[linux-2.6-block.git] / 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/mshyperv.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_WIN10_V5):
		return VERSION_WIN10;

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

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

	init_completion(&msginfo->waitevent);

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

	memset(msg, 0, sizeof(*msg));
	msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
	msg->vmbus_version_requested = version;

	/*
	 * VMBus protocol 5.0 (VERSION_WIN10_V5) requires that we must use
	 * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate Contact Message,
	 * and for subsequent messages, we must use the Message Connection ID
	 * field in the host-returned Version Response Message. And, with
	 * VERSION_WIN10_V5, we don't use msg->interrupt_page, but we tell
	 * the host explicitly that we still use VMBUS_MESSAGE_SINT(2) for
	 * compatibility.
	 *
	 * On old hosts, we should always use VMBUS_MESSAGE_CONNECTION_ID (1).
	 */
	if (version >= VERSION_WIN10_V5) {
		msg->msg_sint = VMBUS_MESSAGE_SINT;
		vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID_4;
	} else {
		msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
		vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID;
	}

	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) {
		cur_cpu = get_cpu();
		msg->target_vcpu = hv_cpu_number_to_vp_number(cur_cpu);
		vmbus_connection.connect_cpu = cur_cpu;
		put_cpu();
	} else {
		msg->target_vcpu = 0;
		vmbus_connection.connect_cpu = 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);

	trace_vmbus_negotiate_version(msg, ret);

	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;

		if (version >= VERSION_WIN10_V5)
			vmbus_connection.msg_conn_id =
				msginfo->response.version_response.msg_conn_id;
	} else {
		return -ECONNREFUSED;
	}

	return ret;
}

/*
 * 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;
	}

	vmbus_connection.handle_primary_chan_wq =
		create_workqueue("hv_pri_chan");
	if (!vmbus_connection.handle_primary_chan_wq) {
		ret = -ENOMEM;
		goto cleanup;
	}

	vmbus_connection.handle_sub_chan_wq =
		create_workqueue("hv_sub_chan");
	if (!vmbus_connection.handle_sub_chan_wq) {
		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;
}

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

	if (vmbus_connection.handle_sub_chan_wq)
		destroy_workqueue(vmbus_connection.handle_sub_chan_wq);

	if (vmbus_connection.handle_primary_chan_wq)
		destroy_workqueue(vmbus_connection.handle_primary_chan_wq);

	if (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;
}

/*
 * 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;
}

/*
 * 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;

	trace_vmbus_on_event(channel);

	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);
}

/*
 * vmbus_post_msg - Send a msg on the vmbus's message connection
 */
int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
{
	struct vmbus_channel_message_header *hdr;
	union hv_connection_id conn_id;
	int ret = 0;
	int retries = 0;
	u32 usec = 1;

	conn_id.asu32 = 0;
	conn_id.u.id = vmbus_connection.msg_conn_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:
			/*
			 * See vmbus_negotiate_version(): VMBus protocol 5.0
			 * requires that we must use
			 * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate
			 * Contact message, but on old hosts that only
			 * support VMBus protocol 4.0 or lower, here we get
			 * HV_STATUS_INVALID_CONNECTION_ID and we should
			 * return an error immediately without retrying.
			 */
			hdr = buffer;
			if (hdr->msgtype == CHANNELMSG_INITIATE_CONTACT)
				return -EINVAL;
			/*
			 * We could get this if we send messages too
			 * frequently.
			 */
			ret = -EAGAIN;
			break;
		case HV_STATUS_INSUFFICIENT_MEMORY:
		case HV_STATUS_INSUFFICIENT_BUFFERS:
			ret = -ENOBUFS;
			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 (retries < 22)
			usec *= 2;
	}
	return ret;
}

/*
 * 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);

