Commit c25aaf81 authored by KY Srinivasan's avatar KY Srinivasan Committed by David S. Miller
Browse files

hyperv: Enable sendbuf mechanism on the send path 



We send packets using a copy-free mechanism (this is the Guest to Host transport
via VMBUS). While this is obviously optimal for large packets,
it may not be optimal for small packets. Hyper-V host supports
a second mechanism for sending packets that is "copy based". We implement that
mechanism in this patch.

In this version of the patch I have addressed a comment from David Miller.

With this patch (and all of the other offload and VRSS patches), we are now able
to almost saturate a 10G interface between Linux VMs on Hyper-V
on different hosts - close to  9 Gbps as measured via iperf.

Signed-off-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: default avatarHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cc80ee13

drivers/net/hyperv/hyperv_net.h

+14 −0
Original line number Diff line number Diff line
@@ -140,6 +140,8 @@ struct hv_netvsc_packet { 
	void *send_completion_ctx;

	void (*send_completion)(void *context);



	u32 send_buf_index;



	/* This points to the memory after page_buf */

	struct rndis_message *rndis_msg;
@@ -582,6 +584,9 @@ struct nvsp_message { 


#define NETVSC_RECEIVE_BUFFER_SIZE		(1024*1024*16)	/* 16MB */

#define NETVSC_RECEIVE_BUFFER_SIZE_LEGACY	(1024*1024*15)  /* 15MB */

#define NETVSC_SEND_BUFFER_SIZE			(1024 * 1024)   /* 1MB */

#define NETVSC_INVALID_INDEX			-1





#define NETVSC_RECEIVE_BUFFER_ID		0xcafe
@@ -607,6 +612,15 @@ struct netvsc_device { 
	u32 recv_section_cnt;

	struct nvsp_1_receive_buffer_section *recv_section;



	/* Send buffer allocated by us */

	void *send_buf;

	u32 send_buf_size;

	u32 send_buf_gpadl_handle;

	u32 send_section_cnt;

	u32 send_section_size;

	unsigned long *send_section_map;

	int map_words;



	/* Used for NetVSP initialization protocol */

	struct completion channel_init_wait;

	struct nvsp_message channel_init_pkt;

drivers/net/hyperv/netvsc.c

+218 −8
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#include <linux/slab.h>

#include <linux/netdevice.h>

#include <linux/if_ether.h>

#include <asm/sync_bitops.h>



#include "hyperv_net.h"
@@ -80,7 +81,7 @@ get_in_err: 
}





static int netvsc_destroy_recv_buf(struct netvsc_device *net_device)

static int netvsc_destroy_buf(struct netvsc_device *net_device)

{

	struct nvsp_message *revoke_packet;

	int ret = 0;
@@ -146,10 +147,62 @@ static int netvsc_destroy_recv_buf(struct netvsc_device *net_device) 
		net_device->recv_section = NULL;

	}



	/* Deal with the send buffer we may have setup.

	 * If we got a  send section size, it means we received a

	 * SendsendBufferComplete msg (ie sent

	 * NvspMessage1TypeSendReceiveBuffer msg) therefore, we need

	 * to send a revoke msg here

	 */

	if (net_device->send_section_size) {

		/* 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_recv_buf.id = 0;



		ret = vmbus_sendpacket(net_device->dev->channel,

				       revoke_packet,

				       sizeof(struct nvsp_message),

				       (unsigned long)revoke_packet,

				       VM_PKT_DATA_INBAND, 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 ret;

		}

	}

	/* Teardown the gpadl on the vsp end */

	if (net_device->send_buf_gpadl_handle) {

		ret = vmbus_teardown_gpadl(net_device->dev->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 ret;

		}

		net_device->recv_buf_gpadl_handle = 0;

	}

	if (net_device->send_buf) {

		/* Free up the receive buffer */

		free_pages((unsigned long)net_device->send_buf,

			   get_order(net_device->send_buf_size));

		net_device->send_buf = NULL;

	}

	kfree(net_device->send_section_map);



	return ret;

}



static int netvsc_init_recv_buf(struct hv_device *device)

static int netvsc_init_buf(struct hv_device *device)

{

	int ret = 0;

	int t;
@@ -248,10 +301,90 @@ static int netvsc_init_recv_buf(struct hv_device *device) 
		goto cleanup;

	}



	/* Now setup the send buffer.

