Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1856 insertions, 0 deletions

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
new file mode 100644
index 000000000..da737d959
--- /dev/null
+++ b/drivers/net/hyperv/netvsc.c
@@ -0,0 +1,1856 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2009, Microsoft Corporation.
+ *
+ * Authors:
+ *   Haiyang Zhang <haiyangz@microsoft.com>
+ *   Hank Janssen  <hjanssen@microsoft.com>
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/mm.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/netdevice.h>
+#include <linux/if_ether.h>
+#include <linux/vmalloc.h>
+#include <linux/rtnetlink.h>
+#include <linux/prefetch.h>
+#include <linux/filter.h>
+
+#include <asm/sync_bitops.h>
+#include <asm/mshyperv.h>
+
+#include "hyperv_net.h"
+#include "netvsc_trace.h"
+
+/*
+ * Switch the data path from the synthetic interface to the VF
+ * interface.
+ */
+int netvsc_switch_datapath(struct net_device *ndev, bool vf)
+{
+	struct net_device_context *net_device_ctx = netdev_priv(ndev);
+	struct hv_device *dev = net_device_ctx->device_ctx;
+	struct netvsc_device *nv_dev = rtnl_dereference(net_device_ctx->nvdev);
+	struct nvsp_message *init_pkt = &nv_dev->channel_init_pkt;
+	int ret, retry = 0;
+
+	/* Block sending traffic to VF if it's about to be gone */
+	if (!vf)
+		net_device_ctx->data_path_is_vf = vf;
+
+	memset(init_pkt, 0, sizeof(struct nvsp_message));
+	init_pkt->hdr.msg_type = NVSP_MSG4_TYPE_SWITCH_DATA_PATH;
+	if (vf)
+		init_pkt->msg.v4_msg.active_dp.active_datapath =
+			NVSP_DATAPATH_VF;
+	else
+		init_pkt->msg.v4_msg.active_dp.active_datapath =
+			NVSP_DATAPATH_SYNTHETIC;
+
+again:
+	trace_nvsp_send(ndev, init_pkt);
+
+	ret = vmbus_sendpacket(dev->channel, init_pkt,
+			       sizeof(struct nvsp_message),
+			       (unsigned long)init_pkt, VM_PKT_DATA_INBAND,
+			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+
+	/* If failed to switch to/from VF, let data_path_is_vf stay false,
+	 * so we use synthetic path to send data.
+	 */
+	if (ret) {
+		if (ret != -EAGAIN) {
+			netdev_err(ndev,
+				   "Unable to send sw datapath msg, err: %d\n",
+				   ret);
+			return ret;
+		}
+
+		if (retry++ < RETRY_MAX) {
+			usleep_range(RETRY_US_LO, RETRY_US_HI);
+			goto again;
+		} else {
+			netdev_err(
+				ndev,
+				"Retry failed to send sw datapath msg, err: %d\n",
+				ret);
+			return ret;
+		}
+	}
+
+	wait_for_completion(&nv_dev->channel_init_wait);
+	net_device_ctx->data_path_is_vf = vf;
+
+	return 0;
+}
+
+/* Worker to setup sub channels on initial setup
+ * Initial hotplug event occurs in softirq context
+ * and can't wait for channels.
+ */
+static void netvsc_subchan_work(struct work_struct *w)
+{
+	struct netvsc_device *nvdev =
+		container_of(w, struct netvsc_device, subchan_work);
+	struct rndis_device *rdev;
+	int i, ret;
+
+	/* Avoid deadlock with device removal already under RTNL */
+	if (!rtnl_trylock()) {
+		schedule_work(w);
+		return;
+	}
+
+	rdev = nvdev->extension;
+	if (rdev) {
+		ret = rndis_set_subchannel(rdev->ndev, nvdev, NULL);
+		if (ret == 0) {
+			netif_device_attach(rdev->ndev);
+		} else {
+			/* fallback to only primary channel */
+			for (i = 1; i < nvdev->num_chn; i++)
+				netif_napi_del(&nvdev->chan_table[i].napi);
+
+			nvdev->max_chn = 1;
+			nvdev->num_chn = 1;
+		}
+	}
+
+	rtnl_unlock();
+}
+
+static struct netvsc_device *alloc_net_device(void)
+{
+	struct netvsc_device *net_device;
+
+	net_device = kzalloc(sizeof(struct netvsc_device), GFP_KERNEL);
+	if (!net_device)
+		return NULL;
+
+	init_waitqueue_head(&net_device->wait_drain);
+	net_device->destroy = false;
+	net_device->tx_disable = true;
+
+	net_device->max_pkt = RNDIS_MAX_PKT_DEFAULT;
+	net_device->pkt_align = RNDIS_PKT_ALIGN_DEFAULT;
+
+	init_completion(&net_device->channel_init_wait);
+	init_waitqueue_head(&net_device->subchan_open);
+	INIT_WORK(&net_device->subchan_work, netvsc_subchan_work);
+
+	return net_device;
+}
+
+static void free_netvsc_device(struct rcu_head *head)
+{
+	struct netvsc_device *nvdev
+		= container_of(head, struct netvsc_device, rcu);
+	int i;
+
+	kfree(nvdev->extension);
+
+	if (nvdev->recv_original_buf)
+		vfree(nvdev->recv_original_buf);
+	else
+		vfree(nvdev->recv_buf);
+
+	if (nvdev->send_original_buf)
+		vfree(nvdev->send_original_buf);
+	else
+		vfree(nvdev->send_buf);
+
+	bitmap_free(nvdev->send_section_map);
+
+	for (i = 0; i < VRSS_CHANNEL_MAX; i++) {
+		xdp_rxq_info_unreg(&nvdev->chan_table[i].xdp_rxq);
+		kfree(nvdev->chan_table[i].recv_buf);
+		vfree(nvdev->chan_table[i].mrc.slots);
+	}
+
+	kfree(nvdev);
+}
+
+static void free_netvsc_device_rcu(struct netvsc_device *nvdev)
+{
+	call_rcu(&nvdev->rcu, free_netvsc_device);
+}
+
+static void netvsc_revoke_recv_buf(struct hv_device *device,
+				   struct netvsc_device *net_device,
+				   struct net_device *ndev)
+{
+	struct nvsp_message *revoke_packet;
+	int ret;
+
+	/*
+	 * If we got a section count, it means we received a
+	 * SendReceiveBufferComplete msg (ie sent
+	 * NvspMessage1TypeSendReceiveBuffer msg) therefore, we need
+	 * to send a revoke msg here
+	 */
+	if (net_device->recv_section_cnt) {
+		/* Send the revoke receive buffer */
+		revoke_packet = &net_device->revoke_packet;
+		memset(revoke_packet, 0, sizeof(struct nvsp_message));
+
+		revoke_packet->hdr.msg_type =
+			NVSP_MSG1_TYPE_REVOKE_RECV_BUF;
+		revoke_packet->msg.v1_msg.
+		revoke_recv_buf.id = NETVSC_RECEIVE_BUFFER_ID;
+
+		trace_nvsp_send(ndev, revoke_packet);
+
+		ret = vmbus_sendpacket(device->channel,
+				       revoke_packet,
+				       sizeof(struct nvsp_message),
+				       VMBUS_RQST_ID_NO_RESPONSE,
+				       VM_PKT_DATA_INBAND, 0);
+		/* If the failure is because the channel is rescinded;
+		 * ignore the failure since we cannot send on a rescinded
+		 * channel. This would allow us to properly cleanup
+		 * even when the channel is rescinded.
+		 */
+		if (device->channel->rescind)
+			ret = 0;
+		/*
+		 * If we failed here, we might as well return and
+		 * have a leak rather than continue and a bugchk
+		 */
+		if (ret != 0) {
+			netdev_err(ndev, "unable to send "
+				"revoke receive buffer to netvsp\n");
+			return;
+		}
+		net_device->recv_section_cnt = 0;
+	}
+}
+
+static void netvsc_revoke_send_buf(struct hv_device *device,
+				   struct netvsc_device *net_device,
+				   struct net_device *ndev)
+{
+	struct nvsp_message *revoke_packet;
+	int ret;
+
+	/* Deal with the send buffer we may have setup.
+	 * If we got a  send section size, it means we received a
+	 * NVSP_MSG1_TYPE_SEND_SEND_BUF_COMPLETE msg (ie sent
+	 * NVSP_MSG1_TYPE_SEND_SEND_BUF msg) therefore, we need
+	 * to send a revoke msg here
+	 */
+	if (net_device->send_section_cnt) {
+		/* Send the revoke receive buffer */
+		revoke_packet = &net_device->revoke_packet;
+		memset(revoke_packet, 0, sizeof(struct nvsp_message));
+
+		revoke_packet->hdr.msg_type =
+			NVSP_MSG1_TYPE_REVOKE_SEND_BUF;
+		revoke_packet->msg.v1_msg.revoke_send_buf.id =
+			NETVSC_SEND_BUFFER_ID;
+
+		trace_nvsp_send(ndev, revoke_packet);
+
+		ret = vmbus_sendpacket(device->channel,
+				       revoke_packet,
+				       sizeof(struct nvsp_message),
+				       VMBUS_RQST_ID_NO_RESPONSE,
+				       VM_PKT_DATA_INBAND, 0);
+
+		/* If the failure is because the channel is rescinded;
+		 * ignore the failure since we cannot send on a rescinded
+		 * channel. This would allow us to properly cleanup
+		 * even when the channel is rescinded.
