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Subject[patch 24/28]xen: Add the Xen virtual network device driver.
The network device frontend driver allows the kernel to access network
devices exported exported by a virtual machine containing a physical
network device driver.



Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Cc: Ian Pratt <ian.pratt@xensource.com>
Cc: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: Stephen Hemminger <shemminger@linux-foundation.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Keir Fraser <Keir.Fraser@cl.cam.ac.uk>
Cc: netdev@vger.kernel.org

---
drivers/net/Kconfig | 12
drivers/net/Makefile | 2
drivers/net/xen-netfront.c | 1995 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 2009 insertions(+)
===================================================================
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -2507,6 +2507,18 @@ source "drivers/atm/Kconfig"

source "drivers/s390/net/Kconfig"

+config XEN_NETDEV_FRONTEND
+ tristate "Xen network device frontend driver"
+ depends on XEN
+ default y
+ help
+ The network device frontend driver allows the kernel to
+ access network devices exported exported by a virtual
+ machine containing a physical network device driver. The
+ frontend driver is intended for unprivileged guest domains;
+ if you are compiling a kernel for a Xen guest, you almost
+ certainly want to enable this.
+
config ISERIES_VETH
tristate "iSeries Virtual Ethernet driver support"
depends on PPC_ISERIES
===================================================================
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -218,3 +218,5 @@ obj-$(CONFIG_FS_ENET) += fs_enet/
obj-$(CONFIG_FS_ENET) += fs_enet/

obj-$(CONFIG_NETXEN_NIC) += netxen/
+
+obj-$(CONFIG_XEN_NETDEV_FRONTEND) += xen-netfront.o
===================================================================
--- /dev/null
+++ b/drivers/net/xen-netfront.c
@@ -0,0 +1,1995 @@
+/*
+ * Virtual network driver for conversing with remote driver backends.
+ *
+ * Copyright (c) 2002-2005, K A Fraser
+ * Copyright (c) 2005, XenSource Ltd
+ *
+ * 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 <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/skbuff.h>
+#include <linux/ethtool.h>
+#include <linux/if_ether.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <linux/moduleparam.h>
+#include <linux/mm.h>
+#include <net/ip.h>
+
+#include <xen/xenbus.h>
+#include <xen/events.h>
+#include <xen/page.h>
+#include <xen/grant_table.h>
+
+#include <xen/interface/io/netif.h>
+#include <xen/interface/memory.h>
+#include <xen/interface/grant_table.h>
+
+static struct ethtool_ops xennet_ethtool_ops;
+
+struct netfront_cb {
+ struct page *page;
+ unsigned offset;
+};
+
+#define NETFRONT_SKB_CB(skb) ((struct netfront_cb *)((skb)->cb))
+
+/*
+ * Mutually-exclusive module options to select receive data path:
+ * copy : Packets are copied by network backend into local memory
+ * flip : Page containing packet data is transferred to our ownership
+ * For fully-virtualised guests there is no option - copying must be used.
+ * For paravirtualised guests, flipping is the default.
+ */
+typedef enum rx_mode {
+ RX_COPY = 0,
+ RX_FLIP = 1,
+} rx_mode_t;
+
+static enum rx_mode rx_mode = RX_FLIP;
+
+#define param_check_rx_mode_t(name, p) __param_check(name, p, rx_mode_t)
+
+static int param_set_rx_mode_t(const char *val, struct kernel_param *kp)
+{
+ enum rx_mode *rxmp = kp->arg;
+ int ret = 0;
+
+ if (strcmp(val, "copy") == 0)
+ *rxmp = RX_COPY;
+ else if (strcmp(val, "flip") == 0)
+ *rxmp = RX_FLIP;
+ else
+ ret = -EINVAL;
+
+ return ret;
+}
+
+static int param_get_rx_mode_t(char *buffer, struct kernel_param *kp)
+{
+ enum rx_mode *rxmp = kp->arg;
+
+ return sprintf(buffer, "%s", *rxmp == RX_COPY ? "copy" : "flip");
+}
+
+MODULE_PARM_DESC(rx_mode, "How to get packets from card: \"copy\" or \"flip\"");
+module_param(rx_mode, rx_mode_t, 0400);
+
+#define RX_COPY_THRESHOLD 256
+
+#define GRANT_INVALID_REF 0
+
+#define NET_TX_RING_SIZE __RING_SIZE((struct xen_netif_tx_sring *)0, PAGE_SIZE)
+#define NET_RX_RING_SIZE __RING_SIZE((struct xen_netif_rx_sring *)0, PAGE_SIZE)
+#define TX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256)
+
+struct netfront_info {
+ struct list_head list;
+ struct net_device *netdev;
+
+ struct net_device_stats stats;
+
+ struct xen_netif_tx_front_ring tx;
+ struct xen_netif_rx_front_ring rx;
+
+ spinlock_t tx_lock;
+ spinlock_t rx_lock;
+
+ unsigned int evtchn;
+ unsigned int copying_receiver;
+
+ /* Receive-ring batched refills. */
+#define RX_MIN_TARGET 8
+#define RX_DFL_MIN_TARGET 64
+#define RX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256)
+ unsigned rx_min_target, rx_max_target, rx_target;
+ struct sk_buff_head rx_batch;
+
+ struct timer_list rx_refill_timer;
+
+ /*
+ * {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries
+ * are linked from tx_skb_freelist through skb_entry.link.
+ *
+ * NB. Freelist index entries are always going to be less than
+ * PAGE_OFFSET, whereas pointers to skbs will always be equal or
+ * greater than PAGE_OFFSET: we use this property to distinguish
+ * them.
+ */
+ union skb_entry {
+ struct sk_buff *skb;
+ unsigned link;
+ } tx_skbs[NET_TX_RING_SIZE];;
+ grant_ref_t gref_tx_head;
+ grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
+ unsigned tx_skb_freelist;
+
+ struct sk_buff *rx_skbs[NET_RX_RING_SIZE];
+ grant_ref_t gref_rx_head;
+ grant_ref_t grant_rx_ref[NET_RX_RING_SIZE];
+
+ struct xenbus_device *xbdev;
+ int tx_ring_ref;
+ int rx_ring_ref;
+
+ unsigned long rx_pfn_array[NET_RX_RING_SIZE];
+ struct multicall_entry rx_mcl[NET_RX_RING_SIZE+1];
+ struct mmu_update rx_mmu[NET_RX_RING_SIZE];
+};
+
+struct netfront_rx_info {
+ struct xen_netif_rx_response rx;
+ struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
+};
+
+/*
+ * Access macros for acquiring freeing slots in tx_skbs[].
+ */
+
+static void add_id_to_freelist(unsigned *head, union skb_entry *list, unsigned short id)
+{
+ list[id].link = *head;
+ *head = id;
+}
+
+static unsigned short get_id_from_freelist(unsigned *head, union skb_entry *list)
+{
+ unsigned int id = *head;
+ *head = list[id].link;
+ return id;
+}
+
+static int xennet_rxidx(RING_IDX idx)
+{
+ return idx & (NET_RX_RING_SIZE - 1);
+}
+
+static struct sk_buff *xennet_get_rx_skb(struct netfront_info *np,
+ RING_IDX ri)
+{
+ int i = xennet_rxidx(ri);
+ struct sk_buff *skb = np->rx_skbs[i];
+ np->rx_skbs[i] = NULL;
+ return skb;
+}
+
+static grant_ref_t xennet_get_rx_ref(struct netfront_info *np,
+ RING_IDX ri)
+{
+ int i = xennet_rxidx(ri);
+ grant_ref_t ref = np->grant_rx_ref[i];
+ np->grant_rx_ref[i] = GRANT_INVALID_REF;
+ return ref;
+}
+
+#ifdef CONFIG_SYSFS
+static int xennet_sysfs_addif(struct net_device *netdev);
+static void xennet_sysfs_delif(struct net_device *netdev);
+#else /* !CONFIG_SYSFS */
+#define xennet_sysfs_addif(dev) (0)
+#define xennet_sysfs_delif(dev) do { } while(0)
+#endif
+
+static int xennet_can_sg(struct net_device *dev)
+{
+ return dev->features & NETIF_F_SG;
+}
+
+
+static void rx_refill_timeout(unsigned long data)
+{
+ struct net_device *dev = (struct net_device *)data;
+ netif_rx_schedule(dev);
+}
+
+static int netfront_tx_slot_available(struct netfront_info *np)
+{
+ return ((np->tx.req_prod_pvt - np->tx.rsp_cons) <
+ (TX_MAX_TARGET - MAX_SKB_FRAGS - 2));
+}
+
+static void xennet_maybe_wake_tx(struct net_device *dev)
+{
+ struct netfront_info *np = netdev_priv(dev);
+
+ if (unlikely(netif_queue_stopped(dev)) &&
+ netfront_tx_slot_available(np) &&
+ likely(netif_running(dev)))
+ netif_wake_queue(dev);
+}
+
+static void xennet_alloc_rx_buffers(struct net_device *dev)
+{
+ unsigned short id;
+ struct netfront_info *np = netdev_priv(dev);
+ struct sk_buff *skb;
+ struct page *page;
+ int i, batch_target, notify;
+ RING_IDX req_prod = np->rx.req_prod_pvt;
+ struct xen_memory_reservation reservation;
+ grant_ref_t ref;
+ unsigned long pfn;
+ void *vaddr;
+ int nr_flips;
+ struct xen_netif_rx_request *req;
+
+ if (unlikely(!netif_carrier_ok(dev)))
+ return;
+
+ /*
+ * Allocate skbuffs greedily, even though we batch updates to the
+ * receive ring. This creates a less bursty demand on the memory
+ * allocator, so should reduce the chance of failed allocation requests
+ * both for ourself and for other kernel subsystems.
