Merge branch 'xen-upstream' of ssh://master.kernel.org/pub/scm/linux/kernel/git/jeremy/xen

* 'xen-upstream' of ssh://master.kernel.org/pub/scm/linux/kernel/git/jeremy/xen: (44 commits)
  xen: disable all non-virtual drivers
  xen: use iret directly when possible
  xen: suppress abs symbol warnings for unused reloc pointers
  xen: Attempt to patch inline versions of common operations
  xen: Place vcpu_info structure into per-cpu memory
  xen: handle external requests for shutdown, reboot and sysrq
  xen: machine operations
  xen: add virtual network device driver
  xen: add virtual block device driver.
  xen: add the Xenbus sysfs and virtual device hotplug driver
  xen: Add grant table support
  xen: use the hvc console infrastructure for Xen console
  xen: hack to prevent bad segment register reload
  xen: lazy-mmu operations
  xen: Add support for preemption
  xen: SMP guest support
  xen: Implement sched_clock
  xen: Account for stolen time
  xen: ignore RW mapping of RO pages in pagetable_init
  xen: Complete pagetable pinning
  ...

4 files changed, 1878 insertions, 1 deletions

diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 43d03178064..5fb659f8b20 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -2486,6 +2486,18 @@ 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
diff --git a/drivers/net/Makefile b/drivers/net/Makefile
index eb4167622a6..0e286ab8855 100644
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -127,6 +127,8 @@ obj-$(CONFIG_PPPOL2TP) += pppox.o pppol2tp.o
 obj-$(CONFIG_SLIP) += slip.o
 obj-$(CONFIG_SLHC) += slhc.o
 
+obj-$(CONFIG_XEN_NETDEV_FRONTEND) += xen-netfront.o
+
 obj-$(CONFIG_DUMMY) += dummy.o
 obj-$(CONFIG_IFB) += ifb.o
 obj-$(CONFIG_MACVLAN) += macvlan.o
diff --git a/drivers/net/hamradio/baycom_epp.c b/drivers/net/hamradio/baycom_epp.c
index 84aa2117c0e..355c6cf3d11 100644
--- a/drivers/net/hamradio/baycom_epp.c
+++ b/drivers/net/hamradio/baycom_epp.c
@@ -320,7 +320,7 @@ static int eppconfig(struct baycom_state *bc)
 	sprintf(portarg, "%ld", bc->pdev->port->base);
 	printk(KERN_DEBUG "%s: %s -s -p %s -m %s\n", bc_drvname, eppconfig_path, portarg, modearg);
 
-	return call_usermodehelper(eppconfig_path, argv, envp, 1);
+	return call_usermodehelper(eppconfig_path, argv, envp, UMH_WAIT_PROC);
 }
 
 /* ---------------------------------------------------------------------- */
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
new file mode 100644
index 00000000000..489f69c5d6c
--- /dev/null
+++ b/drivers/net/xen-netfront.c
@@ -0,0 +1,1863 @@
+/*
+ * 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))
+
+#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;
+
+	/* 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++) {
+		skb = __skb_dequeue(&np->rx_batch);
+		if (skb == 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);
+		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();		/* barrier so backend seens requests */
+	}
+
+	/* 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();		/* update shared area */
+	} 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)
+{
+	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 (;;) {
+		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;
+		}
+
+		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;
+
+	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;
+	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 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);
+
+	budget = *pbudget;
+	if (budget > 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);
+
+		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++;
+	}
+
+	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;</