--- /dev/null
+/*
+ * Back-end of the driver for virtual network devices. This portion of the
+ * driver exports a 'unified' network-device interface that can be accessed
+ * by any operating system that implements a compatible front end. A
+ * reference front-end implementation can be found in:
+ * drivers/net/xen-netfront.c
+ *
+ * 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 <linux/if_vlan.h>
+#include <linux/udp.h>
+#include <linux/highmem.h>
+
+#include <net/tcp.h>
+
+#include <xen/xen.h>
+#include <xen/events.h>
+#include <xen/interface/memory.h>
+
+#include <asm/xen/hypercall.h>
+#include <asm/xen/page.h>
+
+/* Provide an option to disable split event channels at load time as
+ * event channels are limited resource. Split event channels are
+ * enabled by default.
+ */
+bool separate_tx_rx_irq = 1;
+module_param(separate_tx_rx_irq, bool, 0644);
+
+/* The time that packets can stay on the guest Rx internal queue
+ * before they are dropped.
+ */
+unsigned int rx_drain_timeout_msecs = 10000;
+module_param(rx_drain_timeout_msecs, uint, 0444);
+
+/* The length of time before the frontend is considered unresponsive
+ * because it isn't providing Rx slots.
+ */
+unsigned int rx_stall_timeout_msecs = 60000;
+module_param(rx_stall_timeout_msecs, uint, 0444);
+
+unsigned int xenvif_max_queues;
+module_param_named(max_queues, xenvif_max_queues, uint, 0644);
+MODULE_PARM_DESC(max_queues,
+ "Maximum number of queues per virtual interface");
+
+/*
+ * This is the maximum slots a skb can have. If a guest sends a skb
+ * which exceeds this limit it is considered malicious.
+ */
+#define FATAL_SKB_SLOTS_DEFAULT 20
+static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
+module_param(fatal_skb_slots, uint, 0444);
+
+/* The amount to copy out of the first guest Tx slot into the skb's
+ * linear area. If the first slot has more data, it will be mapped
+ * and put into the first frag.
+ *
+ * This is sized to avoid pulling headers from the frags for most
+ * TCP/IP packets.
+ */
+#define XEN_NETBACK_TX_COPY_LEN 128
+
+
+static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
+ u8 status);
+
+static void make_tx_response(struct xenvif_queue *queue,
+ struct xen_netif_tx_request *txp,
+ s8 st);
+static void push_tx_responses(struct xenvif_queue *queue);
+
+static inline int tx_work_todo(struct xenvif_queue *queue);
+
+static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue,
+ u16 id,
+ s8 st,
+ u16 offset,
+ u16 size,
+ u16 flags);
+
+static inline unsigned long idx_to_pfn(struct xenvif_queue *queue,
+ u16 idx)
+{
+ return page_to_pfn(queue->mmap_pages[idx]);
+}
+
+static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue,
+ u16 idx)
+{
+ return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx));
+}
+
+#define callback_param(vif, pending_idx) \
+ (vif->pending_tx_info[pending_idx].callback_struct)
+
+/* Find the containing VIF's structure from a pointer in pending_tx_info array
+ */
+static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info *ubuf)
+{
+ u16 pending_idx = ubuf->desc;
+ struct pending_tx_info *temp =
+ container_of(ubuf, struct pending_tx_info, callback_struct);
+ return container_of(temp - pending_idx,
+ struct xenvif_queue,
+ pending_tx_info[0]);
+}
+
+static u16 frag_get_pending_idx(skb_frag_t *frag)
+{
+ return (u16)frag->page_offset;
+}
+
+static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
+{
+ frag->page_offset = pending_idx;
+}
+
+static inline pending_ring_idx_t pending_index(unsigned i)
+{
+ return i & (MAX_PENDING_REQS-1);
+}
+
+bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue, int needed)
+{
+ RING_IDX prod, cons;
+
+ 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)
+ netif_tx_stop_queue(netdev_get_tx_queue(queue->vif->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)
+ netif_tx_wake_queue(netdev_get_tx_queue(queue->vif->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 copy_prod, copy_cons;
+ unsigned 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;
+
+ req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++);
+
+ 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;
+}
+
+/*
+ * 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 gnttab_copy *copy_gop;
+ struct xenvif_rx_meta *meta;
+ unsigned long bytes;
+ int gso_type = XEN_NETIF_GSO_TYPE_NONE;
+
+ /* Data must not cross a page boundary. */
+ BUG_ON(size + offset > PAGE_SIZE<<compound_order(page));
+
+ meta = npo->meta + npo->meta_prod - 1;
+
+ /* Skip unused frames from start of page */
+ page += offset >> PAGE_SHIFT;
+ offset &= ~PAGE_MASK;
+
+ while (size > 0) {
+ struct xen_page_foreign *foreign;
+
+ BUG_ON(offset >= PAGE_SIZE);
+ BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
+
+ if (npo->copy_off == MAX_BUFFER_OFFSET)
+ meta = get_next_rx_buffer(queue, npo);
+
+ bytes = PAGE_SIZE - offset;
+ if (bytes > size)
+ bytes = size;
+
+ if (npo->copy_off + bytes > MAX_BUFFER_OFFSET)
+ bytes = MAX_BUFFER_OFFSET - npo->copy_off;
+
+ copy_gop = npo->copy + npo->copy_prod++;
+ copy_gop->flags = GNTCOPY_dest_gref;
+ copy_gop->len = bytes;
+
+ 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 =
+ virt_to_mfn(page_address(page));
+ }
+ 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 += bytes;
+ meta->size += bytes;
+
+ offset += bytes;
+ size -= bytes;
+
+ /* Next frame */
+ if (offset == PAGE_SIZE && size) {
+ BUG_ON(!PageCompound(page));
+ page++;
+ offset = 0;
+ }
+
+ /* Leave a gap for the GSO descriptor. */
+ 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;
