[mirror_ubuntu-bionic-kernel.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),
};
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;
	}
}

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	41	};
95096f2f	42	EXPORT_SYMBOL_GPL(vmbus_connection);
3e7ee490	43
37f7278b S	44	/*
	45	* Negotiated protocol version with the host.
	46	*/
	47	__u32 vmbus_proto_version;
	48	EXPORT_SYMBOL_GPL(vmbus_proto_version);
	49
610071c3 S	50	static __u32 vmbus_get_next_version(__u32 current_version)
	51	{
	52	switch (current_version) {
	53	case (VERSION_WIN7):
	54	return VERSION_WS2008;
	55
	56	case (VERSION_WIN8):
	57	return VERSION_WIN7;
	58
03367ef5 S	59	case (VERSION_WIN8_1):
	60	return VERSION_WIN8;
	61
6c4e5f9c KM	62	case (VERSION_WIN10):
	63	return VERSION_WIN8_1;
	64
610071c3 S	65	case (VERSION_WS2008):
	66	default:
	67	return VERSION_INVAL;
	68	}
	69	}
	70
	71	static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
	72	__u32 version)
	73	{
	74	int ret = 0;
	75	struct vmbus_channel_initiate_contact *msg;
	76	unsigned long flags;
610071c3 S	77
	78	init_completion(&msginfo->waitevent);
	79
	80	msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
	81
	82	msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
	83	msg->vmbus_version_requested = version;
	84	msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
8681db44 GKH	85	msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
8681db44 GKH	86	msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
b282e4c0 S	87	/*
	88	* We want all channel messages to be delivered on CPU 0.
	89	* This has been the behavior pre-win8. This is not
	90	* perf issue and having all channel messages delivered on CPU 0
	91	* would be ok.
72686447 AN	92	* For post win8 hosts, we support receiving channel messagges on
	93	* all the CPUs. This is needed for kexec to work correctly where
	94	* the CPU attempting to connect may not be CPU 0.
b282e4c0	95	*/
72686447 AN	96	if (version >= VERSION_WIN8_1) {
	97	msg->target_vcpu = hv_context.vp_index[get_cpu()];
	98	put_cpu();
	99	} else {
	100	msg->target_vcpu = 0;
	101	}
610071c3 S	102
	103	/*
	104	* Add to list before we send the request since we may
	105	* receive the response before returning from this routine
	106	*/
	107	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
	108	list_add_tail(&msginfo->msglistentry,
	109	&vmbus_connection.chn_msg_list);
	110
	111	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
	112
	113	ret = vmbus_post_msg(msg,
	114	sizeof(struct vmbus_channel_initiate_contact));
	115	if (ret != 0) {
	116	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
	117	list_del(&msginfo->msglistentry);
	118	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
	119	flags);
	120	return ret;
	121	}
	122
	123	/* Wait for the connection response */
269f9794	124	wait_for_completion(&msginfo->waitevent);
610071c3 S	125
	126	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
	127	list_del(&msginfo->msglistentry);
	128	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
	129
	130	/* Check if successful */
	131	if (msginfo->response.version_response.version_supported) {
	132	vmbus_connection.conn_state = CONNECTED;
	133	} else {
610071c3 S	134	return -ECONNREFUSED;
	135	}
	136
	137	return ret;
	138	}
	139
3e189519	140	/*
c6977677	141	* vmbus_connect - Sends a connect request on the partition service connection
fd8b85ea	142	*/
c6977677	143	int vmbus_connect(void)
3e7ee490	144	{
fd8b85ea	145	int ret = 0;
15b2f647	146	struct vmbus_channel_msginfo *msginfo = NULL;
610071c3	147	__u32 version;
3e7ee490	148
454f18a9	149	/* Initialize the vmbus connection */
da9fcb72 HZ	150	vmbus_connection.conn_state = CONNECTING;
	151	vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
	152	if (!vmbus_connection.work_queue) {
3a7546d9	153	ret = -ENOMEM;
b0043863	154	goto cleanup;
de65a384	155	}
3e7ee490	156
da9fcb72	157	INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
15b2f647	158	spin_lock_init(&vmbus_connection.channelmsg_lock);
3e7ee490	159
da9fcb72	160	INIT_LIST_HEAD(&vmbus_connection.chn_list);
