[deliverable/linux.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/hyperv.h>
#include "hyperv_vmbus.h"


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

/*
 * 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;
	}
}

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[get_cpu()];
		put_cpu();
	} 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));
	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;
}

/*
 * 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("Hyper-V Host Build:%d-%d.%d-%d-%d.%d; Vmbus version:%d.%d\n",
		    host_info_eax, host_info_ebx >> 16,
		    host_info_ebx & 0xFFFF, host_info_ecx,
		    host_info_edx >> 24, host_info_edx & 0xFFFFFF,
		    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.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;
}

/*
 * Map the given relid to the corresponding channel based on the
 * per-cpu list of channels that have been affinitized to this CPU.
 * This will be used in the channel callback path as we can do this
 * mapping in a lock-free fashion.
 */
static struct vmbus_channel *pcpu_relid2channel(u32 relid)
{
	struct vmbus_channel *channel;
	struct vmbus_channel *found_channel  = NULL;
	int cpu = smp_processor_id();
	struct list_head *pcpu_head = &hv_context.percpu_list[cpu];

	list_for_each_entry(channel, pcpu_head, percpu_list) {
		if (channel->offermsg.child_relid == relid) {
			found_channel = channel;
			break;
		}
	}

	return found_channel;
}

/*
 * 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;
}

/*
 * process_chn_event - Process a channel event notification
 */
static void process_chn_event(u32 relid)
{
	struct vmbus_channel *channel;
	void *arg;
	bool read_state;
	u32 bytes_to_read;

	/*
	 * Find the channel based on this relid and invokes the
	 * channel callback to process the event
	 */
	channel = pcpu_relid2channel(relid);

	if (!channel)
		return;

	/*
	 * A channel once created is persistent even when there
	 * is no driver handling the device. An unloading driver
	 * sets the onchannel_callback to NULL on the same CPU
	 * as where this interrupt is handled (in an interrupt context).
	 * Thus, checking and invoking the driver specific callback takes
	 * care of orderly unloading of the driver.
	 */

	if (channel->onchannel_callback != NULL) {
		arg = channel->channel_callback_context;
		read_state = channel->batched_reading;
		/*
		 * This callback reads the messages sent by the host.
		 * We can 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.
		 */

		do {
			if (read_state)
				hv_begin_read(&channel->inbound);
			channel->onchannel_callback(arg);
			if (read_state)
				bytes_to_read = hv_end_read(&channel->inbound);
			else
				bytes_to_read = 0;
		} while (read_state && (bytes_to_read != 0));
	}
}

/*
 * vmbus_on_event - Handler for events
 */
void vmbus_on_event(unsigned long data)
{
	u32 dword;
	u32 maxdword;
	int bit;
	u32 relid;
	u32 *recv_int_page = NULL;
	void *page_addr;
	int cpu = smp_processor_id();
	union hv_synic_event_flags *event;

	if (vmbus_proto_version < VERSION_WIN8) {
		maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
		recv_int_page = vmbus_connection.recv_int_page;
	} else {
		/*
		 * When the host is win8 and beyond, the event page
		 * can be directly checked to get the id of the channel
		 * that has the interrupt pending.
		 */
		maxdword = HV_EVENT_FLAGS_DWORD_COUNT;
		page_addr = hv_context.synic_event_page[cpu];
		event = (union hv_synic_event_flags *)page_addr +
						 VMBUS_MESSAGE_SINT;
		recv_int_page = event->flags32;
	}


