Staging: hv: add the Hyper-V virtual network driver

This is the virtual network driver when running Linux on top of Hyper-V.

Signed-off-by: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/hv/NetVsc.h

@@ -0,0 +1,91 @@
+/*
+ *
+ * Copyright (c) 2009, Microsoft Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * Authors:
+ *   Hank Janssen  <hjanssen@microsoft.com>
+ *
+ */
+
+
+#ifndef _NETVSC_H_
+#define _NETVSC_H_
+
+#include "VmbusPacketFormat.h"
+#include "nvspprotocol.h"
+
+#include "List.h"
+
+#include "NetVscApi.h"
+//
+// #defines
+//
+//#define NVSC_MIN_PROTOCOL_VERSION                       1
+//#define NVSC_MAX_PROTOCOL_VERSION                       1
+
+#define NETVSC_SEND_BUFFER_SIZE				64*1024 // 64K
+#define NETVSC_SEND_BUFFER_ID				0xface
+
+
+#define NETVSC_RECEIVE_BUFFER_SIZE			1024*1024 // 1MB
+
+#define NETVSC_RECEIVE_BUFFER_ID			0xcafe
+
+#define NETVSC_RECEIVE_SG_COUNT				1
+
+// Preallocated receive packets
+#define NETVSC_RECEIVE_PACKETLIST_COUNT		256
+
+//
+// Data types
+//
+
+// Per netvsc channel-specific
+typedef struct _NETVSC_DEVICE {
+	DEVICE_OBJECT					*Device;
+
+	int								RefCount;
+
+	int								NumOutstandingSends;
+	// List of free preallocated NETVSC_PACKET to represent receive packet
+	LIST_ENTRY						ReceivePacketList;
+	HANDLE							ReceivePacketListLock;
+
+	// Send buffer allocated by us but manages by NetVSP
+	PVOID							SendBuffer;
+	UINT32							SendBufferSize;
+	UINT32							SendBufferGpadlHandle;
+	UINT32							SendSectionSize;
+
+	// Receive buffer allocated by us but manages by NetVSP
+	PVOID							ReceiveBuffer;
+	UINT32							ReceiveBufferSize;
+	UINT32							ReceiveBufferGpadlHandle;
+	UINT32							ReceiveSectionCount;
+	PNVSP_1_RECEIVE_BUFFER_SECTION	ReceiveSections;
+
+	// Used for NetVSP initialization protocol
+	HANDLE							ChannelInitEvent;
+	NVSP_MESSAGE					ChannelInitPacket;
+
+	NVSP_MESSAGE					RevokePacket;
+	//UCHAR							HwMacAddr[HW_MACADDR_LEN];
+
+	// Holds rndis device info
+	void							*Extension;
+} NETVSC_DEVICE;
+
+#endif // _NETVSC_H_

drivers/staging/hv/RndisFilter.h

@@ -0,0 +1,61 @@
+/*
+ *
+ * Copyright (c) 2009, Microsoft Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * Authors:
+ *   Haiyang Zhang <haiyangz@microsoft.com>
+ *   Hank Janssen  <hjanssen@microsoft.com>
+ *
+ */
+
+
+#ifndef _RNDISFILTER_H_
+#define _RNDISFILTER_H_
+
+#define __struct_bcount(x)
+
+#include "osd.h"
+#include "NetVsc.h"
+
+#include "rndis.h"
+
+#define RNDIS_HEADER_SIZE	(sizeof(RNDIS_MESSAGE) - sizeof(RNDIS_MESSAGE_CONTAINER))
+
+#define NDIS_PACKET_TYPE_DIRECTED	0x00000001
+#define NDIS_PACKET_TYPE_MULTICAST	0x00000002
+#define NDIS_PACKET_TYPE_ALL_MULTICAST	0x00000004
+#define NDIS_PACKET_TYPE_BROADCAST	0x00000008
+#define NDIS_PACKET_TYPE_SOURCE_ROUTING	0x00000010
+#define NDIS_PACKET_TYPE_PROMISCUOUS	0x00000020
+#define NDIS_PACKET_TYPE_SMT		0x00000040
+#define NDIS_PACKET_TYPE_ALL_LOCAL	0x00000080
+#define NDIS_PACKET_TYPE_GROUP		0x00000100