d6f591e3	161	mutex_init(&vmbus_connection.channel_mutex);
3e7ee490	162
454f18a9 BP	163	/*
	164	* Setup the vmbus event connection for channel interrupt
	165	* abstraction stuff
	166	*/
df3493e0 S	167	vmbus_connection.int_page =
df3493e0 S	168	(void *)__get_free_pages(GFP_KERNEL\|__GFP_ZERO, 0);
da9fcb72	169	if (vmbus_connection.int_page == NULL) {
3a7546d9	170	ret = -ENOMEM;
b0043863	171	goto cleanup;
3e7ee490 HJ	172	}
3e7ee490 HJ	173
da9fcb72 HZ	174	vmbus_connection.recv_int_page = vmbus_connection.int_page;
	175	vmbus_connection.send_int_page =
	176	(void *)((unsigned long)vmbus_connection.int_page +
fd8b85ea	177	(PAGE_SIZE >> 1));
3e7ee490	178
fd8b85ea GKH	179	/*
	180	* Setup the monitor notification facility. The 1st page for
	181	* parent->child and the 2nd page for child->parent
454f18a9	182	*/
8681db44 GKH	183	vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL\|__GFP_ZERO), 0);
	184	vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL\|__GFP_ZERO), 0);
	185	if ((vmbus_connection.monitor_pages[0] == NULL) \|\|
	186	(vmbus_connection.monitor_pages[1] == NULL)) {
3a7546d9	187	ret = -ENOMEM;
b0043863	188	goto cleanup;
3e7ee490 HJ	189	}
3e7ee490 HJ	190
15b2f647	191	msginfo = kzalloc(sizeof(*msginfo) +
fd8b85ea GKH	192	sizeof(struct vmbus_channel_initiate_contact),
fd8b85ea GKH	193	GFP_KERNEL);
15b2f647	194	if (msginfo == NULL) {
8cad0af9	195	ret = -ENOMEM;
b0043863	196	goto cleanup;
3e7ee490 HJ	197	}
3e7ee490 HJ	198
454f18a9	199	/*
610071c3 S	200	* Negotiate a compatible VMBUS version number with the
	201	* host. We start with the highest number we can support
	202	* and work our way down until we negotiate a compatible
	203	* version.
454f18a9	204	*/
3e7ee490	205
2a5c43a8	206	version = VERSION_CURRENT;
3e7ee490	207
610071c3 S	208	do {
610071c3 S	209	ret = vmbus_negotiate_version(msginfo, version);
8bbf9f44	210	if (ret == -ETIMEDOUT)
666b9adc S	211	goto cleanup;
	212
	213	if (vmbus_connection.conn_state == CONNECTED)
610071c3	214	break;
3e7ee490	215
610071c3 S	216	version = vmbus_get_next_version(version);
610071c3 S	217	} while (version != VERSION_INVAL);
3e7ee490	218
610071c3	219	if (version == VERSION_INVAL)
b0043863	220	goto cleanup;
3e7ee490	221
37f7278b	222	vmbus_proto_version = version;
3bacaf0c S	223	pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d; Vmbus version:%d.%d\n",
	224	host_info_eax, host_info_ebx >> 16,
	225	host_info_ebx & 0xFFFF, host_info_ecx,
	226	host_info_edx >> 24, host_info_edx & 0xFFFFFF,
	227	version >> 16, version & 0xFFFF);
	228
15b2f647	229	kfree(msginfo);
3e7ee490 HJ	230	return 0;
3e7ee490 HJ	231
b0043863	232	cleanup:
3bacaf0c	233	pr_err("Unable to connect to host\n");
09a19628	234
da9fcb72	235	vmbus_connection.conn_state = DISCONNECTED;
09a19628 VK	236	vmbus_disconnect();
	237
	238	kfree(msginfo);
	239
	240	return ret;
	241	}
3e7ee490	242
09a19628 VK	243	void vmbus_disconnect(void)
09a19628 VK	244	{
2db84eff S	245	/*
	246	* First send the unload request to the host.
	247	*/
75ff3a8a	248	vmbus_initiate_unload(false);
2db84eff	249
09a19628 VK	250	if (vmbus_connection.work_queue) {
09a19628 VK	251	drain_workqueue(vmbus_connection.work_queue);
da9fcb72	252	destroy_workqueue(vmbus_connection.work_queue);
09a19628	253	}
3e7ee490	254
da9fcb72	255	if (vmbus_connection.int_page) {
df3493e0	256	free_pages((unsigned long)vmbus_connection.int_page, 0);
da9fcb72	257	vmbus_connection.int_page = NULL;
3e7ee490 HJ	258	}
3e7ee490 HJ	259
a100d88d RK	260	free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0);
a100d88d RK	261	free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0);
8681db44 GKH	262	vmbus_connection.monitor_pages[0] = NULL;
8681db44 GKH	263	vmbus_connection.monitor_pages[1] = NULL;
3e7ee490 HJ	264	}
3e7ee490 HJ	265
3a28fa35 S	266	/*
	267	* Map the given relid to the corresponding channel based on the
	268	* per-cpu list of channels that have been affinitized to this CPU.
	269	* This will be used in the channel callback path as we can do this
	270	* mapping in a lock-free fashion.