+ }
+
+ if (*head && ((1 << gso_type) & queue->vif->gso_mask))
+ queue->rx.req_cons++;
+
+ *head = 0; /* There must be something in this buffer now. */
+
+ }
+}
+
+/*
+ * 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) {
+ req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++);
+ 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;
+ }
+
+ req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++);
+ 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 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);
+ }
+}
+
+void xenvif_kick_thread(struct xenvif_queue *queue)
+{
+ wake_up(&queue->wq);
+}
+
+static void xenvif_rx_action(struct xenvif_queue *queue)
+{
+ 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, XEN_NETBK_RX_SLOTS_MAX)
+ && (skb = xenvif_rx_dequeue(queue)) != NULL) {
+ RING_IDX old_req_cons;
+ RING_IDX ring_slots_used;
+
+ queue->last_rx_time = jiffies;
+
+ old_req_cons = queue->rx.req_cons;
+ XENVIF_RX_CB(skb)->meta_slots_used = xenvif_gop_skb(skb, &npo, queue);
+ ring_slots_used = queue->rx.req_cons - old_req_cons;
+
+ __skb_queue_tail(&rxq, skb);
+ }
+
+ BUG_ON(npo.meta_prod > ARRAY_SIZE(queue->meta));
+
+ if (!npo.copy_prod)
+ goto done;
+
+ BUG_ON(npo.copy_prod > MAX_GRANT_COPY_OPS);
+ gnttab_batch_copy(queue->grant_copy_op, npo.copy_prod);
+
+ while ((skb = __skb_dequeue(&rxq)) != NULL) {
+
+ if ((1 << queue->meta[npo.meta_cons].gso_type) &
+ queue->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(queue->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) &
+ queue->vif->gso_mask) {
+ struct xen_netif_extra_info *gso =
+ (struct xen_netif_extra_info *)
+ RING_GET_RESPONSE(&queue->rx,
+ queue->rx.rsp_prod_pvt++);
+
+ resp->flags |= XEN_NETRXF_extra_info;
+
+ gso->u.gso.type = queue->meta[npo.meta_cons].gso_type;
+ gso->u.gso.size = queue->meta[npo.meta_cons].gso_size;
+ gso->u.gso.pad = 0;
+ gso->u.gso.features = 0;
+
+ gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
+ gso->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);
+}
+
+void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue)
+{
+ int more_to_do;
+
+ RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do);
+
+ if (more_to_do)
+ napi_schedule(&queue->napi);
+}
+
+static void tx_add_credit(struct xenvif_queue *queue)
+{
+ unsigned long max_burst, max_credit;
+
+ /*
+ * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
+ * Otherwise the interface can seize up due to insufficient credit.
+ */
+ max_burst = RING_GET_REQUEST(&queue->tx, queue->tx.req_cons)->size;
+ max_burst = min(max_burst, 131072UL);
+ max_burst = max(max_burst, queue->credit_bytes);
+
+ /* Take care that adding a new chunk of credit doesn't wrap to zero. */
+ max_credit = queue->remaining_credit + queue->credit_bytes;
+ if (max_credit < queue->remaining_credit)
+ max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
+
+ queue->remaining_credit = min(max_credit, max_burst);
+}
+
+void xenvif_tx_credit_callback(unsigned long data)
+{
+ struct xenvif_queue *queue = (struct xenvif_queue *)data;
+ tx_add_credit(queue);
+ xenvif_napi_schedule_or_enable_events(queue);
+}
+
+static void xenvif_tx_err(struct xenvif_queue *queue,
+ struct xen_netif_tx_request *txp, RING_IDX end)
+{
+ RING_IDX cons = queue->tx.req_cons;
+ unsigned long flags;
+
+ do {
+ spin_lock_irqsave(&queue->response_lock, flags);
+ make_tx_response(queue, txp, XEN_NETIF_RSP_ERROR);
+ push_tx_responses(queue);
+ spin_unlock_irqrestore(&queue->response_lock, flags);
+ if (cons == end)
+ break;
+ txp = RING_GET_REQUEST(&queue->tx, cons++);
+ } while (1);
+ queue->tx.req_cons = cons;
+}
+
+static void xenvif_fatal_tx_err(struct xenvif *vif)
+{
+ netdev_err(vif->dev, "fatal error; disabling device\n");
+ vif->disabled = true;
+ /* Disable the vif from queue 0's kthread */
+ if (vif->queues)
+ xenvif_kick_thread(&vif->queues[0]);
+}
+
+static int xenvif_count_requests(struct xenvif_queue *queue,
+ struct xen_netif_tx_request *first,
+ struct xen_netif_tx_request *txp,
+ int work_to_do)
+{
+ RING_IDX cons = queue->tx.req_cons;
+ int slots = 0;
+ int drop_err = 0;
+ int more_data;
+
+ if (!(first->flags & XEN_NETTXF_more_data))
+ return 0;
+
+ do {
+ struct xen_netif_tx_request dropped_tx = { 0 };
+
+ if (slots >= work_to_do) {
+ netdev_err(queue->vif->dev,
+ "Asked for %d slots but exceeds this limit\n",
+ work_to_do);
+ xenvif_fatal_tx_err(queue->vif);
+ return -ENODATA;
+ }
+
+ /* This guest is really using too many slots and
+ * considered malicious.
+ */
+ if (unlikely(slots >= fatal_skb_slots)) {
+ netdev_err(queue->vif->dev,
+ "Malicious frontend using %d slots, threshold %u\n",
+ slots, fatal_skb_slots);
+ xenvif_fatal_tx_err(queue->vif);
+ return -E2BIG;
+ }
+
+ /* Xen network protocol had implicit dependency on
+ * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
+ * the historical MAX_SKB_FRAGS value 18 to honor the
+ * same behavior as before. Any packet using more than
+ * 18 slots but less than fatal_skb_slots slots is
+ * dropped
+ */
+ if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
+ if (net_ratelimit())
+ netdev_dbg(queue->vif->dev,
+ "Too many slots (%d) exceeding limit (%d), dropping packet\n",
+ slots, XEN_NETBK_LEGACY_SLOTS_MAX);
+ drop_err = -E2BIG;
+ }
+
+ if (drop_err)
+ txp = &dropped_tx;
+
+ memcpy(txp, RING_GET_REQUEST(&queue->tx, cons + slots),
+ sizeof(*txp));
+
+ /* If the guest submitted a frame >= 64 KiB then
+ * first->size overflowed and following slots will
+ * appear to be larger than the frame.