+#define NDIS_PACKET_TYPE_ALL_FUNCTIONAL	0x00000200
+#define NDIS_PACKET_TYPE_FUNCTIONAL	0x00000400
+#define NDIS_PACKET_TYPE_MAC_FRAME	0x00000800
+
+
+
+//
+// Interface
+//
+int
+RndisFilterInit(
+	NETVSC_DRIVER_OBJECT *Driver
+	);
+
+
+#endif // _RNDISFILTER_H_

drivers/staging/hv/netvsc_drv.c

@@ -0,0 +1,720 @@
+/*
+ *
+ * Copyright (c) 2009, Microsoft Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * Authors:
+ *   Hank Janssen  <hjanssen@microsoft.com>
+ *
+ */
+
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/highmem.h>
+#include <linux/device.h>
+#if defined(KERNEL_2_6_5) || defined(KERNEL_2_6_9)
+#include <asm/io.h>
+#else
+#include <linux/io.h>
+#endif
+#include <linux/delay.h>
+#include <linux/netdevice.h>
+#include <linux/inetdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/skbuff.h>
+#include <linux/in.h>
+#include <net/arp.h>
+#include <net/route.h>
+#include <net/sock.h>
+#include <net/pkt_sched.h>
+
+#include "logging.h"
+#include "vmbus.h"
+
+#include "NetVscApi.h"
+
+MODULE_LICENSE("GPL");
+
+//
+// Static decl
+//
+static int netvsc_probe(struct device *device);
+static int netvsc_remove(struct device *device);
+static int netvsc_open(struct net_device *net);
+static void netvsc_xmit_completion(void *context);
+static int netvsc_start_xmit (struct sk_buff *skb, struct net_device *net);
+static int netvsc_recv_callback(DEVICE_OBJECT *device_obj, NETVSC_PACKET* Packet);
+static int netvsc_close(struct net_device *net);
+static struct net_device_stats *netvsc_get_stats(struct net_device *net);
+static void netvsc_linkstatus_callback(DEVICE_OBJECT *device_obj, unsigned int status);
+
+//
+// Data types
+//
+struct net_device_context {
+	struct device_context	*device_ctx; // point back to our device context
+	struct net_device_stats stats;
+};
+
+struct netvsc_driver_context {
+	// !! These must be the first 2 fields !!
+	struct driver_context	drv_ctx;
+	NETVSC_DRIVER_OBJECT	drv_obj;
+};
+
+//
+// Globals
+//
+
+static int netvsc_ringbuffer_size = NETVSC_DEVICE_RING_BUFFER_SIZE;
+
+// The one and only one
+static struct netvsc_driver_context g_netvsc_drv;
+
+//
+// Routines
+//
+
+/*++
+
+Name:	netvsc_drv_init()
+
+Desc:	NetVsc driver initialization
+
+--*/
+int netvsc_drv_init(PFN_DRIVERINITIALIZE pfn_drv_init)
+{
+	int ret=0;
+	NETVSC_DRIVER_OBJECT *net_drv_obj=&g_netvsc_drv.drv_obj;
+	struct driver_context *drv_ctx=&g_netvsc_drv.drv_ctx;
+
+	DPRINT_ENTER(NETVSC_DRV);
+
+	vmbus_get_interface(&net_drv_obj->Base.VmbusChannelInterface);
+
+	net_drv_obj->RingBufferSize = netvsc_ringbuffer_size;
+	net_drv_obj->OnReceiveCallback = netvsc_recv_callback;
+	net_drv_obj->OnLinkStatusChanged = netvsc_linkstatus_callback;
+
+	// Callback to client driver to complete the initialization
+	pfn_drv_init(&net_drv_obj->Base);
+
+	drv_ctx->driver.name = net_drv_obj->Base.name;
+	memcpy(&drv_ctx->class_id, &net_drv_obj->Base.deviceType, sizeof(GUID));
+
+#if defined(KERNEL_2_6_5) || defined(KERNEL_2_6_9)
+	drv_ctx->driver.probe = netvsc_probe;
