Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso...
[platform/upstream/kernel-adaptation-pc.git] / drivers / hv / connection.c
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  */
23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
24
25 #include <linux/kernel.h>
26 #include <linux/sched.h>
27 #include <linux/wait.h>
28 #include <linux/delay.h>
29 #include <linux/mm.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"
36
37
38 struct vmbus_connection vmbus_connection = {
39         .conn_state             = DISCONNECTED,
40         .next_gpadl_handle      = ATOMIC_INIT(0xE1E10),
41 };
42
43 /*
44  * Negotiated protocol version with the host.
45  */
46 __u32 vmbus_proto_version;
47 EXPORT_SYMBOL_GPL(vmbus_proto_version);
48
49 static __u32 vmbus_get_next_version(__u32 current_version)
50 {
51         switch (current_version) {
52         case (VERSION_WIN7):
53                 return VERSION_WS2008;
54
55         case (VERSION_WIN8):
56                 return VERSION_WIN7;
57
58         case (VERSION_WS2008):
59         default:
60                 return VERSION_INVAL;
61         }
62 }
63
64 static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
65                                         __u32 version)
66 {
67         int ret = 0;
68         struct vmbus_channel_initiate_contact *msg;
69         unsigned long flags;
70         int t;
71
72         init_completion(&msginfo->waitevent);
73
74         msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
75
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 +
82                                  PAGE_SIZE));
83
84         /*
85          * Add to list before we send the request since we may
86          * receive the response before returning from this routine
87          */
88         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
89         list_add_tail(&msginfo->msglistentry,
90                       &vmbus_connection.chn_msg_list);
91
92         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
93
94         ret = vmbus_post_msg(msg,
95                                sizeof(struct vmbus_channel_initiate_contact));
96         if (ret != 0) {
97                 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
98                 list_del(&msginfo->msglistentry);
99                 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
100                                         flags);
101                 return ret;
102         }
103
104         /* Wait for the connection response */
105         t =  wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
106         if (t == 0) {
107                 spin_lock_irqsave(&vmbus_connection.channelmsg_lock,
108                                 flags);
109                 list_del(&msginfo->msglistentry);
110                 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
111                                         flags);
112                 return -ETIMEDOUT;
113         }
114
115         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
116         list_del(&msginfo->msglistentry);
117         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
118
119         /* Check if successful */
120         if (msginfo->response.version_response.version_supported) {
121                 vmbus_connection.conn_state = CONNECTED;
122         } else {
123                 return -ECONNREFUSED;
124         }
125
126         return ret;
127 }
128
129 /*
130  * vmbus_connect - Sends a connect request on the partition service connection
131  */
132 int vmbus_connect(void)
133 {
134         int ret = 0;
135         struct vmbus_channel_msginfo *msginfo = NULL;
136         __u32 version;
137
138         /* Initialize the vmbus connection */
139         vmbus_connection.conn_state = CONNECTING;
140         vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
141         if (!vmbus_connection.work_queue) {
142                 ret = -ENOMEM;
143                 goto cleanup;
144         }
145
146         INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
147         spin_lock_init(&vmbus_connection.channelmsg_lock);
148
149         INIT_LIST_HEAD(&vmbus_connection.chn_list);
150         spin_lock_init(&vmbus_connection.channel_lock);
151
152         /*
153          * Setup the vmbus event connection for channel interrupt
154          * abstraction stuff
155          */
156         vmbus_connection.int_page =
157         (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
158         if (vmbus_connection.int_page == NULL) {
159                 ret = -ENOMEM;
160                 goto cleanup;
161         }
162
163         vmbus_connection.recv_int_page = vmbus_connection.int_page;
164         vmbus_connection.send_int_page =
165                 (void *)((unsigned long)vmbus_connection.int_page +
166                         (PAGE_SIZE >> 1));
167
168         /*
169          * Setup the monitor notification facility. The 1st page for
170          * parent->child and the 2nd page for child->parent
171          */
172         vmbus_connection.monitor_pages =
173         (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 1);
174         if (vmbus_connection.monitor_pages == NULL) {
175                 ret = -ENOMEM;
176                 goto cleanup;
177         }
178
179         msginfo = kzalloc(sizeof(*msginfo) +
180                           sizeof(struct vmbus_channel_initiate_contact),
181                           GFP_KERNEL);
182         if (msginfo == NULL) {
183                 ret = -ENOMEM;
184                 goto cleanup;
185         }
186
187         /*
188          * Negotiate a compatible VMBUS version number with the
189          * host. We start with the highest number we can support
190          * and work our way down until we negotiate a compatible
191          * version.