+ */
+ batch_target = np->rx_target - (req_prod - np->rx.rsp_cons);
+ for (i = skb_queue_len(&np->rx_batch); i < batch_target; i++) {
+ skb = __netdev_alloc_skb(dev, RX_COPY_THRESHOLD,
+ GFP_ATOMIC | __GFP_NOWARN);
+ if (unlikely(!skb))
+ goto no_skb;
+
+ page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
+ if (!page) {
+ kfree_skb(skb);
+no_skb:
+ /* Any skbuffs queued for refill? Force them out. */
+ if (i != 0)
+ goto refill;
+ /* Could not allocate any skbuffs. Try again later. */
+ mod_timer(&np->rx_refill_timer,
+ jiffies + (HZ/10));
+ break;
+ }
+
+ skb_shinfo(skb)->frags[0].page = page;
+ skb_shinfo(skb)->nr_frags = 1;
+ __skb_queue_tail(&np->rx_batch, skb);
+ }
+
+ /* Is the batch large enough to be worthwhile? */
+ if (i < (np->rx_target/2)) {
+ if (req_prod > np->rx.sring->req_prod)
+ goto push;
+ return;
+ }
+
+ /* Adjust our fill target if we risked running out of buffers. */
+ if (((req_prod - np->rx.sring->rsp_prod) < (np->rx_target / 4)) &&
+ ((np->rx_target *= 2) > np->rx_max_target))
+ np->rx_target = np->rx_max_target;
+
+ refill:
+ for (nr_flips = i = 0; ; i++) {
+ if ((skb = __skb_dequeue(&np->rx_batch)) == NULL)
+ break;
+
+ skb->dev = dev;
+
+ id = xennet_rxidx(req_prod + i);
+
+ BUG_ON(np->rx_skbs[id]);
+ np->rx_skbs[id] = skb;
+
+ ref = gnttab_claim_grant_reference(&np->gref_rx_head);
+ BUG_ON((signed short)ref < 0);
+ np->grant_rx_ref[id] = ref;
+
+ pfn = page_to_pfn(skb_shinfo(skb)->frags[0].page);
+ vaddr = page_address(skb_shinfo(skb)->frags[0].page);
+
+ req = RING_GET_REQUEST(&np->rx, req_prod + i);
+ if (!np->copying_receiver) {
+ gnttab_grant_foreign_transfer_ref(ref,
+ np->xbdev->otherend_id,
+ pfn);
+ np->rx_pfn_array[nr_flips] = pfn_to_mfn(pfn);
+ if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+ /* Remove this page before passing
+ * back to Xen. */
+ set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
+ MULTI_update_va_mapping(np->rx_mcl+i,
+ (unsigned long)vaddr,
+ __pte(0), 0);
+ }
+ nr_flips++;
+ } else {
+ gnttab_grant_foreign_access_ref(ref,
+ np->xbdev->otherend_id,
+ pfn_to_mfn(pfn),
+ 0);
+ }
+
+ req->id = id;
+ req->gref = ref;
+ }
+
+ if (nr_flips != 0) {
+ reservation.extent_start = np->rx_pfn_array;
+ reservation.nr_extents = nr_flips;
+ reservation.extent_order = 0;
+ reservation.address_bits = 0;
+ reservation.domid = DOMID_SELF;
+
+ if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+ /* After all PTEs have been zapped, flush the TLB. */
+ np->rx_mcl[i-1].args[MULTI_UVMFLAGS_INDEX] =
+ UVMF_TLB_FLUSH|UVMF_ALL;
+
+ /* Give away a batch of pages. */
+ np->rx_mcl[i].op = __HYPERVISOR_memory_op;
+ np->rx_mcl[i].args[0] = XENMEM_decrease_reservation;
+ np->rx_mcl[i].args[1] = (unsigned long)&reservation;
+
+ /* Zap PTEs and give away pages in one big
+ * multicall. */
+ (void)HYPERVISOR_multicall(np->rx_mcl, i+1);
+
+ /* Check return status of HYPERVISOR_memory_op(). */
+ if (unlikely(np->rx_mcl[i].result != i))
+ panic("Unable to reduce memory reservation\n");
+ } else {
+ if (HYPERVISOR_memory_op(XENMEM_decrease_reservation,
+ &reservation) != i)
+ panic("Unable to reduce memory reservation\n");
+ }
+ } else {
+ wmb();
+ }
+
+ /* Above is a suitable barrier to ensure backend will see requests. */
+ np->rx.req_prod_pvt = req_prod + i;
+ push:
+ RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->rx, notify);
+ if (notify)
+ notify_remote_via_irq(np->netdev->irq);
+}
+
+static int xennet_open(struct net_device *dev)
+{
+ struct netfront_info *np = netdev_priv(dev);
+
+ memset(&np->stats, 0, sizeof(np->stats));
+
+ spin_lock_bh(&np->rx_lock);
+ if (netif_carrier_ok(dev)) {
+ xennet_alloc_rx_buffers(dev);
+ np->rx.sring->rsp_event = np->rx.rsp_cons + 1;
+ if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))
+ netif_rx_schedule(dev);
+ }
+ spin_unlock_bh(&np->rx_lock);
+
+ xennet_maybe_wake_tx(dev);
+
+ return 0;
+}
+
+static void xennet_tx_buf_gc(struct net_device *dev)
+{
+ RING_IDX cons, prod;
+ unsigned short id;
+ struct netfront_info *np = netdev_priv(dev);
+ struct sk_buff *skb;
+
+ BUG_ON(!netif_carrier_ok(dev));
+
+ do {
+ prod = np->tx.sring->rsp_prod;
+ rmb(); /* Ensure we see responses up to 'rp'. */
+
+ for (cons = np->tx.rsp_cons; cons != prod; cons++) {
+ struct xen_netif_tx_response *txrsp;
+
+ txrsp = RING_GET_RESPONSE(&np->tx, cons);
+ if (txrsp->status == NETIF_RSP_NULL)
+ continue;
+
+ id = txrsp->id;
+ skb = np->tx_skbs[id].skb;
+ if (unlikely(gnttab_query_foreign_access(
+ np->grant_tx_ref[id]) != 0)) {
+ printk(KERN_ALERT "xennet_tx_buf_gc: warning "
+ "-- grant still in use by backend "
+ "domain.\n");
+ BUG();
+ }
+ gnttab_end_foreign_access_ref(
+ np->grant_tx_ref[id], GNTMAP_readonly);
+ gnttab_release_grant_reference(
+ &np->gref_tx_head, np->grant_tx_ref[id]);
+ np->grant_tx_ref[id] = GRANT_INVALID_REF;
+ add_id_to_freelist(&np->tx_skb_freelist, np->tx_skbs, id);
+ dev_kfree_skb_irq(skb);
+ }
+
+ np->tx.rsp_cons = prod;
+
+ /*
+ * Set a new event, then check for race with update of tx_cons.
+ * Note that it is essential to schedule a callback, no matter
+ * how few buffers are pending. Even if there is space in the
+ * transmit ring, higher layers may be blocked because too much
+ * data is outstanding: in such cases notification from Xen is
+ * likely to be the only kick that we'll get.
