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_WIN8_1):
61 case (VERSION_WS2008):
67 static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
71 struct vmbus_channel_initiate_contact *msg;
74 init_completion(&msginfo->waitevent);
76 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
78 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
79 msg->vmbus_version_requested = version;
80 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
81 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
82 msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
83 if (version == VERSION_WIN8_1) {
84 msg->target_vcpu = hv_context.vp_index[get_cpu()];
89 * Add to list before we send the request since we may
90 * receive the response before returning from this routine
92 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
93 list_add_tail(&msginfo->msglistentry,
94 &vmbus_connection.chn_msg_list);
96 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
98 ret = vmbus_post_msg(msg,
99 sizeof(struct vmbus_channel_initiate_contact));
101 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
102 list_del(&msginfo->msglistentry);
103 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
108 /* Wait for the connection response */
109 wait_for_completion(&msginfo->waitevent);
111 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
112 list_del(&msginfo->msglistentry);
113 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
115 /* Check if successful */
116 if (msginfo->response.version_response.version_supported) {
117 vmbus_connection.conn_state = CONNECTED;
119 return -ECONNREFUSED;
126 * vmbus_connect - Sends a connect request on the partition service connection
128 int vmbus_connect(void)
131 struct vmbus_channel_msginfo *msginfo = NULL;
134 /* Initialize the vmbus connection */
135 vmbus_connection.conn_state = CONNECTING;
136 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
137 if (!vmbus_connection.work_queue) {
142 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
143 spin_lock_init(&vmbus_connection.channelmsg_lock);
145 INIT_LIST_HEAD(&vmbus_connection.chn_list);
146 spin_lock_init(&vmbus_connection.channel_lock);
149 * Setup the vmbus event connection for channel interrupt
152 vmbus_connection.int_page =
153 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
154 if (vmbus_connection.int_page == NULL) {
159 vmbus_connection.recv_int_page = vmbus_connection.int_page;
160 vmbus_connection.send_int_page =
161 (void *)((unsigned long)vmbus_connection.int_page +
165 * Setup the monitor notification facility. The 1st page for
166 * parent->child and the 2nd page for child->parent
168 vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
169 vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
170 if ((vmbus_connection.monitor_pages[0] == NULL) ||
171 (vmbus_connection.monitor_pages[1] == NULL)) {
176 msginfo = kzalloc(sizeof(*msginfo) +
177 sizeof(struct vmbus_channel_initiate_contact),
179 if (msginfo == NULL) {
185 * Negotiate a compatible VMBUS version number with the
186 * host. We start with the highest number we can support
187 * and work our way down until we negotiate a compatible
191 version = VERSION_CURRENT;
194 ret = vmbus_negotiate_version(msginfo, version);
195 if (ret == -ETIMEDOUT)
198 if (vmbus_connection.conn_state == CONNECTED)
201 version = vmbus_get_next_version(version);
202 } while (version != VERSION_INVAL);
204 if (version == VERSION_INVAL)
207 vmbus_proto_version = version;
208 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d; Vmbus version:%d.%d\n",
209 host_info_eax, host_info_ebx >> 16,
210 host_info_ebx & 0xFFFF, host_info_ecx,
211 host_info_edx >> 24, host_info_edx & 0xFFFFFF,
212 version >> 16, version & 0xFFFF);
218 pr_err("Unable to connect to host\n");
219 vmbus_connection.conn_state = DISCONNECTED;
221 if (vmbus_connection.work_queue)
222 destroy_workqueue(vmbus_connection.work_queue);
224 if (vmbus_connection.int_page) {
225 free_pages((unsigned long)vmbus_connection.int_page, 0);
226 vmbus_connection.int_page = NULL;
229 free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0);
230 free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0);
231 vmbus_connection.monitor_pages[0] = NULL;
232 vmbus_connection.monitor_pages[1] = NULL;
240 * Map the given relid to the corresponding channel based on the
241 * per-cpu list of channels that have been affinitized to this CPU.
242 * This will be used in the channel callback path as we can do this
243 * mapping in a lock-free fashion.