	++channel->sig_events;

	hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
}
EXPORT_SYMBOL_GPL(vmbus_set_event);
Commit	Line	Data
3e7ee490 HJ	1	/*
	2	*
	3	* Copyright (c) 2009, Microsoft Corporation.
	4	*
	5	* This program is free software; you can redistribute it and/or modify it
	6	* under the terms and conditions of the GNU General Public License,
	7	* version 2, as published by the Free Software Foundation.
	8	*
	9	* This program is distributed in the hope it will be useful, but WITHOUT
	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	12	* more details.
	13	*
	14	* You should have received a copy of the GNU General Public License along with
	15	* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
	16	* Place - Suite 330, Boston, MA 02111-1307 USA.
	17	*
	18	* Authors:
	19	* Haiyang Zhang <haiyangz@microsoft.com>
	20	* Hank Janssen <hjanssen@microsoft.com>
	21	*
	22	*/
0a46618d HJ	23	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
0a46618d HJ	24
a0086dc5	25	#include <linux/kernel.h>
0c3b7b2f S	26	#include <linux/sched.h>
0c3b7b2f S	27	#include <linux/wait.h>
5289d3d1	28	#include <linux/delay.h>
a0086dc5	29	#include <linux/mm.h>
5a0e3ad6	30	#include <linux/slab.h>
a0086dc5	31	#include <linux/vmalloc.h>
46a97191	32	#include <linux/hyperv.h>
37f7278b	33	#include <linux/export.h>
fc53662f VK	34	#include <asm/mshyperv.h>
fc53662f VK	35
0f2a6619	36	#include "hyperv_vmbus.h"
3e7ee490	37
3e7ee490	38
da9fcb72 HZ	39	struct vmbus_connection vmbus_connection = {
	40	.conn_state = DISCONNECTED,
	41	.next_gpadl_handle = ATOMIC_INIT(0xE1E10),
3e7ee490	42	};
95096f2f	43	EXPORT_SYMBOL_GPL(vmbus_connection);
3e7ee490	44
37f7278b S	45	/*
	46	* Negotiated protocol version with the host.
	47	*/
	48	__u32 vmbus_proto_version;
	49	EXPORT_SYMBOL_GPL(vmbus_proto_version);
	50
610071c3 S	51	static __u32 vmbus_get_next_version(__u32 current_version)
	52	{
	53	switch (current_version) {
	54	case (VERSION_WIN7):
	55	return VERSION_WS2008;
	56
	57	case (VERSION_WIN8):
	58	return VERSION_WIN7;
	59
03367ef5 S	60	case (VERSION_WIN8_1):
	61	return VERSION_WIN8;
	62
6c4e5f9c KM	63	case (VERSION_WIN10):
	64	return VERSION_WIN8_1;
	65
ae20b254 DC	66	case (VERSION_WIN10_V5):
	67	return VERSION_WIN10;
	68
610071c3 S	69	case (VERSION_WS2008):
	70	default:
	71	return VERSION_INVAL;
	72	}
	73	}
	74
	75	static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
	76	__u32 version)
	77	{
	78	int ret = 0;
41e270f6	79	unsigned int cur_cpu;
610071c3 S	80	struct vmbus_channel_initiate_contact *msg;
610071c3 S	81	unsigned long flags;
610071c3 S	82
	83	init_completion(&msginfo->waitevent);
	84
	85	msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
	86
ae20b254	87	memset(msg, 0, sizeof(*msg));
610071c3 S	88	msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
610071c3 S	89	msg->vmbus_version_requested = version;
ae20b254 DC	90
	91	/*
	92	* VMBus protocol 5.0 (VERSION_WIN10_V5) requires that we must use
	93	* VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate Contact Message,
	94	* and for subsequent messages, we must use the Message Connection ID
	95	* field in the host-returned Version Response Message. And, with
	96	* VERSION_WIN10_V5, we don't use msg->interrupt_page, but we tell
	97	* the host explicitly that we still use VMBUS_MESSAGE_SINT(2) for
	98	* compatibility.