+ */
+ np->tx.sring->rsp_event =
+ prod + ((np->tx.sring->req_prod - prod) >> 1) + 1;
+ mb();
+ } while ((cons == prod) && (prod != np->tx.sring->rsp_prod));
+
+ xennet_maybe_wake_tx(dev);
+}
+
+static void xennet_make_frags(struct sk_buff *skb, struct net_device *dev,
+ struct xen_netif_tx_request *tx)
+{
+ struct netfront_info *np = netdev_priv(dev);
+ char *data = skb->data;
+ unsigned long mfn;
+ RING_IDX prod = np->tx.req_prod_pvt;
+ int frags = skb_shinfo(skb)->nr_frags;
+ unsigned int offset = offset_in_page(data);
+ unsigned int len = skb_headlen(skb);
+ unsigned int id;
+ grant_ref_t ref;
+ int i;
+
+ /* While the header overlaps a page boundary (including being
+ larger than a page), split it it into page-sized chunks. */
+ while (len > PAGE_SIZE - offset) {
+ tx->size = PAGE_SIZE - offset;
+ tx->flags |= NETTXF_more_data;
+ len -= tx->size;
+ data += tx->size;
+ offset = 0;
+
+ id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
+ np->tx_skbs[id].skb = skb_get(skb);
+ tx = RING_GET_REQUEST(&np->tx, prod++);
+ tx->id = id;
+ ref = gnttab_claim_grant_reference(&np->gref_tx_head);
+ BUG_ON((signed short)ref < 0);
+
+ mfn = virt_to_mfn(data);
+ gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id,
+ mfn, GNTMAP_readonly);
+
+ tx->gref = np->grant_tx_ref[id] = ref;
+ tx->offset = offset;
+ tx->size = len;
+ tx->flags = 0;
+ }
+
+ /* Grant backend access to each skb fragment page. */
+ for (i = 0; i < frags; i++) {
+ skb_frag_t *frag = skb_shinfo(skb)->frags + i;
+
+ tx->flags |= NETTXF_more_data;
+
+ id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
+ np->tx_skbs[id].skb = skb_get(skb);
+ tx = RING_GET_REQUEST(&np->tx, prod++);
+ tx->id = id;
+ ref = gnttab_claim_grant_reference(&np->gref_tx_head);
+ BUG_ON((signed short)ref < 0);
+
+ mfn = pfn_to_mfn(page_to_pfn(frag->page));
+ gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id,
+ mfn, GNTMAP_readonly);
+
+ tx->gref = np->grant_tx_ref[id] = ref;
+ tx->offset = frag->page_offset;
+ tx->size = frag->size;
+ tx->flags = 0;
+ }
+
+ np->tx.req_prod_pvt = prod;
+}
+
+static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+ unsigned short id;
+ struct netfront_info *np = netdev_priv(dev);
+ struct xen_netif_tx_request *tx;
+ struct xen_netif_extra_info *extra;
+ char *data = skb->data;
+ RING_IDX i;
+ grant_ref_t ref;
+ unsigned long mfn;
+ int notify;
+ int frags = skb_shinfo(skb)->nr_frags;
+ unsigned int offset = offset_in_page(data);
+ unsigned int len = skb_headlen(skb);
+
+ frags += (offset + len + PAGE_SIZE - 1) / PAGE_SIZE;
+ if (unlikely(frags > MAX_SKB_FRAGS + 1)) {
+ printk(KERN_ALERT "xennet: skb rides the rocket: %d frags\n",
+ frags);
+ dump_stack();
+ goto drop;
+ }
+
+ spin_lock_irq(&np->tx_lock);
+
+ if (unlikely(!netif_carrier_ok(dev) ||
+ (frags > 1 && !xennet_can_sg(dev)) ||
+ netif_needs_gso(dev, skb))) {
+ spin_unlock_irq(&np->tx_lock);
+ goto drop;
+ }
+
+ i = np->tx.req_prod_pvt;
+
+ id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
+ np->tx_skbs[id].skb = skb;
+
+ tx = RING_GET_REQUEST(&np->tx, i);
+
+ tx->id = id;
+ ref = gnttab_claim_grant_reference(&np->gref_tx_head);
+ BUG_ON((signed short)ref < 0);
+ mfn = virt_to_mfn(data);
+ gnttab_grant_foreign_access_ref(
+ ref, np->xbdev->otherend_id, mfn, GNTMAP_readonly);
+ tx->gref = np->grant_tx_ref[id] = ref;
+ tx->offset = offset;
+ tx->size = len;
+ extra = NULL;
+
+ tx->flags = 0;
+ if (skb->ip_summed == CHECKSUM_PARTIAL)
+ /* local packet? */
+ tx->flags |= NETTXF_csum_blank | NETTXF_data_validated;
+ else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
+ /* remote but checksummed. */
+ tx->flags |= NETTXF_data_validated;
+
+ if (skb_shinfo(skb)->gso_size) {
+ struct xen_netif_extra_info *gso;
+
+ gso = (struct xen_netif_extra_info *)
+ RING_GET_REQUEST(&np->tx, ++i);
+
+ if (extra)
+ extra->flags |= XEN_NETIF_EXTRA_FLAG_MORE;
+ else
+ tx->flags |= NETTXF_extra_info;
+
+ gso->u.gso.size = skb_shinfo(skb)->gso_size;
+ gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
+ gso->u.gso.pad = 0;
+ gso->u.gso.features = 0;
+
+ gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
+ gso->flags = 0;
+ extra = gso;
+ }
+
+ np->tx.req_prod_pvt = i + 1;
+
+ xennet_make_frags(skb, dev, tx);
+ tx->size = skb->len;
+
+ RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->tx, notify);
+ if (notify)
+ notify_remote_via_irq(np->netdev->irq);
+
+ xennet_tx_buf_gc(dev);
+
+ if (!netfront_tx_slot_available(np))
+ netif_stop_queue(dev);
+
+ spin_unlock_irq(&np->tx_lock);
+
+ np->stats.tx_bytes += skb->len;
+ np->stats.tx_packets++;
+
+ return 0;
+
+ drop:
+ np->stats.tx_dropped++;
+ dev_kfree_skb(skb);
+ return 0;
+}
+
+static int xennet_close(struct net_device *dev)
+{
+ struct netfront_info *np = netdev_priv(dev);
+ netif_stop_queue(np->netdev);
+ return 0;
+}
+
+static struct net_device_stats *xennet_get_stats(struct net_device *dev)
+{
+ struct netfront_info *np = netdev_priv(dev);
+ return &np->stats;
+}
+
+static void xennet_move_rx_slot(struct netfront_info *np, struct sk_buff *skb,
+ grant_ref_t ref)
+{
+ int new = xennet_rxidx(np->rx.req_prod_pvt);
+
+ BUG_ON(np->rx_skbs[new]);
+ np->rx_skbs[new] = skb;
+ np->grant_rx_ref[new] = ref;
+ RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->id = new;
+ RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->gref = ref;
+ np->rx.req_prod_pvt++;
+}
+
+static int xennet_get_extras(struct netfront_info *np,
+ struct xen_netif_extra_info *extras,
+ RING_IDX rp)
+
+{
+ struct xen_netif_extra_info *extra;
+ struct device *dev = &np->netdev->dev;
+ RING_IDX cons = np->rx.rsp_cons;
+ int err = 0;
+
+ do {
+ struct sk_buff *skb;
+ grant_ref_t ref;
+
+ if (unlikely(cons + 1 == rp)) {
+ if (net_ratelimit())
+ dev_warn(dev, "Missing extra info\n");
+ err = -EBADR;
+ break;
+ }
+
+ extra = (struct xen_netif_extra_info *)
+ RING_GET_RESPONSE(&np->rx, ++cons);
+
+ if (unlikely(!extra->type ||
+ extra->type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
+ if (net_ratelimit())
+ dev_warn(dev, "Invalid extra type: %d\n",
+ extra->type);
+ err = -EINVAL;
+ } else {
+ memcpy(&extras[extra->type - 1], extra,
+ sizeof(*extra));
+ }
+
+ skb = xennet_get_rx_skb(np, cons);
+ ref = xennet_get_rx_ref(np, cons);
+ xennet_move_rx_slot(np, skb, ref);
+ } while (extra->flags & XEN_NETIF_EXTRA_FLAG_MORE);
+
+ np->rx.rsp_cons = cons;
+ return err;
+}
+
+static int xennet_get_responses(struct netfront_info *np,
+ struct netfront_rx_info *rinfo, RING_IDX rp,
+ struct sk_buff_head *list,
+ int *pages_flipped_p)
+{
+ int pages_flipped = *pages_flipped_p;
+ struct mmu_update *mmu;
+ struct multicall_entry *mcl;
+ struct xen_netif_rx_response *rx = &rinfo->rx;
+ struct xen_netif_extra_info *extras = rinfo->extras;
+ struct device *dev = &np->netdev->dev;
+ RING_IDX cons = np->rx.rsp_cons;
+ struct sk_buff *skb = xennet_get_rx_skb(np, cons);
+ grant_ref_t ref = xennet_get_rx_ref(np, cons);
+ int max = MAX_SKB_FRAGS + (rx->status <= RX_COPY_THRESHOLD);
+ int frags = 1;
+ int err = 0;
+ unsigned long ret;
+
+ if (rx->flags & NETRXF_extra_info) {
+ err = xennet_get_extras(np, extras, rp);
+ cons = np->rx.rsp_cons;
+ }
+
+ for (;;) {
+ unsigned long mfn;
+
+ if (unlikely(rx->status < 0 ||
+ rx->offset + rx->status > PAGE_SIZE)) {
+ if (net_ratelimit())
+ dev_warn(dev, "rx->offset: %x, size: %u\n",
+ rx->offset, rx->status);
+ xennet_move_rx_slot(np, skb, ref);
+ err = -EINVAL;
+ goto next;
+ }
+
+ /*
+ * This definitely indicates a bug, either in this driver or in
+ * the backend driver. In future this should flag the bad
+ * situation to the system controller to reboot the backed.