	/* Check events */
	if (!recv_int_page)
		return;
	for (dword = 0; dword < maxdword; dword++) {
		if (!recv_int_page[dword])
			continue;
		for (bit = 0; bit < 32; bit++) {
			if (sync_test_and_clear_bit(bit,
				(unsigned long *)&recv_int_page[dword])) {
				relid = (dword << 5) + bit;

				if (relid == 0)
					/*
					 * Special case - vmbus
					 * channel protocol msg
					 */
					continue;

				process_chn_event(relid);
			}
		}
	}
}

/*
 * vmbus_post_msg - Send a msg on the vmbus's message connection
 */
int vmbus_post_msg(void *buffer, size_t buflen)
{
	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 < 20) {
		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++;
		udelay(usec);
		if (usec < 2048)
			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) {
		/* Each u32 represents 32 channels */
		sync_set_bit(child_relid & 31,
			(unsigned long *)vmbus_connection.send_int_page +
			(child_relid >> 5));
	}

	hv_do_hypercall(HVCALL_SIGNAL_EVENT, channel->sig_event, NULL);
}
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>
407dd164	34	#include <asm/hyperv.h>
0f2a6619	35	#include "hyperv_vmbus.h"
3e7ee490	36
3e7ee490	37
da9fcb72 HZ	38	struct vmbus_connection vmbus_connection = {
	39	.conn_state = DISCONNECTED,
	40	.next_gpadl_handle = ATOMIC_INIT(0xE1E10),
3e7ee490 HJ	41	};
3e7ee490 HJ	42
37f7278b S	43	/*
	44	* Negotiated protocol version with the host.
	45	*/
	46	__u32 vmbus_proto_version;
	47	EXPORT_SYMBOL_GPL(vmbus_proto_version);
	48
610071c3 S	49	static __u32 vmbus_get_next_version(__u32 current_version)
	50	{
	51	switch (current_version) {
	52	case (VERSION_WIN7):
	53	return VERSION_WS2008;
	54
	55	case (VERSION_WIN8):
	56	return VERSION_WIN7;
	57
03367ef5 S	58	case (VERSION_WIN8_1):
	59	return VERSION_WIN8;
	60
6c4e5f9c KM	61	case (VERSION_WIN10):
	62	return VERSION_WIN8_1;
	63
610071c3 S	64	case (VERSION_WS2008):
	65	default:
	66	return VERSION_INVAL;
	67	}
	68	}
	69
	70	static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
	71	__u32 version)
	72	{
	73	int ret = 0;
	74	struct vmbus_channel_initiate_contact *msg;
	75	unsigned long flags;
610071c3 S	76
	77	init_completion(&msginfo->waitevent);
	78
	79	msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
	80
	81	msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
	82	msg->vmbus_version_requested = version;
	83	msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
8681db44 GKH	84	msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
8681db44 GKH	85	msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
b282e4c0 S	86	/*
	87	* We want all channel messages to be delivered on CPU 0.
	88	* This has been the behavior pre-win8. This is not
	89	* perf issue and having all channel messages delivered on CPU 0
	90	* would be ok.
72686447 AN	91	* For post win8 hosts, we support receiving channel messagges on
	92	* all the CPUs. This is needed for kexec to work correctly where
	93	* the CPU attempting to connect may not be CPU 0.
b282e4c0	94	*/
72686447 AN	95	if (version >= VERSION_WIN8_1) {
	96	msg->target_vcpu = hv_context.vp_index[get_cpu()];
	97	put_cpu();
	98	} else {
	99	msg->target_vcpu = 0;
	100	}
610071c3 S	101
	102	/*
	103	* Add to list before we send the request since we may
	104	* receive the response before returning from this routine
	105	*/