+	drv_ctx->driver.remove = netvsc_remove;
+#else
+	drv_ctx->probe = netvsc_probe;
+	drv_ctx->remove = netvsc_remove;
+#endif
+
+	// The driver belongs to vmbus
+	vmbus_child_driver_register(drv_ctx);
+
+	DPRINT_EXIT(NETVSC_DRV);
+
+	return ret;
+}
+
+/*++
+
+Name:	netvsc_get_stats()
+
+Desc:	Get the network stats
+
+--*/
+static struct net_device_stats *netvsc_get_stats(struct net_device *net)
+{
+	struct net_device_context *net_device_ctx = netdev_priv(net);
+
+	return &net_device_ctx->stats;
+}
+
+/*++
+
+Name:	netvsc_set_multicast_list()
+
+Desc:	Set the multicast list
+
+Remark:	No-op here
+--*/
+static void netvsc_set_multicast_list(UNUSED_VAR(struct net_device *net))
+{
+}
+
+
+/*++
+
+Name:	netvsc_probe()
+
+Desc:	Add the specified new device to this driver
+
+--*/
+static int netvsc_probe(struct device *device)
+{
+	int ret=0;
+
+	struct driver_context *driver_ctx = driver_to_driver_context(device->driver);
+	struct netvsc_driver_context *net_drv_ctx = (struct netvsc_driver_context*)driver_ctx;
+	NETVSC_DRIVER_OBJECT *net_drv_obj = &net_drv_ctx->drv_obj;
+
+	struct device_context *device_ctx = device_to_device_context(device);
+	DEVICE_OBJECT *device_obj = &device_ctx->device_obj;
+
+	struct net_device *net = NULL;
+	struct net_device_context *net_device_ctx;
+	NETVSC_DEVICE_INFO device_info;
+
+	DPRINT_ENTER(NETVSC_DRV);
+
+	if (!net_drv_obj->Base.OnDeviceAdd)
+	{
+		return -1;
+	}
+
+	net = alloc_netdev(sizeof(struct net_device_context), "seth%d", ether_setup);
+	//net = alloc_etherdev(sizeof(struct net_device_context));
+	if (!net)
+	{
+		return -1;
+	}
+
+	// Set initial state
+	netif_carrier_off(net);
+	netif_stop_queue(net);
+
+	net_device_ctx = netdev_priv(net);
+	net_device_ctx->device_ctx = device_ctx;
+	device->driver_data = net;
+
+	// Notify the netvsc driver of the new device
+	ret = net_drv_obj->Base.OnDeviceAdd(device_obj, (void*)&device_info);
+	if (ret != 0)
+	{
+		free_netdev(net);
+		device->driver_data = NULL;
+
+		DPRINT_ERR(NETVSC_DRV, "unable to add netvsc device (ret %d)", ret);
+		return ret;
+	}
+
+	// If carrier is still off ie we did not get a link status callback, update it if necessary
+	// FIXME: We should use a atomic or test/set instead to avoid getting out of sync with the device's link status
+	if (!netif_carrier_ok(net))
+	{
+		if (!device_info.LinkState)
+		{
+			netif_carrier_on(net);
+		}
+	}
+
+	memcpy(net->dev_addr, device_info.MacAddr, ETH_ALEN);
+
+	net->open				= netvsc_open;
+	net->hard_start_xmit	= netvsc_start_xmit;
+	net->stop				= netvsc_close;
+	net->get_stats			= netvsc_get_stats;
+	net->set_multicast_list = netvsc_set_multicast_list;
+
+#if !defined(KERNEL_2_6_27)
+	SET_MODULE_OWNER(net);
+#endif
+	SET_NETDEV_DEV(net, device);
+
+	ret = register_netdev(net);
+	if (ret != 0)
+	{
+		// Remove the device and release the resource
+		net_drv_obj->Base.OnDeviceRemove(device_obj);
+		free_netdev(net);
+	}
+
+	DPRINT_EXIT(NETVSC_DRV);
+
+	return ret;
+}
+
+static int netvsc_remove(struct device *device)