+ */
+ if (ref == GRANT_INVALID_REF) {
+ if (net_ratelimit())
+ dev_warn(dev, "Bad rx response id %d.\n",
+ rx->id);
+ err = -EINVAL;
+ goto next;
+ }
+
+ if (!np->copying_receiver) {
+ /* Memory pressure, insufficient buffer
+ * headroom, ... */
+ mfn = gnttab_end_foreign_transfer_ref(ref);
+ if (!mfn) {
+ if (net_ratelimit())
+ dev_warn(dev, "Unfulfilled rx req "
+ "(id=%d, st=%d).\n",
+ rx->id, rx->status);
+ xennet_move_rx_slot(np, skb, ref);
+ err = -ENOMEM;
+ goto next;
+ }
+
+ if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+ /* Remap the page. */
+ struct page *page =
+ skb_shinfo(skb)->frags[0].page;
+ unsigned long pfn = page_to_pfn(page);
+ void *vaddr = page_address(page);
+
+ mcl = np->rx_mcl + pages_flipped;
+ mmu = np->rx_mmu + pages_flipped;
+
+ MULTI_update_va_mapping(mcl,
+ (unsigned long)vaddr,
+ mfn_pte(mfn, PAGE_KERNEL),
+ 0);
+ mmu->ptr = ((u64)mfn << PAGE_SHIFT)
+ | MMU_MACHPHYS_UPDATE;
+ mmu->val = pfn;
+
+ set_phys_to_machine(pfn, mfn);
+ }
+ pages_flipped++;
+ } else {
+ ret = gnttab_end_foreign_access_ref(ref, 0);
+ BUG_ON(!ret);
+ }
+
+ gnttab_release_grant_reference(&np->gref_rx_head, ref);
+
+ __skb_queue_tail(list, skb);
+
+next:
+ if (!(rx->flags & NETRXF_more_data))
+ break;
+
+ if (cons + frags == rp) {
+ if (net_ratelimit())
+ dev_warn(dev, "Need more frags\n");
+ err = -ENOENT;
+ break;
+ }
+
+ rx = RING_GET_RESPONSE(&np->rx, cons + frags);
+ skb = xennet_get_rx_skb(np, cons + frags);
+ ref = xennet_get_rx_ref(np, cons + frags);
+ frags++;
+ }
+
+ if (unlikely(frags > max)) {
+ if (net_ratelimit())
+ dev_warn(dev, "Too many frags\n");
+ err = -E2BIG;
+ }
+
+ if (unlikely(err))
+ np->rx.rsp_cons = cons + frags;
+
+ *pages_flipped_p = pages_flipped;
+
+ return err;
+}
+
+static int xennet_set_skb_gso(struct sk_buff *skb,
+ struct xen_netif_extra_info *gso)
+{
+ if (!gso->u.gso.size) {
+ if (net_ratelimit())
+ printk(KERN_WARNING "GSO size must not be zero.\n");
+ return -EINVAL;
+ }
+
+ /* Currently only TCPv4 S.O. is supported. */
+ if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) {
+ if (net_ratelimit())
+ printk(KERN_WARNING "Bad GSO type %d.\n", gso->u.gso.type);
+ return -EINVAL;
+ }
+
+ skb_shinfo(skb)->gso_size = gso->u.gso.size;
+ skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
+
+ /* Header must be checked, and gso_segs computed. */
+ skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
+ skb_shinfo(skb)->gso_segs = 0;
+
+ return 0;
+}
+
+static RING_IDX xennet_fill_frags(struct netfront_info *np,
+ struct sk_buff *skb,
+ struct sk_buff_head *list)
+{
+ struct skb_shared_info *shinfo = skb_shinfo(skb);
+ int nr_frags = shinfo->nr_frags;
+ RING_IDX cons = np->rx.rsp_cons;
+ skb_frag_t *frag = shinfo->frags + nr_frags;
+ struct sk_buff *nskb;
+
+ while ((nskb = __skb_dequeue(list))) {
+ struct xen_netif_rx_response *rx =
+ RING_GET_RESPONSE(&np->rx, ++cons);
+
+ frag->page = skb_shinfo(nskb)->frags[0].page;
+ frag->page_offset = rx->offset;
+ frag->size = rx->status;
+
+ skb->data_len += rx->status;
+
+ skb_shinfo(nskb)->nr_frags = 0;
+ kfree_skb(nskb);
+
+ frag++;
+ nr_frags++;
+ }
+
+ shinfo->nr_frags = nr_frags;
+ return cons;
+}
+
+static int skb_checksum_setup(struct sk_buff *skb)
+{
+ struct iphdr *iph;
+ unsigned char *th;
+ int err = -EPROTO;
+
+ if (skb->protocol != htons(ETH_P_IP))
+ goto out;
+
+ iph = (void *)skb->data;
+ th = skb->data + 4 * iph->ihl;
+ if (th >= skb_tail_pointer(skb))
+ goto out;
+
+ skb->csum_start = th - skb->head;
+ switch (iph->protocol) {
+ case IPPROTO_TCP:
+ skb->csum_offset = offsetof(struct tcphdr, check);
+ break;
+ case IPPROTO_UDP:
+ skb->csum_offset = offsetof(struct udphdr, check);
+ break;
+ default:
+ if (net_ratelimit())
+ printk(KERN_ERR "Attempting to checksum a non-"
+ "TCP/UDP packet, dropping a protocol"
+ " %d packet", iph->protocol);
+ goto out;
+ }
+
+ if ((th + skb->csum_offset + 2) > skb_tail_pointer(skb))
+ goto out;
+
+ err = 0;
+
+out:
+ return err;
+}
+
+static int handle_incoming_queue(struct net_device *dev,
+ struct sk_buff_head *rxq)
+{
+ struct netfront_info *np = netdev_priv(dev);
+ int packets_dropped = 0;
+ struct sk_buff *skb;
+
+ while ((skb = __skb_dequeue(rxq)) != NULL) {
+ struct page *page = NETFRONT_SKB_CB(skb)->page;
+ void *vaddr = page_address(page);
+ unsigned offset = NETFRONT_SKB_CB(skb)->offset;
+
+ memcpy(skb->data, vaddr + offset,
+ skb_headlen(skb));
+
+ if (page != skb_shinfo(skb)->frags[0].page)
+ __free_page(page);
+
+ /* Ethernet work: Delayed to here as it peeks the header. */
+ skb->protocol = eth_type_trans(skb, dev);
+
+ if (skb->ip_summed == CHECKSUM_PARTIAL) {
+ if (skb_checksum_setup(skb)) {
+ kfree_skb(skb);
+ packets_dropped++;
+ np->stats.rx_errors++;
+ continue;
+ }
+ }
+
+ np->stats.rx_packets++;
+ np->stats.rx_bytes += skb->len;
+
+ /* Pass it up. */
+ netif_receive_skb(skb);
+ dev->last_rx = jiffies;
+ }
+
+ return packets_dropped;
+}
+
+static int xennet_poll(struct net_device *dev, int *pbudget)
+{
+ struct netfront_info *np = netdev_priv(dev);
+ struct sk_buff *skb;
+ struct netfront_rx_info rinfo;
+ struct xen_netif_rx_response *rx = &rinfo.rx;
+ struct xen_netif_extra_info *extras = rinfo.extras;
+ RING_IDX i, rp;
+ struct multicall_entry *mcl;
+ int work_done, budget, more_to_do = 1;
+ struct sk_buff_head rxq;
+ struct sk_buff_head errq;
+ struct sk_buff_head tmpq;
+ unsigned long flags;
+ unsigned int len;
+ int pages_flipped = 0;
+ int err;
+
+ spin_lock(&np->rx_lock);
+
+ if (unlikely(!netif_carrier_ok(dev))) {
+ spin_unlock(&np->rx_lock);
+ return 0;
+ }
+
+ skb_queue_head_init(&rxq);
