3 * Copyright (c) 2009, Microsoft Corporation.
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.
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
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.
19 * Haiyang Zhang <haiyangz@microsoft.com>
20 * Hank Janssen <hjanssen@microsoft.com>
23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
25 #include <linux/kernel.h>
26 #include <linux/sched.h>
27 #include <linux/wait.h>
28 #include <linux/delay.h>
30 #include <linux/slab.h>
31 #include <linux/vmalloc.h>
32 #include <linux/hyperv.h>
33 #include <linux/export.h>
34 #include <asm/hyperv.h>
35 #include <asm/mshyperv.h>
37 #include "hyperv_vmbus.h"
40 struct vmbus_connection vmbus_connection = {
41 .conn_state = DISCONNECTED,
42 .next_gpadl_handle = ATOMIC_INIT(0xE1E10),
44 EXPORT_SYMBOL_GPL(vmbus_connection);
47 * Negotiated protocol version with the host.
49 __u32 vmbus_proto_version;
50 EXPORT_SYMBOL_GPL(vmbus_proto_version);
52 static __u32 vmbus_get_next_version(__u32 current_version)
54 switch (current_version) {
56 return VERSION_WS2008;
61 case (VERSION_WIN8_1):
65 return VERSION_WIN8_1;
67 case (VERSION_WS2008):
73 static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
77 struct vmbus_channel_initiate_contact *msg;
80 init_completion(&msginfo->waitevent);
82 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
84 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
85 msg->vmbus_version_requested = version;
86 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
87 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
88 msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
90 * We want all channel messages to be delivered on CPU 0.
91 * This has been the behavior pre-win8. This is not
92 * perf issue and having all channel messages delivered on CPU 0
94 * For post win8 hosts, we support receiving channel messagges on
95 * all the CPUs. This is needed for kexec to work correctly where
96 * the CPU attempting to connect may not be CPU 0.
98 if (version >= VERSION_WIN8_1) {
100 hv_cpu_number_to_vp_number(smp_processor_id());
101 vmbus_connection.connect_cpu = smp_processor_id();
103 msg->target_vcpu = 0;
104 vmbus_connection.connect_cpu = 0;
108 * Add to list before we send the request since we may
109 * receive the response before returning from this routine
111 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
112 list_add_tail(&msginfo->msglistentry,
113 &vmbus_connection.chn_msg_list);
115 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
117 ret = vmbus_post_msg(msg,
118 sizeof(struct vmbus_channel_initiate_contact),
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 return -ECONNREFUSED;
146 * vmbus_connect - Sends a connect request on the partition service connection
148 int vmbus_connect(void)
151 struct vmbus_channel_msginfo *msginfo = NULL;
154 /* Initialize the vmbus connection */
155 vmbus_connection.conn_state = CONNECTING;
156 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
157 if (!vmbus_connection.work_queue) {
162 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
163 spin_lock_init(&vmbus_connection.channelmsg_lock);
165 INIT_LIST_HEAD(&vmbus_connection.chn_list);
166 mutex_init(&vmbus_connection.channel_mutex);
169 * Setup the vmbus event connection for channel interrupt
172 vmbus_connection.int_page =
173 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
174 if (vmbus_connection.int_page == NULL) {
179 vmbus_connection.recv_int_page = vmbus_connection.int_page;
180 vmbus_connection.send_int_page =
181 (void *)((unsigned long)vmbus_connection.int_page +
185 * Setup the monitor notification facility. The 1st page for
186 * parent->child and the 2nd page for child->parent
188 vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
189 vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
190 if ((vmbus_connection.monitor_pages[0] == NULL) ||
191 (vmbus_connection.monitor_pages[1] == NULL)) {
196 msginfo = kzalloc(sizeof(*msginfo) +
197 sizeof(struct vmbus_channel_initiate_contact),
199 if (msginfo == NULL) {
205 * Negotiate a compatible VMBUS version number with the
206 * host. We start with the highest number we can support
207 * and work our way down until we negotiate a compatible
211 version = VERSION_CURRENT;
214 ret = vmbus_negotiate_version(msginfo, version);
215 if (ret == -ETIMEDOUT)
218 if (vmbus_connection.conn_state == CONNECTED)
221 version = vmbus_get_next_version(version);
222 } while (version != VERSION_INVAL);
224 if (version == VERSION_INVAL)
227 vmbus_proto_version = version;
228 pr_info("Vmbus version:%d.%d\n",
229 version >> 16, version & 0xFFFF);
235 pr_err("Unable to connect to host\n");
237 vmbus_connection.conn_state = DISCONNECTED;
245 void vmbus_disconnect(void)
248 * First send the unload request to the host.