+ *
+ * This cannot be fatal error as there are buggy
+ * frontends that do this.
+ *
+ * Consume all slots and drop the packet.
+ */
+ if (!drop_err && txp->size > first->size) {
+ if (net_ratelimit())
+ netdev_dbg(queue->vif->dev,
+ "Invalid tx request, slot size %u > remaining size %u\n",
+ txp->size, first->size);
+ drop_err = -EIO;
+ }
+
+ first->size -= txp->size;
+ slots++;
+
+ if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) {
+ netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %x, size: %u\n",
+ txp->offset, txp->size);
+ xenvif_fatal_tx_err(queue->vif);
+ return -EINVAL;
+ }
+
+ more_data = txp->flags & XEN_NETTXF_more_data;
+
+ if (!drop_err)
+ txp++;
+
+ } while (more_data);
+
+ if (drop_err) {
+ xenvif_tx_err(queue, first, cons + slots);
+ return drop_err;
+ }
+
+ return slots;
+}
+
+
+struct xenvif_tx_cb {
+ u16 pending_idx;
+};
+
+#define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
+
+static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
+ u16 pending_idx,
+ struct xen_netif_tx_request *txp,
+ struct gnttab_map_grant_ref *mop)
+{
+ queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
+ gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
+ GNTMAP_host_map | GNTMAP_readonly,
+ txp->gref, queue->vif->domid);
+
+ memcpy(&queue->pending_tx_info[pending_idx].req, txp,
+ sizeof(*txp));
+}
+
+static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
+{
+ struct sk_buff *skb =
+ alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
+ GFP_ATOMIC | __GFP_NOWARN);
+ if (unlikely(skb == NULL))
+ return NULL;
+
+ /* Packets passed to netif_rx() must have some headroom. */
+ skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
+
+ /* Initialize it here to avoid later surprises */
+ skb_shinfo(skb)->destructor_arg = NULL;
+
+ return skb;
+}
+
+static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *queue,
+ struct sk_buff *skb,
+ struct xen_netif_tx_request *txp,
+ struct gnttab_map_grant_ref *gop)
+{
+ struct skb_shared_info *shinfo = skb_shinfo(skb);
+ skb_frag_t *frags = shinfo->frags;
+ u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
+ int start;
+ pending_ring_idx_t index;
+ unsigned int nr_slots, frag_overflow = 0;
+
+ /* At this point shinfo->nr_frags is in fact the number of
+ * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
+ */
+ if (shinfo->nr_frags > MAX_SKB_FRAGS) {
+ frag_overflow = shinfo->nr_frags - MAX_SKB_FRAGS;
+ BUG_ON(frag_overflow > MAX_SKB_FRAGS);
+ shinfo->nr_frags = MAX_SKB_FRAGS;
+ }
+ nr_slots = shinfo->nr_frags;
+
+ /* Skip first skb fragment if it is on same page as header fragment. */
+ start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
+
+ for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
+ shinfo->nr_frags++, txp++, gop++) {
+ index = pending_index(queue->pending_cons++);
+ pending_idx = queue->pending_ring[index];
+ xenvif_tx_create_map_op(queue, pending_idx, txp, gop);
+ frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
+ }
+
+ if (frag_overflow) {
+ struct sk_buff *nskb = xenvif_alloc_skb(0);
+ if (unlikely(nskb == NULL)) {
+ if (net_ratelimit())
+ netdev_err(queue->vif->dev,
+ "Can't allocate the frag_list skb.\n");
+ return NULL;
+ }
+
+ shinfo = skb_shinfo(nskb);
+ frags = shinfo->frags;
+
+ for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
+ shinfo->nr_frags++, txp++, gop++) {
+ index = pending_index(queue->pending_cons++);
+ pending_idx = queue->pending_ring[index];
+ xenvif_tx_create_map_op(queue, pending_idx, txp, gop);
+ frag_set_pending_idx(&frags[shinfo->nr_frags],
+ pending_idx);
+ }
+
+ skb_shinfo(skb)->frag_list = nskb;
+ }
+
+ return gop;
+}
+
+static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
+ u16 pending_idx,
+ grant_handle_t handle)
+{
+ if (unlikely(queue->grant_tx_handle[pending_idx] !=
+ NETBACK_INVALID_HANDLE)) {
+ netdev_err(queue->vif->dev,
+ "Trying to overwrite active handle! pending_idx: %x\n",
+ pending_idx);
+ BUG();
+ }
+ queue->grant_tx_handle[pending_idx] = handle;
+}
+
+static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue,
+ u16 pending_idx)
+{
+ if (unlikely(queue->grant_tx_handle[pending_idx] ==
+ NETBACK_INVALID_HANDLE)) {
+ netdev_err(queue->vif->dev,
+ "Trying to unmap invalid handle! pending_idx: %x\n",
+ pending_idx);
+ BUG();
+ }
+ queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
+}
+
+static int xenvif_tx_check_gop(struct xenvif_queue *queue,
+ struct sk_buff *skb,
+ struct gnttab_map_grant_ref **gopp_map,
+ struct gnttab_copy **gopp_copy)
+{
+ struct gnttab_map_grant_ref *gop_map = *gopp_map;
+ u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
+ /* This always points to the shinfo of the skb being checked, which
+ * could be either the first or the one on the frag_list
+ */
+ struct skb_shared_info *shinfo = skb_shinfo(skb);
+ /* If this is non-NULL, we are currently checking the frag_list skb, and
+ * this points to the shinfo of the first one
+ */
+ struct skb_shared_info *first_shinfo = NULL;
+ int nr_frags = shinfo->nr_frags;
+ const bool sharedslot = nr_frags &&
+ frag_get_pending_idx(&shinfo->frags[0]) == pending_idx;
+ int i, err;
+
+ /* Check status of header. */
+ err = (*gopp_copy)->status;
+ if (unlikely(err)) {
+ if (net_ratelimit())
+ netdev_dbg(queue->vif->dev,
+ "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
+ (*gopp_copy)->status,
+ pending_idx,
+ (*gopp_copy)->source.u.ref);
+ /* The first frag might still have this slot mapped */
+ if (!sharedslot)
+ xenvif_idx_release(queue, pending_idx,
+ XEN_NETIF_RSP_ERROR);
+ }
+ (*gopp_copy)++;
+
+check_frags:
+ for (i = 0; i < nr_frags; i++, gop_map++) {
+ int j, newerr;
+
+ pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
+
+ /* Check error status: if okay then remember grant handle. */
+ newerr = gop_map->status;
+
+ if (likely(!newerr)) {
+ xenvif_grant_handle_set(queue,
+ pending_idx,
+ gop_map->handle);
+ /* Had a previous error? Invalidate this fragment. */
+ if (unlikely(err)) {
+ xenvif_idx_unmap(queue, pending_idx);
+ /* If the mapping of the first frag was OK, but
+ * the header's copy failed, and they are
+ * sharing a slot, send an error
+ */
+ if (i == 0 && sharedslot)
+ xenvif_idx_release(queue, pending_idx,
+ XEN_NETIF_RSP_ERROR);
+ else
+ xenvif_idx_release(queue, pending_idx,
+ XEN_NETIF_RSP_OKAY);
+ }
+ continue;
+ }
+
+ /* Error on this fragment: respond to client with an error. */
+ if (net_ratelimit())
+ netdev_dbg(queue->vif->dev,
+ "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n",
+ i,
+ gop_map->status,
+ pending_idx,
+ gop_map->ref);
+
+ xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
+
+ /* Not the first error? Preceding frags already invalidated. */
+ if (err)
+ continue;
+
+ /* First error: if the header haven't shared a slot with the
+ * first frag, release it as well.
