Release 4.12 drivers/hv/connection.c

/*
 *
 * 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>
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/delay.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/hyperv.h>
#include <linux/export.h>
#include <asm/hyperv.h>
#include "hyperv_vmbus.h"



struct vmbus_connection vmbus_connection = {
	.conn_state		= DISCONNECTED,
	.next_gpadl_handle	= ATOMIC_INIT(0xE1E10),
};

EXPORT_SYMBOL_GPL(vmbus_connection);

/*
 * Negotiated protocol version with the host.
 */

__u32 vmbus_proto_version;

EXPORT_SYMBOL_GPL(vmbus_proto_version);



static __u32 vmbus_get_next_version(__u32 current_version)
{
	switch (current_version) {
	case (VERSION_WIN7):
		return VERSION_WS2008;

	case (VERSION_WIN8):
		return VERSION_WIN7;

	case (VERSION_WIN8_1):
		return VERSION_WIN8;

	case (VERSION_WIN10):
		return VERSION_WIN8_1;

	case (VERSION_WS2008):
	default:
		return VERSION_INVAL;
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
K. Y. Srinivasan
45
80.36%
2
40.00%
Keith Mange
8
14.29%
1
20.00%
Greg Kroah-Hartman
2
3.57%
1
20.00%
Hank Janssen
1
1.79%
1
20.00%
Total
56
100.00%
5
100.00%



static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
					__u32 version)
{
	int ret = 0;
	struct vmbus_channel_initiate_contact *msg;
	unsigned long flags;

	init_completion(&msginfo->waitevent);

	msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;

	msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
	msg->vmbus_version_requested = version;
	msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
	msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
	msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
	/*
         * We want all channel messages to be delivered on CPU 0.
         * This has been the behavior pre-win8. This is not
         * perf issue and having all channel messages delivered on CPU 0
         * would be ok.
         * For post win8 hosts, we support receiving channel messagges on
         * all the CPUs. This is needed for kexec to work correctly where
         * the CPU attempting to connect may not be CPU 0.
         */
	if (version >= VERSION_WIN8_1)
		msg->target_vcpu = hv_context.vp_index[smp_processor_id()];
	else
		msg->target_vcpu = 0;

	/*
         * Add to list before we send the request since we may
         * receive the response before returning from this routine
         */
	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
	list_add_tail(&msginfo->msglistentry,
		      &vmbus_connection.chn_msg_list);

	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);

	ret = vmbus_post_msg(msg,
			     sizeof(struct vmbus_channel_initiate_contact),
			     true);
	if (ret != 0) {
		spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
		list_del(&msginfo->msglistentry);
		spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
					flags);
		return ret;
	}

	/* Wait for the connection response */
	wait_for_completion(&msginfo->waitevent);

	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
	list_del(&msginfo->msglistentry);
	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);

	/* Check if successful */
	if (msginfo->response.version_response.version_supported) {
		vmbus_connection.conn_state = CONNECTED;
	} else {
		return -ECONNREFUSED;
	}

	return ret;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
K. Y. Srinivasan
171
61.07%
6
33.33%
Hank Janssen
54
19.29%
1
5.56%
Greg Kroah-Hartman
22
7.86%
6
33.33%
Alex Ng
19
6.79%
1
5.56%
Haiyang Zhang
9
3.21%
1
5.56%
Vitaly Kuznetsov
2
0.71%
1
5.56%
Bill Pemberton
2
0.71%
1
5.56%
Stephen Hemminger
1
0.36%
1
5.56%
Total
280
100.00%
18
100.00%

/*
 * vmbus_connect - Sends a connect request on the partition service connection
 */


int vmbus_connect(void)
{
	int ret = 0;
	struct vmbus_channel_msginfo *msginfo = NULL;
	__u32 version;

	/* Initialize the vmbus connection */
	vmbus_connection.conn_state = CONNECTING;
	vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
	if (!vmbus_connection.work_queue) {
		ret = -ENOMEM;
		goto cleanup;
	}

	INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
	spin_lock_init(&vmbus_connection.channelmsg_lock);

	INIT_LIST_HEAD(&vmbus_connection.chn_list);
	mutex_init(&vmbus_connection.channel_mutex);

	/*
         * Setup the vmbus event connection for channel interrupt
         * abstraction stuff
         */
	vmbus_connection.int_page =
	(void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
	if (vmbus_connection.int_page == NULL) {
		ret = -ENOMEM;
		goto cleanup;
	}

	vmbus_connection.recv_int_page = vmbus_connection.int_page;
	vmbus_connection.send_int_page =
		(void *)((unsigned long)vmbus_connection.int_page +
			(PAGE_SIZE >> 1));

