]>
Commit | Line | Data |
---|---|---|
96dd86fa S |
1 | /* |
2 | * An implementation of host initiated guest snapshot. | |
3 | * | |
4 | * | |
5 | * Copyright (C) 2013, Microsoft, Inc. | |
6 | * Author : K. Y. Srinivasan <kys@microsoft.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify it | |
9 | * under the terms of the GNU General Public License version 2 as published | |
10 | * by the Free Software Foundation. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, but | |
13 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or | |
15 | * NON INFRINGEMENT. See the GNU General Public License for more | |
16 | * details. | |
17 | * | |
18 | */ | |
19 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
20 | ||
21 | #include <linux/net.h> | |
22 | #include <linux/nls.h> | |
23 | #include <linux/connector.h> | |
24 | #include <linux/workqueue.h> | |
25 | #include <linux/hyperv.h> | |
26 | ||
3647a83d | 27 | #include "hyperv_vmbus.h" |
6472f80a | 28 | #include "hv_utils_transport.h" |
3647a83d | 29 | |
6741335b S |
30 | #define VSS_MAJOR 5 |
31 | #define VSS_MINOR 0 | |
3a491605 | 32 | #define VSS_VERSION (VSS_MAJOR << 16 | VSS_MINOR) |
6741335b | 33 | |
64914207 | 34 | #define VSS_USERSPACE_TIMEOUT (msecs_to_jiffies(10 * 1000)) |
96dd86fa S |
35 | |
36 | /* | |
086a6f68 VK |
37 | * Global state maintained for transaction that is being processed. For a class |
38 | * of integration services, including the "VSS service", the specified protocol | |
39 | * is a "request/response" protocol which means that there can only be single | |
40 | * outstanding transaction from the host at any given point in time. We use | |
41 | * this to simplify memory management in this driver - we cache and process | |
42 | * only one message at a time. | |
96dd86fa | 43 | * |
086a6f68 VK |
44 | * While the request/response protocol is guaranteed by the host, we further |
45 | * ensure this by serializing packet processing in this driver - we do not | |
46 | * read additional packets from the VMBUs until the current packet is fully | |
47 | * handled. | |
96dd86fa S |
48 | */ |
49 | ||
50 | static struct { | |
086a6f68 | 51 | int state; /* hvutil_device_state */ |
96dd86fa S |
52 | int recv_len; /* number of bytes received. */ |
53 | struct vmbus_channel *recv_channel; /* chn we got the request */ | |
54 | u64 recv_req_id; /* request ID. */ | |
55 | struct hv_vss_msg *msg; /* current message */ | |
56 | } vss_transaction; | |
57 | ||
58 | ||
59 | static void vss_respond_to_host(int error); | |
60 | ||
cd8dc054 VK |
61 | /* |
62 | * This state maintains the version number registered by the daemon. | |
63 | */ | |
64 | static int dm_reg_value; | |
65 | ||
6472f80a | 66 | static const char vss_devname[] = "vmbus/hv_vss"; |
96dd86fa | 67 | static __u8 *recv_buffer; |
6472f80a | 68 | static struct hvutil_transport *hvt; |
96dd86fa | 69 | |
64914207 | 70 | static void vss_timeout_func(struct work_struct *dummy); |
497af84b | 71 | static void vss_handle_request(struct work_struct *dummy); |
64914207 VK |
72 | |
73 | static DECLARE_DELAYED_WORK(vss_timeout_work, vss_timeout_func); | |
497af84b | 74 | static DECLARE_WORK(vss_handle_request_work, vss_handle_request); |
96dd86fa | 75 | |
3cace4a6 OH |
76 | static void vss_poll_wrapper(void *channel) |
77 | { | |
78 | /* Transaction is finished, reset the state here to avoid races. */ | |
79 | vss_transaction.state = HVUTIL_READY; | |