+ */
+ if (!sharedslot)
+ xenvif_idx_release(queue,
+ XENVIF_TX_CB(skb)->pending_idx,
+ XEN_NETIF_RSP_OKAY);
+
+ /* Invalidate preceding fragments of this skb. */
+ for (j = 0; j < i; j++) {
+ pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
+ xenvif_idx_unmap(queue, pending_idx);
+ xenvif_idx_release(queue, pending_idx,
+ XEN_NETIF_RSP_OKAY);
+ }
+
+ /* And if we found the error while checking the frag_list, unmap
+ * the first skb's frags
+ */
+ if (first_shinfo) {
+ for (j = 0; j < first_shinfo->nr_frags; j++) {
+ pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]);
+ xenvif_idx_unmap(queue, pending_idx);
+ xenvif_idx_release(queue, pending_idx,
+ XEN_NETIF_RSP_OKAY);
+ }
+ }
+
+ /* Remember the error: invalidate all subsequent fragments. */
+ err = newerr;
+ }
+
+ if (skb_has_frag_list(skb) && !first_shinfo) {
+ first_shinfo = skb_shinfo(skb);
+ shinfo = skb_shinfo(skb_shinfo(skb)->frag_list);
+ nr_frags = shinfo->nr_frags;
+
+ goto check_frags;
+ }
+
+ *gopp_map = gop_map;
+ return err;
+}
+
+static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
+{
+ struct skb_shared_info *shinfo = skb_shinfo(skb);
+ int nr_frags = shinfo->nr_frags;
+ int i;
+ u16 prev_pending_idx = INVALID_PENDING_IDX;
+
+ for (i = 0; i < nr_frags; i++) {
+ skb_frag_t *frag = shinfo->frags + i;
+ struct xen_netif_tx_request *txp;
+ struct page *page;
+ u16 pending_idx;
+
+ pending_idx = frag_get_pending_idx(frag);
+
+ /* If this is not the first frag, chain it to the previous*/
+ if (prev_pending_idx == INVALID_PENDING_IDX)
+ skb_shinfo(skb)->destructor_arg =
+ &callback_param(queue, pending_idx);
+ else
+ callback_param(queue, prev_pending_idx).ctx =
+ &callback_param(queue, pending_idx);
+
+ callback_param(queue, pending_idx).ctx = NULL;
+ prev_pending_idx = pending_idx;
+
+ txp = &queue->pending_tx_info[pending_idx].req;
+ page = virt_to_page(idx_to_kaddr(queue, pending_idx));
+ __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
+ skb->len += txp->size;
+ skb->data_len += txp->size;
+ skb->truesize += txp->size;
+
+ /* Take an extra reference to offset network stack's put_page */
+ get_page(queue->mmap_pages[pending_idx]);
+ }
+}
+
+static int xenvif_get_extras(struct xenvif_queue *queue,
+ struct xen_netif_extra_info *extras,
+ int work_to_do)
+{
+ struct xen_netif_extra_info extra;
+ RING_IDX cons = queue->tx.req_cons;
+
+ do {
+ if (unlikely(work_to_do-- <= 0)) {
+ netdev_err(queue->vif->dev, "Missing extra info\n");
+ xenvif_fatal_tx_err(queue->vif);
+ return -EBADR;
+ }
+
+ memcpy(&extra, RING_GET_REQUEST(&queue->tx, cons),
+ sizeof(extra));
+ if (unlikely(!extra.type ||
+ extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
+ queue->tx.req_cons = ++cons;
+ netdev_err(queue->vif->dev,
+ "Invalid extra type: %d\n", extra.type);
+ xenvif_fatal_tx_err(queue->vif);
+ return -EINVAL;
+ }
+
+ memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
+ queue->tx.req_cons = ++cons;
+ } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
+
+ return work_to_do;
+}
+
+static int xenvif_set_skb_gso(struct xenvif *vif,
+ struct sk_buff *skb,
+ struct xen_netif_extra_info *gso)
+{
+ if (!gso->u.gso.size) {
+ netdev_err(vif->dev, "GSO size must not be zero.\n");
+ xenvif_fatal_tx_err(vif);
+ return -EINVAL;
+ }
+
+ switch (gso->u.gso.type) {
+ case XEN_NETIF_GSO_TYPE_TCPV4:
+ skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
+ break;
+ case XEN_NETIF_GSO_TYPE_TCPV6:
+ skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
+ break;
+ default:
+ netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
+ xenvif_fatal_tx_err(vif);
+ return -EINVAL;
+ }
+
+ skb_shinfo(skb)->gso_size = gso->u.gso.size;
+ /* gso_segs will be calculated later */
+
+ return 0;
+}
+
+static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb)
+{
+ bool recalculate_partial_csum = false;
+
+ /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
+ * peers can fail to set NETRXF_csum_blank when sending a GSO
+ * frame. In this case force the SKB to CHECKSUM_PARTIAL and
+ * recalculate the partial checksum.