	99	*
	100	* On old hosts, we should always use VMBUS_MESSAGE_CONNECTION_ID (1).
	101	*/
	102	if (version >= VERSION_WIN10_V5) {
	103	msg->msg_sint = VMBUS_MESSAGE_SINT;
	104	vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID_4;
	105	} else {
	106	msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
	107	vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID;
	108	}
	109
8681db44 GKH	110	msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
8681db44 GKH	111	msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
b282e4c0 S	112	/*
	113	* We want all channel messages to be delivered on CPU 0.
	114	* This has been the behavior pre-win8. This is not
	115	* perf issue and having all channel messages delivered on CPU 0
	116	* would be ok.
72686447 AN	117	* For post win8 hosts, we support receiving channel messagges on
	118	* all the CPUs. This is needed for kexec to work correctly where
	119	* the CPU attempting to connect may not be CPU 0.
b282e4c0	120	*/
54a66265	121	if (version >= VERSION_WIN8_1) {
41e270f6 DC	122	cur_cpu = get_cpu();
	123	msg->target_vcpu = hv_cpu_number_to_vp_number(cur_cpu);
	124	vmbus_connection.connect_cpu = cur_cpu;
	125	put_cpu();
54a66265	126	} else {
72686447	127	msg->target_vcpu = 0;
54a66265 S	128	vmbus_connection.connect_cpu = 0;
54a66265 S	129	}
610071c3 S	130
	131	/*
	132	* Add to list before we send the request since we may
	133	* receive the response before returning from this routine
	134	*/
	135	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
	136	list_add_tail(&msginfo->msglistentry,
	137	&vmbus_connection.chn_msg_list);
	138
	139	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
	140
	141	ret = vmbus_post_msg(msg,
c0bb0392 VK	142	sizeof(struct vmbus_channel_initiate_contact),
c0bb0392 VK	143	true);
034ebf55 VK	144
	145	trace_vmbus_negotiate_version(msg, ret);
	146
610071c3 S	147	if (ret != 0) {
	148	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
	149	list_del(&msginfo->msglistentry);
	150	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
	151	flags);
	152	return ret;
	153	}
	154
	155	/* Wait for the connection response */
269f9794	156	wait_for_completion(&msginfo->waitevent);
610071c3 S	157
	158	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
	159	list_del(&msginfo->msglistentry);
	160	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
	161
	162	/* Check if successful */
	163	if (msginfo->response.version_response.version_supported) {
	164	vmbus_connection.conn_state = CONNECTED;
ae20b254 DC	165
	166	if (version >= VERSION_WIN10_V5)
	167	vmbus_connection.msg_conn_id =
	168	msginfo->response.version_response.msg_conn_id;
610071c3	169	} else {
610071c3 S	170	return -ECONNREFUSED;
	171	}
	172
	173	return ret;
	174	}
	175
3e189519	176	/*
c6977677	177	* vmbus_connect - Sends a connect request on the partition service connection
fd8b85ea	178	*/
c6977677	179	int vmbus_connect(void)
3e7ee490	180	{
fd8b85ea	181	int ret = 0;
15b2f647	182	struct vmbus_channel_msginfo *msginfo = NULL;
610071c3	183	__u32 version;
3e7ee490	184
454f18a9	185	/* Initialize the vmbus connection */
da9fcb72 HZ	186	vmbus_connection.conn_state = CONNECTING;
	187	vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
	188	if (!vmbus_connection.work_queue) {
3a7546d9	189	ret = -ENOMEM;
b0043863	190	goto cleanup;
de65a384	191	}
