1 // SPDX-License-Identifier: GPL-2.0-only
4 * Copyright (c) 2009, Microsoft Corporation.
7 * Haiyang Zhang <haiyangz@microsoft.com>
8 * Hank Janssen <hjanssen@microsoft.com>
10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12 #include <linux/kernel.h>
13 #include <linux/sched.h>
14 #include <linux/wait.h>
15 #include <linux/delay.h>
17 #include <linux/slab.h>
18 #include <linux/vmalloc.h>
19 #include <linux/hyperv.h>
20 #include <linux/export.h>
21 #include <asm/mshyperv.h>
23 #include "hyperv_vmbus.h"
26 struct vmbus_connection vmbus_connection = {
27 .conn_state = DISCONNECTED,
28 .next_gpadl_handle = ATOMIC_INIT(0xE1E10),
30 .ready_for_suspend_event= COMPLETION_INITIALIZER(
31 vmbus_connection.ready_for_suspend_event),
32 .ready_for_resume_event = COMPLETION_INITIALIZER(
33 vmbus_connection.ready_for_resume_event),
35 EXPORT_SYMBOL_GPL(vmbus_connection);
38 * Negotiated protocol version with the host.
40 __u32 vmbus_proto_version;
41 EXPORT_SYMBOL_GPL(vmbus_proto_version);
43 static __u32 vmbus_get_next_version(__u32 current_version)
45 switch (current_version) {
47 return VERSION_WS2008;
52 case (VERSION_WIN8_1):
56 return VERSION_WIN8_1;
58 case (VERSION_WIN10_V5):
61 case (VERSION_WS2008):
67 int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)
70 struct vmbus_channel_initiate_contact *msg;
73 init_completion(&msginfo->waitevent);
75 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
77 memset(msg, 0, sizeof(*msg));
78 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
79 msg->vmbus_version_requested = version;
82 * VMBus protocol 5.0 (VERSION_WIN10_V5) requires that we must use
83 * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate Contact Message,
84 * and for subsequent messages, we must use the Message Connection ID
85 * field in the host-returned Version Response Message. And, with
86 * VERSION_WIN10_V5, we don't use msg->interrupt_page, but we tell
87 * the host explicitly that we still use VMBUS_MESSAGE_SINT(2) for
90 * On old hosts, we should always use VMBUS_MESSAGE_CONNECTION_ID (1).
92 if (version >= VERSION_WIN10_V5) {
93 msg->msg_sint = VMBUS_MESSAGE_SINT;
94 vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID_4;
96 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
97 vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID;
100 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
101 msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
102 msg->target_vcpu = hv_cpu_number_to_vp_number(VMBUS_CONNECT_CPU);
105 * Add to list before we send the request since we may
106 * receive the response before returning from this routine
108 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
109 list_add_tail(&msginfo->msglistentry,
110 &vmbus_connection.chn_msg_list);
112 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
114 ret = vmbus_post_msg(msg,
115 sizeof(struct vmbus_channel_initiate_contact),
118 trace_vmbus_negotiate_version(msg, ret);
121 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
122 list_del(&msginfo->msglistentry);
123 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
128 /* Wait for the connection response */
129 wait_for_completion(&msginfo->waitevent);
131 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
132 list_del(&msginfo->msglistentry);
133 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
135 /* Check if successful */
136 if (msginfo->response.version_response.version_supported) {
137 vmbus_connection.conn_state = CONNECTED;
139 if (version >= VERSION_WIN10_V5)
140 vmbus_connection.msg_conn_id =
141 msginfo->response.version_response.msg_conn_id;
143 return -ECONNREFUSED;
150 * vmbus_connect - Sends a connect request on the partition service connection
152 int vmbus_connect(void)
155 struct vmbus_channel_msginfo *msginfo = NULL;
158 /* Initialize the vmbus connection */
159 vmbus_connection.conn_state = CONNECTING;
160 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
161 if (!vmbus_connection.work_queue) {
166 vmbus_connection.handle_primary_chan_wq =
167 create_workqueue("hv_pri_chan");
168 if (!vmbus_connection.handle_primary_chan_wq) {
173 vmbus_connection.handle_sub_chan_wq =
174 create_workqueue("hv_sub_chan");
175 if (!vmbus_connection.handle_sub_chan_wq) {
180 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
181 spin_lock_init(&vmbus_connection.channelmsg_lock);
183 INIT_LIST_HEAD(&vmbus_connection.chn_list);
184 mutex_init(&vmbus_connection.channel_mutex);
187 * Setup the vmbus event connection for channel interrupt
190 vmbus_connection.int_page =
191 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
192 if (vmbus_connection.int_page == NULL) {
197 vmbus_connection.recv_int_page = vmbus_connection.int_page;
198 vmbus_connection.send_int_page =
199 (void *)((unsigned long)vmbus_connection.int_page +
203 * Setup the monitor notification facility. The 1st page for
204 * parent->child and the 2nd page for child->parent
206 vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
207 vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
208 if ((vmbus_connection.monitor_pages[0] == NULL) ||
209 (vmbus_connection.monitor_pages[1] == NULL)) {
214 msginfo = kzalloc(sizeof(*msginfo) +
215 sizeof(struct vmbus_channel_initiate_contact),
217 if (msginfo == NULL) {
223 * Negotiate a compatible VMBUS version number with the
224 * host. We start with the highest number we can support
225 * and work our way down until we negotiate a compatible
229 version = VERSION_CURRENT;
232 ret = vmbus_negotiate_version(msginfo, version);
233 if (ret == -ETIMEDOUT)
236 if (vmbus_connection.conn_state == CONNECTED)
239 version = vmbus_get_next_version(version);
240 } while (version != VERSION_INVAL);
242 if (version == VERSION_INVAL)
245 vmbus_proto_version = version;
246 pr_info("Vmbus version:%d.%d\n",
247 version >> 16, version & 0xFFFF);
253 pr_err("Unable to connect to host\n");
255 vmbus_connection.conn_state = DISCONNECTED;
263 void vmbus_disconnect(void)
266 * First send the unload request to the host.