+ */
+ if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
+ queue->stats.rx_gso_checksum_fixup++;
+ skb->ip_summed = CHECKSUM_PARTIAL;
+ recalculate_partial_csum = true;
+ }
+
+ /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
+ if (skb->ip_summed != CHECKSUM_PARTIAL)
+ return 0;
+
+ return skb_checksum_setup(skb, recalculate_partial_csum);
+}
+
+static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
+{
+ u64 now = get_jiffies_64();
+ u64 next_credit = queue->credit_window_start +
+ msecs_to_jiffies(queue->credit_usec / 1000);
+
+ /* Timer could already be pending in rare cases. */
+ if (timer_pending(&queue->credit_timeout))
+ return true;
+
+ /* Passed the point where we can replenish credit? */
+ if (time_after_eq64(now, next_credit)) {
+ queue->credit_window_start = now;
+ tx_add_credit(queue);
+ }
+
+ /* Still too big to send right now? Set a callback. */
+ if (size > queue->remaining_credit) {
+ queue->credit_timeout.data =
+ (unsigned long)queue;
+ mod_timer(&queue->credit_timeout,
+ next_credit);
+ queue->credit_window_start = next_credit;
+
+ return true;
+ }
+
+ return false;
+}
+
+static void xenvif_tx_build_gops(struct xenvif_queue *queue,
+ int budget,
+ unsigned *copy_ops,
+ unsigned *map_ops)
+{
+ struct gnttab_map_grant_ref *gop = queue->tx_map_ops, *request_gop;
+ struct sk_buff *skb;
+ int ret;
+
+ while (skb_queue_len(&queue->tx_queue) < budget) {
+ struct xen_netif_tx_request txreq;
+ struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
+ struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
+ u16 pending_idx;
+ RING_IDX idx;
+ int work_to_do;
+ unsigned int data_len;
+ pending_ring_idx_t index;
+
+ if (queue->tx.sring->req_prod - queue->tx.req_cons >
+ XEN_NETIF_TX_RING_SIZE) {
+ netdev_err(queue->vif->dev,
+ "Impossible number of requests. "
+ "req_prod %d, req_cons %d, size %ld\n",
+ queue->tx.sring->req_prod, queue->tx.req_cons,
+ XEN_NETIF_TX_RING_SIZE);
+ xenvif_fatal_tx_err(queue->vif);
+ break;
+ }
+
+ work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx);
+ if (!work_to_do)
+ break;
+
+ idx = queue->tx.req_cons;
+ rmb(); /* Ensure that we see the request before we copy it. */
+ memcpy(&txreq, RING_GET_REQUEST(&queue->tx, idx), sizeof(txreq));
+
+ /* Credit-based scheduling. */
+ if (txreq.size > queue->remaining_credit &&
+ tx_credit_exceeded(queue, txreq.size))
+ break;
+
+ queue->remaining_credit -= txreq.size;
+
+ work_to_do--;
+ queue->tx.req_cons = ++idx;
+
+ memset(extras, 0, sizeof(extras));
+ if (txreq.flags & XEN_NETTXF_extra_info) {
+ work_to_do = xenvif_get_extras(queue, extras,
+ work_to_do);
+ idx = queue->tx.req_cons;
+ if (unlikely(work_to_do < 0))
+ break;
+ }
+
+ ret = xenvif_count_requests(queue, &txreq, txfrags, work_to_do);
+ if (unlikely(ret < 0))
+ break;
+
+ idx += ret;
+
+ if (unlikely(txreq.size < ETH_HLEN)) {
+ netdev_dbg(queue->vif->dev,
+ "Bad packet size: %d\n", txreq.size);
+ xenvif_tx_err(queue, &txreq, idx);
+ break;
+ }
+
+ /* No crossing a page as the payload mustn't fragment. */
+ if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) {
+ netdev_err(queue->vif->dev,
+ "txreq.offset: %x, size: %u, end: %lu\n",
+ txreq.offset, txreq.size,
+ (unsigned long)(txreq.offset&~PAGE_MASK) + txreq.size);
+ xenvif_fatal_tx_err(queue->vif);
+ break;
+ }
+
+ index = pending_index(queue->pending_cons);
+ pending_idx = queue->pending_ring[index];
+
+ data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN &&
+ ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
+ XEN_NETBACK_TX_COPY_LEN : txreq.size;
+
+ skb = xenvif_alloc_skb(data_len);
+ if (unlikely(skb == NULL)) {
+ netdev_dbg(queue->vif->dev,
+ "Can't allocate a skb in start_xmit.\n");
+ xenvif_tx_err(queue, &txreq, idx);
+ break;
+ }
+
+ if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
+ struct xen_netif_extra_info *gso;
+ gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
+
+ if (xenvif_set_skb_gso(queue->vif, skb, gso)) {
+ /* Failure in xenvif_set_skb_gso is fatal. */
+ kfree_skb(skb);
+ break;
+ }
+ }
+
+ XENVIF_TX_CB(skb)->pending_idx = pending_idx;
+
+ __skb_put(skb, data_len);
+ queue->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref;
+ queue->tx_copy_ops[*copy_ops].source.domid = queue->vif->domid;
+ queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
+
+ queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
+ virt_to_mfn(skb->data);
+ queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
+ queue->tx_copy_ops[*copy_ops].dest.offset =
+ offset_in_page(skb->data);
+
+ queue->tx_copy_ops[*copy_ops].len = data_len;
+ queue->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref;
+
+ (*copy_ops)++;
+
+ skb_shinfo(skb)->nr_frags = ret;
+ if (data_len < txreq.size) {
+ skb_shinfo(skb)->nr_frags++;
+ frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
+ pending_idx);
+ xenvif_tx_create_map_op(queue, pending_idx, &txreq, gop);
+ gop++;
+ } else {
+ frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
+ INVALID_PENDING_IDX);
+ memcpy(&queue->pending_tx_info[pending_idx].req, &txreq,
+ sizeof(txreq));
+ }
+
+ queue->pending_cons++;
+
+ request_gop = xenvif_get_requests(queue, skb, txfrags, gop);
+ if (request_gop == NULL) {
+ kfree_skb(skb);
+ xenvif_tx_err(queue, &txreq, idx);
+ break;
+ }
+ gop = request_gop;
+
+ __skb_queue_tail(&queue->tx_queue, skb);
+
+ queue->tx.req_cons = idx;
+
+ if (((gop-queue->tx_map_ops) >= ARRAY_SIZE(queue->tx_map_ops)) ||
+ (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops)))
+ break;
+ }
+
+ (*map_ops) = gop - queue->tx_map_ops;
+ return;
+}
+
+/* Consolidate skb with a frag_list into a brand new one with local pages on
+ * frags. Returns 0 or -ENOMEM if can't allocate new pages.