3e7ee490	192
37c2578c DC	193	vmbus_connection.handle_primary_chan_wq =
	194	create_workqueue("hv_pri_chan");
	195	if (!vmbus_connection.handle_primary_chan_wq) {
	196	ret = -ENOMEM;
	197	goto cleanup;
	198	}
	199
	200	vmbus_connection.handle_sub_chan_wq =
	201	create_workqueue("hv_sub_chan");
	202	if (!vmbus_connection.handle_sub_chan_wq) {
	203	ret = -ENOMEM;
	204	goto cleanup;
	205	}
	206
da9fcb72	207	INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
15b2f647	208	spin_lock_init(&vmbus_connection.channelmsg_lock);
3e7ee490	209
da9fcb72	210	INIT_LIST_HEAD(&vmbus_connection.chn_list);
d6f591e3	211	mutex_init(&vmbus_connection.channel_mutex);
3e7ee490	212
454f18a9 BP	213	/*
	214	* Setup the vmbus event connection for channel interrupt
	215	* abstraction stuff
	216	*/
df3493e0 S	217	vmbus_connection.int_page =
df3493e0 S	218	(void *)__get_free_pages(GFP_KERNEL\|__GFP_ZERO, 0);
da9fcb72	219	if (vmbus_connection.int_page == NULL) {
3a7546d9	220	ret = -ENOMEM;
b0043863	221	goto cleanup;
3e7ee490 HJ	222	}
3e7ee490 HJ	223
da9fcb72 HZ	224	vmbus_connection.recv_int_page = vmbus_connection.int_page;
	225	vmbus_connection.send_int_page =
	226	(void *)((unsigned long)vmbus_connection.int_page +
fd8b85ea	227	(PAGE_SIZE >> 1));
3e7ee490	228
fd8b85ea GKH	229	/*
	230	* Setup the monitor notification facility. The 1st page for
	231	* parent->child and the 2nd page for child->parent
454f18a9	232	*/
8681db44 GKH	233	vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL\|__GFP_ZERO), 0);
	234	vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL\|__GFP_ZERO), 0);
	235	if ((vmbus_connection.monitor_pages[0] == NULL) \|\|
	236	(vmbus_connection.monitor_pages[1] == NULL)) {
3a7546d9	237	ret = -ENOMEM;
b0043863	238	goto cleanup;
3e7ee490 HJ	239	}
3e7ee490 HJ	240
15b2f647	241	msginfo = kzalloc(sizeof(*msginfo) +
fd8b85ea GKH	242	sizeof(struct vmbus_channel_initiate_contact),
fd8b85ea GKH	243	GFP_KERNEL);
15b2f647	244	if (msginfo == NULL) {
8cad0af9	245	ret = -ENOMEM;
b0043863	246	goto cleanup;
3e7ee490 HJ	247	}
3e7ee490 HJ	248
454f18a9	249	/*
610071c3 S	250	* Negotiate a compatible VMBUS version number with the
	251	* host. We start with the highest number we can support
	252	* and work our way down until we negotiate a compatible
	253	* version.
454f18a9	254	*/
3e7ee490	255
2a5c43a8	256	version = VERSION_CURRENT;
3e7ee490	257
610071c3 S	258	do {
610071c3 S	259	ret = vmbus_negotiate_version(msginfo, version);
8bbf9f44	260	if (ret == -ETIMEDOUT)
666b9adc S	261	goto cleanup;
	262
	263	if (vmbus_connection.conn_state == CONNECTED)
610071c3	264	break;
3e7ee490	265
610071c3 S	266	version = vmbus_get_next_version(version);
610071c3 S	267	} while (version != VERSION_INVAL);
3e7ee490	268
610071c3	269	if (version == VERSION_INVAL)
b0043863	270	goto cleanup;
3e7ee490	271
37f7278b	272	vmbus_proto_version = version;
8de8af7e S	273	pr_info("Vmbus version:%d.%d\n",
8de8af7e S	274	version >> 16, version & 0xFFFF);
3bacaf0c	275
15b2f647	276	kfree(msginfo);
3e7ee490 HJ	277	return 0;
3e7ee490 HJ	278
b0043863	279	cleanup:
3bacaf0c	280	pr_err("Unable to connect to host\n");
09a19628	281
da9fcb72	282	vmbus_connection.conn_state = DISCONNECTED;
09a19628 VK	283	vmbus_disconnect();
	284
	285	kfree(msginfo);
	286
	287	return ret;
	288	}
3e7ee490	289
09a19628 VK	290	void vmbus_disconnect(void)