245 static struct vmbus_channel *pcpu_relid2channel(u32 relid)
247 struct vmbus_channel *channel;
248 struct vmbus_channel *found_channel = NULL;
249 int cpu = smp_processor_id();
250 struct list_head *pcpu_head = &hv_context.percpu_list[cpu];
252 list_for_each_entry(channel, pcpu_head, percpu_list) {
253 if (channel->offermsg.child_relid == relid) {
254 found_channel = channel;
259 return found_channel;
263 * relid2channel - Get the channel object given its
264 * child relative id (ie channel id)
266 struct vmbus_channel *relid2channel(u32 relid)
268 struct vmbus_channel *channel;
269 struct vmbus_channel *found_channel = NULL;
271 struct list_head *cur, *tmp;
272 struct vmbus_channel *cur_sc;
274 spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
275 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
276 if (channel->offermsg.child_relid == relid) {
277 found_channel = channel;
279 } else if (!list_empty(&channel->sc_list)) {
281 * Deal with sub-channels.
283 list_for_each_safe(cur, tmp, &channel->sc_list) {
284 cur_sc = list_entry(cur, struct vmbus_channel,
286 if (cur_sc->offermsg.child_relid == relid) {
287 found_channel = cur_sc;
293 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
295 return found_channel;
299 * process_chn_event - Process a channel event notification
301 static void process_chn_event(u32 relid)
303 struct vmbus_channel *channel;
309 * Find the channel based on this relid and invokes the
310 * channel callback to process the event
312 channel = pcpu_relid2channel(relid);
315 pr_err("channel not found for relid - %u\n", relid);
320 * A channel once created is persistent even when there
321 * is no driver handling the device. An unloading driver
322 * sets the onchannel_callback to NULL on the same CPU
323 * as where this interrupt is handled (in an interrupt context).
324 * Thus, checking and invoking the driver specific callback takes
325 * care of orderly unloading of the driver.
328 if (channel->onchannel_callback != NULL) {
329 arg = channel->channel_callback_context;
330 read_state = channel->batched_reading;
332 * This callback reads the messages sent by the host.
333 * We can optimize host to guest signaling by ensuring:
334 * 1. While reading the channel, we disable interrupts from
336 * 2. Ensure that we process all posted messages from the host
337 * before returning from this callback.
338 * 3. Once we return, enable signaling from the host. Once this
339 * state is set we check to see if additional packets are
340 * available to read. In this case we repeat the process.
345 hv_begin_read(&channel->inbound);
346 channel->onchannel_callback(arg);
348 bytes_to_read = hv_end_read(&channel->inbound);
351 } while (read_state && (bytes_to_read != 0));
353 pr_err("no channel callback for relid - %u\n", relid);
359 * vmbus_on_event - Handler for events
361 void vmbus_on_event(unsigned long data)
367 u32 *recv_int_page = NULL;
369 int cpu = smp_processor_id();
370 union hv_synic_event_flags *event;
372 if ((vmbus_proto_version == VERSION_WS2008) ||
373 (vmbus_proto_version == VERSION_WIN7)) {
374 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
375 recv_int_page = vmbus_connection.recv_int_page;
378 * When the host is win8 and beyond, the event page
379 * can be directly checked to get the id of the channel
380 * that has the interrupt pending.
382 maxdword = HV_EVENT_FLAGS_DWORD_COUNT;
383 page_addr = hv_context.synic_event_page[cpu];
384 event = (union hv_synic_event_flags *)page_addr +
386 recv_int_page = event->flags32;
394 for (dword = 0; dword < maxdword; dword++) {
395 if (!recv_int_page[dword])
397 for (bit = 0; bit < 32; bit++) {
398 if (sync_test_and_clear_bit(bit,
399 (unsigned long *)&recv_int_page[dword])) {
400 relid = (dword << 5) + bit;
404 * Special case - vmbus
405 * channel protocol msg
409 process_chn_event(relid);
416 * vmbus_post_msg - Send a msg on the vmbus's message connection
418 int vmbus_post_msg(void *buffer, size_t buflen)
420 union hv_connection_id conn_id;
425 conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
428 * hv_post_message() can have transient failures because of
429 * insufficient resources. Retry the operation a couple of
430 * times before giving up.
432 while (retries < 10) {
433 ret = hv_post_message(conn_id, 1, buffer, buflen);
436 case HV_STATUS_INSUFFICIENT_BUFFERS:
440 case HV_STATUS_SUCCESS:
443 pr_err("hv_post_msg() failed; error code:%d\n", ret);
454 * vmbus_set_event - Send an event notification to the parent
456 int vmbus_set_event(struct vmbus_channel *channel)
458 u32 child_relid = channel->offermsg.child_relid;
460 if (!channel->is_dedicated_interrupt) {
461 /* Each u32 represents 32 channels */
462 sync_set_bit(child_relid & 31,
463 (unsigned long *)vmbus_connection.send_int_page +
467 return hv_signal_event(channel->sig_event);