192          */
193
194         version = VERSION_CURRENT;
195
196         do {
197                 ret = vmbus_negotiate_version(msginfo, version);
198                 if (ret == 0)
199                         break;
200
201                 version = vmbus_get_next_version(version);
202         } while (version != VERSION_INVAL);
203
204         if (version == VERSION_INVAL)
205                 goto cleanup;
206
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);
213
214         kfree(msginfo);
215         return 0;
216
217 cleanup:
218         pr_err("Unable to connect to host\n");
219         vmbus_connection.conn_state = DISCONNECTED;
220
221         if (vmbus_connection.work_queue)
222                 destroy_workqueue(vmbus_connection.work_queue);
223
224         if (vmbus_connection.int_page) {
225                 free_pages((unsigned long)vmbus_connection.int_page, 0);
226                 vmbus_connection.int_page = NULL;
227         }
228
229         if (vmbus_connection.monitor_pages) {
230                 free_pages((unsigned long)vmbus_connection.monitor_pages, 1);
231                 vmbus_connection.monitor_pages = NULL;
232         }
233
234         kfree(msginfo);
235
236         return ret;
237 }
238
239
240 /*
241  * relid2channel - Get the channel object given its
242  * child relative id (ie channel id)
243  */
244 struct vmbus_channel *relid2channel(u32 relid)
245 {
246         struct vmbus_channel *channel;
247         struct vmbus_channel *found_channel  = NULL;
248         unsigned long flags;
249         struct list_head *cur, *tmp;
250         struct vmbus_channel *cur_sc;
251
252         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
253         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
254                 if (channel->offermsg.child_relid == relid) {
255                         found_channel = channel;
256                         break;
257                 } else if (!list_empty(&channel->sc_list)) {
258                         /*
259                          * Deal with sub-channels.
260                          */
261                         list_for_each_safe(cur, tmp, &channel->sc_list) {
262                                 cur_sc = list_entry(cur, struct vmbus_channel,
263                                                         sc_list);
264                                 if (cur_sc->offermsg.child_relid == relid) {
265                                         found_channel = cur_sc;
266                                         break;
267                                 }
268                         }
269                 }
270         }
271         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
272
273         return found_channel;
274 }
275
276 /*
277  * process_chn_event - Process a channel event notification
278  */
279 static void process_chn_event(u32 relid)
280 {
281         struct vmbus_channel *channel;
282         unsigned long flags;
283         void *arg;
284         bool read_state;
285         u32 bytes_to_read;
286
287         /*
288          * Find the channel based on this relid and invokes the
289          * channel callback to process the event
290          */
291         channel = relid2channel(relid);
292
293         if (!channel) {
294                 pr_err("channel not found for relid - %u\n", relid);
295                 return;
296         }
297
298         /*
299          * A channel once created is persistent even when there
300          * is no driver handling the device. An unloading driver
301          * sets the onchannel_callback to NULL under the
302          * protection of the channel inbound_lock. Thus, checking
303          * and invoking the driver specific callback takes care of
304          * orderly unloading of the driver.
305          */
306
307         spin_lock_irqsave(&channel->inbound_lock, flags);
308         if (channel->onchannel_callback != NULL) {
309                 arg = channel->channel_callback_context;
310                 read_state = channel->batched_reading;
311                 /*
312                  * This callback reads the messages sent by the host.