	106	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
	107	list_add_tail(&msginfo->msglistentry,
	108	&vmbus_connection.chn_msg_list);
	109
	110	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
	111
	112	ret = vmbus_post_msg(msg,
	113	sizeof(struct vmbus_channel_initiate_contact));
	114	if (ret != 0) {
	115	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
	116	list_del(&msginfo->msglistentry);
	117	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
	118	flags);
	119	return ret;
	120	}
	121
	122	/* Wait for the connection response */
269f9794	123	wait_for_completion(&msginfo->waitevent);
610071c3 S	124
	125	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
	126	list_del(&msginfo->msglistentry);
	127	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
	128
	129	/* Check if successful */
	130	if (msginfo->response.version_response.version_supported) {
	131	vmbus_connection.conn_state = CONNECTED;
	132	} else {
610071c3 S	133	return -ECONNREFUSED;
	134	}
	135
	136	return ret;
	137	}
	138
3e189519	139	/*
c6977677	140	* vmbus_connect - Sends a connect request on the partition service connection
fd8b85ea	141	*/
c6977677	142	int vmbus_connect(void)
3e7ee490	143	{
fd8b85ea	144	int ret = 0;
15b2f647	145	struct vmbus_channel_msginfo *msginfo = NULL;
610071c3	146	__u32 version;
3e7ee490	147
454f18a9	148	/* Initialize the vmbus connection */
da9fcb72 HZ	149	vmbus_connection.conn_state = CONNECTING;
	150	vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
	151	if (!vmbus_connection.work_queue) {
3a7546d9	152	ret = -ENOMEM;
b0043863	153	goto cleanup;
de65a384	154	}
3e7ee490	155
da9fcb72	156	INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
15b2f647	157	spin_lock_init(&vmbus_connection.channelmsg_lock);
3e7ee490	158
da9fcb72	159	INIT_LIST_HEAD(&vmbus_connection.chn_list);
d6f591e3	160	mutex_init(&vmbus_connection.channel_mutex);
3e7ee490	161
454f18a9 BP	162	/*
	163	* Setup the vmbus event connection for channel interrupt
	164	* abstraction stuff
	165	*/
df3493e0 S	166	vmbus_connection.int_page =
df3493e0 S	167	(void *)__get_free_pages(GFP_KERNEL\|__GFP_ZERO, 0);
da9fcb72	168	if (vmbus_connection.int_page == NULL) {
3a7546d9	169	ret = -ENOMEM;
b0043863	170	goto cleanup;
3e7ee490 HJ	171	}
3e7ee490 HJ	172
da9fcb72 HZ	173	vmbus_connection.recv_int_page = vmbus_connection.int_page;
	174	vmbus_connection.send_int_page =
	175	(void *)((unsigned long)vmbus_connection.int_page +
fd8b85ea	176	(PAGE_SIZE >> 1));
3e7ee490	177
fd8b85ea GKH	178	/*
	179	* Setup the monitor notification facility. The 1st page for
	180	* parent->child and the 2nd page for child->parent
454f18a9	181	*/
8681db44 GKH	182	vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL\|__GFP_ZERO), 0);
	183	vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL\|__GFP_ZERO), 0);
	184	if ((vmbus_connection.monitor_pages[0] == NULL) \|\|
	185	(vmbus_connection.monitor_pages[1] == NULL)) {
3a7546d9	186	ret = -ENOMEM;
b0043863	187	goto cleanup;
3e7ee490 HJ	188	}
3e7ee490 HJ	189
15b2f647	190	msginfo = kzalloc(sizeof(*msginfo) +
fd8b85ea GKH	191	sizeof(struct vmbus_channel_initiate_contact),
fd8b85ea GKH	192	GFP_KERNEL);
15b2f647	193	if (msginfo == NULL) {
8cad0af9	194	ret = -ENOMEM;
b0043863	195	goto cleanup;
3e7ee490 HJ	196	}
3e7ee490 HJ	197
454f18a9	198	/*