+{
+	int ret=0;
+	struct driver_context *driver_ctx = driver_to_driver_context(device->driver);
+	struct netvsc_driver_context *net_drv_ctx = (struct netvsc_driver_context*)driver_ctx;
+	NETVSC_DRIVER_OBJECT *net_drv_obj = &net_drv_ctx->drv_obj;
+
+	struct device_context *device_ctx = device_to_device_context(device);
+	struct net_device *net = (struct net_device *)device_ctx->device.driver_data;
+	DEVICE_OBJECT *device_obj = &device_ctx->device_obj;
+
+	DPRINT_ENTER(NETVSC_DRV);
+
+	if (net == NULL)
+	{
+		DPRINT_INFO(NETVSC, "no net device to remove");
+		DPRINT_EXIT(NETVSC_DRV);
+		return 0;
+	}
+
+	if (!net_drv_obj->Base.OnDeviceRemove)
+	{
+		DPRINT_EXIT(NETVSC_DRV);
+		return -1;
+	}
+
+	// Stop outbound asap
+	netif_stop_queue(net);
+	//netif_carrier_off(net);
+
+	unregister_netdev(net);
+
+	// Call to the vsc driver to let it know that the device is being removed
+	ret = net_drv_obj->Base.OnDeviceRemove(device_obj);
+	if (ret != 0)
+	{
+		// TODO:
+		DPRINT_ERR(NETVSC, "unable to remove vsc device (ret %d)", ret);
+	}
+
+	free_netdev(net);
+
+	DPRINT_EXIT(NETVSC_DRV);
+
+	return ret;
+}
+
+/*++
+
+Name:	netvsc_open()
+
+Desc:	Open the specified interface device
+
+--*/
+static int netvsc_open(struct net_device *net)
+{
+	int ret=0;
+	struct net_device_context *net_device_ctx = netdev_priv(net);
+	struct driver_context *driver_ctx = driver_to_driver_context(net_device_ctx->device_ctx->device.driver);
+	struct netvsc_driver_context *net_drv_ctx = (struct netvsc_driver_context*)driver_ctx;
+	NETVSC_DRIVER_OBJECT *net_drv_obj = &net_drv_ctx->drv_obj;
+
+	DEVICE_OBJECT *device_obj = &net_device_ctx->device_ctx->device_obj;
+
+	DPRINT_ENTER(NETVSC_DRV);
+
+	if (netif_carrier_ok(net))
+	{
+		memset(&net_device_ctx->stats, 0 , sizeof(struct net_device_stats));
+
+		// Open up the device
+		ret = net_drv_obj->OnOpen(device_obj);
+		if (ret != 0)
+		{
+			DPRINT_ERR(NETVSC_DRV, "unable to open device (ret %d).", ret);
+			return ret;
+		}
+
+		netif_start_queue(net);
+	}
+	else
+	{
+		DPRINT_ERR(NETVSC_DRV, "unable to open device...link is down.");
+	}
+
+	DPRINT_EXIT(NETVSC_DRV);
+	return ret;
+}
+
+/*++
+
+Name:	netvsc_close()
+
+Desc:	Close the specified interface device
+
+--*/
+static int netvsc_close(struct net_device *net)
+{
+	int ret=0;
+	struct net_device_context *net_device_ctx = netdev_priv(net);
+	struct driver_context *driver_ctx = driver_to_driver_context(net_device_ctx->device_ctx->device.driver);
+	struct netvsc_driver_context *net_drv_ctx = (struct netvsc_driver_context*)driver_ctx;
+	NETVSC_DRIVER_OBJECT *net_drv_obj = &net_drv_ctx->drv_obj;
+
+	DEVICE_OBJECT *device_obj = &net_device_ctx->device_ctx->device_obj;
+
+	DPRINT_ENTER(NETVSC_DRV);
+
+	netif_stop_queue(net);
+
+	ret = net_drv_obj->OnClose(device_obj);
+	if (ret != 0)
+	{
+		DPRINT_ERR(NETVSC_DRV, "unable to close device (ret %d).", ret);
+	}
+
+	DPRINT_EXIT(NETVSC_DRV);
+
+	return ret;
+}
+
+
+/*++
+
+Name:	netvsc_xmit_completion()
+
