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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 S |
69 | |
70 | static void vss_send_op(struct work_struct *dummy); | |
64914207 VK |
71 | static void vss_timeout_func(struct work_struct *dummy); |
72 | ||
73 | static DECLARE_DELAYED_WORK(vss_timeout_work, vss_timeout_func); | |
96dd86fa S |
74 | static DECLARE_WORK(vss_send_op_work, vss_send_op); |
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 | ||
cd8dc054 VK |
98 | static int vss_handle_handshake(struct hv_vss_msg *vss_msg) |
99 | { | |
100 | u32 our_ver = VSS_OP_REGISTER1; | |
101 | ||
102 | switch (vss_msg->vss_hdr.operation) { | |
103 | case VSS_OP_REGISTER: | |
104 | /* Daemon doesn't expect us to reply */ | |
105 | dm_reg_value = VSS_OP_REGISTER; | |
106 | break; | |
107 | case VSS_OP_REGISTER1: | |
108 | /* Daemon expects us to reply with our own version*/ | |
109 | if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver))) | |
110 | return -EFAULT; | |
111 | dm_reg_value = VSS_OP_REGISTER1; | |
112 | break; | |
113 | default: | |
114 | return -EINVAL; | |
115 | } | |
2d0c3b5a | 116 | hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper); |
7c959127 | 117 | pr_debug("VSS: userspace daemon ver. %d registered\n", dm_reg_value); |
cd8dc054 VK |
118 | return 0; |
119 | } | |
120 | ||
6472f80a | 121 | static int vss_on_msg(void *msg, int len) |
96dd86fa | 122 | { |
6472f80a | 123 | struct hv_vss_msg *vss_msg = (struct hv_vss_msg *)msg; |
96dd86fa | 124 | |
6472f80a VK |
125 | if (len != sizeof(*vss_msg)) |
126 | return -EINVAL; | |
96dd86fa | 127 | |
cd8dc054 VK |
128 | if (vss_msg->vss_hdr.operation == VSS_OP_REGISTER || |
129 | vss_msg->vss_hdr.operation == VSS_OP_REGISTER1) { | |
130 | /* | |
131 | * Don't process registration messages if we're in the middle | |
132 | * of a transaction processing. | |
133 | */ | |
134 | if (vss_transaction.state > HVUTIL_READY) | |
135 | return -EINVAL; | |
136 | return vss_handle_handshake(vss_msg); | |
086a6f68 VK |
137 | } else if (vss_transaction.state == HVUTIL_USERSPACE_REQ) { |
138 | vss_transaction.state = HVUTIL_USERSPACE_RECV; | |
139 | if (cancel_delayed_work_sync(&vss_timeout_work)) { | |
140 | vss_respond_to_host(vss_msg->error); | |
141 | /* Transaction is finished, reset the state. */ | |
3cace4a6 OH |
142 | hv_poll_channel(vss_transaction.recv_channel, |
143 | vss_poll_wrapper); | |
086a6f68 VK |
144 | } |
145 | } else { | |
146 | /* This is a spurious call! */ | |
147 | pr_warn("VSS: Transaction not active\n"); | |
6472f80a | 148 | return -EINVAL; |
96dd86fa | 149 | } |
6472f80a | 150 | return 0; |
96dd86fa S |
151 | } |
152 | ||
153 | ||
154 | static void vss_send_op(struct work_struct *dummy) | |
155 | { | |
156 | int op = vss_transaction.msg->vss_hdr.operation; | |
8d9560eb | 157 | int rc; |
96dd86fa S |
158 | struct hv_vss_msg *vss_msg; |
159 | ||
086a6f68 VK |
160 | /* The transaction state is wrong. */ |
161 | if (vss_transaction.state != HVUTIL_HOSTMSG_RECEIVED) | |
162 | return; | |
163 | ||
6472f80a VK |
164 | vss_msg = kzalloc(sizeof(*vss_msg), GFP_KERNEL); |
165 | if (!vss_msg) | |
96dd86fa S |
166 | return; |
167 | ||
96dd86fa | 168 | vss_msg->vss_hdr.operation = op; |
96dd86fa | 169 | |
086a6f68 | 170 | vss_transaction.state = HVUTIL_USERSPACE_REQ; |
6472f80a | 171 | rc = hvutil_transport_send(hvt, vss_msg, sizeof(*vss_msg)); |
8d9560eb VK |
172 | if (rc) { |
173 | pr_warn("VSS: failed to communicate to the daemon: %d\n", rc); | |
086a6f68 | 174 | if (cancel_delayed_work_sync(&vss_timeout_work)) { |
8d9560eb | 175 | vss_respond_to_host(HV_E_FAIL); |
086a6f68 VK |
176 | vss_transaction.state = HVUTIL_READY; |
177 | } | |
8d9560eb | 178 | } |
086a6f68 | 179 | |
6472f80a | 180 | kfree(vss_msg); |