+ */
+static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *skb)
+{
+ unsigned int offset = skb_headlen(skb);
+ skb_frag_t frags[MAX_SKB_FRAGS];
+ int i, f;
+ struct ubuf_info *uarg;
+ struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
+
+ queue->stats.tx_zerocopy_sent += 2;
+ queue->stats.tx_frag_overflow++;
+
+ xenvif_fill_frags(queue, nskb);
+ /* Subtract frags size, we will correct it later */
+ skb->truesize -= skb->data_len;
+ skb->len += nskb->len;
+ skb->data_len += nskb->len;
+
+ /* create a brand new frags array and coalesce there */
+ for (i = 0; offset < skb->len; i++) {
+ struct page *page;
+ unsigned int len;
+
+ BUG_ON(i >= MAX_SKB_FRAGS);
+ page = alloc_page(GFP_ATOMIC);
+ if (!page) {
+ int j;
+ skb->truesize += skb->data_len;
+ for (j = 0; j < i; j++)
+ put_page(frags[j].page.p);
+ return -ENOMEM;
+ }
+
+ if (offset + PAGE_SIZE < skb->len)
+ len = PAGE_SIZE;
+ else
+ len = skb->len - offset;
+ if (skb_copy_bits(skb, offset, page_address(page), len))
+ BUG();
+
+ offset += len;
+ frags[i].page.p = page;
+ frags[i].page_offset = 0;
+ skb_frag_size_set(&frags[i], len);
+ }
+
+ /* Copied all the bits from the frag list -- free it. */
+ skb_frag_list_init(skb);
+ xenvif_skb_zerocopy_prepare(queue, nskb);
+ kfree_skb(nskb);
+
+ /* Release all the original (foreign) frags. */
+ for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
+ skb_frag_unref(skb, f);
+ uarg = skb_shinfo(skb)->destructor_arg;
+ /* increase inflight counter to offset decrement in callback */
+ atomic_inc(&queue->inflight_packets);
+ uarg->callback(uarg, true);
+ skb_shinfo(skb)->destructor_arg = NULL;
+
+ /* Fill the skb with the new (local) frags. */
+ memcpy(skb_shinfo(skb)->frags, frags, i * sizeof(skb_frag_t));
+ skb_shinfo(skb)->nr_frags = i;
+ skb->truesize += i * PAGE_SIZE;
+
+ return 0;
+}
+
+static int xenvif_tx_submit(struct xenvif_queue *queue)
+{
+ struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops;
+ struct gnttab_copy *gop_copy = queue->tx_copy_ops;
+ struct sk_buff *skb;
+ int work_done = 0;
+
+ while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) {
+ struct xen_netif_tx_request *txp;
+ u16 pending_idx;
+ unsigned data_len;
+
+ pending_idx = XENVIF_TX_CB(skb)->pending_idx;
+ txp = &queue->pending_tx_info[pending_idx].req;
+
+ /* Check the remap error code. */
+ if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) {
+ /* If there was an error, xenvif_tx_check_gop is
+ * expected to release all the frags which were mapped,
+ * so kfree_skb shouldn't do it again
+ */
+ skb_shinfo(skb)->nr_frags = 0;
+ if (skb_has_frag_list(skb)) {
+ struct sk_buff *nskb =
+ skb_shinfo(skb)->frag_list;
+ skb_shinfo(nskb)->nr_frags = 0;
+ }
+ kfree_skb(skb);
+ continue;
+ }
+
+ data_len = skb->len;
+ callback_param(queue, pending_idx).ctx = NULL;
+ if (data_len < txp->size) {
+ /* Append the packet payload as a fragment. */
+ txp->offset += data_len;
+ txp->size -= data_len;
+ } else {
+ /* Schedule a response immediately. */
+ xenvif_idx_release(queue, pending_idx,
+ XEN_NETIF_RSP_OKAY);
+ }
+
+ if (txp->flags & XEN_NETTXF_csum_blank)
+ skb->ip_summed = CHECKSUM_PARTIAL;
+ else if (txp->flags & XEN_NETTXF_data_validated)
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+ xenvif_fill_frags(queue, skb);
+
+ if (unlikely(skb_has_frag_list(skb))) {
+ if (xenvif_handle_frag_list(queue, skb)) {
+ if (net_ratelimit())
+ netdev_err(queue->vif->dev,
+ "Not enough memory to consolidate frag_list!\n");
+ xenvif_skb_zerocopy_prepare(queue, skb);
+ kfree_skb(skb);
+ continue;
+ }
+ }
+
+ skb->dev = queue->vif->dev;
+ skb->protocol = eth_type_trans(skb, skb->dev);
+ skb_reset_network_header(skb);
+
+ if (checksum_setup(queue, skb)) {
+ netdev_dbg(queue->vif->dev,
+ "Can't setup checksum in net_tx_action\n");
+ /* We have to set this flag to trigger the callback */
+ if (skb_shinfo(skb)->destructor_arg)
+ xenvif_skb_zerocopy_prepare(queue, skb);
+ kfree_skb(skb);
+ continue;
+ }
+
+ skb_probe_transport_header(skb, 0);
+
+ /* If the packet is GSO then we will have just set up the
+ * transport header offset in checksum_setup so it's now
+ * straightforward to calculate gso_segs.
