_type; |
| |
| skb = xenvif_rx_dequeue(queue); |
| |
| queue->stats.tx_bytes += skb->len; |
| queue->stats.tx_packets++; |
| |
| /* Reset packet state. */ |
| memset(pkt, 0, sizeof(struct xenvif_pkt_state)); |
| |
| pkt->skb = skb; |
| pkt->frag_iter = skb; |
| pkt->remaining_len = skb->len; |
| pkt->frag = -1; |
| |
| gso_type = xenvif_gso_type(skb); |
| if ((1 << gso_type) & queue->vif->gso_mask) { |
| struct xen_netif_extra_info *extra; |
| |
| extra = &pkt->extras[XEN_NETIF_EXTRA_TYPE_GSO - 1]; |
| |
| extra->u.gso.type = gso_type; |
| extra->u.gso.size = skb_shinfo(skb)->gso_size; |
| extra->u.gso.pad = 0; |
| extra->u.gso.features = 0; |
| extra->type = XEN_NETIF_EXTRA_TYPE_GSO; |
| extra->flags = 0; |
| |
| pkt->extra_count++; |
| } |
| |
| if (skb->sw_hash) { |
| struct xen_netif_extra_info *extra; |
| |
| extra = &pkt->extras[XEN_NETIF_EXTRA_TYPE_HASH - 1]; |
| |
| 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; |
| |
| pkt->extra_count++; |
| } |
| } |
| |
| static void xenvif_rx_complete(struct xenvif_queue *queue, |
| struct xenvif_pkt_state *pkt) |
| { |
| /* All responses are ready to be pushed. */ |
| queue->rx.rsp_prod_pvt = queue->rx.req_cons; |
| |
| __skb_queue_tail(queue->rx_copy.completed, pkt->skb); |
| } |
| |
| static void xenvif_rx_next_frag(struct xenvif_pkt_state *pkt) |
| { |
| struct sk_buff *frag_iter = pkt->frag_iter; |
| unsigned int nr_frags = skb_shinfo(frag_iter)->nr_frags; |
| |
| pkt->frag++; |
| pkt->frag_offset = 0; |
| |
| if (pkt->frag >= nr_frags) { |
| if (frag_iter == pkt->skb) |
| pkt->frag_iter = skb_shinfo(frag_iter)->frag_list; |
| else |
| pkt->frag_iter = frag_iter->next; |
| |
| pkt->frag = -1; |
| } |
| } |
| |
| static void xenvif_rx_next_chunk(struct xenvif_queue *queue, |
| struct xenvif_pkt_state *pkt, |
| unsigned int offset, void **data, |
| size_t *len) |
| { |
| struct sk_buff *frag_iter = pkt->frag_iter; |
| void *frag_data; |
| size_t frag_len, chunk_len; |
| |
| BUG_ON(!frag_iter); |
| |
| if (pkt->frag == -1) { |
| frag_data = frag_iter->data; |
| frag_len = skb_headlen(frag_iter); |
| } else { |
| skb_frag_t *frag = &skb_shinfo(frag_iter)->frags[pkt->frag]; |
| |
| frag_data = skb_frag_address(frag); |
| frag_len = skb_frag_size(frag); |
| } |
| |
| frag_data += pkt->frag_offset; |
| frag_len -= pkt->frag_offset; |
| |
| chunk_len = min_t(size_t, frag_len, XEN_PAGE_SIZE - offset); |
| chunk_len = min_t(size_t, chunk_len, XEN_PAGE_SIZE - |
| xen_offset_in_page(frag_data)); |
| |
| pkt->frag_offset += chunk_len; |
| |
| /* Advance to next frag? */ |
| if (frag_len == chunk_len) |
| xenvif_rx_next_frag(pkt); |
| |
| *data = frag_data; |
| *len = chunk_len; |
| } |
| |
| static void xenvif_rx_data_slot(struct xenvif_queue *queue, |
| struct xenvif_pkt_state *pkt, |
| struct xen_netif_rx_request *req, |
| struct xen_netif_rx_response *rsp) |
| { |
| unsigned int offset = 0; |
| unsigned int flags; |
| |
| do { |
| size_t len; |
| void *data; |
| |
| xenvif_rx_next_chunk(queue, pkt, offset, &data, &len); |
| xenvif_rx_copy_add(queue, req, offset, data, len); |
| |
| offset += len; |
| pkt->remaining_len -= len; |
| |
| } while (offset < XEN_PAGE_SIZE && pkt->remaining_len > 0); |
| |
| if (pkt->remaining_len > 0) |
| flags = XEN_NETRXF_more_data; |
| else |
| flags = 0; |
| |
| if (pkt->slot == 0) { |
| struct sk_buff *skb = pkt->skb; |
| |
| if (skb->ip_summed == CHECKSUM_PARTIAL) |
| flags |= XEN_NETRXF_csum_blank | |
| XEN_NETRXF_data_validated; |
| else if (skb->ip_summed == CHECKSUM_UNNECESSARY) |
| flags |= XEN_NETRXF_data_validated; |
| |