80 | hv_vss_onchannelcallback(channel); | |
81 | } | |
82 | ||
96dd86fa S |
83 | /* |
84 | * Callback when data is received from user mode. | |
85 | */ | |
86 | ||
64914207 VK |
87 | static void vss_timeout_func(struct work_struct *dummy) |
88 | { | |
89 | /* | |
90 | * Timeout waiting for userspace component to reply happened. | |
91 | */ | |
92 | pr_warn("VSS: timeout waiting for daemon to reply\n"); | |
93 | vss_respond_to_host(HV_E_FAIL); | |
38c06c29 | 94 | |
3cace4a6 | 95 | hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper); |
64914207 VK |
96 | } |
97 | ||
e0fa3e5e VK |
98 | static void vss_register_done(void) |
99 | { | |
100 | hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper); | |
101 | pr_debug("VSS: userspace daemon registered\n"); | |
102 | } | |
103 | ||
cd8dc054 VK |
104 | static int vss_handle_handshake(struct hv_vss_msg *vss_msg) |
105 | { | |
106 | u32 our_ver = VSS_OP_REGISTER1; | |
107 | ||
108 | switch (vss_msg->vss_hdr.operation) { | |
109 | case VSS_OP_REGISTER: | |
110 | /* Daemon doesn't expect us to reply */ | |
111 | dm_reg_value = VSS_OP_REGISTER; | |
112 | break; | |
113 | case VSS_OP_REGISTER1: | |
e0fa3e5e VK |
114 | /* Daemon expects us to reply with our own version */ |
115 | if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver), | |
116 | vss_register_done)) | |
cd8dc054 VK |
117 | return -EFAULT; |
118 | dm_reg_value = VSS_OP_REGISTER1; | |
119 | break; | |
120 | default: | |
121 | return -EINVAL; | |
122 | } | |
e0fa3e5e | 123 | pr_debug("VSS: userspace daemon ver. %d connected\n", dm_reg_value); |
cd8dc054 VK |
124 | return 0; |
125 | } | |
126 | ||
6472f80a | 127 | static int vss_on_msg(void *msg, int len) |
96dd86fa | 128 | { |
6472f80a | 129 | struct hv_vss_msg *vss_msg = (struct hv_vss_msg *)msg; |
96dd86fa | 130 | |
6472f80a VK |
131 | if (len != sizeof(*vss_msg)) |
132 | return -EINVAL; | |
96dd86fa | 133 | |
cd8dc054 VK |
134 | if (vss_msg->vss_hdr.operation == VSS_OP_REGISTER || |
135 | vss_msg->vss_hdr.operation == VSS_OP_REGISTER1) { | |
136 | /* | |
137 | * Don't process registration messages if we're in the middle | |
138 | * of a transaction processing. | |
139 | */ | |
140 | if (vss_transaction.state > HVUTIL_READY) | |
141 | return -EINVAL; | |
142 | return vss_handle_handshake(vss_msg); | |
086a6f68 VK |
143 | } else if (vss_transaction.state == HVUTIL_USERSPACE_REQ) { |
144 | vss_transaction.state = HVUTIL_USERSPACE_RECV; | |
db886e4d AN |
145 | |
146 | if (vss_msg->vss_hdr.operation == VSS_OP_HOT_BACKUP) | |
147 | vss_transaction.msg->vss_cf.flags = | |
148 | VSS_HBU_NO_AUTO_RECOVERY; | |
149 | ||
086a6f68 VK |
150 | if (cancel_delayed_work_sync(&vss_timeout_work)) { |
151 | vss_respond_to_host(vss_msg->error); | |
152 | /* Transaction is finished, reset the state. */ | |
3cace4a6 OH |
153 | hv_poll_channel(vss_transaction.recv_channel, |
154 | vss_poll_wrapper); | |
086a6f68 VK |
155 | } |
156 | } else { | |
157 | /* This is a spurious call! */ | |
158 | pr_warn("VSS: Transaction not active\n"); | |
6472f80a | 159 | return -EINVAL; |
96dd86fa | 160 | } |
6472f80a | 161 | return 0; |
96dd86fa S |
162 | } |
163 | ||
497af84b | 164 | static void vss_send_op(void) |
96dd86fa S |
165 | { |
166 | int op = vss_transaction.msg->vss_hdr.operation; | |
8d9560eb | 167 | int rc; |
96dd86fa S |
168 | struct hv_vss_msg *vss_msg; |
169 | ||
086a6f68 VK |
170 | /* The transaction state is wrong. */ |