+ */
+ if (skb_is_gso(skb)) {
+ int mss = skb_shinfo(skb)->gso_size;
+ int hdrlen = skb_transport_header(skb) -
+ skb_mac_header(skb) +
+ tcp_hdrlen(skb);
+
+ skb_shinfo(skb)->gso_segs =
+ DIV_ROUND_UP(skb->len - hdrlen, mss);
+ }
+
+ queue->stats.rx_bytes += skb->len;
+ queue->stats.rx_packets++;
+
+ work_done++;
+
+ /* Set this flag right before netif_receive_skb, otherwise
+ * someone might think this packet already left netback, and
+ * do a skb_copy_ubufs while we are still in control of the
+ * skb. E.g. the __pskb_pull_tail earlier can do such thing.
+ */
+ if (skb_shinfo(skb)->destructor_arg) {
+ xenvif_skb_zerocopy_prepare(queue, skb);
+ queue->stats.tx_zerocopy_sent++;
+ }
+
+ netif_receive_skb(skb);
+ }
+
+ return work_done;
+}
+
+void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success)
+{
+ unsigned long flags;
+ pending_ring_idx_t index;
+ struct xenvif_queue *queue = ubuf_to_queue(ubuf);
+
+ /* This is the only place where we grab this lock, to protect callbacks
+ * from each other.
+ */
+ spin_lock_irqsave(&queue->callback_lock, flags);
+ do {
+ u16 pending_idx = ubuf->desc;
+ ubuf = (struct ubuf_info *) ubuf->ctx;
+ BUG_ON(queue->dealloc_prod - queue->dealloc_cons >=
+ MAX_PENDING_REQS);
+ index = pending_index(queue->dealloc_prod);
+ queue->dealloc_ring[index] = pending_idx;
+ /* Sync with xenvif_tx_dealloc_action:
+ * insert idx then incr producer.
+ */
+ smp_wmb();
+ queue->dealloc_prod++;
+ } while (ubuf);
+ wake_up(&queue->dealloc_wq);
+ spin_unlock_irqrestore(&queue->callback_lock, flags);
+
+ if (likely(zerocopy_success))
+ queue->stats.tx_zerocopy_success++;
+ else
+ queue->stats.tx_zerocopy_fail++;
+ xenvif_skb_zerocopy_complete(queue);
+}
+
+static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue)
+{
+ struct gnttab_unmap_grant_ref *gop;
+ pending_ring_idx_t dc, dp;
+ u16 pending_idx, pending_idx_release[MAX_PENDING_REQS];
+ unsigned int i = 0;
+
+ dc = queue->dealloc_cons;
+ gop = queue->tx_unmap_ops;
+
+ /* Free up any grants we have finished using */
+ do {
+ dp = queue->dealloc_prod;
+
+ /* Ensure we see all indices enqueued by all
+ * xenvif_zerocopy_callback().
+ */
+ smp_rmb();
+
+ while (dc != dp) {
+ BUG_ON(gop - queue->tx_unmap_ops > MAX_PENDING_REQS);
+ pending_idx =
+ queue->dealloc_ring[pending_index(dc++)];
+
+ pending_idx_release[gop-queue->tx_unmap_ops] =
+ pending_idx;
+ queue->pages_to_unmap[gop-queue->tx_unmap_ops] =
+ queue->mmap_pages[pending_idx];
+ gnttab_set_unmap_op(gop,
+ idx_to_kaddr(queue, pending_idx),
+ GNTMAP_host_map,
+ queue->grant_tx_handle[pending_idx]);
+ xenvif_grant_handle_reset(queue, pending_idx);
+ ++gop;
+ }
+
+ } while (dp != queue->dealloc_prod);
+
+ queue->dealloc_cons = dc;
+
+ if (gop - queue->tx_unmap_ops > 0) {
+ int ret;
+ ret = gnttab_unmap_refs(queue->tx_unmap_ops,
+ NULL,
+ queue->pages_to_unmap,
+ gop - queue->tx_unmap_ops);
+ if (ret) {
+ netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tx ret %d\n",
+ gop - queue->tx_unmap_ops, ret);
+ for (i = 0; i < gop - queue->tx_unmap_ops; ++i) {
+ if (gop[i].status != GNTST_okay)
+ netdev_err(queue->vif->dev,
+ " host_addr: %llx handle: %x status: %d\n",
+ gop[i].host_addr,
+ gop[i].handle,
+ gop[i].status);
+ }
+ BUG();
+ }
+ }
+
+ for (i = 0; i < gop - queue->tx_unmap_ops; ++i)
+ xenvif_idx_release(queue, pending_idx_release[i],
+ XEN_NETIF_RSP_OKAY);
+}
+
+
+/* Called after netfront has transmitted */
+int xenvif_tx_action(struct xenvif_queue *queue, int budget)
+{
+ unsigned nr_mops, nr_cops = 0;
+ int work_done, ret;
+
+ if (unlikely(!tx_work_todo(queue)))
+ return 0;
+
+ xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops);
+
+ if (nr_cops == 0)
+ return 0;
+
+ gnttab_batch_copy(queue->tx_copy_ops, nr_cops);
+ if (nr_mops != 0) {
+ ret = gnttab_map_refs(queue->tx_map_ops,
+ NULL,
+ queue->pages_to_map,
+ nr_mops);
+ BUG_ON(ret);
+ }
+
+ work_done = xenvif_tx_submit(queue);
+
+ return work_done;
+}
+
+static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
+ u8 status)
+{
+ struct pending_tx_info *pending_tx_info;
+ pending_ring_idx_t index;
+ unsigned long flags;
+
+ pending_tx_info = &queue->pending_tx_info[pending_idx];
+
+ spin_lock_irqsave(&queue->response_lock, flags);
+
+ make_tx_response(queue, &pending_tx_info->req, status);
+
+ /* Release the pending index before pusing the Tx response so
+ * its available before a new Tx request is pushed by the
+ * frontend.