| if (pkt->extra_count != 0) |
| flags |= XEN_NETRXF_extra_info; |
| } |
| |
| rsp->offset = 0; |
| rsp->flags = flags; |
| rsp->id = req->id; |
| rsp->status = (s16)offset; |
| } |
| |
| static void xenvif_rx_extra_slot(struct xenvif_queue *queue, |
| struct xenvif_pkt_state *pkt, |
| struct xen_netif_rx_request *req, |
| struct xen_netif_rx_response *rsp) |
| { |
| struct xen_netif_extra_info *extra = (void *)rsp; |
| unsigned int i; |
| |
| pkt->extra_count--; |
| |
| for (i = 0; i < ARRAY_SIZE(pkt->extras); i++) { |
| if (pkt->extras[i].type) { |
| *extra = pkt->extras[i]; |
| |
| if (pkt->extra_count != 0) |
| extra->flags |= XEN_NETIF_EXTRA_FLAG_MORE; |
| |
| pkt->extras[i].type = 0; |
| return; |
| } |
| } |
| BUG(); |
| } |
| |
| static void xenvif_rx_skb(struct xenvif_queue *queue) |
| { |
| struct xenvif_pkt_state pkt; |
| |
| xenvif_rx_next_skb(queue, &pkt); |
| |
| queue->last_rx_time = jiffies; |
| |
| do { |
| struct xen_netif_rx_request *req; |
| struct xen_netif_rx_response *rsp; |
| |
| req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons); |
| rsp = RING_GET_RESPONSE(&queue->rx, queue->rx.req_cons); |
| |
| /* Extras must go after the first data slot */ |
| if (pkt.slot != 0 && pkt.extra_count != 0) |
| xenvif_rx_extra_slot(queue, &pkt, req, rsp); |
| else |
| xenvif_rx_data_slot(queue, &pkt, req, rsp); |
| |
| queue->rx.req_cons++; |
| pkt.slot++; |
| } while (pkt.remaining_len > 0 || pkt.extra_count != 0); |
| |
| xenvif_rx_complete(queue, &pkt); |
| } |
| |
| #define RX_BATCH_SIZE 64 |
| |
| void xenvif_rx_action(struct xenvif_queue *queue) |
| { |
| struct sk_buff_head completed_skbs; |
| unsigned int work_done = 0; |
| |
| __skb_queue_head_init(&completed_skbs); |
| queue->rx_copy.completed = &completed_skbs; |
| |
| while (xenvif_rx_ring_slots_available(queue) && |
| work_done < RX_BATCH_SIZE) { |
| xenvif_rx_skb(queue); |
| work_done++; |
| } |
| |
| /* Flush any pending copies and complete all skbs. */ |
| xenvif_rx_copy_flush(queue); |
| } |
| |
| static RING_IDX xenvif_rx_queue_slots(const struct xenvif_queue *queue) |
| { |
| RING_IDX prod, cons; |
| |
| prod = queue->rx.sring->req_prod; |
| cons = queue->rx.req_cons; |
| |
| return prod - cons; |
| } |
| |
| static bool xenvif_rx_queue_stalled(const struct xenvif_queue *queue) |
| { |
| unsigned int needed = READ_ONCE(queue->rx_slots_needed); |
| |
| return !queue->stalled && |
| xenvif_rx_queue_slots(queue) < needed && |
| time_after(jiffies, |
| queue->last_rx_time + queue->vif->stall_timeout); |
| } |
| |
| static bool xenvif_rx_queue_ready(struct xenvif_queue *queue) |
| { |
| unsigned int needed = READ_ONCE(queue->rx_slots_needed); |
| |
| return queue->stalled && xenvif_rx_queue_slots(queue) >= needed; |
| } |
| |
| bool xenvif_have_rx_work(struct xenvif_queue *queue, bool test_kthread) |
| { |
| return xenvif_rx_ring_slots_available(queue) || |
| (queue->vif->stall_timeout && |
| (xenvif_rx_queue_stalled(queue) || |
| xenvif_rx_queue_ready(queue))) || |
| (test_kthread && 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, true)) |
| return; |
| |
| for (;;) { |
| long ret; |
| |
| prepare_to_wait(&queue->wq, &wait, TASK_INTERRUPTIBLE); |
| if (xenvif_have_rx_work(queue, true)) |
| break; |
| if (atomic_fetch_andnot(NETBK_RX_EOI | NETBK_COMMON_EOI, |
| &queue->eoi_pending) & |
| (NETBK_RX_EOI | NETBK_COMMON_EOI)) |
| xen_irq_lateeoi(queue->rx_irq, 0); |
| |
| 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); |
| |
| cond_resched(); |
| } |
| |
| /* Bin any remaining skbs */ |
| xenvif_rx_queue_purge(queue); |
| |
| return 0; |
| } |