+ skb_queue_head_init(&errq);
+ skb_queue_head_init(&tmpq);
+
+ if ((budget = *pbudget) > dev->quota)
+ budget = dev->quota;
+ rp = np->rx.sring->rsp_prod;
+ rmb(); /* Ensure we see queued responses up to 'rp'. */
+
+ i = np->rx.rsp_cons;
+ work_done = 0;
+ while ((i != rp) && (work_done < budget)) {
+ memcpy(rx, RING_GET_RESPONSE(&np->rx, i), sizeof(*rx));
+ memset(extras, 0, sizeof(rinfo.extras));
+
+ err = xennet_get_responses(np, &rinfo, rp, &tmpq,
+ &pages_flipped);
+
+ if (unlikely(err)) {
+err:
+ while ((skb = __skb_dequeue(&tmpq)))
+ __skb_queue_tail(&errq, skb);
+ np->stats.rx_errors++;
+ i = np->rx.rsp_cons;
+ continue;
+ }
+
+ skb = __skb_dequeue(&tmpq);
+
+ if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
+ struct xen_netif_extra_info *gso;
+ gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
+
+ if (unlikely(xennet_set_skb_gso(skb, gso))) {
+ __skb_queue_head(&tmpq, skb);
+ np->rx.rsp_cons += skb_queue_len(&tmpq);
+ goto err;
+ }
+ }
+
+ NETFRONT_SKB_CB(skb)->page = skb_shinfo(skb)->frags[0].page;
+ NETFRONT_SKB_CB(skb)->offset = rx->offset;
+
+ len = rx->status;
+ if (len > RX_COPY_THRESHOLD)
+ len = RX_COPY_THRESHOLD;
+ skb_put(skb, len);
+
+ if (rx->status > len) {
+ skb_shinfo(skb)->frags[0].page_offset =
+ rx->offset + len;
+ skb_shinfo(skb)->frags[0].size = rx->status - len;
+ skb->data_len = rx->status - len;
+ } else {
+ skb_shinfo(skb)->frags[0].page = NULL;
+ skb_shinfo(skb)->nr_frags = 0;
+ }
+
+ i = xennet_fill_frags(np, skb, &tmpq);
+
+ /*
+ * Truesize approximates the size of true data plus
+ * any supervisor overheads. Adding hypervisor
+ * overheads has been shown to significantly reduce
+ * achievable bandwidth with the default receive
+ * buffer size. It is therefore not wise to account
+ * for it here.
+ *
+ * After alloc_skb(RX_COPY_THRESHOLD), truesize is set
+ * to RX_COPY_THRESHOLD + the supervisor
+ * overheads. Here, we add the size of the data pulled
+ * in xennet_fill_frags().
+ *
+ * We also adjust for any unused space in the main
+ * data area by subtracting (RX_COPY_THRESHOLD -
+ * len). This is especially important with drivers
+ * which split incoming packets into header and data,
+ * using only 66 bytes of the main data area (see the
+ * e1000 driver for example.) On such systems,
+ * without this last adjustement, our achievable
+ * receive throughout using the standard receive
+ * buffer size was cut by 25%(!!!).
+ */
+ skb->truesize += skb->data_len - (RX_COPY_THRESHOLD - len);
+ skb->len += skb->data_len;
+
+ if (rx->flags & NETRXF_csum_blank)
+ skb->ip_summed = CHECKSUM_PARTIAL;
+ else if (rx->flags & NETRXF_data_validated)
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+ __skb_queue_tail(&rxq, skb);
+
+ np->rx.rsp_cons = ++i;
+ work_done++;
+ }
+
+ if (pages_flipped) {
+ /* Do all the remapping work, and M2P updates. */
+ if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+ mcl = np->rx_mcl + pages_flipped;
+ MULTI_mmu_update(mcl, np->rx_mmu,
+ pages_flipped, 0, DOMID_SELF);
+ (void)HYPERVISOR_multicall(np->rx_mcl,
+ pages_flipped + 1);
+ }
+ }
+
+ while ((skb = __skb_dequeue(&errq)))
+ kfree_skb(skb);
+
+ work_done -= handle_incoming_queue(dev, &rxq);
+
+ /* If we get a callback with very few responses, reduce fill target. */
+ /* NB. Note exponential increase, linear decrease. */
+ if (((np->rx.req_prod_pvt - np->rx.sring->rsp_prod) >
+ ((3*np->rx_target) / 4)) &&
+ (--np->rx_target < np->rx_min_target))
+ np->rx_target = np->rx_min_target;
+
+ xennet_alloc_rx_buffers(dev);
+
+ *pbudget -= work_done;
+ dev->quota -= work_done;
+
+ if (work_done < budget) {
+ local_irq_save(flags);
+
+ RING_FINAL_CHECK_FOR_RESPONSES(&np->rx, more_to_do);
+ if (!more_to_do)
+ __netif_rx_complete(dev);
+
+ local_irq_restore(flags);
+ }
+
+ spin_unlock(&np->rx_lock);
+
+ return more_to_do;
+}
+
+static int xennet_change_mtu(struct net_device *dev, int mtu)
+{
+ int max = xennet_can_sg(dev) ? 65535 - ETH_HLEN : ETH_DATA_LEN;
+
+ if (mtu > max)
+ return -EINVAL;
+ dev->mtu = mtu;
+ return 0;
+}
+
+static void xennet_release_tx_bufs(struct netfront_info *np)
+{
+ struct sk_buff *skb;
+ int i;
+
+ for (i = 0; i < NET_TX_RING_SIZE; i++) {
+ /* Skip over entries which are actually freelist references */
+ if ((unsigned long)np->tx_skbs[i].skb < PAGE_OFFSET)
+ continue;
+
+ skb = np->tx_skbs[i].skb;
+ gnttab_end_foreign_access_ref(np->grant_tx_ref[i],
+ GNTMAP_readonly);
+ gnttab_release_grant_reference(&np->gref_tx_head,
+ np->grant_tx_ref[i]);
+ np->grant_tx_ref[i] = GRANT_INVALID_REF;
+ add_id_to_freelist(&np->tx_skb_freelist, np->tx_skbs, i);
+ dev_kfree_skb_irq(skb);
+ }
+}
+
+static void xennet_release_rx_bufs(struct netfront_info *np)
+{
+ struct mmu_update *mmu = np->rx_mmu;
+ struct multicall_entry *mcl = np->rx_mcl;
+ struct sk_buff_head free_list;
+ struct sk_buff *skb;
+ unsigned long mfn;
+ int xfer = 0, noxfer = 0, unused = 0;
+ int id, ref;
+
+ if (np->copying_receiver) {
+ dev_warn(&np->netdev->dev, "%s: fix me for copying receiver.\n",
+ __func__);
+ return;
+ }
+
+ skb_queue_head_init(&free_list);
+
+ spin_lock_bh(&np->rx_lock);
+
+ for (id = 0; id < NET_RX_RING_SIZE; id++) {
+ if ((ref = np->grant_rx_ref[id]) == GRANT_INVALID_REF) {
+ unused++;
+ continue;
+ }
+
+ skb = np->rx_skbs[id];
+ mfn = gnttab_end_foreign_transfer_ref(ref);
+ gnttab_release_grant_reference(&np->gref_rx_head, ref);
+ np->grant_rx_ref[id] = GRANT_INVALID_REF;
+
+ if (0 == mfn) {
+ skb_shinfo(skb)->nr_frags = 0;
+ dev_kfree_skb(skb);
+ noxfer++;
+ continue;
+ }
+
+ if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+ /* Remap the page. */