+		 */
+		if (device->channel->rescind)
+			ret = 0;
+
+		/* If we failed here, we might as well return and
+		 * have a leak rather than continue and a bugchk
+		 */
+		if (ret != 0) {
+			netdev_err(ndev, "unable to send "
+				   "revoke send buffer to netvsp\n");
+			return;
+		}
+		net_device->send_section_cnt = 0;
+	}
+}
+
+static void netvsc_teardown_recv_gpadl(struct hv_device *device,
+				       struct netvsc_device *net_device,
+				       struct net_device *ndev)
+{
+	int ret;
+
+	if (net_device->recv_buf_gpadl_handle.gpadl_handle) {
+		ret = vmbus_teardown_gpadl(device->channel,
+					   &net_device->recv_buf_gpadl_handle);
+
+		/* If we failed here, we might as well return and have a leak
+		 * rather than continue and a bugchk
+		 */
+		if (ret != 0) {
+			netdev_err(ndev,
+				   "unable to teardown receive buffer's gpadl\n");
+			return;
+		}
+	}
+}
+
+static void netvsc_teardown_send_gpadl(struct hv_device *device,
+				       struct netvsc_device *net_device,
+				       struct net_device *ndev)
+{
+	int ret;
+
+	if (net_device->send_buf_gpadl_handle.gpadl_handle) {
+		ret = vmbus_teardown_gpadl(device->channel,
+					   &net_device->send_buf_gpadl_handle);
+
+		/* If we failed here, we might as well return and have a leak
+		 * rather than continue and a bugchk
+		 */
+		if (ret != 0) {
+			netdev_err(ndev,
+				   "unable to teardown send buffer's gpadl\n");
+			return;
+		}
+	}
+}
+
+int netvsc_alloc_recv_comp_ring(struct netvsc_device *net_device, u32 q_idx)
+{
+	struct netvsc_channel *nvchan = &net_device->chan_table[q_idx];
+	int node = cpu_to_node(nvchan->channel->target_cpu);
+	size_t size;
+
+	size = net_device->recv_completion_cnt * sizeof(struct recv_comp_data);
+	nvchan->mrc.slots = vzalloc_node(size, node);
+	if (!nvchan->mrc.slots)
+		nvchan->mrc.slots = vzalloc(size);
+
+	return nvchan->mrc.slots ? 0 : -ENOMEM;
+}
+
+static int netvsc_init_buf(struct hv_device *device,
+			   struct netvsc_device *net_device,
+			   const struct netvsc_device_info *device_info)
+{
+	struct nvsp_1_message_send_receive_buffer_complete *resp;
+	struct net_device *ndev = hv_get_drvdata(device);
+	struct nvsp_message *init_packet;
+	unsigned int buf_size;
+	int i, ret = 0;
+	void *vaddr;
+
+	/* Get receive buffer area. */
+	buf_size = device_info->recv_sections * device_info->recv_section_size;
+	buf_size = roundup(buf_size, PAGE_SIZE);
+
+	/* Legacy hosts only allow smaller receive buffer */
+	if (net_device->nvsp_version <= NVSP_PROTOCOL_VERSION_2)
+		buf_size = min_t(unsigned int, buf_size,
+				 NETVSC_RECEIVE_BUFFER_SIZE_LEGACY);
+
+	net_device->recv_buf = vzalloc(buf_size);
+	if (!net_device->recv_buf) {
+		netdev_err(ndev,
+			   "unable to allocate receive buffer of size %u\n",
+			   buf_size);
+		ret = -ENOMEM;
+		goto cleanup;
+	}
+
+	net_device->recv_buf_size = buf_size;
+
+	/*
+	 * Establish the gpadl handle for this buffer on this
+	 * channel.  Note: This call uses the vmbus connection rather
+	 * than the channel to establish the gpadl handle.
+	 */
+	ret = vmbus_establish_gpadl(device->channel, net_device->recv_buf,
+				    buf_size,
+				    &net_device->recv_buf_gpadl_handle);
+	if (ret != 0) {
+		netdev_err(ndev,
+			"unable to establish receive buffer's gpadl\n");
+		goto cleanup;
+	}
+
+	if (hv_isolation_type_snp()) {
+		vaddr = hv_map_memory(net_device->recv_buf, buf_size);
+		if (!vaddr) {
+			ret = -ENOMEM;
+			goto cleanup;
+		}
+
+		net_device->recv_original_buf = net_device->recv_buf;
+		net_device->recv_buf = vaddr;
+	}
+
+	/* Notify the NetVsp of the gpadl handle */
+	init_packet = &net_device->channel_init_pkt;
+	memset(init_packet, 0, sizeof(struct nvsp_message));
+	init_packet->hdr.msg_type = NVSP_MSG1_TYPE_SEND_RECV_BUF;
+	init_packet->msg.v1_msg.send_recv_buf.
+		gpadl_handle = net_device->recv_buf_gpadl_handle.gpadl_handle;
+	init_packet->msg.v1_msg.
+		send_recv_buf.id = NETVSC_RECEIVE_BUFFER_ID;
+
+	trace_nvsp_send(ndev, init_packet);
+
+	/* Send the gpadl notification request */
+	ret = vmbus_sendpacket(device->channel, init_packet,
+			       sizeof(struct nvsp_message),
+			       (unsigned long)init_packet,
+			       VM_PKT_DATA_INBAND,
+			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+	if (ret != 0) {
+		netdev_err(ndev,
+			"unable to send receive buffer's gpadl to netvsp\n");
+		goto cleanup;
+	}
+
+	wait_for_completion(&net_device->channel_init_wait);
+
+	/* Check the response */
+	resp = &init_packet->msg.v1_msg.send_recv_buf_complete;
+	if (resp->status != NVSP_STAT_SUCCESS) {
+		netdev_err(ndev,
+			   "Unable to complete receive buffer initialization with NetVsp - status %d\n",
+			   resp->status);
+		ret = -EINVAL;
+		goto cleanup;
+	}
+
+	/* Parse the response */
+	netdev_dbg(ndev, "Receive sections: %u sub_allocs: size %u count: %u\n",
+		   resp->num_sections, resp->sections[0].sub_alloc_size,
+		   resp->sections[0].num_sub_allocs);
+
+	/* There should only be one section for the entire receive buffer */
+	if (resp->num_sections != 1 || resp->sections[0].offset != 0) {
+		ret = -EINVAL;
+		goto cleanup;
+	}
+
+	net_device->recv_section_size = resp->sections[0].sub_alloc_size;
+	net_device->recv_section_cnt = resp->sections[0].num_sub_allocs;
+
+	/* Ensure buffer will not overflow */
+	if (net_device->recv_section_size < NETVSC_MTU_MIN || (u64)net_device->recv_section_size *
+	    (u64)net_device->recv_section_cnt > (u64)buf_size) {
+		netdev_err(ndev, "invalid recv_section_size %u\n",
+			   net_device->recv_section_size);
+		ret = -EINVAL;
+		goto cleanup;
+	}
+
+	for (i = 0; i < VRSS_CHANNEL_MAX; i++) {
+		struct netvsc_channel *nvchan = &net_device->chan_table[i];
+
+		nvchan->recv_buf = kzalloc(net_device->recv_section_size, GFP_KERNEL);
+		if (nvchan->recv_buf == NULL) {
+			ret = -ENOMEM;
+			goto cleanup;
+		}
+	}
+
+	/* Setup receive completion ring.
+	 * Add 1 to the recv_section_cnt because at least one entry in a
+	 * ring buffer has to be empty.
+	 */
+	net_device->recv_completion_cnt = net_device->recv_section_cnt + 1;
+	ret = netvsc_alloc_recv_comp_ring(net_device, 0);
+	if (ret)
+		goto cleanup;
+
+	/* Now setup the send buffer. */
+	buf_size = device_info->send_sections * device_info->send_section_size;
+	buf_size = round_up(buf_size, PAGE_SIZE);
+
+	net_device->send_buf = vzalloc(buf_size);
+	if (!net_device->send_buf) {
+		netdev_err(ndev, "unable to allocate send buffer of size %u\n",
+			   buf_size);
+		ret = -ENOMEM;
+		goto cleanup;
+	}
+	net_device->send_buf_size = buf_size;
+
+	/* Establish the gpadl handle for this buffer on this
+	 * channel.  Note: This call uses the vmbus connection rather
+	 * than the channel to establish the gpadl handle.