	271	*/
	272	static struct vmbus_channel *pcpu_relid2channel(u32 relid)
	273	{
	274	struct vmbus_channel *channel;
	275	struct vmbus_channel *found_channel = NULL;
	276	int cpu = smp_processor_id();
	277	struct list_head *pcpu_head = &hv_context.percpu_list[cpu];
	278
	279	list_for_each_entry(channel, pcpu_head, percpu_list) {
	280	if (channel->offermsg.child_relid == relid) {
	281	found_channel = channel;
	282	break;
	283	}
	284	}
	285
	286	return found_channel;
	287	}
3e7ee490	288
3e189519	289	/*
c6977677 HZ	290	* relid2channel - Get the channel object given its
c6977677 HZ	291	* child relative id (ie channel id)
fd8b85ea	292	*/
d43e2fe7	293	struct vmbus_channel *relid2channel(u32 relid)
3e7ee490	294	{
aded7165	295	struct vmbus_channel *channel;
15b2f647	296	struct vmbus_channel *found_channel = NULL;
e68d2971 S	297	struct list_head cur, tmp;
e68d2971 S	298	struct vmbus_channel *cur_sc;
3e7ee490	299
85d9aa70 DC	300	BUG_ON(!mutex_is_locked(&vmbus_connection.channel_mutex));
85d9aa70 DC	301
da9fcb72	302	list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
15b2f647 HZ	303	if (channel->offermsg.child_relid == relid) {
15b2f647 HZ	304	found_channel = channel;
3e7ee490	305	break;
e68d2971 S	306	} else if (!list_empty(&channel->sc_list)) {
	307	/*
	308	* Deal with sub-channels.
	309	*/
	310	list_for_each_safe(cur, tmp, &channel->sc_list) {
	311	cur_sc = list_entry(cur, struct vmbus_channel,
	312	sc_list);
	313	if (cur_sc->offermsg.child_relid == relid) {
	314	found_channel = cur_sc;
	315	break;
	316	}
	317	}
3e7ee490 HJ	318	}
3e7ee490 HJ	319	}
3e7ee490	320
15b2f647	321	return found_channel;
3e7ee490 HJ	322	}
3e7ee490 HJ	323
3e189519	324	/*
c6977677	325	* process_chn_event - Process a channel event notification
fd8b85ea	326	*/
35436487	327	static void process_chn_event(u32 relid)
3e7ee490	328	{
aded7165	329	struct vmbus_channel *channel;
f878f3d5 S	330	void *arg;
	331	bool read_state;
	332	u32 bytes_to_read;
3e7ee490	333
454f18a9 BP	334	/*
	335	* Find the channel based on this relid and invokes the
	336	* channel callback to process the event
	337	*/
3a28fa35	338	channel = pcpu_relid2channel(relid);
3e7ee490	339
37f492ce	340	if (!channel)
24326039	341	return;
24326039 S	342
	343	/*
	344	* A channel once created is persistent even when there
	345	* is no driver handling the device. An unloading driver
d3ba720d S	346	* sets the onchannel_callback to NULL on the same CPU
	347	* as where this interrupt is handled (in an interrupt context).
	348	* Thus, checking and invoking the driver specific callback takes
	349	* care of orderly unloading of the driver.
24326039 S	350	*/
24326039 S	351
f878f3d5 S	352	if (channel->onchannel_callback != NULL) {
	353	arg = channel->channel_callback_context;
	354	read_state = channel->batched_reading;
	355	/*
	356	* This callback reads the messages sent by the host.
	357	* We can optimize host to guest signaling by ensuring:
	358	* 1. While reading the channel, we disable interrupts from
	359	* host.
	360	* 2. Ensure that we process all posted messages from the host
	361	* before returning from this callback.
	362	* 3. Once we return, enable signaling from the host. Once this
	363	* state is set we check to see if additional packets are
	364	* available to read. In this case we repeat the process.
	365	*/
	366
	367	do {
affb1aff S	368	if (read_state)
affb1aff S	369	hv_begin_read(&channel->inbound);
f878f3d5	370	channel->onchannel_callback(arg);
affb1aff S	371	if (read_state)
	372	bytes_to_read = hv_end_read(&channel->inbound);
	373	else
	374	bytes_to_read = 0;
f878f3d5	375	} while (read_state && (bytes_to_read != 0));
f878f3d5	376	}
3e7ee490 HJ	377	}
3e7ee490 HJ	378
3e189519	379	/*
c6977677	380	* vmbus_on_event - Handler for events
fd8b85ea	381	*/
6de3d6aa	382	void vmbus_on_event(unsigned long data)
3e7ee490	383	{
35436487	384	u32 dword;
6552ecd7	385	u32 maxdword;
3e7ee490	386	int bit;
35436487	387	u32 relid;
6552ecd7 S	388	u32 *recv_int_page = NULL;
	389	void *page_addr;
	390	int cpu = smp_processor_id();
	391	union hv_synic_event_flags *event;
	392
6c4e5f9c	393	if (vmbus_proto_version < VERSION_WIN8) {
6552ecd7 S	394	maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
	395	recv_int_page = vmbus_connection.recv_int_page;
	396	} else {
	397	/*
	398	* When the host is win8 and beyond, the event page
	399	* can be directly checked to get the id of the channel
	400	* that has the interrupt pending.