171 | if (vss_transaction.state != HVUTIL_HOSTMSG_RECEIVED) | |
172 | return; | |
173 | ||
6472f80a VK |
174 | vss_msg = kzalloc(sizeof(*vss_msg), GFP_KERNEL); |
175 | if (!vss_msg) | |
96dd86fa S |
176 | return; |
177 | ||
96dd86fa | 178 | vss_msg->vss_hdr.operation = op; |
96dd86fa | 179 | |
086a6f68 | 180 | vss_transaction.state = HVUTIL_USERSPACE_REQ; |
497af84b AN |
181 | |
182 | schedule_delayed_work(&vss_timeout_work, VSS_USERSPACE_TIMEOUT); | |
183 | ||
e0fa3e5e | 184 | rc = hvutil_transport_send(hvt, vss_msg, sizeof(*vss_msg), NULL); |
8d9560eb VK |
185 | if (rc) { |
186 | pr_warn("VSS: failed to communicate to the daemon: %d\n", rc); | |
086a6f68 | 187 | if (cancel_delayed_work_sync(&vss_timeout_work)) { |
8d9560eb | 188 | vss_respond_to_host(HV_E_FAIL); |
086a6f68 VK |
189 | vss_transaction.state = HVUTIL_READY; |
190 | } | |
8d9560eb | 191 | } |
086a6f68 | 192 | |
6472f80a | 193 | kfree(vss_msg); |
96dd86fa S |
194 | |
195 | return; | |
196 | } | |
197 | ||
497af84b AN |
198 | static void vss_handle_request(struct work_struct *dummy) |
199 | { | |
200 | switch (vss_transaction.msg->vss_hdr.operation) { | |
201 | /* | |
202 | * Initiate a "freeze/thaw" operation in the guest. | |
203 | * We respond to the host once the operation is complete. | |
204 | * | |
205 | * We send the message to the user space daemon and the operation is | |
206 | * performed in the daemon. | |
207 | */ | |
208 | case VSS_OP_THAW: | |
209 | case VSS_OP_FREEZE: | |
db886e4d | 210 | case VSS_OP_HOT_BACKUP: |
497af84b AN |
211 | if (vss_transaction.state < HVUTIL_READY) { |
212 | /* Userspace is not registered yet */ | |
213 | vss_respond_to_host(HV_E_FAIL); | |
214 | return; | |
215 | } | |
216 | vss_transaction.state = HVUTIL_HOSTMSG_RECEIVED; | |
217 | vss_send_op(); | |
218 | return; | |
497af84b AN |
219 | case VSS_OP_GET_DM_INFO: |
220 | vss_transaction.msg->dm_info.flags = 0; | |
221 | break; | |
222 | default: | |
223 | break; | |
224 | } | |
225 | ||
226 | vss_respond_to_host(0); | |
227 | hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper); | |
228 | } | |
229 | ||
96dd86fa S |
230 | /* |
231 | * Send a response back to the host. | |
232 | */ | |
233 | ||
234 | static void | |
235 | vss_respond_to_host(int error) | |
236 | { | |
237 | struct icmsg_hdr *icmsghdrp; | |
238 | u32 buf_len; | |
239 | struct vmbus_channel *channel; | |
240 | u64 req_id; | |
241 | ||
96dd86fa S |
242 | /* |
243 | * Copy the global state for completing the transaction. Note that | |
244 | * only one transaction can be active at a time. | |
245 | */ | |
246 | ||
247 | buf_len = vss_transaction.recv_len; | |
248 | channel = vss_transaction.recv_channel; | |
249 | req_id = vss_transaction.recv_req_id; | |
96dd86fa S |
250 | |
251 | icmsghdrp = (struct icmsg_hdr *) | |
252 | &recv_buffer[sizeof(struct vmbuspipe_hdr)]; | |
253 | ||
254 | if (channel->onchannel_callback == NULL) | |
255 | /* | |
256 | * We have raced with util driver being unloaded; | |
257 | * silently return. | |
258 | */ | |
259 | return; | |
260 | ||
261 | icmsghdrp->status = error; | |
262 | ||
263 | icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE; | |
264 | ||
265 | vmbus_sendpacket(channel, recv_buffer, buf_len, req_id, | |
266 | VM_PKT_DATA_INBAND, 0); | |
267 | ||
268 | } | |
269 | ||
270 | /* | |
271 | * This callback is invoked when we get a VSS message from the host. | |