+	 */
+	ret = vmbus_establish_gpadl(device->channel, net_device->send_buf,
+				    buf_size,
+				    &net_device->send_buf_gpadl_handle);
+	if (ret != 0) {
+		netdev_err(ndev,
+			   "unable to establish send buffer's gpadl\n");
+		goto cleanup;
+	}
+
+	if (hv_isolation_type_snp()) {
+		vaddr = hv_map_memory(net_device->send_buf, buf_size);
+		if (!vaddr) {
+			ret = -ENOMEM;
+			goto cleanup;
+		}
+
+		net_device->send_original_buf = net_device->send_buf;
+		net_device->send_buf = vaddr;
+	}
+
+	/* Notify the NetVsp of the gpadl handle */
+	init_packet = &net_device->channel_init_pkt;
+	memset(init_packet, 0, sizeof(struct nvsp_message));
+	init_packet->hdr.msg_type = NVSP_MSG1_TYPE_SEND_SEND_BUF;
+	init_packet->msg.v1_msg.send_send_buf.gpadl_handle =
+		net_device->send_buf_gpadl_handle.gpadl_handle;
+	init_packet->msg.v1_msg.send_send_buf.id = NETVSC_SEND_BUFFER_ID;
+
+	trace_nvsp_send(ndev, init_packet);
+
+	/* Send the gpadl notification request */
+	ret = vmbus_sendpacket(device->channel, init_packet,
+			       sizeof(struct nvsp_message),
+			       (unsigned long)init_packet,
+			       VM_PKT_DATA_INBAND,
+			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+	if (ret != 0) {
+		netdev_err(ndev,
+			   "unable to send send buffer's gpadl to netvsp\n");
+		goto cleanup;
+	}
+
+	wait_for_completion(&net_device->channel_init_wait);
+
+	/* Check the response */
+	if (init_packet->msg.v1_msg.
+	    send_send_buf_complete.status != NVSP_STAT_SUCCESS) {
+		netdev_err(ndev, "Unable to complete send buffer "
+			   "initialization with NetVsp - status %d\n",
+			   init_packet->msg.v1_msg.
+			   send_send_buf_complete.status);
+		ret = -EINVAL;
+		goto cleanup;
+	}
+
+	/* Parse the response */
+	net_device->send_section_size = init_packet->msg.
+				v1_msg.send_send_buf_complete.section_size;
+	if (net_device->send_section_size < NETVSC_MTU_MIN) {
+		netdev_err(ndev, "invalid send_section_size %u\n",
+			   net_device->send_section_size);
+		ret = -EINVAL;
+		goto cleanup;
+	}
+
+	/* Section count is simply the size divided by the section size. */
+	net_device->send_section_cnt = buf_size / net_device->send_section_size;
+
+	netdev_dbg(ndev, "Send section size: %d, Section count:%d\n",
+		   net_device->send_section_size, net_device->send_section_cnt);
+
+	/* Setup state for managing the send buffer. */
+	net_device->send_section_map = bitmap_zalloc(net_device->send_section_cnt,
+						     GFP_KERNEL);
+	if (!net_device->send_section_map) {
+		ret = -ENOMEM;
+		goto cleanup;
+	}
+
+	goto exit;
+
+cleanup:
+	netvsc_revoke_recv_buf(device, net_device, ndev);
+	netvsc_revoke_send_buf(device, net_device, ndev);
+	netvsc_teardown_recv_gpadl(device, net_device, ndev);
+	netvsc_teardown_send_gpadl(device, net_device, ndev);
+
+exit:
+	return ret;
+}
+
+/* Negotiate NVSP protocol version */
+static int negotiate_nvsp_ver(struct hv_device *device,
+			      struct netvsc_device *net_device,
+			      struct nvsp_message *init_packet,
+			      u32 nvsp_ver)
+{
+	struct net_device *ndev = hv_get_drvdata(device);
+	int ret;
+
+	memset(init_packet, 0, sizeof(struct nvsp_message));
+	init_packet->hdr.msg_type = NVSP_MSG_TYPE_INIT;
+	init_packet->msg.init_msg.init.min_protocol_ver = nvsp_ver;
+	init_packet->msg.init_msg.init.max_protocol_ver = nvsp_ver;
+	trace_nvsp_send(ndev, init_packet);
+
+	/* Send the init request */
+	ret = vmbus_sendpacket(device->channel, init_packet,
+			       sizeof(struct nvsp_message),
+			       (unsigned long)init_packet,
+			       VM_PKT_DATA_INBAND,
+			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+
+	if (ret != 0)
+		return ret;
+
+	wait_for_completion(&net_device->channel_init_wait);
+
+	if (init_packet->msg.init_msg.init_complete.status !=
+	    NVSP_STAT_SUCCESS)
+		return -EINVAL;
+
+	if (nvsp_ver == NVSP_PROTOCOL_VERSION_1)
+		return 0;
+
+	/* NVSPv2 or later: Send NDIS config */
+	memset(init_packet, 0, sizeof(struct nvsp_message));
+	init_packet->hdr.msg_type = NVSP_MSG2_TYPE_SEND_NDIS_CONFIG;
+	init_packet->msg.v2_msg.send_ndis_config.mtu = ndev->mtu + ETH_HLEN;
+	init_packet->msg.v2_msg.send_ndis_config.capability.ieee8021q = 1;
+
+	if (nvsp_ver >= NVSP_PROTOCOL_VERSION_5) {
+		if (hv_is_isolation_supported())
+			netdev_info(ndev, "SR-IOV not advertised by guests on the host supporting isolation\n");
+		else
+			init_packet->msg.v2_msg.send_ndis_config.capability.sriov = 1;
+
+		/* Teaming bit is needed to receive link speed updates */
+		init_packet->msg.v2_msg.send_ndis_config.capability.teaming = 1;
+	}
+
+	if (nvsp_ver >= NVSP_PROTOCOL_VERSION_61)
+		init_packet->msg.v2_msg.send_ndis_config.capability.rsc = 1;
+
+	trace_nvsp_send(ndev, init_packet);
+
+	ret = vmbus_sendpacket(device->channel, init_packet,
+				sizeof(struct nvsp_message),
+				VMBUS_RQST_ID_NO_RESPONSE,
+				VM_PKT_DATA_INBAND, 0);
+
+	return ret;
+}
+
+static int netvsc_connect_vsp(struct hv_device *device,
+			      struct netvsc_device *net_device,
+			      const struct netvsc_device_info *device_info)
+{
+	struct net_device *ndev = hv_get_drvdata(device);
+	static const u32 ver_list[] = {
+		NVSP_PROTOCOL_VERSION_1, NVSP_PROTOCOL_VERSION_2,
+		NVSP_PROTOCOL_VERSION_4, NVSP_PROTOCOL_VERSION_5,
+		NVSP_PROTOCOL_VERSION_6, NVSP_PROTOCOL_VERSION_61
+	};
+	struct nvsp_message *init_packet;
+	int ndis_version, i, ret;
+
+	init_packet = &net_device->channel_init_pkt;
+
+	/* Negotiate the latest NVSP protocol supported */
+	for (i = ARRAY_SIZE(ver_list) - 1; i >= 0; i--)
+		if (negotiate_nvsp_ver(device, net_device, init_packet,
+				       ver_list[i])  == 0) {
+			net_device->nvsp_version = ver_list[i];
+			break;
+		}
+
+	if (i < 0) {
+		ret = -EPROTO;
+		goto cleanup;
+	}
+
+	if (hv_is_isolation_supported() && net_device->nvsp_version < NVSP_PROTOCOL_VERSION_61) {
+		netdev_err(ndev, "Invalid NVSP version 0x%x (expected >= 0x%x) from the host supporting isolation\n",
+			   net_device->nvsp_version, NVSP_PROTOCOL_VERSION_61);
+		ret = -EPROTO;
+		goto cleanup;
+	}
+
+	pr_debug("Negotiated NVSP version:%x\n", net_device->nvsp_version);
+
+	/* Send the ndis version */
+	memset(init_packet, 0, sizeof(struct nvsp_message));
+
+	if (net_device->nvsp_version <= NVSP_PROTOCOL_VERSION_4)
+		ndis_version = 0x00060001;
+	else
+		ndis_version = 0x0006001e;
+
+	init_packet->hdr.msg_type = NVSP_MSG1_TYPE_SEND_NDIS_VER;
+	init_packet->msg.v1_msg.
+		send_ndis_ver.ndis_major_ver =
+				(ndis_version & 0xFFFF0000) >> 16;
+	init_packet->msg.v1_msg.