610071c3 S	199	* Negotiate a compatible VMBUS version number with the
	200	* host. We start with the highest number we can support
	201	* and work our way down until we negotiate a compatible
	202	* version.
454f18a9	203	*/
3e7ee490	204
2a5c43a8	205	version = VERSION_CURRENT;
3e7ee490	206
610071c3 S	207	do {
610071c3 S	208	ret = vmbus_negotiate_version(msginfo, version);
8bbf9f44	209	if (ret == -ETIMEDOUT)
666b9adc S	210	goto cleanup;
	211
	212	if (vmbus_connection.conn_state == CONNECTED)
610071c3	213	break;
3e7ee490	214
610071c3 S	215	version = vmbus_get_next_version(version);
610071c3 S	216	} while (version != VERSION_INVAL);
3e7ee490	217
610071c3	218	if (version == VERSION_INVAL)
b0043863	219	goto cleanup;
3e7ee490	220
37f7278b	221	vmbus_proto_version = version;
3bacaf0c S	222	pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d; Vmbus version:%d.%d\n",
	223	host_info_eax, host_info_ebx >> 16,
	224	host_info_ebx & 0xFFFF, host_info_ecx,
	225	host_info_edx >> 24, host_info_edx & 0xFFFFFF,
	226	version >> 16, version & 0xFFFF);
	227
15b2f647	228	kfree(msginfo);
3e7ee490 HJ	229	return 0;
3e7ee490 HJ	230
b0043863	231	cleanup:
3bacaf0c	232	pr_err("Unable to connect to host\n");
09a19628	233
da9fcb72	234	vmbus_connection.conn_state = DISCONNECTED;
09a19628 VK	235	vmbus_disconnect();
	236
	237	kfree(msginfo);
	238
	239	return ret;
	240	}
3e7ee490	241
09a19628 VK	242	void vmbus_disconnect(void)
09a19628 VK	243	{
2db84eff S	244	/*
	245	* First send the unload request to the host.
	246	*/
75ff3a8a	247	vmbus_initiate_unload(false);
2db84eff	248
09a19628 VK	249	if (vmbus_connection.work_queue) {
09a19628 VK	250	drain_workqueue(vmbus_connection.work_queue);
da9fcb72	251	destroy_workqueue(vmbus_connection.work_queue);
09a19628	252	}
3e7ee490	253
da9fcb72	254	if (vmbus_connection.int_page) {
df3493e0	255	free_pages((unsigned long)vmbus_connection.int_page, 0);
da9fcb72	256	vmbus_connection.int_page = NULL;
3e7ee490 HJ	257	}
3e7ee490 HJ	258
a100d88d RK	259	free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0);
a100d88d RK	260	free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0);
8681db44 GKH	261	vmbus_connection.monitor_pages[0] = NULL;
8681db44 GKH	262	vmbus_connection.monitor_pages[1] = NULL;
3e7ee490 HJ	263	}
3e7ee490 HJ	264
3a28fa35 S	265	/*
	266	* Map the given relid to the corresponding channel based on the
	267	* per-cpu list of channels that have been affinitized to this CPU.
	268	* This will be used in the channel callback path as we can do this
	269	* mapping in a lock-free fashion.
	270	*/
	271	static struct vmbus_channel *pcpu_relid2channel(u32 relid)
	272	{
	273	struct vmbus_channel *channel;
	274	struct vmbus_channel *found_channel = NULL;
	275	int cpu = smp_processor_id();
	276	struct list_head *pcpu_head = &hv_context.percpu_list[cpu];
	277
	278	list_for_each_entry(channel, pcpu_head, percpu_list) {
	279	if (channel->offermsg.child_relid == relid) {
	280	found_channel = channel;
	281	break;
	282	}
	283	}
	284
	285	return found_channel;
	286	}
3e7ee490	287
3e189519	288	/*
c6977677 HZ	289	* relid2channel - Get the channel object given its
c6977677 HZ	290	* child relative id (ie channel id)
fd8b85ea	291	*/
d43e2fe7	292	struct vmbus_channel *relid2channel(u32 relid)
3e7ee490	293	{
aded7165	294	struct vmbus_channel *channel;