+Desc:	Send completion processing
+
+--*/
+static void netvsc_xmit_completion(void *context)
+{
+	NETVSC_PACKET *packet = (NETVSC_PACKET *)context;
+	struct sk_buff *skb = (struct sk_buff *)(ULONG_PTR)packet->Completion.Send.SendCompletionTid;
+	struct net_device* net;
+
+	DPRINT_ENTER(NETVSC_DRV);
+
+	kfree(packet);
+
+	if (skb)
+	{
+		net = skb->dev;
+
+		dev_kfree_skb_any(skb);
+
+		if (netif_queue_stopped(net))
+		{
+			DPRINT_INFO(NETVSC_DRV, "net device (%p) waking up...", net);
+
+			netif_wake_queue(net);
+		}
+	}
+
+	DPRINT_EXIT(NETVSC_DRV);
+}
+
+/*++
+
+Name:	netvsc_start_xmit()
+
+Desc:	Start a send
+
+--*/
+static int netvsc_start_xmit (struct sk_buff *skb, struct net_device *net)
+{
+	int ret=0;
+	struct net_device_context *net_device_ctx = netdev_priv(net);
+	struct driver_context *driver_ctx = driver_to_driver_context(net_device_ctx->device_ctx->device.driver);
+	struct netvsc_driver_context *net_drv_ctx = (struct netvsc_driver_context*)driver_ctx;
+	NETVSC_DRIVER_OBJECT *net_drv_obj = &net_drv_ctx->drv_obj;
+
+	int i=0;
+	NETVSC_PACKET* packet;
+	int num_frags;
+	int retries=0;
+
+	DPRINT_ENTER(NETVSC_DRV);
+
+	// Support only 1 chain of frags
+	ASSERT(skb_shinfo(skb)->frag_list == NULL);
+	ASSERT(skb->dev == net);
+
+	DPRINT_DBG(NETVSC_DRV, "xmit packet - len %d data_len %d", skb->len, skb->data_len);
+
+	// Add 1 for skb->data and any additional ones requested
+	num_frags = skb_shinfo(skb)->nr_frags + 1 + net_drv_obj->AdditionalRequestPageBufferCount;
+
+	// Allocate a netvsc packet based on # of frags.
+	packet = kzalloc(sizeof(NETVSC_PACKET) + (num_frags * sizeof(PAGE_BUFFER)) + net_drv_obj->RequestExtSize, GFP_ATOMIC);
+	if (!packet)
+	{
+		DPRINT_ERR(NETVSC_DRV, "unable to allocate NETVSC_PACKET");
+		return -1;
+	}
+
+	packet->Extension = (void*)(unsigned long)packet + sizeof(NETVSC_PACKET) + (num_frags * sizeof(PAGE_BUFFER)) ;
+
+	// Setup the rndis header
+	packet->PageBufferCount = num_frags;
+
+	// TODO: Flush all write buffers/ memory fence ???
+	//wmb();
+
+	// Initialize it from the skb
+	ASSERT(skb->data);
+	packet->TotalDataBufferLength	= skb->len;
+
+	// Start filling in the page buffers starting at AdditionalRequestPageBufferCount offset
+	packet->PageBuffers[net_drv_obj->AdditionalRequestPageBufferCount].Pfn		= virt_to_phys(skb->data) >> PAGE_SHIFT;
+	packet->PageBuffers[net_drv_obj->AdditionalRequestPageBufferCount].Offset	= (unsigned long)skb->data & (PAGE_SIZE -1);
+	packet->PageBuffers[net_drv_obj->AdditionalRequestPageBufferCount].Length	= skb->len - skb->data_len;
+
+	ASSERT((skb->len - skb->data_len) <= PAGE_SIZE);
+
+	for (i=net_drv_obj->AdditionalRequestPageBufferCount+1; i<num_frags; i++)
+	{
+		packet->PageBuffers[i].Pfn		= page_to_pfn(skb_shinfo(skb)->frags[i-(net_drv_obj->AdditionalRequestPageBufferCount+1)].page);
+		packet->PageBuffers[i].Offset	= skb_shinfo(skb)->frags[i-(net_drv_obj->AdditionalRequestPageBufferCount+1)].page_offset;
+		packet->PageBuffers[i].Length	= skb_shinfo(skb)->frags[i-(net_drv_obj->AdditionalRequestPageBufferCount+1)].size;