272 | * The host ensures that only one VSS transaction can be active at a time. | |
273 | */ | |
274 | ||
275 | void hv_vss_onchannelcallback(void *context) | |
276 | { | |
277 | struct vmbus_channel *channel = context; | |
278 | u32 recvlen; | |
279 | u64 requestid; | |
280 | struct hv_vss_msg *vss_msg; | |
281 | ||
282 | ||
283 | struct icmsg_hdr *icmsghdrp; | |
284 | struct icmsg_negotiate *negop = NULL; | |
285 | ||
3cace4a6 | 286 | if (vss_transaction.state > HVUTIL_READY) |
96dd86fa | 287 | return; |
96dd86fa S |
288 | |
289 | vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen, | |
290 | &requestid); | |
291 | ||
292 | if (recvlen > 0) { | |
293 | icmsghdrp = (struct icmsg_hdr *)&recv_buffer[ | |
294 | sizeof(struct vmbuspipe_hdr)]; | |
295 | ||
296 | if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) { | |
297 | vmbus_prep_negotiate_resp(icmsghdrp, negop, | |
3a491605 S |
298 | recv_buffer, UTIL_FW_VERSION, |
299 | VSS_VERSION); | |
96dd86fa S |
300 | } else { |
301 | vss_msg = (struct hv_vss_msg *)&recv_buffer[ | |
302 | sizeof(struct vmbuspipe_hdr) + | |
303 | sizeof(struct icmsg_hdr)]; | |
304 | ||
305 | /* | |
306 | * Stash away this global state for completing the | |
307 | * transaction; note transactions are serialized. | |
308 | */ | |
309 | ||
310 | vss_transaction.recv_len = recvlen; | |
96dd86fa | 311 | vss_transaction.recv_req_id = requestid; |
96dd86fa S |
312 | vss_transaction.msg = (struct hv_vss_msg *)vss_msg; |
313 | ||
497af84b AN |
314 | schedule_work(&vss_handle_request_work); |
315 | return; | |
96dd86fa S |
316 | } |
317 | ||
318 | icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | |
319 | | ICMSGHDRFLAG_RESPONSE; | |
320 | ||
321 | vmbus_sendpacket(channel, recv_buffer, | |
322 | recvlen, requestid, | |
323 | VM_PKT_DATA_INBAND, 0); | |
324 | } | |
325 | ||
326 | } | |
327 | ||
6472f80a VK |
328 | static void vss_on_reset(void) |
329 | { | |
330 | if (cancel_delayed_work_sync(&vss_timeout_work)) | |
331 | vss_respond_to_host(HV_E_FAIL); | |
332 | vss_transaction.state = HVUTIL_DEVICE_INIT; | |
333 | } | |
334 | ||
96dd86fa S |
335 | int |
336 | hv_vss_init(struct hv_util_service *srv) | |
337 | { | |
ed9ba608 OH |
338 | if (vmbus_proto_version < VERSION_WIN8_1) { |
339 | pr_warn("Integration service 'Backup (volume snapshot)'" | |
340 | " not supported on this host version.\n"); | |
341 | return -ENOTSUPP; | |
342 | } | |
96dd86fa | 343 | recv_buffer = srv->recv_buffer; |
b9830d12 | 344 | vss_transaction.recv_channel = srv->channel; |
96dd86fa S |
345 | |
346 | /* | |
347 | * When this driver loads, the user level daemon that | |
348 | * processes the host requests may not yet be running. | |
349 | * Defer processing channel callbacks until the daemon | |
350 | * has registered. | |
351 | */ | |
086a6f68 VK |
352 | vss_transaction.state = HVUTIL_DEVICE_INIT; |
353 | ||
6472f80a VK |
354 | hvt = hvutil_transport_init(vss_devname, CN_VSS_IDX, CN_VSS_VAL, |
355 | vss_on_msg, vss_on_reset); | |
356 | if (!hvt) | |
357 | return -EFAULT; | |
358 | ||
96dd86fa S |
359 | return 0; |
360 | } | |
361 | ||
362 | void hv_vss_deinit(void) | |
363 | { | |
086a6f68 | 364 | vss_transaction.state = HVUTIL_DEVICE_DYING; |
64914207 | 365 | cancel_delayed_work_sync(&vss_timeout_work); |
497af84b | 366 | cancel_work_sync(&vss_handle_request_work); |
6472f80a | 367 | hvutil_transport_destroy(hvt); |
96dd86fa | 368 | } |