+		send_ndis_ver.ndis_minor_ver =
+				ndis_version & 0xFFFF;
+
+	trace_nvsp_send(ndev, init_packet);
+
+	/* Send the init request */
+	ret = vmbus_sendpacket(device->channel, init_packet,
+				sizeof(struct nvsp_message),
+				VMBUS_RQST_ID_NO_RESPONSE,
+				VM_PKT_DATA_INBAND, 0);
+	if (ret != 0)
+		goto cleanup;
+
+
+	ret = netvsc_init_buf(device, net_device, device_info);
+
+cleanup:
+	return ret;
+}
+
+/*
+ * netvsc_device_remove - Callback when the root bus device is removed
+ */
+void netvsc_device_remove(struct hv_device *device)
+{
+	struct net_device *ndev = hv_get_drvdata(device);
+	struct net_device_context *net_device_ctx = netdev_priv(ndev);
+	struct netvsc_device *net_device
+		= rtnl_dereference(net_device_ctx->nvdev);
+	int i;
+
+	/*
+	 * Revoke receive buffer. If host is pre-Win2016 then tear down
+	 * receive buffer GPADL. Do the same for send buffer.
+	 */
+	netvsc_revoke_recv_buf(device, net_device, ndev);
+	if (vmbus_proto_version < VERSION_WIN10)
+		netvsc_teardown_recv_gpadl(device, net_device, ndev);
+
+	netvsc_revoke_send_buf(device, net_device, ndev);
+	if (vmbus_proto_version < VERSION_WIN10)
+		netvsc_teardown_send_gpadl(device, net_device, ndev);
+
+	RCU_INIT_POINTER(net_device_ctx->nvdev, NULL);
+
+	/* Disable NAPI and disassociate its context from the device. */
+	for (i = 0; i < net_device->num_chn; i++) {
+		/* See also vmbus_reset_channel_cb(). */
+		napi_disable(&net_device->chan_table[i].napi);
+		netif_napi_del(&net_device->chan_table[i].napi);
+	}
+
+	/*
+	 * At this point, no one should be accessing net_device
+	 * except in here
+	 */
+	netdev_dbg(ndev, "net device safe to remove\n");
+
+	/* Now, we can close the channel safely */
+	vmbus_close(device->channel);
+
+	/*
+	 * If host is Win2016 or higher then we do the GPADL tear down
+	 * here after VMBus is closed.
+	*/
+	if (vmbus_proto_version >= VERSION_WIN10) {
+		netvsc_teardown_recv_gpadl(device, net_device, ndev);
+		netvsc_teardown_send_gpadl(device, net_device, ndev);
+	}
+
+	if (net_device->recv_original_buf)
+		hv_unmap_memory(net_device->recv_buf);
+
+	if (net_device->send_original_buf)
+		hv_unmap_memory(net_device->send_buf);
+
+	/* Release all resources */
+	free_netvsc_device_rcu(net_device);
+}
+
+#define RING_AVAIL_PERCENT_HIWATER 20
+#define RING_AVAIL_PERCENT_LOWATER 10
+
+static inline void netvsc_free_send_slot(struct netvsc_device *net_device,
+					 u32 index)
+{
+	sync_change_bit(index, net_device->send_section_map);
+}
+
+static void netvsc_send_tx_complete(struct net_device *ndev,
+				    struct netvsc_device *net_device,
+				    struct vmbus_channel *channel,
+				    const struct vmpacket_descriptor *desc,
+				    int budget)
+{
+	struct net_device_context *ndev_ctx = netdev_priv(ndev);
+	struct sk_buff *skb;
+	u16 q_idx = 0;
+	int queue_sends;
+	u64 cmd_rqst;
+
+	cmd_rqst = channel->request_addr_callback(channel, desc->trans_id);
+	if (cmd_rqst == VMBUS_RQST_ERROR) {
+		netdev_err(ndev, "Invalid transaction ID %llx\n", desc->trans_id);
+		return;
+	}
+
+	skb = (struct sk_buff *)(unsigned long)cmd_rqst;
+
+	/* Notify the layer above us */
+	if (likely(skb)) {
+		struct hv_netvsc_packet *packet
+			= (struct hv_netvsc_packet *)skb->cb;
+		u32 send_index = packet->send_buf_index;
+		struct netvsc_stats_tx *tx_stats;
+
+		if (send_index != NETVSC_INVALID_INDEX)
+			netvsc_free_send_slot(net_device, send_index);
+		q_idx = packet->q_idx;
+
+		tx_stats = &net_device->chan_table[q_idx].tx_stats;
+
+		u64_stats_update_begin(&tx_stats->syncp);
+		tx_stats->packets += packet->total_packets;
+		tx_stats->bytes += packet->total_bytes;
+		u64_stats_update_end(&tx_stats->syncp);
+
+		netvsc_dma_unmap(ndev_ctx->device_ctx, packet);
+		napi_consume_skb(skb, budget);
+	}
+
+	queue_sends =
+		atomic_dec_return(&net_device->chan_table[q_idx].queue_sends);
+
+	if (unlikely(net_device->destroy)) {
+		if (queue_sends == 0)
+			wake_up(&net_device->wait_drain);
+	} else {
+		struct netdev_queue *txq = netdev_get_tx_queue(ndev, q_idx);
+
+		if (netif_tx_queue_stopped(txq) && !net_device->tx_disable &&
+		    (hv_get_avail_to_write_percent(&channel->outbound) >
+		     RING_AVAIL_PERCENT_HIWATER || queue_sends < 1)) {
+			netif_tx_wake_queue(txq);
+			ndev_ctx->eth_stats.wake_queue++;
+		}
+	}
+}
+
+static void netvsc_send_completion(struct net_device *ndev,
+				   struct netvsc_device *net_device,
+				   struct vmbus_channel *incoming_channel,
+				   const struct vmpacket_descriptor *desc,
+				   int budget)
+{
+	const struct nvsp_message *nvsp_packet;
+	u32 msglen = hv_pkt_datalen(desc);
+	struct nvsp_message *pkt_rqst;
+	u64 cmd_rqst;
+	u32 status;
+
+	/* First check if this is a VMBUS completion without data payload */
+	if (!msglen) {
+		cmd_rqst = incoming_channel->request_addr_callback(incoming_channel,
+								   desc->trans_id);
+		if (cmd_rqst == VMBUS_RQST_ERROR) {
+			netdev_err(ndev, "Invalid transaction ID %llx\n", desc->trans_id);
+			return;
+		}
+
+		pkt_rqst = (struct nvsp_message *)(uintptr_t)cmd_rqst;
+		switch (pkt_rqst->hdr.msg_type) {
+		case NVSP_MSG4_TYPE_SWITCH_DATA_PATH:
+			complete(&net_device->channel_init_wait);
+			break;
+
+		default:
+			netdev_err(ndev, "Unexpected VMBUS completion!!\n");
+		}
+		return;
+	}
+
+	/* Ensure packet is big enough to read header fields */
+	if (msglen < sizeof(struct nvsp_message_header)) {
+		netdev_err(ndev, "nvsp_message length too small: %u\n", msglen);
+		return;
+	}
+
+	nvsp_packet = hv_pkt_data(desc);
+	switch (nvsp_packet->hdr.msg_type) {
+	case NVSP_MSG_TYPE_INIT_COMPLETE:
+		if (msglen < sizeof(struct nvsp_message_header) +
+				sizeof(struct nvsp_message_init_complete)) {
+			netdev_err(ndev, "nvsp_msg length too small: %u\n",
+				   msglen);
+			return;
+		}
+		fallthrough;
+
+	case NVSP_MSG1_TYPE_SEND_RECV_BUF_COMPLETE:
+		if (msglen < sizeof(struct nvsp_message_header) +
+				sizeof(struct nvsp_1_message_send_receive_buffer_complete)) {
+			netdev_err(ndev, "nvsp_msg1 length too small: %u\n",
+				   msglen);
+			return;
+		}
+		fallthrough;
+
+	case NVSP_MSG1_TYPE_SEND_SEND_BUF_COMPLETE:
+		if (msglen < sizeof(struct nvsp_message_header) +
+				sizeof(struct nvsp_1_message_send_send_buffer_complete)) {
+			netdev_err(ndev, "nvsp_msg1 length too small: %u\n",
+				   msglen);
+			return;
+		}
+		fallthrough;
+
+	case NVSP_MSG5_TYPE_SUBCHANNEL:
+		if (msglen < sizeof(struct nvsp_message_header) +
+				sizeof(struct nvsp_5_subchannel_complete)) {
+			netdev_err(ndev, "nvsp_msg5 length too small: %u\n",
+				   msglen);
+			return;
+		}
+		/* Copy the response back */
+		memcpy(&net_device->channel_init_pkt, nvsp_packet,
+		       sizeof(struct nvsp_message));
+		complete(&net_device->channel_init_wait);
+		break;
+
+	case NVSP_MSG1_TYPE_SEND_RNDIS_PKT_COMPLETE:
+		if (msglen < sizeof(struct nvsp_message_header) +
+		    sizeof(struct nvsp_1_message_send_rndis_packet_complete)) {
+			if (net_ratelimit())
+				netdev_err(ndev, "nvsp_rndis_pkt_complete length too small: %u\n",
+					   msglen);
+			return;
+		}
+
+		/* If status indicates an error, output a message so we know
+		 * there's a problem. But process the completion anyway so the
+		 * resources are released.