+ struct page *page = skb_shinfo(skb)->frags[0].page;
+ unsigned long pfn = page_to_pfn(page);
+ void *vaddr = page_address(page);
+
+ MULTI_update_va_mapping(mcl, (unsigned long)vaddr,
+ mfn_pte(mfn, PAGE_KERNEL),
+ 0);
+ mcl++;
+ mmu->ptr = ((u64)mfn << PAGE_SHIFT)
+ | MMU_MACHPHYS_UPDATE;
+ mmu->val = pfn;
+ mmu++;
+
+ set_phys_to_machine(pfn, mfn);
+ }
+ __skb_queue_tail(&free_list, skb);
+ xfer++;
+ }
+
+ dev_info(&np->netdev->dev, "%s: %d xfer, %d noxfer, %d unused\n",
+ __func__, xfer, noxfer, unused);
+
+ if (xfer) {
+ if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+ /* Do all the remapping work and M2P updates. */
+ MULTI_mmu_update(mcl, np->rx_mmu, mmu - np->rx_mmu,
+ 0, DOMID_SELF);
+ mcl++;
+ HYPERVISOR_multicall(np->rx_mcl, mcl - np->rx_mcl);
+ }
+ }
+
+ while ((skb = __skb_dequeue(&free_list)) != NULL)
+ dev_kfree_skb(skb);
+
+ spin_unlock_bh(&np->rx_lock);
+}
+
+static void xennet_uninit(struct net_device *dev)
+{
+ struct netfront_info *np = netdev_priv(dev);
+ xennet_release_tx_bufs(np);
+ xennet_release_rx_bufs(np);
+ gnttab_free_grant_references(np->gref_tx_head);
+ gnttab_free_grant_references(np->gref_rx_head);
+}
+
+static struct net_device * __devinit xennet_create_dev(struct xenbus_device *dev)
+{
+ int i, err;
+ struct net_device *netdev;
+ struct netfront_info *np;
+
+ netdev = alloc_etherdev(sizeof(struct netfront_info));
+ if (!netdev) {
+ printk(KERN_WARNING "%s> alloc_etherdev failed.\n",
+ __func__);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ np = netdev_priv(netdev);
+ np->xbdev = dev;
+
+ spin_lock_init(&np->tx_lock);
+ spin_lock_init(&np->rx_lock);
+
+ skb_queue_head_init(&np->rx_batch);
+ np->rx_target = RX_DFL_MIN_TARGET;
+ np->rx_min_target = RX_DFL_MIN_TARGET;
+ np->rx_max_target = RX_MAX_TARGET;
+
+ init_timer(&np->rx_refill_timer);
+ np->rx_refill_timer.data = (unsigned long)netdev;
+ np->rx_refill_timer.function = rx_refill_timeout;
+
+ /* Initialise tx_skbs as a free chain containing every entry. */
+ np->tx_skb_freelist = 0;
+ for (i = 0; i < NET_TX_RING_SIZE; i++) {
+ np->tx_skbs[i].link = i+1;
+ np->grant_tx_ref[i] = GRANT_INVALID_REF;
+ }
+
+ /* Clear out rx_skbs */
+ for (i = 0; i < NET_RX_RING_SIZE; i++) {
+ np->rx_skbs[i] = NULL;
+ np->grant_rx_ref[i] = GRANT_INVALID_REF;
+ }
+
+ /* A grant for every tx ring slot */
+ if (gnttab_alloc_grant_references(TX_MAX_TARGET,
+ &np->gref_tx_head) < 0) {
+ printk(KERN_ALERT "#### netfront can't alloc tx grant refs\n");
+ err = -ENOMEM;
+ goto exit;
+ }
+ /* A grant for every rx ring slot */
+ if (gnttab_alloc_grant_references(RX_MAX_TARGET,
+ &np->gref_rx_head) < 0) {
+ printk(KERN_ALERT "#### netfront can't alloc rx grant refs\n");
+ err = -ENOMEM;
+ goto exit_free_tx;
+ }
+
+ netdev->open = xennet_open;
+ netdev->hard_start_xmit = xennet_start_xmit;
+ netdev->stop = xennet_close;
+ netdev->get_stats = xennet_get_stats;
+ netdev->poll = xennet_poll;
+ netdev->uninit = xennet_uninit;
+ netdev->change_mtu = xennet_change_mtu;
+ netdev->weight = 64;
+ netdev->features = NETIF_F_IP_CSUM;
+
+ SET_ETHTOOL_OPS(netdev, &xennet_ethtool_ops);
+ SET_MODULE_OWNER(netdev);
+ SET_NETDEV_DEV(netdev, &dev->dev);
+
+ np->netdev = netdev;
+
+ netif_carrier_off(netdev);
+
+ return netdev;
+
+ exit_free_tx:
+ gnttab_free_grant_references(np->gref_tx_head);
+ exit:
+ free_netdev(netdev);
+ return ERR_PTR(err);
+}
+
+/**
+ * Entry point to this code when a new device is created. Allocate the basic
+ * structures and the ring buffers for communication with the backend, and
+ * inform the backend of the appropriate details for those.
+ */
+static int __devinit netfront_probe(struct xenbus_device *dev,
+ const struct xenbus_device_id *id)
+{
+ int err;
+ struct net_device *netdev;
+ struct netfront_info *info;
+
+ netdev = xennet_create_dev(dev);
+ if (IS_ERR(netdev)) {
+ err = PTR_ERR(netdev);
+ xenbus_dev_fatal(dev, err, "creating netdev");
+ return err;
+ }
+
+ info = netdev_priv(netdev);
+ dev->dev.driver_data = info;
+
+ err = register_netdev(info->netdev);
+ if (err) {
+ printk(KERN_WARNING "%s: register_netdev err=%d\n",
+ __func__, err);
+ goto fail;
+ }
+
+ err = xennet_sysfs_addif(info->netdev);
+ if (err) {
+ unregister_netdev(info->netdev);
+ printk(KERN_WARNING "%s: add sysfs failed err=%d\n",
+ __func__, err);
+ goto fail;
+ }
+
+ return 0;
+
+ fail:
+ free_netdev(netdev);
+ dev->dev.driver_data = NULL;
+ return err;
+}
+
+static void xennet_end_access(int ref, void *page)
+{
+ /* This frees the page as a side-effect */
+ if (ref != GRANT_INVALID_REF)
+ gnttab_end_foreign_access(ref, 0, (unsigned long)page);
+}
+
+static void xennet_disconnect_backend(struct netfront_info *info)
+{
+ /* Stop old i/f to prevent errors whilst we rebuild the state. */
+ spin_lock_bh(&info->rx_lock);
+ spin_lock_irq(&info->tx_lock);
+ netif_carrier_off(info->netdev);
+ spin_unlock_irq(&info->tx_lock);
+ spin_unlock_bh(&info->rx_lock);
+
+ if (info->netdev->irq)
+ unbind_from_irqhandler(info->netdev->irq, info->netdev);
+ info->evtchn = info->netdev->irq = 0;
+
+ /* End access and free the pages */
+ xennet_end_access(info->tx_ring_ref, info->tx.sring);
+ xennet_end_access(info->rx_ring_ref, info->rx.sring);
+
+ info->tx_ring_ref = GRANT_INVALID_REF;
+ info->rx_ring_ref = GRANT_INVALID_REF;
+ info->tx.sring = NULL;
+ info->rx.sring = NULL;
+}
+
+/**
+ * We are reconnecting to the backend, due to a suspend/resume, or a backend
+ * driver restart. We tear down our netif structure and recreate it, but
+ * leave the device-layer structures intact so that this is transparent to the
+ * rest of the kernel.
