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 "hyperv_vmbus.h"
38 struct vmbus_connection vmbus_connection = {
39 .conn_state = DISCONNECTED,
40 .next_gpadl_handle = ATOMIC_INIT(0xE1E10),
44 * Negotiated protocol version with the host.
46 __u32 vmbus_proto_version;
47 EXPORT_SYMBOL_GPL(vmbus_proto_version);
49 static __u32 vmbus_get_next_version(__u32 current_version)
51 switch (current_version) {
53 return VERSION_WS2008;
58 case (VERSION_WS2008):
64 static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
68 struct vmbus_channel_initiate_contact *msg;
72 init_completion(&msginfo->waitevent);
74 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
76 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
77 msg->vmbus_version_requested = version;
78 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
79 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages);
80 msg->monitor_page2 = virt_to_phys(
81 (void *)((unsigned long)vmbus_connection.monitor_pages +
85 * Add to list before we send the request since we may
86 * receive the response before returning from this routine
88 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
89 list_add_tail(&msginfo->msglistentry,
90 &vmbus_connection.chn_msg_list);
92 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
94 ret = vmbus_post_msg(msg,
95 sizeof(struct vmbus_channel_initiate_contact));
97 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
98 list_del(&msginfo->msglistentry);
99 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
104 /* Wait for the connection response */
105 t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
107 spin_lock_irqsave(&vmbus_connection.channelmsg_lock,
109 list_del(&msginfo->msglistentry);
110 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
115 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
116 list_del(&msginfo->msglistentry);
117 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
119 /* Check if successful */
120 if (msginfo->response.version_response.version_supported) {
121 vmbus_connection.conn_state = CONNECTED;
123 pr_err("Unable to connect, "
124 "Version %d not supported by Hyper-V\n",
126 return -ECONNREFUSED;
133 * vmbus_connect - Sends a connect request on the partition service connection
135 int vmbus_connect(void)
138 struct vmbus_channel_msginfo *msginfo = NULL;
141 /* Initialize the vmbus connection */
142 vmbus_connection.conn_state = CONNECTING;
143 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
144 if (!vmbus_connection.work_queue) {
149 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
150 spin_lock_init(&vmbus_connection.channelmsg_lock);
152 INIT_LIST_HEAD(&vmbus_connection.chn_list);
153 spin_lock_init(&vmbus_connection.channel_lock);
156 * Setup the vmbus event connection for channel interrupt
159 vmbus_connection.int_page =
160 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
161 if (vmbus_connection.int_page == NULL) {
166 vmbus_connection.recv_int_page = vmbus_connection.int_page;
167 vmbus_connection.send_int_page =
168 (void *)((unsigned long)vmbus_connection.int_page +
172 * Setup the monitor notification facility. The 1st page for
173 * parent->child and the 2nd page for child->parent
175 vmbus_connection.monitor_pages =
176 (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 1);
177 if (vmbus_connection.monitor_pages == NULL) {
182 msginfo = kzalloc(sizeof(*msginfo) +
183 sizeof(struct vmbus_channel_initiate_contact),
185 if (msginfo == NULL) {
191 * Negotiate a compatible VMBUS version number with the
192 * host. We start with the highest number we can support
193 * and work our way down until we negotiate a compatible
197 version = VERSION_WS2008;
200 ret = vmbus_negotiate_version(msginfo, version);
204 version = vmbus_get_next_version(version);
205 } while (version != VERSION_INVAL);
207 if (version == VERSION_INVAL)
210 vmbus_proto_version = version;
211 pr_info("Negotiated host information %d\n", version);
216 vmbus_connection.conn_state = DISCONNECTED;
218 if (vmbus_connection.work_queue)
219 destroy_workqueue(vmbus_connection.work_queue);
221 if (vmbus_connection.int_page) {
222 free_pages((unsigned long)vmbus_connection.int_page, 0);
223 vmbus_connection.int_page = NULL;
226 if (vmbus_connection.monitor_pages) {
227 free_pages((unsigned long)vmbus_connection.monitor_pages, 1);
228 vmbus_connection.monitor_pages = NULL;
238 * relid2channel - Get the channel object given its
239 * child relative id (ie channel id)
241 struct vmbus_channel *relid2channel(u32 relid)
243 struct vmbus_channel *channel;
244 struct vmbus_channel *found_channel = NULL;
247 spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
248 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
249 if (channel->offermsg.child_relid == relid) {
250 found_channel = channel;
254 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
256 return found_channel;
260 * process_chn_event - Process a channel event notification
262 static void process_chn_event(u32 relid)
264 struct vmbus_channel *channel;
271 * Find the channel based on this relid and invokes the
272 * channel callback to process the event
274 channel = relid2channel(relid);
277 pr_err("channel not found for relid - %u\n", relid);
282 * A channel once created is persistent even when there
283 * is no driver handling the device. An unloading driver
284 * sets the onchannel_callback to NULL under the
285 * protection of the channel inbound_lock. Thus, checking
286 * and invoking the driver specific callback takes care of
287 * orderly unloading of the driver.
290 spin_lock_irqsave(&channel->inbound_lock, flags);
291 if (channel->onchannel_callback != NULL) {
292 arg = channel->channel_callback_context;
293 read_state = channel->batched_reading;
295 * This callback reads the messages sent by the host.
296 * We can optimize host to guest signaling by ensuring:
297 * 1. While reading the channel, we disable interrupts from
299 * 2. Ensure that we process all posted messages from the host
300 * before returning from this callback.
301 * 3. Once we return, enable signaling from the host. Once this
302 * state is set we check to see if additional packets are
303 * available to read. In this case we repeat the process.
307 hv_begin_read(&channel->inbound);
308 channel->onchannel_callback(arg);
309 bytes_to_read = hv_end_read(&channel->inbound);
310 } while (read_state && (bytes_to_read != 0));
312 pr_err("no channel callback for relid - %u\n", relid);
315 spin_unlock_irqrestore(&channel->inbound_lock, flags);
319 * vmbus_on_event - Handler for events
321 void vmbus_on_event(unsigned long data)
324 u32 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
327 u32 *recv_int_page = vmbus_connection.recv_int_page;
332 for (dword = 0; dword < maxdword; dword++) {
333 if (!recv_int_page[dword])
335 for (bit = 0; bit < 32; bit++) {
336 if (sync_test_and_clear_bit(bit,
337 (unsigned long *)&recv_int_page[dword])) {
338 relid = (dword << 5) + bit;
342 * Special case - vmbus
343 * channel protocol msg
347 process_chn_event(relid);
354 * vmbus_post_msg - Send a msg on the vmbus's message connection
356 int vmbus_post_msg(void *buffer, size_t buflen)
358 union hv_connection_id conn_id;
363 conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
366 * hv_post_message() can have transient failures because of
367 * insufficient resources. Retry the operation a couple of
368 * times before giving up.
370 while (retries < 3) {
371 ret = hv_post_message(conn_id, 1, buffer, buflen);
372 if (ret != HV_STATUS_INSUFFICIENT_BUFFERS)
381 * vmbus_set_event - Send an event notification to the parent
383 int vmbus_set_event(struct vmbus_channel *channel)
385 u32 child_relid = channel->offermsg.child_relid;
387 if (!channel->is_dedicated_interrupt) {
388 /* Each u32 represents 32 channels */
389 sync_set_bit(child_relid & 31,
390 (unsigned long *)vmbus_connection.send_int_page +
394 return hv_signal_event(channel->sig_event);