+		 */
+		status = nvsp_packet->msg.v1_msg.send_rndis_pkt_complete.status;
+		if (status != NVSP_STAT_SUCCESS && net_ratelimit())
+			netdev_err(ndev, "nvsp_rndis_pkt_complete error status: %x\n",
+				   status);
+
+		netvsc_send_tx_complete(ndev, net_device, incoming_channel,
+					desc, budget);
+		break;
+
+	default:
+		netdev_err(ndev,
+			   "Unknown send completion type %d received!!\n",
+			   nvsp_packet->hdr.msg_type);
+	}
+}
+
+static u32 netvsc_get_next_send_section(struct netvsc_device *net_device)
+{
+	unsigned long *map_addr = net_device->send_section_map;
+	unsigned int i;
+
+	for_each_clear_bit(i, map_addr, net_device->send_section_cnt) {
+		if (sync_test_and_set_bit(i, map_addr) == 0)
+			return i;
+	}
+
+	return NETVSC_INVALID_INDEX;
+}
+
+static void netvsc_copy_to_send_buf(struct netvsc_device *net_device,
+				    unsigned int section_index,
+				    u32 pend_size,
+				    struct hv_netvsc_packet *packet,
+				    struct rndis_message *rndis_msg,
+				    struct hv_page_buffer *pb,
+				    bool xmit_more)
+{
+	char *start = net_device->send_buf;
+	char *dest = start + (section_index * net_device->send_section_size)
+		     + pend_size;
+	int i;
+	u32 padding = 0;
+	u32 page_count = packet->cp_partial ? packet->rmsg_pgcnt :
+		packet->page_buf_cnt;
+	u32 remain;
+
+	/* Add padding */
+	remain = packet->total_data_buflen & (net_device->pkt_align - 1);
+	if (xmit_more && remain) {
+		padding = net_device->pkt_align - remain;
+		rndis_msg->msg_len += padding;
+		packet->total_data_buflen += padding;
+	}
+
+	for (i = 0; i < page_count; i++) {
+		char *src = phys_to_virt(pb[i].pfn << HV_HYP_PAGE_SHIFT);
+		u32 offset = pb[i].offset;
+		u32 len = pb[i].len;
+
+		memcpy(dest, (src + offset), len);
+		dest += len;
+	}
+
+	if (padding)
+		memset(dest, 0, padding);
+}
+
+void netvsc_dma_unmap(struct hv_device *hv_dev,
+		      struct hv_netvsc_packet *packet)
+{
+	int i;
+
+	if (!hv_is_isolation_supported())
+		return;
+
+	if (!packet->dma_range)
+		return;
+
+	for (i = 0; i < packet->page_buf_cnt; i++)
+		dma_unmap_single(&hv_dev->device, packet->dma_range[i].dma,
+				 packet->dma_range[i].mapping_size,
+				 DMA_TO_DEVICE);
+
+	kfree(packet->dma_range);
+}
+
+/* netvsc_dma_map - Map swiotlb bounce buffer with data page of
+ * packet sent by vmbus_sendpacket_pagebuffer() in the Isolation
+ * VM.
+ *
+ * In isolation VM, netvsc send buffer has been marked visible to
+ * host and so the data copied to send buffer doesn't need to use
+ * bounce buffer. The data pages handled by vmbus_sendpacket_pagebuffer()
+ * may not be copied to send buffer and so these pages need to be
+ * mapped with swiotlb bounce buffer. netvsc_dma_map() is to do
+ * that. The pfns in the struct hv_page_buffer need to be converted
+ * to bounce buffer's pfn. The loop here is necessary because the
+ * entries in the page buffer array are not necessarily full
+ * pages of data.  Each entry in the array has a separate offset and
+ * len that may be non-zero, even for entries in the middle of the
+ * array.  And the entries are not physically contiguous.  So each
+ * entry must be individually mapped rather than as a contiguous unit.
+ * So not use dma_map_sg() here.
+ */
+static int netvsc_dma_map(struct hv_device *hv_dev,
+			  struct hv_netvsc_packet *packet,
+			  struct hv_page_buffer *pb)
+{
+	u32 page_count = packet->page_buf_cnt;
+	dma_addr_t dma;
+	int i;
+
+	if (!hv_is_isolation_supported())
+		return 0;
+
+	packet->dma_range = kcalloc(page_count,
+				    sizeof(*packet->dma_range),
+				    GFP_ATOMIC);
+	if (!packet->dma_range)
+		return -ENOMEM;
+
+	for (i = 0; i < page_count; i++) {
+		char *src = phys_to_virt((pb[i].pfn << HV_HYP_PAGE_SHIFT)
+					 + pb[i].offset);
+		u32 len = pb[i].len;
+
+		dma = dma_map_single(&hv_dev->device, src, len,
+				     DMA_TO_DEVICE);
+		if (dma_mapping_error(&hv_dev->device, dma)) {
+			kfree(packet->dma_range);
+			return -ENOMEM;
+		}
+
+		/* pb[].offset and pb[].len are not changed during dma mapping
+		 * and so not reassign.
+		 */
+		packet->dma_range[i].dma = dma;
+		packet->dma_range[i].mapping_size = len;
+		pb[i].pfn = dma >> HV_HYP_PAGE_SHIFT;
+	}
+
+	return 0;
+}
+
+static inline int netvsc_send_pkt(
+	struct hv_device *device,
+	struct hv_netvsc_packet *packet,
+	struct netvsc_device *net_device,
+	struct hv_page_buffer *pb,
+	struct sk_buff *skb)
+{
+	struct nvsp_message nvmsg;
+	struct nvsp_1_message_send_rndis_packet *rpkt =
+		&nvmsg.msg.v1_msg.send_rndis_pkt;
+	struct netvsc_channel * const nvchan =
+		&net_device->chan_table[packet->q_idx];
+	struct vmbus_channel *out_channel = nvchan->channel;
+	struct net_device *ndev = hv_get_drvdata(device);
+	struct net_device_context *ndev_ctx = netdev_priv(ndev);
+	struct netdev_queue *txq = netdev_get_tx_queue(ndev, packet->q_idx);
+	u64 req_id;
+	int ret;
+	u32 ring_avail = hv_get_avail_to_write_percent(&out_channel->outbound);
+
+	memset(&nvmsg, 0, sizeof(struct nvsp_message));
+	nvmsg.hdr.msg_type = NVSP_MSG1_TYPE_SEND_RNDIS_PKT;
+	if (skb)
+		rpkt->channel_type = 0;		/* 0 is RMC_DATA */
+	else
+		rpkt->channel_type = 1;		/* 1 is RMC_CONTROL */
+
+	rpkt->send_buf_section_index = packet->send_buf_index;
+	if (packet->send_buf_index == NETVSC_INVALID_INDEX)
+		rpkt->send_buf_section_size = 0;
+	else
+		rpkt->send_buf_section_size = packet->total_data_buflen;
+
+	req_id = (ulong)skb;
+
+	if (out_channel->rescind)
+		return -ENODEV;
+
+	trace_nvsp_send_pkt(ndev, out_channel, rpkt);
+
+	packet->dma_range = NULL;
+	if (packet->page_buf_cnt) {
+		if (packet->cp_partial)
+			pb += packet->rmsg_pgcnt;
+
+		ret = netvsc_dma_map(ndev_ctx->device_ctx, packet, pb);
+		if (ret) {
+			ret = -EAGAIN;
+			goto exit;
+		}
+
+		ret = vmbus_sendpacket_pagebuffer(out_channel,
+						  pb, packet->page_buf_cnt,
+						  &nvmsg, sizeof(nvmsg),
+						  req_id);
+
+		if (ret)
+			netvsc_dma_unmap(ndev_ctx->device_ctx, packet);
+	} else {
+		ret = vmbus_sendpacket(out_channel,
+				       &nvmsg, sizeof(nvmsg),
+				       req_id, VM_PKT_DATA_INBAND,
+				       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+	}
+
+exit:
+	if (ret == 0) {
+		atomic_inc_return(&nvchan->queue_sends);
+
+		if (ring_avail < RING_AVAIL_PERCENT_LOWATER) {
+			netif_tx_stop_queue(txq);
+			ndev_ctx->eth_stats.stop_queue++;
+		}
+	} else if (ret == -EAGAIN) {
+		netif_tx_stop_queue(txq);
+		ndev_ctx->eth_stats.stop_queue++;
+	} else {
+		netdev_err(ndev,
+			   "Unable to send packet pages %u len %u, ret %d\n",
+			   packet->page_buf_cnt, packet->total_data_buflen,
+			   ret);
+	}
+
+	if (netif_tx_queue_stopped(txq) &&
+	    atomic_read(&nvchan->queue_sends) < 1 &&
+	    !net_device->tx_disable) {
+		netif_tx_wake_queue(txq);
+		ndev_ctx->eth_stats.wake_queue++;
+		if (ret == -EAGAIN)
+			ret = -ENOSPC;
+	}
+
+	return ret;
+}
+
+/* Move packet out of multi send data (msd), and clear msd */
+static inline void move_pkt_msd(struct hv_netvsc_packet **msd_send,
+				struct sk_buff **msd_skb,
+				struct multi_send_data *msdp)
+{
+	*msd_skb = msdp->skb;
+	*msd_send = msdp->pkt;
+	msdp->skb = NULL;
+	msdp->pkt = NULL;
+	msdp->count = 0;
+}
+
+/* RCU already held by caller */
+/* Batching/bouncing logic is designed to attempt to optimize
+ * performance.
