1 files changed, 680 insertions, 0 deletions

diff --git a/drivers/net/xen-netback/rx.c b/drivers/net/xen-netback/rx.c
new file mode 100644
index 000000000..0ba754ebc
--- /dev/null
+++ b/drivers/net/xen-netback/rx.c
@@ -0,0 +1,680 @@
+/*
+ * 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;
+}
+
+bool xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb)
+{
+	unsigned long flags;
+	bool ret = true;
+
+	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));
+		ret = false;
+	} 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);
+
+	return ret;
+}
+
+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 (queue->vif->xdp_headroom) {
+		struct xen_netif_extra_info *extra;
+
+		extra = &pkt->extras[XEN_NETIF_EXTRA_TYPE_XDP - 1];
+
+		memset(extra, 0, sizeof(struct xen_netif_extra_info));
+		extra->u.xdp.headroom = queue->vif->xdp_headroom;
+		extra->type = XEN_NETIF_EXTRA_TYPE_XDP;
+		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 = queue->vif->xdp_headroom;
+	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
+
+static 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) &&
+	       !skb_queue_empty(&queue->rx_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;
+}