+	}
+
+	// Set the completion routine
+	packet->Completion.Send.OnSendCompletion = netvsc_xmit_completion;
+	packet->Completion.Send.SendCompletionContext = packet;
+	packet->Completion.Send.SendCompletionTid = (ULONG_PTR)skb;
+
+retry_send:
+	ret = net_drv_obj->OnSend(&net_device_ctx->device_ctx->device_obj, packet);
+
+	if (ret == 0)
+	{
+#ifdef KERNEL_2_6_5
+#define NETDEV_TX_OK	0
+#define NETDEV_TX_BUSY	0
+#endif
+		ret = NETDEV_TX_OK;
+		net_device_ctx->stats.tx_bytes += skb->len;
+		net_device_ctx->stats.tx_packets++;
+	}
+	else
+	{
+		retries++;
+		if (retries < 4)
+		{
+			DPRINT_ERR(NETVSC_DRV, "unable to send...retrying %d...", retries);
+			udelay(100);
+			goto retry_send;
+		}
+
+		// no more room or we are shutting down
+		DPRINT_ERR(NETVSC_DRV, "unable to send (%d)...marking net device (%p) busy", ret, net);
+		DPRINT_INFO(NETVSC_DRV, "net device (%p) stopping", net);
+
+		ret = NETDEV_TX_BUSY;
+		net_device_ctx->stats.tx_dropped++;
+
+		netif_stop_queue(net);
+
+		// Null it since the caller will free it instead of the completion routine
+		packet->Completion.Send.SendCompletionTid = 0;
+
+		// Release the resources since we will not get any send completion
+		netvsc_xmit_completion((void*)packet);
+	}
+
+	DPRINT_DBG(NETVSC_DRV, "# of xmits %lu total size %lu", net_device_ctx->stats.tx_packets, net_device_ctx->stats.tx_bytes);
+
+	DPRINT_EXIT(NETVSC_DRV);
+	return ret;
+}
+
+
+/*++
+
+Name:	netvsc_linkstatus_callback()
+
+Desc:	Link up/down notification
+
+--*/
+static void netvsc_linkstatus_callback(DEVICE_OBJECT *device_obj, unsigned int status)
+{
+	struct device_context* device_ctx = to_device_context(device_obj);
+	struct net_device* net = (struct net_device *)device_ctx->device.driver_data;
+
+	DPRINT_ENTER(NETVSC_DRV);
+
+	if (!net)
+	{
+		DPRINT_ERR(NETVSC_DRV, "got link status but net device not initialized yet");
+		return;
+	}
+
+	if (status == 1)
+	{
+		netif_carrier_on(net);
+		netif_wake_queue(net);
+	}
+	else
+	{
+		netif_carrier_off(net);
+		netif_stop_queue(net);
+	}
+	DPRINT_EXIT(NETVSC_DRV);
+}
+
+
+/*++
+
+Name:	netvsc_recv_callback()
+
+Desc:	Callback when we receive a packet from the "wire" on the specify device
+
+--*/
+static int netvsc_recv_callback(DEVICE_OBJECT *device_obj, NETVSC_PACKET* packet)
+{
+	int ret=0;
+	struct device_context *device_ctx = to_device_context(device_obj);
+	struct net_device *net = (struct net_device *)device_ctx->device.driver_data;
+	struct net_device_context *net_device_ctx;
+
+	struct sk_buff *skb;
+	void *data;
+	int i=0;
+	unsigned long flags;
+
+	DPRINT_ENTER(NETVSC_DRV);
+
+	if (!net)
+	{
+		DPRINT_ERR(NETVSC_DRV, "got receive callback but net device not initialized yet");
+		return 0;
+	}
+
+	net_device_ctx = netdev_priv(net);
+
+	// Allocate a skb - TODO preallocate this
+	//skb = alloc_skb(packet->TotalDataBufferLength, GFP_ATOMIC);
+	skb = dev_alloc_skb(packet->TotalDataBufferLength + 2); // Pad 2-bytes to align IP header to 16 bytes