313                  * We can optimize host to guest signaling by ensuring:
314                  * 1. While reading the channel, we disable interrupts from
315                  *    host.
316                  * 2. Ensure that we process all posted messages from the host
317                  *    before returning from this callback.
318                  * 3. Once we return, enable signaling from the host. Once this
319                  *    state is set we check to see if additional packets are
320                  *    available to read. In this case we repeat the process.
321                  */
322
323                 do {
324                         hv_begin_read(&channel->inbound);
325                         channel->onchannel_callback(arg);
326                         bytes_to_read = hv_end_read(&channel->inbound);
327                 } while (read_state && (bytes_to_read != 0));
328         } else {
329                 pr_err("no channel callback for relid - %u\n", relid);
330         }
331
332         spin_unlock_irqrestore(&channel->inbound_lock, flags);
333 }
334
335 /*
336  * vmbus_on_event - Handler for events
337  */
338 void vmbus_on_event(unsigned long data)
339 {
340         u32 dword;
341         u32 maxdword;
342         int bit;
343         u32 relid;
344         u32 *recv_int_page = NULL;
345         void *page_addr;
346         int cpu = smp_processor_id();
347         union hv_synic_event_flags *event;
348
349         if ((vmbus_proto_version == VERSION_WS2008) ||
350                 (vmbus_proto_version == VERSION_WIN7)) {
351                 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
352                 recv_int_page = vmbus_connection.recv_int_page;
353         } else {
354                 /*
355                  * When the host is win8 and beyond, the event page
356                  * can be directly checked to get the id of the channel
357                  * that has the interrupt pending.
358                  */
359                 maxdword = HV_EVENT_FLAGS_DWORD_COUNT;
360                 page_addr = hv_context.synic_event_page[cpu];
361                 event = (union hv_synic_event_flags *)page_addr +
362                                                  VMBUS_MESSAGE_SINT;
363                 recv_int_page = event->flags32;
364         }
365
366
367
368         /* Check events */
369         if (!recv_int_page)
370                 return;
371         for (dword = 0; dword < maxdword; dword++) {
372                 if (!recv_int_page[dword])
373                         continue;
374                 for (bit = 0; bit < 32; bit++) {
375                         if (sync_test_and_clear_bit(bit,
376                                 (unsigned long *)&recv_int_page[dword])) {
377                                 relid = (dword << 5) + bit;
378
379                                 if (relid == 0)
380                                         /*
381                                          * Special case - vmbus
382                                          * channel protocol msg
383                                          */
384                                         continue;
385
386                                 process_chn_event(relid);
387                         }
388                 }
389         }
390 }
391
392 /*
393  * vmbus_post_msg - Send a msg on the vmbus's message connection
394  */
395 int vmbus_post_msg(void *buffer, size_t buflen)
396 {
397         union hv_connection_id conn_id;
398         int ret = 0;
399         int retries = 0;
400
401         conn_id.asu32 = 0;
402         conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
403
404         /*
405          * hv_post_message() can have transient failures because of
406          * insufficient resources. Retry the operation a couple of
407          * times before giving up.
408          */
409         while (retries < 3) {
410                 ret =  hv_post_message(conn_id, 1, buffer, buflen);
411                 if (ret != HV_STATUS_INSUFFICIENT_BUFFERS)
412                         return ret;
413                 retries++;
414                 msleep(100);
415         }
416         return ret;
417 }
418
419 /*
420  * vmbus_set_event - Send an event notification to the parent
421  */
422 int vmbus_set_event(struct vmbus_channel *channel)
423 {
424         u32 child_relid = channel->offermsg.child_relid;
425
426         if (!channel->is_dedicated_interrupt) {
427                 /* Each u32 represents 32 channels */
428                 sync_set_bit(child_relid & 31,
429                         (unsigned long *)vmbus_connection.send_int_page +
430                         (child_relid >> 5));
431         }
432
433         return hv_signal_event(channel->sig_event);
434 }