09a19628 VK	291	{
2db84eff S	292	/*
	293	* First send the unload request to the host.
	294	*/
75ff3a8a	295	vmbus_initiate_unload(false);
2db84eff	296
37c2578c DC	297	if (vmbus_connection.handle_sub_chan_wq)
	298	destroy_workqueue(vmbus_connection.handle_sub_chan_wq);
	299
	300	if (vmbus_connection.handle_primary_chan_wq)
	301	destroy_workqueue(vmbus_connection.handle_primary_chan_wq);
	302
	303	if (vmbus_connection.work_queue)
da9fcb72	304	destroy_workqueue(vmbus_connection.work_queue);
3e7ee490	305
da9fcb72	306	if (vmbus_connection.int_page) {
df3493e0	307	free_pages((unsigned long)vmbus_connection.int_page, 0);
da9fcb72	308	vmbus_connection.int_page = NULL;
3e7ee490 HJ	309	}
3e7ee490 HJ	310
a100d88d RK	311	free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0);
a100d88d RK	312	free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0);
8681db44 GKH	313	vmbus_connection.monitor_pages[0] = NULL;
8681db44 GKH	314	vmbus_connection.monitor_pages[1] = NULL;
3e7ee490 HJ	315	}
3e7ee490 HJ	316
3e189519	317	/*
c6977677 HZ	318	* relid2channel - Get the channel object given its
c6977677 HZ	319	* child relative id (ie channel id)
fd8b85ea	320	*/
d43e2fe7	321	struct vmbus_channel *relid2channel(u32 relid)
3e7ee490	322	{
aded7165	323	struct vmbus_channel *channel;
15b2f647	324	struct vmbus_channel *found_channel = NULL;
e68d2971 S	325	struct list_head cur, tmp;
e68d2971 S	326	struct vmbus_channel *cur_sc;
3e7ee490	327
85d9aa70 DC	328	BUG_ON(!mutex_is_locked(&vmbus_connection.channel_mutex));
85d9aa70 DC	329
da9fcb72	330	list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
15b2f647 HZ	331	if (channel->offermsg.child_relid == relid) {
15b2f647 HZ	332	found_channel = channel;
3e7ee490	333	break;
e68d2971 S	334	} else if (!list_empty(&channel->sc_list)) {
	335	/*
	336	* Deal with sub-channels.
	337	*/
	338	list_for_each_safe(cur, tmp, &channel->sc_list) {
	339	cur_sc = list_entry(cur, struct vmbus_channel,
	340	sc_list);
	341	if (cur_sc->offermsg.child_relid == relid) {
	342	found_channel = cur_sc;
	343	break;
	344	}
	345	}
3e7ee490 HJ	346	}
3e7ee490 HJ	347	}
3e7ee490	348
15b2f647	349	return found_channel;
3e7ee490 HJ	350	}
3e7ee490 HJ	351
3e189519	352	/*
631e63a9	353	* vmbus_on_event - Process a channel event notification
ada6eb11 SH	354	*
	355	* For batched channels (default) optimize host to guest signaling
	356	* by ensuring:
	357	* 1. While reading the channel, we disable interrupts from host.
	358	* 2. Ensure that we process all posted messages from the host
	359	* before returning from this callback.
	360	* 3. Once we return, enable signaling from the host. Once this
	361	* state is set we check to see if additional packets are
	362	* available to read. In this case we repeat the process.
	363	* If this tasklet has been running for a long time
	364	* then reschedule ourselves.
fd8b85ea	365	*/
631e63a9	366	void vmbus_on_event(unsigned long data)
3e7ee490	367	{
631e63a9	368	struct vmbus_channel channel = (void ) data;
ada6eb11	369	unsigned long time_limit = jiffies + 2;
3e7ee490	370
991f8f1c VK	371	trace_vmbus_on_event(channel);
991f8f1c VK	372
ada6eb11 SH	373	do {
	374	void (callback_fn)(void );
	375
	376	/* A channel once created is persistent even when
	377	* there is no driver handling the device. An
	378	* unloading driver sets the onchannel_callback to NULL.