+	ASSERT(skb);
+	skb_reserve(skb, 2);
+	skb->dev = net;
+
+	// for kmap_atomic
+	local_irq_save(flags);
+
+	// Copy to skb. This copy is needed here since the memory pointed by NETVSC_PACKET
+	// cannot be deallocated
+	for (i=0; i<packet->PageBufferCount; i++)
+	{
+	    data = kmap_atomic(pfn_to_page(packet->PageBuffers[i].Pfn), KM_IRQ1);
+	    data = (void*)(unsigned long)data + packet->PageBuffers[i].Offset;
+
+	    memcpy(skb_put(skb, packet->PageBuffers[i].Length), data, packet->PageBuffers[i].Length);
+
+	    kunmap_atomic((void*)((unsigned long)data - packet->PageBuffers[i].Offset), KM_IRQ1);
+	}
+
+	local_irq_restore(flags);
+
+	skb->protocol = eth_type_trans(skb, net);
+
+	skb->ip_summed = CHECKSUM_NONE;
+
+	// Pass the skb back up. Network stack will deallocate the skb when it is done
+	ret = netif_rx(skb);
+
+	switch (ret)
+	{
+	case NET_RX_DROP:
+		net_device_ctx->stats.rx_dropped++;
+		break;
+	default:
+		net_device_ctx->stats.rx_packets++;
+		net_device_ctx->stats.rx_bytes += skb->len;
+		break;
+
+	}
+	DPRINT_DBG(NETVSC_DRV, "# of recvs %lu total size %lu", net_device_ctx->stats.rx_packets, net_device_ctx->stats.rx_bytes);
+
+	DPRINT_EXIT(NETVSC_DRV);
+
+	return 0;
+}
+
+static int netvsc_drv_exit_cb(struct device *dev, void *data)
+{
+	struct device **curr = (struct device **)data;
+	*curr = dev;
+	return 1; // stop iterating
+}
+
+/*++
+
+Name:	netvsc_drv_exit()
+
+Desc:
+
+--*/
+void netvsc_drv_exit(void)
+{
+	NETVSC_DRIVER_OBJECT *netvsc_drv_obj=&g_netvsc_drv.drv_obj;
+	struct driver_context *drv_ctx=&g_netvsc_drv.drv_ctx;
+
+	struct device *current_dev=NULL;
+#if defined(KERNEL_2_6_5) || defined(KERNEL_2_6_9)
+#define driver_for_each_device(drv, start, data, fn) \
+	struct list_head *ptr, *n; \
+	list_for_each_safe(ptr, n, &((drv)->devices)) {\
+		struct device *curr_dev;\
+		curr_dev = list_entry(ptr, struct device, driver_list);\
+		fn(curr_dev, data);\
+	}
+#endif
+
+	DPRINT_ENTER(NETVSC_DRV);
+
+	while (1)
+	{
+		current_dev = NULL;
+
+		// Get the device
+		driver_for_each_device(&drv_ctx->driver, NULL, (void*)&current_dev, netvsc_drv_exit_cb);
+
+		if (current_dev == NULL)
+			break;
+
+		// Initiate removal from the top-down
+		DPRINT_INFO(NETVSC_DRV, "unregistering device (%p)...", current_dev);
+
+		device_unregister(current_dev);
+	}
+
+	if (netvsc_drv_obj->Base.OnCleanup)
+		netvsc_drv_obj->Base.OnCleanup(&netvsc_drv_obj->Base);
+
+	vmbus_child_driver_unregister(drv_ctx);
+
+	DPRINT_EXIT(NETVSC_DRV);
+
+	return;
+}
+
+static int __init netvsc_init(void)
+{
+	int ret;
+
+	DPRINT_ENTER(NETVSC_DRV);
+	DPRINT_INFO(NETVSC_DRV, "Netvsc initializing....");
+
+	ret = netvsc_drv_init(NetVscInitialize);
+
+	DPRINT_EXIT(NETVSC_DRV);
+
+	return ret;
+}
+
+static void __exit netvsc_exit(void)
+{
+	DPRINT_ENTER(NETVSC_DRV);
+
+	netvsc_drv_exit();
+
+	DPRINT_EXIT(NETVSC_DRV);
+}
+
+module_param(netvsc_ringbuffer_size, int, S_IRUGO);
+
+module_init(netvsc_init);
+module_exit(netvsc_exit);