+ *
+ * For small, non-LSO packets we copy the packet to a send buffer
+ * which is pre-registered with the Hyper-V side. This enables the
+ * hypervisor to avoid remapping the aperture to access the packet
+ * descriptor and data.
+ *
+ * If we already started using a buffer and the netdev is transmitting
+ * a burst of packets, keep on copying into the buffer until it is
+ * full or we are done collecting a burst. If there is an existing
+ * buffer with space for the RNDIS descriptor but not the packet, copy
+ * the RNDIS descriptor to the buffer, keeping the packet in place.
+ *
+ * If we do batching and send more than one packet using a single
+ * NetVSC message, free the SKBs of the packets copied, except for the
+ * last packet. This is done to streamline the handling of the case
+ * where the last packet only had the RNDIS descriptor copied to the
+ * send buffer, with the data pointers included in the NetVSC message.
+ */
+int netvsc_send(struct net_device *ndev,
+		struct hv_netvsc_packet *packet,
+		struct rndis_message *rndis_msg,
+		struct hv_page_buffer *pb,
+		struct sk_buff *skb,
+		bool xdp_tx)
+{
+	struct net_device_context *ndev_ctx = netdev_priv(ndev);
+	struct netvsc_device *net_device
+		= rcu_dereference_bh(ndev_ctx->nvdev);
+	struct hv_device *device = ndev_ctx->device_ctx;
+	int ret = 0;
+	struct netvsc_channel *nvchan;
+	u32 pktlen = packet->total_data_buflen, msd_len = 0;
+	unsigned int section_index = NETVSC_INVALID_INDEX;
+	struct multi_send_data *msdp;
+	struct hv_netvsc_packet *msd_send = NULL, *cur_send = NULL;
+	struct sk_buff *msd_skb = NULL;
+	bool try_batch, xmit_more;
+
+	/* If device is rescinded, return error and packet will get dropped. */
+	if (unlikely(!net_device || net_device->destroy))
+		return -ENODEV;
+
+	nvchan = &net_device->chan_table[packet->q_idx];
+	packet->send_buf_index = NETVSC_INVALID_INDEX;
+	packet->cp_partial = false;
+
+	/* Send a control message or XDP packet directly without accessing
+	 * msd (Multi-Send Data) field which may be changed during data packet
+	 * processing.
+	 */
+	if (!skb || xdp_tx)
+		return netvsc_send_pkt(device, packet, net_device, pb, skb);
+
+	/* batch packets in send buffer if possible */
+	msdp = &nvchan->msd;
+	if (msdp->pkt)
+		msd_len = msdp->pkt->total_data_buflen;
+
+	try_batch =  msd_len > 0 && msdp->count < net_device->max_pkt;
+	if (try_batch && msd_len + pktlen + net_device->pkt_align <
+	    net_device->send_section_size) {
+		section_index = msdp->pkt->send_buf_index;
+
+	} else if (try_batch && msd_len + packet->rmsg_size <
+		   net_device->send_section_size) {
+		section_index = msdp->pkt->send_buf_index;
+		packet->cp_partial = true;
+
+	} else if (pktlen + net_device->pkt_align <
+		   net_device->send_section_size) {
+		section_index = netvsc_get_next_send_section(net_device);
+		if (unlikely(section_index == NETVSC_INVALID_INDEX)) {
+			++ndev_ctx->eth_stats.tx_send_full;
+		} else {
+			move_pkt_msd(&msd_send, &msd_skb, msdp);
+			msd_len = 0;
+		}
+	}
+
+	/* Keep aggregating only if stack says more data is coming
+	 * and not doing mixed modes send and not flow blocked
+	 */
+	xmit_more = netdev_xmit_more() &&
+		!packet->cp_partial &&
+		!netif_xmit_stopped(netdev_get_tx_queue(ndev, packet->q_idx));
+
+	if (section_index != NETVSC_INVALID_INDEX) {
+		netvsc_copy_to_send_buf(net_device,
+					section_index, msd_len,
+					packet, rndis_msg, pb, xmit_more);
+
+		packet->send_buf_index = section_index;
+
+		if (packet->cp_partial) {
+			packet->page_buf_cnt -= packet->rmsg_pgcnt;
+			packet->total_data_buflen = msd_len + packet->rmsg_size;
+		} else {
+			packet->page_buf_cnt = 0;
+			packet->total_data_buflen += msd_len;
+		}
+
+		if (msdp->pkt) {
+			packet->total_packets += msdp->pkt->total_packets;
+			packet->total_bytes += msdp->pkt->total_bytes;
+		}
+
+		if (msdp->skb)
+			dev_consume_skb_any(msdp->skb);
+
+		if (xmit_more) {
+			msdp->skb = skb;
+			msdp->pkt = packet;
+			msdp->count++;
+		} else {
+			cur_send = packet;
+			msdp->skb = NULL;
+			msdp->pkt = NULL;
+			msdp->count = 0;
+		}
+	} else {
+		move_pkt_msd(&msd_send, &msd_skb, msdp);
+		cur_send = packet;
+	}
+
+	if (msd_send) {
+		int m_ret = netvsc_send_pkt(device, msd_send, net_device,
+					    NULL, msd_skb);
+
+		if (m_ret != 0) {
+			netvsc_free_send_slot(net_device,
+					      msd_send->send_buf_index);
+			dev_kfree_skb_any(msd_skb);
+		}
+	}
+
+	if (cur_send)
+		ret = netvsc_send_pkt(device, cur_send, net_device, pb, skb);
+
+	if (ret != 0 && section_index != NETVSC_INVALID_INDEX)
+		netvsc_free_send_slot(net_device, section_index);
+
+	return ret;
+}
+
+/* Send pending recv completions */
+static int send_recv_completions(struct net_device *ndev,
+				 struct netvsc_device *nvdev,
+				 struct netvsc_channel *nvchan)
+{
+	struct multi_recv_comp *mrc = &nvchan->mrc;
+	struct recv_comp_msg {
+		struct nvsp_message_header hdr;
+		u32 status;
+	}  __packed;
+	struct recv_comp_msg msg = {
+		.hdr.msg_type = NVSP_MSG1_TYPE_SEND_RNDIS_PKT_COMPLETE,
+	};
+	int ret;
+
+	while (mrc->first != mrc->next) {
+		const struct recv_comp_data *rcd
+			= mrc->slots + mrc->first;
+
+		msg.status = rcd->status;
+		ret = vmbus_sendpacket(nvchan->channel, &msg, sizeof(msg),
+				       rcd->tid, VM_PKT_COMP, 0);
+		if (unlikely(ret)) {
+			struct net_device_context *ndev_ctx = netdev_priv(ndev);
+
+			++ndev_ctx->eth_stats.rx_comp_busy;
+			return ret;
+		}
+
+		if (++mrc->first == nvdev->recv_completion_cnt)
+			mrc->first = 0;
+	}
+
+	/* receive completion ring has been emptied */
+	if (unlikely(nvdev->destroy))
+		wake_up(&nvdev->wait_drain);
+
+	return 0;
+}
+
+/* Count how many receive completions are outstanding */
+static void recv_comp_slot_avail(const struct netvsc_device *nvdev,
+				 const struct multi_recv_comp *mrc,
+				 u32 *filled, u32 *avail)
+{
+	u32 count = nvdev->recv_completion_cnt;
+
+	if (mrc->next >= mrc->first)
+		*filled = mrc->next - mrc->first;
+	else
+		*filled = (count - mrc->first) + mrc->next;
+
+	*avail = count - *filled - 1;
+}
+
+/* Add receive complete to ring to send to host. */
+static void enq_receive_complete(struct net_device *ndev,
+				 struct netvsc_device *nvdev, u16 q_idx,
+				 u64 tid, u32 status)
+{
+	struct netvsc_channel *nvchan = &nvdev->chan_table[q_idx];
+	struct multi_recv_comp *mrc = &nvchan->mrc;
+	struct recv_comp_data *rcd;
+	u32 filled, avail;
+
+	recv_comp_slot_avail(nvdev, mrc, &filled, &avail);
+
+	if (unlikely(filled > NAPI_POLL_WEIGHT)) {
+		send_recv_completions(ndev, nvdev, nvchan);
+		recv_comp_slot_avail(nvdev, mrc, &filled, &avail);
+	}
+
+	if (unlikely(!avail)) {
+		netdev_err(ndev, "Recv_comp full buf q:%hd, tid:%llx\n",
+			   q_idx, tid);
+		return;
+	}
+
+	rcd = mrc->slots + mrc->next;
+	rcd->tid = tid;
+	rcd->status = status;
+
+	if (++mrc->next == nvdev->recv_completion_cnt)
+		mrc->next = 0;
+}
+
+static int netvsc_receive(struct net_device *ndev,
+			  struct netvsc_device *net_device,
+			  struct netvsc_channel *nvchan,
+			  const struct vmpacket_descriptor *desc)
+{
+	struct net_device_context *net_device_ctx = netdev_priv(ndev);
+	struct vmbus_channel *channel = nvchan->channel;
+	const struct vmtransfer_page_packet_header *vmxferpage_packet
+		= container_of(desc, const struct vmtransfer_page_packet_header, d);