+ */
+static int netfront_resume(struct xenbus_device *dev)
+{
+ struct netfront_info *info = dev->dev.driver_data;
+
+ dev_dbg(&dev->dev, "%s\n", dev->nodename);
+
+ xennet_disconnect_backend(info);
+ return 0;
+}
+
+static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
+{
+ char *s, *e, *macstr;
+ int i;
+
+ macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
+ if (IS_ERR(macstr))
+ return PTR_ERR(macstr);
+
+ for (i = 0; i < ETH_ALEN; i++) {
+ mac[i] = simple_strtoul(s, &e, 16);
+ if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
+ kfree(macstr);
+ return -ENOENT;
+ }
+ s = e+1;
+ }
+
+ kfree(macstr);
+ return 0;
+}
+
+static irqreturn_t xennet_interrupt(int irq, void *dev_id)
+{
+ struct net_device *dev = dev_id;
+ struct netfront_info *np = netdev_priv(dev);
+ unsigned long flags;
+
+ spin_lock_irqsave(&np->tx_lock, flags);
+
+ if (likely(netif_carrier_ok(dev))) {
+ xennet_tx_buf_gc(dev);
+ /* Under tx_lock: protects access to rx shared-ring indexes. */
+ if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))
+ netif_rx_schedule(dev);
+ }
+
+ spin_unlock_irqrestore(&np->tx_lock, flags);
+
+ return IRQ_HANDLED;
+}
+
+static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info)
+{
+ struct xen_netif_tx_sring *txs;
+ struct xen_netif_rx_sring *rxs;
+ int err;
+ struct net_device *netdev = info->netdev;
+
+ info->tx_ring_ref = GRANT_INVALID_REF;
+ info->rx_ring_ref = GRANT_INVALID_REF;
+ info->rx.sring = NULL;
+ info->tx.sring = NULL;
+ netdev->irq = 0;
+
+ err = xen_net_read_mac(dev, netdev->dev_addr);
+ if (err) {
+ xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
+ goto fail;
+ }
+
+ txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_KERNEL);
+ if (!txs) {
+ err = -ENOMEM;
+ xenbus_dev_fatal(dev, err, "allocating tx ring page");
+ goto fail;
+ }
+ SHARED_RING_INIT(txs);
+ FRONT_RING_INIT(&info->tx, txs, PAGE_SIZE);
+
+ err = xenbus_grant_ring(dev, virt_to_mfn(txs));
+ if (err < 0) {
+ free_page((unsigned long)txs);
+ goto fail;
+ }
+
+ info->tx_ring_ref = err;
+ rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_KERNEL);
+ if (!rxs) {
+ err = -ENOMEM;
+ xenbus_dev_fatal(dev, err, "allocating rx ring page");
+ goto fail;
+ }
+ SHARED_RING_INIT(rxs);
+ FRONT_RING_INIT(&info->rx, rxs, PAGE_SIZE);
+
+ err = xenbus_grant_ring(dev, virt_to_mfn(rxs));
+ if (err < 0) {
+ free_page((unsigned long)rxs);
+ goto fail;
+ }
+ info->rx_ring_ref = err;
+
+ err = xenbus_alloc_evtchn(dev, &info->evtchn);
+ if (err)
+ goto fail;
+
+ err = bind_evtchn_to_irqhandler(info->evtchn, xennet_interrupt,
+ IRQF_SAMPLE_RANDOM, netdev->name,
+ netdev);
+ if (err < 0)
+ goto fail;
+ netdev->irq = err;
+ return 0;
+
+ fail:
+ return err;
+}
+
+/* Common code used when first setting up, and when resuming. */
+static int talk_to_backend(struct xenbus_device *dev,
+ struct netfront_info *info)
+{
+ const char *message;
+ struct xenbus_transaction xbt;
+ int err;
+
+ /* Create shared ring, alloc event channel. */
+ err = setup_netfront(dev, info);
+ if (err)
+ goto out;
+
+again:
+ err = xenbus_transaction_start(&xbt);
+ if (err) {
+ xenbus_dev_fatal(dev, err, "starting transaction");
+ goto destroy_ring;
+ }
+
+ err = xenbus_printf(xbt, dev->nodename, "tx-ring-ref","%u",
+ info->tx_ring_ref);
+ if (err) {
+ message = "writing tx ring-ref";
+ goto abort_transaction;
+ }
+ err = xenbus_printf(xbt, dev->nodename, "rx-ring-ref","%u",
+ info->rx_ring_ref);
+ if (err) {
+ message = "writing rx ring-ref";
+ goto abort_transaction;
+ }
+ err = xenbus_printf(xbt, dev->nodename,
+ "event-channel", "%u", info->evtchn);
+ if (err) {
+ message = "writing event-channel";
+ goto abort_transaction;
+ }
+
+ err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u",
+ info->copying_receiver);
+ if (err) {
+ message = "writing request-rx-copy";
+ goto abort_transaction;
+ }
+
+ err = xenbus_printf(xbt, dev->nodename, "feature-rx-notify", "%d", 1);
+ if (err) {
+ message = "writing feature-rx-notify";
+ goto abort_transaction;
+ }
+
+ err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", 1);
+ if (err) {
+ message = "writing feature-sg";
+ goto abort_transaction;
+ }
+
+ err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", "%d", 1);
+ if (err) {
+ message = "writing feature-gso-tcpv4";
+ goto abort_transaction;
+ }
+
+ err = xenbus_transaction_end(xbt, 0);
+ if (err) {
+ if (err == -EAGAIN)
+ goto again;
+ xenbus_dev_fatal(dev, err, "completing transaction");
+ goto destroy_ring;
+ }
+
+ return 0;
+
+ abort_transaction:
+ xenbus_transaction_end(xbt, 1);
+ xenbus_dev_fatal(dev, err, "%s", message);
+ destroy_ring:
+ xennet_disconnect_backend(info);
+ out:
+ return err;
+}
+
+static int xennet_set_sg(struct net_device *dev, u32 data)
+{
+ if (data) {
+ struct netfront_info *np = netdev_priv(dev);
+ int val;
+
+ if (xenbus_scanf(XBT_NIL, np->xbdev->otherend, "feature-sg",
+ "%d", &val) < 0)
+ val = 0;
+ if (!val)
+ return -ENOSYS;
+ } else if (dev->mtu > ETH_DATA_LEN)
+ dev->mtu = ETH_DATA_LEN;
+
+ return ethtool_op_set_sg(dev, data);
+}
+
+static int xennet_set_tso(struct net_device *dev, u32 data)
+{
+ if (data) {
+ struct netfront_info *np = netdev_priv(dev);
+ int val;
+
+ if (xenbus_scanf(XBT_NIL, np->xbdev->otherend,
+ "feature-gso-tcpv4", "%d", &val) < 0)
+ val = 0;
+ if (!val)
+ return -ENOSYS;
+ }
+
+ return ethtool_op_set_tso(dev, data);
+}
+
+static void xennet_set_features(struct net_device *dev)
+{
+ /* Turn off all GSO bits except ROBUST. */
+ dev->features &= (1 << NETIF_F_GSO_SHIFT) - 1;
+ dev->features |= NETIF_F_GSO_ROBUST;
+ xennet_set_sg(dev, 0);
+
+ /* We need checksum offload to enable scatter/gather and TSO. */
+ if (!(dev->features & NETIF_F_IP_CSUM))
+ return;
+
+ if (!xennet_set_sg(dev, 1))
+ xennet_set_tso(dev, 1);
+}
+
+static int xennet_connect(struct net_device *dev)
+{
+ struct netfront_info *np = netdev_priv(dev);
+ int i, requeue_idx, err;
+ struct sk_buff *skb;
+ grant_ref_t ref;
+ struct xen_netif_rx_request *req;
+ unsigned int feature_rx_copy, feature_rx_flip;
+
+ err = xenbus_scanf(XBT_NIL, np->xbdev->otherend,
+ "feature-rx-copy", "%u", &feature_rx_copy);
+ if (err != 1)
+ feature_rx_copy = 0;
+
+ err = xenbus_scanf(XBT_NIL, np->xbdev->otherend,
+ "feature-rx-flip", "%u", &feature_rx_flip);
+ /* Flip is the default, since it was once the only mode of
+ operation. */
+ if (err != 1)
+ feature_rx_flip = 1;
+
+ /*
+ * Copy packets on receive path if:
+ * (a) This was requested by user, and the backend supports it; or
+ * (b) Flipping was requested, but this is unsupported by the backend.