250 vmbus_initiate_unload(false);
252 if (vmbus_connection.work_queue) {
253 drain_workqueue(vmbus_connection.work_queue);
254 destroy_workqueue(vmbus_connection.work_queue);
257 if (vmbus_connection.int_page) {
258 free_pages((unsigned long)vmbus_connection.int_page, 0);
259 vmbus_connection.int_page = NULL;
262 free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0);
263 free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0);
264 vmbus_connection.monitor_pages[0] = NULL;
265 vmbus_connection.monitor_pages[1] = NULL;
269 * relid2channel - Get the channel object given its
270 * child relative id (ie channel id)
272 struct vmbus_channel *relid2channel(u32 relid)
274 struct vmbus_channel *channel;
275 struct vmbus_channel *found_channel = NULL;
276 struct list_head *cur, *tmp;
277 struct vmbus_channel *cur_sc;
279 BUG_ON(!mutex_is_locked(&vmbus_connection.channel_mutex));
281 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
282 if (channel->offermsg.child_relid == relid) {
283 found_channel = channel;
285 } else if (!list_empty(&channel->sc_list)) {
287 * Deal with sub-channels.
289 list_for_each_safe(cur, tmp, &channel->sc_list) {
290 cur_sc = list_entry(cur, struct vmbus_channel,
292 if (cur_sc->offermsg.child_relid == relid) {
293 found_channel = cur_sc;
300 return found_channel;
304 * vmbus_on_event - Process a channel event notification
306 * For batched channels (default) optimize host to guest signaling
308 * 1. While reading the channel, we disable interrupts from host.
309 * 2. Ensure that we process all posted messages from the host
310 * before returning from this callback.
311 * 3. Once we return, enable signaling from the host. Once this
312 * state is set we check to see if additional packets are
313 * available to read. In this case we repeat the process.
314 * If this tasklet has been running for a long time
315 * then reschedule ourselves.
317 void vmbus_on_event(unsigned long data)
319 struct vmbus_channel *channel = (void *) data;
320 unsigned long time_limit = jiffies + 2;
323 void (*callback_fn)(void *);
325 /* A channel once created is persistent even when
326 * there is no driver handling the device. An
327 * unloading driver sets the onchannel_callback to NULL.
329 callback_fn = READ_ONCE(channel->onchannel_callback);
330 if (unlikely(callback_fn == NULL))
333 (*callback_fn)(channel->channel_callback_context);
335 if (channel->callback_mode != HV_CALL_BATCHED)
338 if (likely(hv_end_read(&channel->inbound) == 0))
341 hv_begin_read(&channel->inbound);
342 } while (likely(time_before(jiffies, time_limit)));
344 /* The time limit (2 jiffies) has been reached */
345 tasklet_schedule(&channel->callback_event);
349 * vmbus_post_msg - Send a msg on the vmbus's message connection
351 int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
353 union hv_connection_id conn_id;
359 conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
362 * hv_post_message() can have transient failures because of
363 * insufficient resources. Retry the operation a couple of
364 * times before giving up.
366 while (retries < 100) {
367 ret = hv_post_message(conn_id, 1, buffer, buflen);
370 case HV_STATUS_INVALID_CONNECTION_ID:
372 * We could get this if we send messages too
377 case HV_STATUS_INSUFFICIENT_MEMORY:
378 case HV_STATUS_INSUFFICIENT_BUFFERS:
381 case HV_STATUS_SUCCESS:
384 pr_err("hv_post_msg() failed; error code:%d\n", ret);
389 if (can_sleep && usec > 1000)
391 else if (usec < MAX_UDELAY_MS * 1000)
403 * vmbus_set_event - Send an event notification to the parent
405 void vmbus_set_event(struct vmbus_channel *channel)
407 u32 child_relid = channel->offermsg.child_relid;
409 if (!channel->is_dedicated_interrupt)
410 vmbus_send_interrupt(child_relid);
412 hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
414 EXPORT_SYMBOL_GPL(vmbus_set_event);