+ */
+ index = pending_index(queue->pending_prod++);
+ queue->pending_ring[index] = pending_idx;
+
+ push_tx_responses(queue);
+
+ spin_unlock_irqrestore(&queue->response_lock, flags);
+}
+
+
+static void make_tx_response(struct xenvif_queue *queue,
+ struct xen_netif_tx_request *txp,
+ s8 st)
+{
+ RING_IDX i = queue->tx.rsp_prod_pvt;
+ struct xen_netif_tx_response *resp;
+
+ resp = RING_GET_RESPONSE(&queue->tx, i);
+ resp->id = txp->id;
+ resp->status = st;
+
+ if (txp->flags & XEN_NETTXF_extra_info)
+ RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;
+
+ queue->tx.rsp_prod_pvt = ++i;
+}
+
+static void push_tx_responses(struct xenvif_queue *queue)
+{
+ int notify;
+
+ RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
+ if (notify)
+ notify_remote_via_irq(queue->tx_irq);
+}
+
+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;
+}
+
+void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
+{
+ int ret;
+ struct gnttab_unmap_grant_ref tx_unmap_op;
+
+ gnttab_set_unmap_op(&tx_unmap_op,
+ idx_to_kaddr(queue, pending_idx),
+ GNTMAP_host_map,
+ queue->grant_tx_handle[pending_idx]);
+ xenvif_grant_handle_reset(queue, pending_idx);
+
+ ret = gnttab_unmap_refs(&tx_unmap_op, NULL,
+ &queue->mmap_pages[pending_idx], 1);
+ if (ret) {
+ netdev_err(queue->vif->dev,
+ "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: %x status: %d\n",
+ ret,
+ pending_idx,
+ tx_unmap_op.host_addr,
+ tx_unmap_op.handle,
+ tx_unmap_op.status);
+ BUG();
+ }
+}
+
+static inline int tx_work_todo(struct xenvif_queue *queue)
+{
+ if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx)))
+ return 1;
+
+ return 0;
+}
+
+static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue)
+{
+ return queue->dealloc_cons != queue->dealloc_prod;
+}
+
+void xenvif_unmap_frontend_rings(struct xenvif_queue *queue)
+{
+ if (queue->tx.sring)
+ xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
+ queue->tx.sring);
+ if (queue->rx.sring)
+ xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
+ queue->rx.sring);
+}
+
+int xenvif_map_frontend_rings(struct xenvif_queue *queue,
+ grant_ref_t tx_ring_ref,
+ grant_ref_t rx_ring_ref)
+{
+ void *addr;
+ struct xen_netif_tx_sring *txs;
+ struct xen_netif_rx_sring *rxs;
+
+ int err = -ENOMEM;
+
+ err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
+ &tx_ring_ref, 1, &addr);
+ if (err)
+ goto err;
+
+ txs = (struct xen_netif_tx_sring *)addr;
+ BACK_RING_INIT(&queue->tx, txs, PAGE_SIZE);
+
+ err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
+ &rx_ring_ref, 1, &addr);
+ if (err)
+ goto err;
+
+ rxs = (struct xen_netif_rx_sring *)addr;
+ BACK_RING_INIT(&queue->rx, rxs, PAGE_SIZE);
+
+ return 0;
+
+err:
+ xenvif_unmap_frontend_rings(queue);
+ return err;
+}
+
+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);
+}
+
+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 < XEN_NETBK_RX_SLOTS_MAX
+ && 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 >= XEN_NETBK_RX_SLOTS_MAX;
+}
+
+static bool xenvif_have_rx_work(struct xenvif_queue *queue)
+{
+ return (!skb_queue_empty(&queue->rx_queue)
+ && xenvif_rx_ring_slots_available(queue, XEN_NETBK_RX_SLOTS_MAX))
+ || (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);
+}
+
+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;
+}
+
+static bool xenvif_dealloc_kthread_should_stop(struct xenvif_queue *queue)
+{
+ /* Dealloc thread must remain running until all inflight
+ * packets complete.
+ */
+ return kthread_should_stop() &&
+ !atomic_read(&queue->inflight_packets);
+}
+
+int xenvif_dealloc_kthread(void *data)
+{
+ struct xenvif_queue *queue = data;
+
+ for (;;) {
+ wait_event_interruptible(queue->dealloc_wq,
+ tx_dealloc_work_todo(queue) ||
+ xenvif_dealloc_kthread_should_stop(queue));
+ if (xenvif_dealloc_kthread_should_stop(queue))
+ break;
+
+ xenvif_tx_dealloc_action(queue);
+ cond_resched();
+ }
+
+ /* Unmap anything remaining*/
+ if (tx_dealloc_work_todo(queue))
+ xenvif_tx_dealloc_action(queue);
+
+ return 0;
+}
+
+static int __init netback_init(void)
+{
+ int rc = 0;
+
+ if (!xen_domain())
+ return -ENODEV;
+
+ /* Allow as many queues as there are CPUs, by default */
+ xenvif_max_queues = num_online_cpus();
+
+ if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
+ pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
+ fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
+ fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
+ }
+
+ rc = xenvif_xenbus_init();
+ if (rc)
+ goto failed_init;
+
+#ifdef CONFIG_DEBUG_FS
+ xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL);
+ if (IS_ERR_OR_NULL(xen_netback_dbg_root))
+ pr_warn("Init of debugfs returned %ld!\n",
+ PTR_ERR(xen_netback_dbg_root));
+#endif /* CONFIG_DEBUG_FS */
+
+ return 0;
+
+failed_init:
+ return rc;
+}
+
+module_init(netback_init);
+
+static void __exit netback_fini(void)
+{
+#ifdef CONFIG_DEBUG_FS
+ if (!IS_ERR_OR_NULL(xen_netback_dbg_root))
+ debugfs_remove_recursive(xen_netback_dbg_root);
+#endif /* CONFIG_DEBUG_FS */
+ xenvif_xenbus_fini();
+}
+module_exit(netback_fini);
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_ALIAS("xen-backend:vif");
Code Review / kvmfornfv.git / blobdiff