+	const struct nvsp_message *nvsp = hv_pkt_data(desc);
+	u32 msglen = hv_pkt_datalen(desc);
+	u16 q_idx = channel->offermsg.offer.sub_channel_index;
+	char *recv_buf = net_device->recv_buf;
+	u32 status = NVSP_STAT_SUCCESS;
+	int i;
+	int count = 0;
+
+	/* Ensure packet is big enough to read header fields */
+	if (msglen < sizeof(struct nvsp_message_header)) {
+		netif_err(net_device_ctx, rx_err, ndev,
+			  "invalid nvsp header, length too small: %u\n",
+			  msglen);
+		return 0;
+	}
+
+	/* Make sure this is a valid nvsp packet */
+	if (unlikely(nvsp->hdr.msg_type != NVSP_MSG1_TYPE_SEND_RNDIS_PKT)) {
+		netif_err(net_device_ctx, rx_err, ndev,
+			  "Unknown nvsp packet type received %u\n",
+			  nvsp->hdr.msg_type);
+		return 0;
+	}
+
+	/* Validate xfer page pkt header */
+	if ((desc->offset8 << 3) < sizeof(struct vmtransfer_page_packet_header)) {
+		netif_err(net_device_ctx, rx_err, ndev,
+			  "Invalid xfer page pkt, offset too small: %u\n",
+			  desc->offset8 << 3);
+		return 0;
+	}
+
+	if (unlikely(vmxferpage_packet->xfer_pageset_id != NETVSC_RECEIVE_BUFFER_ID)) {
+		netif_err(net_device_ctx, rx_err, ndev,
+			  "Invalid xfer page set id - expecting %x got %x\n",
+			  NETVSC_RECEIVE_BUFFER_ID,
+			  vmxferpage_packet->xfer_pageset_id);
+		return 0;
+	}
+
+	count = vmxferpage_packet->range_cnt;
+
+	/* Check count for a valid value */
+	if (NETVSC_XFER_HEADER_SIZE(count) > desc->offset8 << 3) {
+		netif_err(net_device_ctx, rx_err, ndev,
+			  "Range count is not valid: %d\n",
+			  count);
+		return 0;
+	}
+
+	/* Each range represents 1 RNDIS pkt that contains 1 ethernet frame */
+	for (i = 0; i < count; i++) {
+		u32 offset = vmxferpage_packet->ranges[i].byte_offset;
+		u32 buflen = vmxferpage_packet->ranges[i].byte_count;
+		void *data;
+		int ret;
+
+		if (unlikely(offset > net_device->recv_buf_size ||
+			     buflen > net_device->recv_buf_size - offset)) {
+			nvchan->rsc.cnt = 0;
+			status = NVSP_STAT_FAIL;
+			netif_err(net_device_ctx, rx_err, ndev,
+				  "Packet offset:%u + len:%u too big\n",
+				  offset, buflen);
+
+			continue;
+		}
+
+		/* We're going to copy (sections of) the packet into nvchan->recv_buf;
+		 * make sure that nvchan->recv_buf is large enough to hold the packet.
+		 */
+		if (unlikely(buflen > net_device->recv_section_size)) {
+			nvchan->rsc.cnt = 0;
+			status = NVSP_STAT_FAIL;
+			netif_err(net_device_ctx, rx_err, ndev,
+				  "Packet too big: buflen=%u recv_section_size=%u\n",
+				  buflen, net_device->recv_section_size);
+
+			continue;
+		}
+
+		data = recv_buf + offset;
+
+		nvchan->rsc.is_last = (i == count - 1);
+
+		trace_rndis_recv(ndev, q_idx, data);
+
+		/* Pass it to the upper layer */
+		ret = rndis_filter_receive(ndev, net_device,
+					   nvchan, data, buflen);
+
+		if (unlikely(ret != NVSP_STAT_SUCCESS)) {
+			/* Drop incomplete packet */
+			nvchan->rsc.cnt = 0;
+			status = NVSP_STAT_FAIL;
+		}
+	}
+
+	enq_receive_complete(ndev, net_device, q_idx,
+			     vmxferpage_packet->d.trans_id, status);
+
+	return count;
+}
+
+static void netvsc_send_table(struct net_device *ndev,
+			      struct netvsc_device *nvscdev,
+			      const struct nvsp_message *nvmsg,
+			      u32 msglen)
+{
+	struct net_device_context *net_device_ctx = netdev_priv(ndev);
+	u32 count, offset, *tab;
+	int i;
+
+	/* Ensure packet is big enough to read send_table fields */
+	if (msglen < sizeof(struct nvsp_message_header) +
+		     sizeof(struct nvsp_5_send_indirect_table)) {
+		netdev_err(ndev, "nvsp_v5_msg length too small: %u\n", msglen);
+		return;
+	}
+
+	count = nvmsg->msg.v5_msg.send_table.count;
+	offset = nvmsg->msg.v5_msg.send_table.offset;
+
+	if (count != VRSS_SEND_TAB_SIZE) {
+		netdev_err(ndev, "Received wrong send-table size:%u\n", count);
+		return;
+	}
+
+	/* If negotiated version <= NVSP_PROTOCOL_VERSION_6, the offset may be
+	 * wrong due to a host bug. So fix the offset here.
+	 */
+	if (nvscdev->nvsp_version <= NVSP_PROTOCOL_VERSION_6 &&
+	    msglen >= sizeof(struct nvsp_message_header) +
+	    sizeof(union nvsp_6_message_uber) + count * sizeof(u32))
+		offset = sizeof(struct nvsp_message_header) +
+			 sizeof(union nvsp_6_message_uber);
+
+	/* Boundary check for all versions */
+	if (msglen < count * sizeof(u32) || offset > msglen - count * sizeof(u32)) {
+		netdev_err(ndev, "Received send-table offset too big:%u\n",
+			   offset);
+		return;
+	}
+
+	tab = (void *)nvmsg + offset;
+
+	for (i = 0; i < count; i++)
+		net_device_ctx->tx_table[i] = tab[i];
+}
+
+static void netvsc_send_vf(struct net_device *ndev,
+			   const struct nvsp_message *nvmsg,
+			   u32 msglen)
+{
+	struct net_device_context *net_device_ctx = netdev_priv(ndev);
+
+	/* Ensure packet is big enough to read its fields */
+	if (msglen < sizeof(struct nvsp_message_header) +
+		     sizeof(struct nvsp_4_send_vf_association)) {
+		netdev_err(ndev, "nvsp_v4_msg length too small: %u\n", msglen);
+		return;
+	}
+
+	net_device_ctx->vf_alloc = nvmsg->msg.v4_msg.vf_assoc.allocated;
+	net_device_ctx->vf_serial = nvmsg->msg.v4_msg.vf_assoc.serial;
+
+	if (net_device_ctx->vf_alloc)
+		complete(&net_device_ctx->vf_add);
+
+	netdev_info(ndev, "VF slot %u %s\n",
+		    net_device_ctx->vf_serial,
+		    net_device_ctx->vf_alloc ? "added" : "removed");
+}
+
+static void netvsc_receive_inband(struct net_device *ndev,
+				  struct netvsc_device *nvscdev,
+				  const struct vmpacket_descriptor *desc)
+{
+	const struct nvsp_message *nvmsg = hv_pkt_data(desc);
+	u32 msglen = hv_pkt_datalen(desc);
+
+	/* Ensure packet is big enough to read header fields */
+	if (msglen < sizeof(struct nvsp_message_header)) {
+		netdev_err(ndev, "inband nvsp_message length too small: %u\n", msglen);
+		return;
+	}
+
+	switch (nvmsg->hdr.msg_type) {
+	case NVSP_MSG5_TYPE_SEND_INDIRECTION_TABLE:
+		netvsc_send_table(ndev, nvscdev, nvmsg, msglen);
+		break;
+
+	case NVSP_MSG4_TYPE_SEND_VF_ASSOCIATION:
+		if (hv_is_isolation_supported())
+			netdev_err(ndev, "Ignore VF_ASSOCIATION msg from the host supporting isolation\n");
+		else
+			netvsc_send_vf(ndev, nvmsg, msglen);
+		break;
+	}
+}
+
+static int netvsc_process_raw_pkt(struct hv_device *device,
+				  struct netvsc_channel *nvchan,
+				  struct netvsc_device *net_device,
+				  struct net_device *ndev,
+				  const struct vmpacket_descriptor *desc,
+				  int budget)
+{
+	struct vmbus_channel *channel = nvchan->channel;
+	const struct nvsp_message *nvmsg = hv_pkt_data(desc);
+
+	trace_nvsp_recv(ndev, channel, nvmsg);
+
+	switch (desc->type) {
+	case VM_PKT_COMP:
+		netvsc_send_completion(ndev, net_device, channel, desc, budget);
+		break;
+
+	case VM_PKT_DATA_USING_XFER_PAGES:
+		return netvsc_receive(ndev, net_device, nvchan, desc);
+
+	case VM_PKT_DATA_INBAND:
+		netvsc_receive_inband(ndev, net_device, desc);
+		break;
+
+	default:
+		netdev_err(ndev, "unhandled packet type %d, tid %llx\n",
+			   desc->type, desc->trans_id);
+		break;
+	}
+
+	return 0;
+}
+
+static struct hv_device *netvsc_channel_to_device(struct vmbus_channel *channel)
+{
+	struct vmbus_channel *primary = channel->primary_channel;
+
+	return primary ? primary->device_obj : channel->device_obj;
+}
+
+/* Network processing softirq
+ * Process data in incoming ring buffer from host
+ * Stops when ring is empty or budget is met or exceeded.