f878f3d5	379	*/
ada6eb11 SH	380	callback_fn = READ_ONCE(channel->onchannel_callback);
	381	if (unlikely(callback_fn == NULL))
	382	return;
f878f3d5	383
ada6eb11 SH	384	(*callback_fn)(channel->channel_callback_context);
	385
	386	if (channel->callback_mode != HV_CALL_BATCHED)
	387	return;
	388
	389	if (likely(hv_end_read(&channel->inbound) == 0))
	390	return;
	391
	392	hv_begin_read(&channel->inbound);
	393	} while (likely(time_before(jiffies, time_limit)));
	394
	395	/* The time limit (2 jiffies) has been reached */
	396	tasklet_schedule(&channel->callback_event);
3e7ee490 HJ	397	}
3e7ee490 HJ	398
3e189519	399	/*
c6977677	400	* vmbus_post_msg - Send a msg on the vmbus's message connection
fd8b85ea	401	*/
c0bb0392	402	int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
3e7ee490	403	{
ae20b254	404	struct vmbus_channel_message_header *hdr;
15b2f647	405	union hv_connection_id conn_id;
5289d3d1 S	406	int ret = 0;
5289d3d1 S	407	int retries = 0;
8de0d7e9	408	u32 usec = 1;
3e7ee490	409
15b2f647	410	conn_id.asu32 = 0;
ae20b254	411	conn_id.u.id = vmbus_connection.msg_conn_id;
5289d3d1 S	412
	413	/*
	414	* hv_post_message() can have transient failures because of
	415	* insufficient resources. Retry the operation a couple of
	416	* times before giving up.
	417	*/
c0bb0392	418	while (retries < 100) {
fdeebcc6 S	419	ret = hv_post_message(conn_id, 1, buffer, buflen);
	420
	421	switch (ret) {
89f9f679	422	case HV_STATUS_INVALID_CONNECTION_ID:
ae20b254 DC	423	/*
	424	* See vmbus_negotiate_version(): VMBus protocol 5.0
	425	* requires that we must use
	426	* VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate
	427	* Contact message, but on old hosts that only
	428	* support VMBus protocol 4.0 or lower, here we get
	429	* HV_STATUS_INVALID_CONNECTION_ID and we should
	430	* return an error immediately without retrying.
	431	*/
89760937	432	hdr = buffer;
ae20b254 DC	433	if (hdr->msgtype == CHANNELMSG_INITIATE_CONTACT)
ae20b254 DC	434	return -EINVAL;
89f9f679 DC	435	/*
	436	* We could get this if we send messages too
	437	* frequently.
	438	*/
	439	ret = -EAGAIN;
	440	break;
	441	case HV_STATUS_INSUFFICIENT_MEMORY:
fdeebcc6	442	case HV_STATUS_INSUFFICIENT_BUFFERS:
48f4ccdf	443	ret = -ENOBUFS;
fdeebcc6 S	444	break;
fdeebcc6 S	445	case HV_STATUS_SUCCESS:
5289d3d1	446	return ret;
fdeebcc6 S	447	default:
	448	pr_err("hv_post_msg() failed; error code:%d\n", ret);
	449	return -EINVAL;
	450	}
	451
5289d3d1	452	retries++;
c0bb0392 VK	453	if (can_sleep && usec > 1000)
	454	msleep(usec / 1000);
	455	else if (usec < MAX_UDELAY_MS * 1000)
	456	udelay(usec);
	457	else
	458	mdelay(usec / 1000);
	459
e917a5e2	460	if (retries < 22)
8de0d7e9	461	usec *= 2;
5289d3d1 S	462	}
5289d3d1 S	463	return ret;
3e7ee490 HJ	464	}
3e7ee490 HJ	465
3e189519	466	/*
c6977677	467	* vmbus_set_event - Send an event notification to the parent
fd8b85ea	468	*/
1b807e10	469	void vmbus_set_event(struct vmbus_channel *channel)
3e7ee490	470	{
21c3bef5	471	u32 child_relid = channel->offermsg.child_relid;
7c369f40	472
5c1bec61 SH	473	if (!channel->is_dedicated_interrupt)
5c1bec61 SH	474	vmbus_send_interrupt(child_relid);
3be77774	475
6981fbf3 SH	476	++channel->sig_events;
6981fbf3 SH	477
05784171	478	hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
3e7ee490	479	}
5cc47247	480	EXPORT_SYMBOL_GPL(vmbus_set_event);