	 */

	net_device->send_buf =

		(void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,

					 get_order(net_device->send_buf_size));

	if (!net_device->send_buf) {

		netdev_err(ndev, "unable to allocate send "

			   "buffer of size %d\n", net_device->send_buf_size);

		ret = -ENOMEM;

		goto cleanup;

	}



	/* 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,

				    net_device->send_buf_size,

				    &net_device->send_buf_gpadl_handle);

	if (ret != 0) {

		netdev_err(ndev,

			   "unable to establish send buffer's gpadl\n");

		goto cleanup;

	}



	/* 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_recv_buf.gpadl_handle =

		net_device->send_buf_gpadl_handle;

	init_packet->msg.v1_msg.send_recv_buf.id = 0;



	/* 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;

	}



	t = wait_for_completion_timeout(&net_device->channel_init_wait, 5*HZ);

	BUG_ON(t == 0);



	/* 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_recv_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;



	/* Section count is simply the size divided by the section size.

	 */

	net_device->send_section_cnt =

		net_device->send_buf_size/net_device->send_section_size;



	dev_info(&device->device, "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->map_words = DIV_ROUND_UP(net_device->send_section_cnt,

					     BITS_PER_LONG);



	net_device->send_section_map =

		kzalloc(net_device->map_words * sizeof(ulong), GFP_KERNEL);

	if (net_device->send_section_map == NULL)

		goto cleanup;



	goto exit;



cleanup:

	netvsc_destroy_recv_buf(net_device);

	netvsc_destroy_buf(net_device);



exit:

	return ret;
@@ -369,8 +502,9 @@ static int netvsc_connect_vsp(struct hv_device *device) 
		net_device->recv_buf_size = NETVSC_RECEIVE_BUFFER_SIZE_LEGACY;

	else

		net_device->recv_buf_size = NETVSC_RECEIVE_BUFFER_SIZE;

	net_device->send_buf_size = NETVSC_SEND_BUFFER_SIZE;



	ret = netvsc_init_recv_buf(device);

	ret = netvsc_init_buf(device);



cleanup:

	return ret;
@@ -378,7 +512,7 @@ cleanup: 


static void netvsc_disconnect_vsp(struct netvsc_device *net_device)

{

	netvsc_destroy_recv_buf(net_device);

	netvsc_destroy_buf(net_device);

}



/*
@@ -440,6 +574,12 @@ static inline u32 hv_ringbuf_avail_percent( 
	return avail_write * 100 / ring_info->ring_datasize;

}



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_completion(struct netvsc_device *net_device,

				   struct hv_device *device,

				   struct vmpacket_descriptor *packet)
@@ -447,6 +587,7 @@ static void netvsc_send_completion(struct netvsc_device *net_device, 
	struct nvsp_message *nvsp_packet;

	struct hv_netvsc_packet *nvsc_packet;

	struct net_device *ndev;

	u32 send_index;



	ndev = net_device->ndev;
@@ -477,6 +618,9 @@ static void netvsc_send_completion(struct netvsc_device *net_device, 


		/* Notify the layer above us */

		if (nvsc_packet) {

			send_index = nvsc_packet->send_buf_index;

			if (send_index != NETVSC_INVALID_INDEX)

				netvsc_free_send_slot(net_device, send_index);

			q_idx = nvsc_packet->q_idx;

			channel = nvsc_packet->channel;

			nvsc_packet->send_completion(nvsc_packet->
@@ -504,6 +648,52 @@ static void netvsc_send_completion(struct netvsc_device *net_device, 