15b2f647	295	struct vmbus_channel *found_channel = NULL;
e68d2971 S	296	struct list_head cur, tmp;
e68d2971 S	297	struct vmbus_channel *cur_sc;
3e7ee490	298
85d9aa70 DC	299	BUG_ON(!mutex_is_locked(&vmbus_connection.channel_mutex));
85d9aa70 DC	300
da9fcb72	301	list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
15b2f647 HZ	302	if (channel->offermsg.child_relid == relid) {
15b2f647 HZ	303	found_channel = channel;
3e7ee490	304	break;
e68d2971 S	305	} else if (!list_empty(&channel->sc_list)) {
	306	/*
	307	* Deal with sub-channels.
	308	*/
	309	list_for_each_safe(cur, tmp, &channel->sc_list) {
	310	cur_sc = list_entry(cur, struct vmbus_channel,
	311	sc_list);
	312	if (cur_sc->offermsg.child_relid == relid) {
	313	found_channel = cur_sc;
	314	break;
	315	}
	316	}
3e7ee490 HJ	317	}
3e7ee490 HJ	318	}
3e7ee490	319
15b2f647	320	return found_channel;
3e7ee490 HJ	321	}
3e7ee490 HJ	322
3e189519	323	/*
c6977677	324	* process_chn_event - Process a channel event notification
fd8b85ea	325	*/
35436487	326	static void process_chn_event(u32 relid)
3e7ee490	327	{
aded7165	328	struct vmbus_channel *channel;
f878f3d5 S	329	void *arg;
	330	bool read_state;
	331	u32 bytes_to_read;
3e7ee490	332
454f18a9 BP	333	/*
	334	* Find the channel based on this relid and invokes the
	335	* channel callback to process the event
	336	*/
3a28fa35	337	channel = pcpu_relid2channel(relid);
3e7ee490	338
37f492ce	339	if (!channel)
24326039	340	return;
24326039 S	341
	342	/*
	343	* A channel once created is persistent even when there
	344	* is no driver handling the device. An unloading driver
d3ba720d S	345	* sets the onchannel_callback to NULL on the same CPU
	346	* as where this interrupt is handled (in an interrupt context).
	347	* Thus, checking and invoking the driver specific callback takes
	348	* care of orderly unloading of the driver.
24326039 S	349	*/
24326039 S	350
f878f3d5 S	351	if (channel->onchannel_callback != NULL) {
	352	arg = channel->channel_callback_context;
	353	read_state = channel->batched_reading;
	354	/*
	355	* This callback reads the messages sent by the host.
	356	* We can optimize host to guest signaling by ensuring:
	357	* 1. While reading the channel, we disable interrupts from
	358	* host.
	359	* 2. Ensure that we process all posted messages from the host
	360	* before returning from this callback.
	361	* 3. Once we return, enable signaling from the host. Once this
	362	* state is set we check to see if additional packets are
	363	* available to read. In this case we repeat the process.
	364	*/
	365
	366	do {
affb1aff S	367	if (read_state)
affb1aff S	368	hv_begin_read(&channel->inbound);
f878f3d5	369	channel->onchannel_callback(arg);
affb1aff S	370	if (read_state)
	371	bytes_to_read = hv_end_read(&channel->inbound);
	372	else
	373	bytes_to_read = 0;
f878f3d5	374	} while (read_state && (bytes_to_read != 0));
f878f3d5	375	}
3e7ee490 HJ	376	}
3e7ee490 HJ	377
3e189519	378	/*
c6977677	379	* vmbus_on_event - Handler for events
fd8b85ea	380	*/
6de3d6aa	381	void vmbus_on_event(unsigned long data)
3e7ee490	382	{
35436487	383	u32 dword;
6552ecd7	384	u32 maxdword;
3e7ee490	385	int bit;
35436487	386	u32 relid;
6552ecd7 S	387	u32 *recv_int_page = NULL;
	388	void *page_addr;
	389	int cpu = smp_processor_id();
	390	union hv_synic_event_flags *event;
	391