	/*
         * Setup the monitor notification facility. The 1st page for
         * parent->child and the 2nd page for child->parent
         */
	vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
	vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
	if ((vmbus_connection.monitor_pages[0] == NULL) ||
	    (vmbus_connection.monitor_pages[1] == NULL)) {
		ret = -ENOMEM;
		goto cleanup;
	}

	msginfo = kzalloc(sizeof(*msginfo) +
			  sizeof(struct vmbus_channel_initiate_contact),
			  GFP_KERNEL);
	if (msginfo == NULL) {
		ret = -ENOMEM;
		goto cleanup;
	}

	/*
         * Negotiate a compatible VMBUS version number with the
         * host. We start with the highest number we can support
         * and work our way down until we negotiate a compatible
         * version.
         */

	version = VERSION_CURRENT;

	do {
		ret = vmbus_negotiate_version(msginfo, version);
		if (ret == -ETIMEDOUT)
			goto cleanup;

		if (vmbus_connection.conn_state == CONNECTED)
			break;

		version = vmbus_get_next_version(version);
	} while (version != VERSION_INVAL);

	if (version == VERSION_INVAL)
		goto cleanup;

	vmbus_proto_version = version;
	pr_info("Vmbus version:%d.%d\n",
		version >> 16, version & 0xFFFF);

	kfree(msginfo);
	return 0;

cleanup:
	pr_err("Unable to connect to host\n");

	vmbus_connection.conn_state = DISCONNECTED;
	vmbus_disconnect();

	kfree(msginfo);

	return ret;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
K. Y. Srinivasan
241
63.93%
9
50.00%
Hank Janssen
64
16.98%
1
5.56%
Greg Kroah-Hartman
44
11.67%
2
11.11%
Haiyang Zhang
12
3.18%
2
11.11%
Vitaly Kuznetsov
12
3.18%
1
5.56%
Dexuan Cui
2
0.53%
1
5.56%
Bill Pemberton
2
0.53%
2
11.11%
Total
377
100.00%
18
100.00%



void vmbus_disconnect(void)
{
	/*
         * First send the unload request to the host.
         */
	vmbus_initiate_unload(false);

	if (vmbus_connection.work_queue) {
		drain_workqueue(vmbus_connection.work_queue);
		destroy_workqueue(vmbus_connection.work_queue);
	}

	if (vmbus_connection.int_page) {
		free_pages((unsigned long)vmbus_connection.int_page, 0);
		vmbus_connection.int_page = NULL;
	}

	free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0);
	free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0);
	vmbus_connection.monitor_pages[0] = NULL;
	vmbus_connection.monitor_pages[1] = NULL;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Hank Janssen
30
26.79%
1
10.00%
Greg Kroah-Hartman
27
24.11%
1
10.00%
Vitaly Kuznetsov
18
16.07%
2
20.00%
Haiyang Zhang
16
14.29%
2
20.00%
K. Y. Srinivasan
14
12.50%
2
20.00%
Bill Pemberton
5
4.46%
1
10.00%
Radim Krčmář
2
1.79%
1
10.00%
Total
112
100.00%
10
100.00%

/*
 * relid2channel - Get the channel object given its
 * child relative id (ie channel id)
 */


struct vmbus_channel *relid2channel(u32 relid)
{
	struct vmbus_channel *channel;
	struct vmbus_channel *found_channel  = NULL;
	struct list_head *cur, *tmp;
	struct vmbus_channel *cur_sc;

	BUG_ON(!mutex_is_locked(&vmbus_connection.channel_mutex));

	list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
		if (channel->offermsg.child_relid == relid) {
			found_channel = channel;
			break;
		} else if (!list_empty(&channel->sc_list)) {
			/*
                         * Deal with sub-channels.
                         */
			list_for_each_safe(cur, tmp, &channel->sc_list) {
				cur_sc = list_entry(cur, struct vmbus_channel,
							sc_list);
				if (cur_sc->offermsg.child_relid == relid) {
					found_channel = cur_sc;
					break;
				}
			}
		}
	}

	return found_channel;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
K. Y. Srinivasan
67
51.15%
1
8.33%
Hank Janssen
36
27.48%
1
8.33%
Haiyang Zhang
11
8.40%
4
33.33%
Greg Kroah-Hartman
8
6.11%
3
25.00%
Dexuan Cui
6
4.58%
2
16.67%
Bill Pemberton
3
2.29%
1
8.33%
Total
131
100.00%
12
100.00%