268 vmbus_initiate_unload(false);
270 if (vmbus_connection.handle_sub_chan_wq)
271 destroy_workqueue(vmbus_connection.handle_sub_chan_wq);
273 if (vmbus_connection.handle_primary_chan_wq)
274 destroy_workqueue(vmbus_connection.handle_primary_chan_wq);
276 if (vmbus_connection.work_queue)
277 destroy_workqueue(vmbus_connection.work_queue);
279 if (vmbus_connection.int_page) {
280 free_pages((unsigned long)vmbus_connection.int_page, 0);
281 vmbus_connection.int_page = NULL;
284 free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0);
285 free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0);
286 vmbus_connection.monitor_pages[0] = NULL;
287 vmbus_connection.monitor_pages[1] = NULL;
291 * relid2channel - Get the channel object given its
292 * child relative id (ie channel id)
294 struct vmbus_channel *relid2channel(u32 relid)
296 struct vmbus_channel *channel;
297 struct vmbus_channel *found_channel = NULL;
298 struct list_head *cur, *tmp;
299 struct vmbus_channel *cur_sc;
301 BUG_ON(!mutex_is_locked(&vmbus_connection.channel_mutex));
303 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
304 if (channel->offermsg.child_relid == relid) {
305 found_channel = channel;
307 } else if (!list_empty(&channel->sc_list)) {
309 * Deal with sub-channels.
311 list_for_each_safe(cur, tmp, &channel->sc_list) {
312 cur_sc = list_entry(cur, struct vmbus_channel,
314 if (cur_sc->offermsg.child_relid == relid) {
315 found_channel = cur_sc;
322 return found_channel;
326 * vmbus_on_event - Process a channel event notification
328 * For batched channels (default) optimize host to guest signaling
330 * 1. While reading the channel, we disable interrupts from host.
331 * 2. Ensure that we process all posted messages from the host
332 * before returning from this callback.
333 * 3. Once we return, enable signaling from the host. Once this
334 * state is set we check to see if additional packets are
335 * available to read. In this case we repeat the process.
336 * If this tasklet has been running for a long time
337 * then reschedule ourselves.
339 void vmbus_on_event(unsigned long data)
341 struct vmbus_channel *channel = (void *) data;
342 unsigned long time_limit = jiffies + 2;
344 trace_vmbus_on_event(channel);
347 void (*callback_fn)(void *);
349 /* A channel once created is persistent even when
350 * there is no driver handling the device. An
351 * unloading driver sets the onchannel_callback to NULL.
353 callback_fn = READ_ONCE(channel->onchannel_callback);
354 if (unlikely(callback_fn == NULL))
357 (*callback_fn)(channel->channel_callback_context);
359 if (channel->callback_mode != HV_CALL_BATCHED)
362 if (likely(hv_end_read(&channel->inbound) == 0))
365 hv_begin_read(&channel->inbound);
366 } while (likely(time_before(jiffies, time_limit)));
368 /* The time limit (2 jiffies) has been reached */
369 tasklet_schedule(&channel->callback_event);
373 * vmbus_post_msg - Send a msg on the vmbus's message connection
375 int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
377 struct vmbus_channel_message_header *hdr;
378 union hv_connection_id conn_id;
384 conn_id.u.id = vmbus_connection.msg_conn_id;
387 * hv_post_message() can have transient failures because of
388 * insufficient resources. Retry the operation a couple of
389 * times before giving up.
391 while (retries < 100) {
392 ret = hv_post_message(conn_id, 1, buffer, buflen);
395 case HV_STATUS_INVALID_CONNECTION_ID:
397 * See vmbus_negotiate_version(): VMBus protocol 5.0
398 * requires that we must use
399 * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate
400 * Contact message, but on old hosts that only
401 * support VMBus protocol 4.0 or lower, here we get
402 * HV_STATUS_INVALID_CONNECTION_ID and we should
403 * return an error immediately without retrying.
406 if (hdr->msgtype == CHANNELMSG_INITIATE_CONTACT)
409 * We could get this if we send messages too
414 case HV_STATUS_INSUFFICIENT_MEMORY:
415 case HV_STATUS_INSUFFICIENT_BUFFERS:
418 case HV_STATUS_SUCCESS:
421 pr_err("hv_post_msg() failed; error code:%d\n", ret);
426 if (can_sleep && usec > 1000)
428 else if (usec < MAX_UDELAY_MS * 1000)
440 * vmbus_set_event - Send an event notification to the parent
442 void vmbus_set_event(struct vmbus_channel *channel)
444 u32 child_relid = channel->offermsg.child_relid;
446 if (!channel->is_dedicated_interrupt)
447 vmbus_send_interrupt(child_relid);
449 ++channel->sig_events;
451 hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
453 EXPORT_SYMBOL_GPL(vmbus_set_event);