+ */
+int netvsc_poll(struct napi_struct *napi, int budget)
+{
+	struct netvsc_channel *nvchan
+		= container_of(napi, struct netvsc_channel, napi);
+	struct netvsc_device *net_device = nvchan->net_device;
+	struct vmbus_channel *channel = nvchan->channel;
+	struct hv_device *device = netvsc_channel_to_device(channel);
+	struct net_device *ndev = hv_get_drvdata(device);
+	int work_done = 0;
+	int ret;
+
+	/* If starting a new interval */
+	if (!nvchan->desc)
+		nvchan->desc = hv_pkt_iter_first(channel);
+
+	nvchan->xdp_flush = false;
+
+	while (nvchan->desc && work_done < budget) {
+		work_done += netvsc_process_raw_pkt(device, nvchan, net_device,
+						    ndev, nvchan->desc, budget);
+		nvchan->desc = hv_pkt_iter_next(channel, nvchan->desc);
+	}
+
+	if (nvchan->xdp_flush)
+		xdp_do_flush();
+
+	/* Send any pending receive completions */
+	ret = send_recv_completions(ndev, net_device, nvchan);
+
+	/* If it did not exhaust NAPI budget this time
+	 *  and not doing busy poll
+	 * then re-enable host interrupts
+	 *  and reschedule if ring is not empty
+	 *   or sending receive completion failed.
+	 */
+	if (work_done < budget &&
+	    napi_complete_done(napi, work_done) &&
+	    (ret || hv_end_read(&channel->inbound)) &&
+	    napi_schedule_prep(napi)) {
+		hv_begin_read(&channel->inbound);
+		__napi_schedule(napi);
+	}
+
+	/* Driver may overshoot since multiple packets per descriptor */
+	return min(work_done, budget);
+}
+
+/* Call back when data is available in host ring buffer.
+ * Processing is deferred until network softirq (NAPI)
+ */
+void netvsc_channel_cb(void *context)
+{
+	struct netvsc_channel *nvchan = context;
+	struct vmbus_channel *channel = nvchan->channel;
+	struct hv_ring_buffer_info *rbi = &channel->inbound;
+
+	/* preload first vmpacket descriptor */
+	prefetch(hv_get_ring_buffer(rbi) + rbi->priv_read_index);
+
+	if (napi_schedule_prep(&nvchan->napi)) {
+		/* disable interrupts from host */
+		hv_begin_read(rbi);
+
+		__napi_schedule_irqoff(&nvchan->napi);
+	}
+}
+
+/*
+ * netvsc_device_add - Callback when the device belonging to this
+ * driver is added
+ */
+struct netvsc_device *netvsc_device_add(struct hv_device *device,
+				const struct netvsc_device_info *device_info)
+{
+	int i, ret = 0;
+	struct netvsc_device *net_device;
+	struct net_device *ndev = hv_get_drvdata(device);
+	struct net_device_context *net_device_ctx = netdev_priv(ndev);
+
+	net_device = alloc_net_device();
+	if (!net_device)
+		return ERR_PTR(-ENOMEM);
+
+	for (i = 0; i < VRSS_SEND_TAB_SIZE; i++)
+		net_device_ctx->tx_table[i] = 0;
+
+	/* Because the device uses NAPI, all the interrupt batching and
+	 * control is done via Net softirq, not the channel handling
+	 */
+	set_channel_read_mode(device->channel, HV_CALL_ISR);
+
+	/* If we're reopening the device we may have multiple queues, fill the
+	 * chn_table with the default channel to use it before subchannels are
+	 * opened.
+	 * Initialize the channel state before we open;
+	 * we can be interrupted as soon as we open the channel.
+	 */
+
+	for (i = 0; i < VRSS_CHANNEL_MAX; i++) {
+		struct netvsc_channel *nvchan = &net_device->chan_table[i];
+
+		nvchan->channel = device->channel;
+		nvchan->net_device = net_device;
+		u64_stats_init(&nvchan->tx_stats.syncp);
+		u64_stats_init(&nvchan->rx_stats.syncp);
+
+		ret = xdp_rxq_info_reg(&nvchan->xdp_rxq, ndev, i, 0);
+
+		if (ret) {
+			netdev_err(ndev, "xdp_rxq_info_reg fail: %d\n", ret);
+			goto cleanup2;
+		}
+
+		ret = xdp_rxq_info_reg_mem_model(&nvchan->xdp_rxq,
+						 MEM_TYPE_PAGE_SHARED, NULL);
+
+		if (ret) {
+			netdev_err(ndev, "xdp reg_mem_model fail: %d\n", ret);
+			goto cleanup2;
+		}
+	}
+
+	/* Enable NAPI handler before init callbacks */
+	netif_napi_add(ndev, &net_device->chan_table[0].napi, netvsc_poll);
+
+	/* Open the channel */
+	device->channel->next_request_id_callback = vmbus_next_request_id;
+	device->channel->request_addr_callback = vmbus_request_addr;
+	device->channel->rqstor_size = netvsc_rqstor_size(netvsc_ring_bytes);
+	device->channel->max_pkt_size = NETVSC_MAX_PKT_SIZE;
+
+	ret = vmbus_open(device->channel, netvsc_ring_bytes,
+			 netvsc_ring_bytes,  NULL, 0,
+			 netvsc_channel_cb, net_device->chan_table);
+
+	if (ret != 0) {
+		netdev_err(ndev, "unable to open channel: %d\n", ret);
+		goto cleanup;
+	}
+
+	/* Channel is opened */
+	netdev_dbg(ndev, "hv_netvsc channel opened successfully\n");
+
+	napi_enable(&net_device->chan_table[0].napi);
+
+	/* Connect with the NetVsp */
+	ret = netvsc_connect_vsp(device, net_device, device_info);
+	if (ret != 0) {
+		netdev_err(ndev,
+			"unable to connect to NetVSP - %d\n", ret);
+		goto close;
+	}
+
+	/* Writing nvdev pointer unlocks netvsc_send(), make sure chn_table is
+	 * populated.
+	 */
+	rcu_assign_pointer(net_device_ctx->nvdev, net_device);
+
+	return net_device;
+
+close:
+	RCU_INIT_POINTER(net_device_ctx->nvdev, NULL);
+	napi_disable(&net_device->chan_table[0].napi);
+
+	/* Now, we can close the channel safely */
+	vmbus_close(device->channel);
+
+cleanup:
+	netif_napi_del(&net_device->chan_table[0].napi);
+
+cleanup2:
+	if (net_device->recv_original_buf)
+		hv_unmap_memory(net_device->recv_buf);
+
+	if (net_device->send_original_buf)
+		hv_unmap_memory(net_device->send_buf);
+
+	free_netvsc_device(&net_device->rcu);
+
+	return ERR_PTR(ret);
+}