/*
 * vmbus_on_event - Process a channel event notification
 *
 * For batched channels (default) optimize host to guest signaling
 * by ensuring:
 * 1. While reading the channel, we disable interrupts from host.
 * 2. Ensure that we process all posted messages from the host
 *    before returning from this callback.
 * 3. Once we return, enable signaling from the host. Once this
 *    state is set we check to see if additional packets are
 *    available to read. In this case we repeat the process.
 *    If this tasklet has been running for a long time
 *    then reschedule ourselves.
 */


void vmbus_on_event(unsigned long data)
{
	struct vmbus_channel *channel = (void *) data;
	unsigned long time_limit = jiffies + 2;

	do {
		void (*callback_fn)(void *);

		/* A channel once created is persistent even when
                 * there is no driver handling the device. An
                 * unloading driver sets the onchannel_callback to NULL.
                 */
		callback_fn = READ_ONCE(channel->onchannel_callback);
		if (unlikely(callback_fn == NULL))
			return;

		(*callback_fn)(channel->channel_callback_context);

		if (channel->callback_mode != HV_CALL_BATCHED)
			return;

		if (likely(hv_end_read(&channel->inbound) == 0))
			return;

		hv_begin_read(&channel->inbound);
	} while (likely(time_before(jiffies, time_limit)));

	/* The time limit (2 jiffies) has been reached */
	tasklet_schedule(&channel->callback_event);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Stephen Hemminger
85
67.46%
3
33.33%
K. Y. Srinivasan
27
21.43%
4
44.44%
Hank Janssen
12
9.52%
1
11.11%
Greg Kroah-Hartman
2
1.59%
1
11.11%
Total
126
100.00%
9
100.00%

/*
 * vmbus_post_msg - Send a msg on the vmbus's message connection
 */


int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
{
	union hv_connection_id conn_id;
	int ret = 0;
	int retries = 0;
	u32 usec = 1;

	conn_id.asu32 = 0;
	conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;

	/*
         * hv_post_message() can have transient failures because of
         * insufficient resources. Retry the operation a couple of
         * times before giving up.
         */
	while (retries < 100) {
		ret = hv_post_message(conn_id, 1, buffer, buflen);

		switch (ret) {
		case HV_STATUS_INVALID_CONNECTION_ID:
			/*
                         * We could get this if we send messages too
                         * frequently.
                         */
			ret = -EAGAIN;
			break;
		case HV_STATUS_INSUFFICIENT_MEMORY:
		case HV_STATUS_INSUFFICIENT_BUFFERS:
			ret = -ENOMEM;
			break;
		case HV_STATUS_SUCCESS:
			return ret;
		default:
			pr_err("hv_post_msg() failed; error code:%d\n", ret);
			return -EINVAL;
		}

		retries++;
		if (can_sleep && usec > 1000)
			msleep(usec / 1000);
		else if (usec < MAX_UDELAY_MS * 1000)
			udelay(usec);
		else
			mdelay(usec / 1000);

		if (usec < 256000)
			usec *= 2;
	}
	return ret;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
K. Y. Srinivasan
68
40.24%
3
20.00%
Vitaly Kuznetsov
37
21.89%
1
6.67%
Hank Janssen
25
14.79%
1
6.67%
Haiyang Zhang
21
12.43%
5
33.33%
Dexuan Cui
12
7.10%
1
6.67%
Greg Kroah-Hartman
6
3.55%
4
26.67%
Total
169
100.00%
15
100.00%

/*
 * vmbus_set_event - Send an event notification to the parent
 */


void vmbus_set_event(struct vmbus_channel *channel)
{
	u32 child_relid = channel->offermsg.child_relid;

	if (!channel->is_dedicated_interrupt)
		vmbus_send_interrupt(child_relid);

	hv_do_hypercall(HVCALL_SIGNAL_EVENT, channel->sig_event, NULL);
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
K. Y. Srinivasan
32
76.19%
4
50.00%
Hank Janssen
7
16.67%
1
12.50%
Haiyang Zhang
2
4.76%
2
25.00%
Stephen Hemminger
1
2.38%
1
12.50%
Total
42
100.00%
8
100.00%


EXPORT_SYMBOL_GPL(vmbus_set_event);
Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
K. Y. Srinivasan
695
50.47%
31
40.79%
Hank Janssen
249
18.08%
2
2.63%
Greg Kroah-Hartman
124
9.01%
15
19.74%
Stephen Hemminger
93
6.75%
6
7.89%
Haiyang Zhang
79
5.74%
7
9.21%
Vitaly Kuznetsov
69
5.01%
3
3.95%
Dexuan Cui
20
1.45%
3
3.95%
Alex Ng
19
1.38%
1
1.32%
Bill Pemberton
16
1.16%
5
6.58%
Keith Mange
8
0.58%
1
1.32%
Tejun Heo
3
0.22%
1
1.32%
Radim Krčmář
2
0.15%
1
1.32%
Total
1377
100.00%
76
100.00%
Directory: drivers/hv

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