	401	*/
	402	maxdword = HV_EVENT_FLAGS_DWORD_COUNT;
	403	page_addr = hv_context.synic_event_page[cpu];
	404	event = (union hv_synic_event_flags *)page_addr +
	405	VMBUS_MESSAGE_SINT;
	406	recv_int_page = event->flags32;
	407	}
	408
	409
3e7ee490	410
454f18a9	411	/* Check events */
242b45aa OH	412	if (!recv_int_page)
	413	return;
	414	for (dword = 0; dword < maxdword; dword++) {
	415	if (!recv_int_page[dword])
	416	continue;
	417	for (bit = 0; bit < 32; bit++) {
d9add43b S	418	if (sync_test_and_clear_bit(bit,
d9add43b S	419	(unsigned long *)&recv_int_page[dword])) {
242b45aa OH	420	relid = (dword << 5) + bit;
242b45aa OH	421
d9add43b	422	if (relid == 0)
6d81d330 S	423	/*
	424	* Special case - vmbus
	425	* channel protocol msg
	426	*/
242b45aa	427	continue;
d9add43b	428
35436487	429	process_chn_event(relid);
3e7ee490	430	}
242b45aa	431	}
3e7ee490	432	}
3e7ee490 HJ	433	}
3e7ee490 HJ	434
3e189519	435	/*
c6977677	436	* vmbus_post_msg - Send a msg on the vmbus's message connection
fd8b85ea	437	*/
c6977677	438	int vmbus_post_msg(void *buffer, size_t buflen)
3e7ee490	439	{
15b2f647	440	union hv_connection_id conn_id;
5289d3d1 S	441	int ret = 0;
5289d3d1 S	442	int retries = 0;
8de0d7e9	443	u32 usec = 1;
3e7ee490	444
15b2f647 HZ	445	conn_id.asu32 = 0;
15b2f647 HZ	446	conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
5289d3d1 S	447
	448	/*
	449	* hv_post_message() can have transient failures because of
	450	* insufficient resources. Retry the operation a couple of
	451	* times before giving up.
	452	*/
e1c0d82d	453	while (retries < 20) {
fdeebcc6 S	454	ret = hv_post_message(conn_id, 1, buffer, buflen);
	455
	456	switch (ret) {
89f9f679 DC	457	case HV_STATUS_INVALID_CONNECTION_ID:
	458	/*
	459	* We could get this if we send messages too
	460	* frequently.
	461	*/
	462	ret = -EAGAIN;
	463	break;
	464	case HV_STATUS_INSUFFICIENT_MEMORY:
fdeebcc6 S	465	case HV_STATUS_INSUFFICIENT_BUFFERS:
fdeebcc6 S	466	ret = -ENOMEM;
fdeebcc6 S	467	break;
fdeebcc6 S	468	case HV_STATUS_SUCCESS:
5289d3d1	469	return ret;
fdeebcc6 S	470	default:
	471	pr_err("hv_post_msg() failed; error code:%d\n", ret);
	472	return -EINVAL;
	473	}
	474
5289d3d1	475	retries++;
8de0d7e9 S	476	udelay(usec);
	477	if (usec < 2048)
	478	usec *= 2;
5289d3d1 S	479	}
5289d3d1 S	480	return ret;
3e7ee490 HJ	481	}
3e7ee490 HJ	482
3e189519	483	/*
c6977677	484	* vmbus_set_event - Send an event notification to the parent
fd8b85ea	485	*/
1b807e10	486	void vmbus_set_event(struct vmbus_channel *channel)
3e7ee490	487	{
21c3bef5	488	u32 child_relid = channel->offermsg.child_relid;
7c369f40	489
3be77774 S	490	if (!channel->is_dedicated_interrupt) {
	491	/* Each u32 represents 32 channels */
	492	sync_set_bit(child_relid & 31,
	493	(unsigned long *)vmbus_connection.send_int_page +
	494	(child_relid >> 5));
	495	}
	496
1b807e10	497	hv_do_hypercall(HVCALL_SIGNAL_EVENT, channel->sig_event, NULL);
3e7ee490	498	}
5cc47247	499	EXPORT_SYMBOL_GPL(vmbus_set_event);