+ */
+ np->copying_receiver = (((rx_mode == RX_COPY) && feature_rx_copy) ||
+ ((rx_mode == RX_FLIP) && !feature_rx_flip));
+
+ err = talk_to_backend(np->xbdev, np);
+ if (err)
+ return err;
+
+ xennet_set_features(dev);
+
+ dev_info(&dev->dev, "has %s receive path.\n",
+ np->copying_receiver ? "copying" : "flipping");
+
+ spin_lock_bh(&np->rx_lock);
+ spin_lock_irq(&np->tx_lock);
+
+ /* Step 1: Discard all pending TX packet fragments. */
+ xennet_release_tx_bufs(np);
+
+ /* Step 2: Rebuild the RX buffer freelist and the RX ring itself. */
+ for (requeue_idx = 0, i = 0; i < NET_RX_RING_SIZE; i++) {
+ if (!np->rx_skbs[i])
+ continue;
+
+ skb = np->rx_skbs[requeue_idx] = xennet_get_rx_skb(np, i);
+ ref = np->grant_rx_ref[requeue_idx] = xennet_get_rx_ref(np, i);
+ req = RING_GET_REQUEST(&np->rx, requeue_idx);
+
+ if (!np->copying_receiver) {
+ gnttab_grant_foreign_transfer_ref(
+ ref, np->xbdev->otherend_id,
+ page_to_pfn(skb_shinfo(skb)->frags->page));
+ } else {
+ gnttab_grant_foreign_access_ref(
+ ref, np->xbdev->otherend_id,
+ pfn_to_mfn(page_to_pfn(skb_shinfo(skb)->
+ frags->page)),
+ 0);
+ }
+ req->gref = ref;
+ req->id = requeue_idx;
+
+ requeue_idx++;
+ }
+
+ np->rx.req_prod_pvt = requeue_idx;
+
+ /*
+ * Step 3: All public and private state should now be sane. Get
+ * ready to start sending and receiving packets and give the driver
+ * domain a kick because we've probably just requeued some
+ * packets.
+ */
+ netif_carrier_on(np->netdev);
+ notify_remote_via_irq(np->netdev->irq);
+ xennet_tx_buf_gc(dev);
+ xennet_alloc_rx_buffers(dev);
+
+ spin_unlock_irq(&np->tx_lock);
+ spin_unlock_bh(&np->rx_lock);
+
+ return 0;
+}
+
+/**
+ * Callback received when the backend's state changes.
+ */
+static void backend_changed(struct xenbus_device *dev,
+ enum xenbus_state backend_state)
+{
+ struct netfront_info *np = dev->dev.driver_data;
+ struct net_device *netdev = np->netdev;
+
+ dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state));
+
+ switch (backend_state) {
+ case XenbusStateInitialising:
+ case XenbusStateInitialised:
+ case XenbusStateConnected:
+ case XenbusStateUnknown:
+ case XenbusStateClosed:
+ break;
+
+ case XenbusStateInitWait:
+ if (dev->state != XenbusStateInitialising)
+ break;
+ if (xennet_connect(netdev) != 0)
+ break;
+ xenbus_switch_state(dev, XenbusStateConnected);
+ break;
+
+ case XenbusStateClosing:
+ xenbus_frontend_closed(dev);
+ break;
+ }
+}
+
+static struct ethtool_ops xennet_ethtool_ops =
+{
+ .get_tx_csum = ethtool_op_get_tx_csum,
+ .set_tx_csum = ethtool_op_set_tx_csum,
+ .get_sg = ethtool_op_get_sg,
+ .set_sg = xennet_set_sg,
+ .get_tso = ethtool_op_get_tso,
+ .set_tso = xennet_set_tso,
+ .get_link = ethtool_op_get_link,
+};
+
+#ifdef CONFIG_SYSFS
+static ssize_t show_rxbuf_min(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct net_device *netdev = to_net_dev(dev);
+ struct netfront_info *info = netdev_priv(netdev);
+
+ return sprintf(buf, "%u\n", info->rx_min_target);
+}
+
+static ssize_t store_rxbuf_min(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct net_device *netdev = to_net_dev(dev);
+ struct netfront_info *np = netdev_priv(netdev);
+ char *endp;
+ unsigned long target;
+
+ if (!capable(CAP_NET_ADMIN))
+ return -EPERM;
+
+ target = simple_strtoul(buf, &endp, 0);
+ if (endp == buf)
+ return -EBADMSG;
+
+ if (target < RX_MIN_TARGET)
+ target = RX_MIN_TARGET;
+ if (target > RX_MAX_TARGET)
+ target = RX_MAX_TARGET;
+
+ spin_lock_bh(&np->rx_lock);
+ if (target > np->rx_max_target)
+ np->rx_max_target = target;
+ np->rx_min_target = target;
+ if (target > np->rx_target)
+ np->rx_target = target;
+
+ xennet_alloc_rx_buffers(netdev);
+
+ spin_unlock_bh(&np->rx_lock);
+ return len;
+}
+
+static ssize_t show_rxbuf_max(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct net_device *netdev = to_net_dev(dev);
+ struct netfront_info *info = netdev_priv(netdev);
+
+ return sprintf(buf, "%u\n", info->rx_max_target);
+}
+
+static ssize_t store_rxbuf_max(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct net_device *netdev = to_net_dev(dev);
+ struct netfront_info *np = netdev_priv(netdev);
+ char *endp;
+ unsigned long target;
+
+ if (!capable(CAP_NET_ADMIN))
+ return -EPERM;
+
+ target = simple_strtoul(buf, &endp, 0);
+ if (endp == buf)
+ return -EBADMSG;
+
+ if (target < RX_MIN_TARGET)
+ target = RX_MIN_TARGET;
+ if (target > RX_MAX_TARGET)
+ target = RX_MAX_TARGET;
+
+ spin_lock_bh(&np->rx_lock);
+ if (target < np->rx_min_target)
+ np->rx_min_target = target;
+ np->rx_max_target = target;
+ if (target < np->rx_target)
+ np->rx_target = target;
+
+ xennet_alloc_rx_buffers(netdev);
+
+ spin_unlock_bh(&np->rx_lock);
+ return len;
+}
+
+static ssize_t show_rxbuf_cur(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct net_device *netdev = to_net_dev(dev);
+ struct netfront_info *info = netdev_priv(netdev);
+
+ return sprintf(buf, "%u\n", info->rx_target);
+}
+
+static struct device_attribute xennet_attrs[] = {
+ __ATTR(rxbuf_min, S_IRUGO|S_IWUSR, show_rxbuf_min, store_rxbuf_min),
+ __ATTR(rxbuf_max, S_IRUGO|S_IWUSR, show_rxbuf_max, store_rxbuf_max),
+ __ATTR(rxbuf_cur, S_IRUGO, show_rxbuf_cur, NULL),
+};
+
+static int xennet_sysfs_addif(struct net_device *netdev)
+{
+ int i;
+ int err;
+
+ for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++) {
+ err = device_create_file(&netdev->dev,
+ &xennet_attrs[i]);
+ if (err)
+ goto fail;
+ }
+ return 0;
+
+ fail:
+ while (--i >= 0)
+ device_remove_file(&netdev->dev, &xennet_attrs[i]);
+ return err;
+}
+
+static void xennet_sysfs_delif(struct net_device *netdev)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++)
+ device_remove_file(&netdev->dev, &xennet_attrs[i]);
+}
+
+#endif /* CONFIG_SYSFS */
+
+static struct xenbus_device_id netfront_ids[] = {
+ { "vif" },
+ { "" }
+};
+
+
+static int __devexit xennet_remove(struct xenbus_device *dev)
+{
+ struct netfront_info *info = dev->dev.driver_data;
+
+ dev_dbg(&dev->dev, "%s\n", dev->nodename);
+
+ unregister_netdev(info->netdev);
+
+ xennet_disconnect_backend(info);
+
+ del_timer_sync(&info->rx_refill_timer);
+
+ xennet_sysfs_delif(info->netdev);
+
+ free_netdev(info->netdev);
+
+ return 0;
+}
+
+static struct xenbus_driver netfront = {
+ .name = "vif",
+ .owner = THIS_MODULE,
+ .ids = netfront_ids,
+ .probe = netfront_probe,
+ .remove = __devexit_p(xennet_remove),
+ .resume = netfront_resume,
+ .otherend_changed = backend_changed,
+};
+
+static int __init netif_init(void)
+{
+ if (!is_running_on_xen())
+ return -ENODEV;
+
+ if (is_initial_xendomain())
+ return 0;
+
+ printk(KERN_INFO "Initialising Xen virtual ethernet driver.\n");
+
+ return xenbus_register_frontend(&netfront);
+}
+module_init(netif_init);
+
+
+static void __exit netif_exit(void)
+{
+ if (is_initial_xendomain())
+ return;
+
+ return xenbus_unregister_driver(&netfront);
+}
+module_exit(netif_exit);
+
+MODULE_DESCRIPTION("Xen virtual network device frontend");
+MODULE_LICENSE("GPL");
--

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