6c4e5f9c	392	if (vmbus_proto_version < VERSION_WIN8) {
6552ecd7 S	393	maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
	394	recv_int_page = vmbus_connection.recv_int_page;
	395	} else {
	396	/*
	397	* When the host is win8 and beyond, the event page
	398	* can be directly checked to get the id of the channel
	399	* that has the interrupt pending.
	400	*/
	401	maxdword = HV_EVENT_FLAGS_DWORD_COUNT;
	402	page_addr = hv_context.synic_event_page[cpu];
	403	event = (union hv_synic_event_flags *)page_addr +
	404	VMBUS_MESSAGE_SINT;
	405	recv_int_page = event->flags32;
	406	}
	407
	408
3e7ee490	409
454f18a9	410	/* Check events */
242b45aa OH	411	if (!recv_int_page)
	412	return;
	413	for (dword = 0; dword < maxdword; dword++) {
	414	if (!recv_int_page[dword])
	415	continue;
	416	for (bit = 0; bit < 32; bit++) {
d9add43b S	417	if (sync_test_and_clear_bit(bit,
d9add43b S	418	(unsigned long *)&recv_int_page[dword])) {
242b45aa OH	419	relid = (dword << 5) + bit;
242b45aa OH	420
d9add43b	421	if (relid == 0)
6d81d330 S	422	/*
	423	* Special case - vmbus
	424	* channel protocol msg
	425	*/
242b45aa	426	continue;
d9add43b	427
35436487	428	process_chn_event(relid);
3e7ee490	429	}
242b45aa	430	}
3e7ee490	431	}
3e7ee490 HJ	432	}
3e7ee490 HJ	433
3e189519	434	/*
c6977677	435	* vmbus_post_msg - Send a msg on the vmbus's message connection
fd8b85ea	436	*/
c6977677	437	int vmbus_post_msg(void *buffer, size_t buflen)
3e7ee490	438	{
15b2f647	439	union hv_connection_id conn_id;
5289d3d1 S	440	int ret = 0;
5289d3d1 S	441	int retries = 0;
8de0d7e9	442	u32 usec = 1;
3e7ee490	443
15b2f647 HZ	444	conn_id.asu32 = 0;
15b2f647 HZ	445	conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
5289d3d1 S	446
	447	/*
	448	* hv_post_message() can have transient failures because of
	449	* insufficient resources. Retry the operation a couple of
	450	* times before giving up.
	451	*/
e1c0d82d	452	while (retries < 20) {
fdeebcc6 S	453	ret = hv_post_message(conn_id, 1, buffer, buflen);
	454
	455	switch (ret) {
89f9f679 DC	456	case HV_STATUS_INVALID_CONNECTION_ID:
	457	/*
	458	* We could get this if we send messages too
	459	* frequently.
	460	*/
	461	ret = -EAGAIN;
	462	break;
	463	case HV_STATUS_INSUFFICIENT_MEMORY:
fdeebcc6 S	464	case HV_STATUS_INSUFFICIENT_BUFFERS:
fdeebcc6 S	465	ret = -ENOMEM;
fdeebcc6 S	466	break;
fdeebcc6 S	467	case HV_STATUS_SUCCESS:
5289d3d1	468	return ret;
fdeebcc6 S	469	default:
	470	pr_err("hv_post_msg() failed; error code:%d\n", ret);
	471	return -EINVAL;
	472	}
	473
5289d3d1	474	retries++;
8de0d7e9 S	475	udelay(usec);
	476	if (usec < 2048)
	477	usec *= 2;
5289d3d1 S	478	}
5289d3d1 S	479	return ret;
3e7ee490 HJ	480	}
3e7ee490 HJ	481
3e189519	482	/*
c6977677	483	* vmbus_set_event - Send an event notification to the parent
fd8b85ea	484	*/
1b807e10	485	void vmbus_set_event(struct vmbus_channel *channel)
3e7ee490	486	{
21c3bef5	487	u32 child_relid = channel->offermsg.child_relid;
7c369f40	488
3be77774 S	489	if (!channel->is_dedicated_interrupt) {
	490	/* Each u32 represents 32 channels */
	491	sync_set_bit(child_relid & 31,
	492	(unsigned long *)vmbus_connection.send_int_page +
	493	(child_relid >> 5));
	494	}
	495
1b807e10	496	hv_do_hypercall(HVCALL_SIGNAL_EVENT, channel->sig_event, NULL);
3e7ee490	497	}
5cc47247	498	EXPORT_SYMBOL_GPL(vmbus_set_event);