}



static u32 netvsc_get_next_send_section(struct netvsc_device *net_device)

{

	unsigned long index;

	u32 max_words = net_device->map_words;

	unsigned long *map_addr = (unsigned long *)net_device->send_section_map;

	u32 section_cnt = net_device->send_section_cnt;

	int ret_val = NETVSC_INVALID_INDEX;

	int i;

	int prev_val;



	for (i = 0; i < max_words; i++) {

		if (!~(map_addr[i]))

			continue;

		index = ffz(map_addr[i]);

		prev_val = sync_test_and_set_bit(index, &map_addr[i]);

		if (prev_val)

			continue;

		if ((index + (i * BITS_PER_LONG)) >= section_cnt)

			break;

		ret_val = (index + (i * BITS_PER_LONG));

		break;

	}

	return ret_val;

}



u32 netvsc_copy_to_send_buf(struct netvsc_device *net_device,

			    unsigned int section_index,

			    struct hv_netvsc_packet *packet)

{

	char *start = net_device->send_buf;

	char *dest = (start + (section_index * net_device->send_section_size));

	int i;

	u32 msg_size = 0;



	for (i = 0; i < packet->page_buf_cnt; i++) {

		char *src = phys_to_virt(packet->page_buf[i].pfn << PAGE_SHIFT);

		u32 offset = packet->page_buf[i].offset;

		u32 len = packet->page_buf[i].len;



		memcpy(dest, (src + offset), len);

		msg_size += len;

		dest += len;

	}

	return msg_size;

}



int netvsc_send(struct hv_device *device,

			struct hv_netvsc_packet *packet)

{
@@ -513,6 +703,10 @@ int netvsc_send(struct hv_device *device, 
	struct net_device *ndev;

	struct vmbus_channel *out_channel = NULL;

	u64 req_id;

	unsigned int section_index = NETVSC_INVALID_INDEX;

	u32 msg_size = 0;

	struct sk_buff *skb;





	net_device = get_outbound_net_device(device);

	if (!net_device)
@@ -528,10 +722,26 @@ int netvsc_send(struct hv_device *device, 
		sendMessage.msg.v1_msg.send_rndis_pkt.channel_type = 1;

	}



	/* Not using send buffer section */

	/* Attempt to send via sendbuf */

	if (packet->total_data_buflen < net_device->send_section_size) {

		section_index = netvsc_get_next_send_section(net_device);

		if (section_index != NETVSC_INVALID_INDEX) {

			msg_size = netvsc_copy_to_send_buf(net_device,

							   section_index,

							   packet);

			skb = (struct sk_buff *)

			      (unsigned long)packet->send_completion_tid;

			if (skb)

				dev_kfree_skb_any(skb);

			packet->page_buf_cnt = 0;

		}

	}

	packet->send_buf_index = section_index;





	sendMessage.msg.v1_msg.send_rndis_pkt.send_buf_section_index =

		0xFFFFFFFF;

	sendMessage.msg.v1_msg.send_rndis_pkt.send_buf_section_size = 0;

		section_index;

	sendMessage.msg.v1_msg.send_rndis_pkt.send_buf_section_size = msg_size;



	if (packet->send_completion)

		req_id = (ulong)packet;

drivers/net/hyperv/netvsc_drv.c

+2 −1
Original line number Diff line number Diff line
@@ -236,10 +236,11 @@ static void netvsc_xmit_completion(void *context) 
	struct hv_netvsc_packet *packet = (struct hv_netvsc_packet *)context;

	struct sk_buff *skb = (struct sk_buff *)

		(unsigned long)packet->send_completion_tid;

	u32 index = packet->send_buf_index;



	kfree(packet);



	if (skb)

	if (skb && (index == NETVSC_INVALID_INDEX))

		dev_kfree_skb_any(skb);

}

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