96dd86fa S |
181 | |
182 | return; | |
183 | } | |
184 | ||
185 | /* | |
186 | * Send a response back to the host. | |
187 | */ | |
188 | ||
189 | static void | |
190 | vss_respond_to_host(int error) | |
191 | { | |
192 | struct icmsg_hdr *icmsghdrp; | |
193 | u32 buf_len; | |
194 | struct vmbus_channel *channel; | |
195 | u64 req_id; | |
196 | ||
96dd86fa S |
197 | /* |
198 | * Copy the global state for completing the transaction. Note that | |
199 | * only one transaction can be active at a time. | |
200 | */ | |
201 | ||
202 | buf_len = vss_transaction.recv_len; | |
203 | channel = vss_transaction.recv_channel; | |
204 | req_id = vss_transaction.recv_req_id; | |
96dd86fa S |
205 | |
206 | icmsghdrp = (struct icmsg_hdr *) | |
207 | &recv_buffer[sizeof(struct vmbuspipe_hdr)]; | |
208 | ||
209 | if (channel->onchannel_callback == NULL) | |
210 | /* | |
211 | * We have raced with util driver being unloaded; | |
212 | * silently return. | |
213 | */ | |
214 | return; | |
215 | ||
216 | icmsghdrp->status = error; | |
217 | ||
218 | icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE; | |
219 | ||
220 | vmbus_sendpacket(channel, recv_buffer, buf_len, req_id, | |
221 | VM_PKT_DATA_INBAND, 0); | |
222 | ||
223 | } | |
224 | ||
225 | /* | |
226 | * This callback is invoked when we get a VSS message from the host. | |
227 | * The host ensures that only one VSS transaction can be active at a time. | |
228 | */ | |
229 | ||
230 | void hv_vss_onchannelcallback(void *context) | |
231 | { | |
232 | struct vmbus_channel *channel = context; | |
233 | u32 recvlen; | |
234 | u64 requestid; | |
235 | struct hv_vss_msg *vss_msg; | |
236 | ||
237 | ||
238 | struct icmsg_hdr *icmsghdrp; | |
239 | struct icmsg_negotiate *negop = NULL; | |
240 | ||
3cace4a6 | 241 | if (vss_transaction.state > HVUTIL_READY) |
96dd86fa | 242 | return; |
96dd86fa S |
243 | |
244 | vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen, | |
245 | &requestid); | |
246 | ||
247 | if (recvlen > 0) { | |
248 | icmsghdrp = (struct icmsg_hdr *)&recv_buffer[ | |
249 | sizeof(struct vmbuspipe_hdr)]; | |
250 | ||
251 | if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) { | |
252 | vmbus_prep_negotiate_resp(icmsghdrp, negop, | |
3a491605 S |
253 | recv_buffer, UTIL_FW_VERSION, |
254 | VSS_VERSION); | |
96dd86fa S |
255 | } else { |
256 | vss_msg = (struct hv_vss_msg *)&recv_buffer[ | |
257 | sizeof(struct vmbuspipe_hdr) + | |
258 | sizeof(struct icmsg_hdr)]; | |
259 | ||
260 | /* | |
261 | * Stash away this global state for completing the | |
262 | * transaction; note transactions are serialized. | |
263 | */ | |
264 | ||
265 | vss_transaction.recv_len = recvlen; | |
266 | vss_transaction.recv_channel = channel; | |
267 | vss_transaction.recv_req_id = requestid; | |
96dd86fa S |
268 | vss_transaction.msg = (struct hv_vss_msg *)vss_msg; |
269 | ||
270 | switch (vss_msg->vss_hdr.operation) { | |
271 | /* | |
272 | * Initiate a "freeze/thaw" | |
273 | * operation in the guest. | |
274 | * We respond to the host once | |
275 | * the operation is complete. | |
276 | * | |
277 | * We send the message to the | |
278 | * user space daemon and the | |
279 | * operation is performed in | |
280 | * the daemon. | |
281 | */ | |
282 | case VSS_OP_FREEZE: | |
283 | case VSS_OP_THAW: | |
086a6f68 VK |
284 | if (vss_transaction.state < HVUTIL_READY) { |
285 | /* Userspace is not registered yet */ | |
286 | vss_respond_to_host(HV_E_FAIL); | |
287 | return; | |
288 | } | |
289 | vss_transaction.state = HVUTIL_HOSTMSG_RECEIVED; | |
96dd86fa | 290 | schedule_work(&vss_send_op_work); |
64914207 VK |
291 | schedule_delayed_work(&vss_timeout_work, |
292 | VSS_USERSPACE_TIMEOUT); | |
96dd86fa S |
293 | return; |
294 | ||
295 | case VSS_OP_HOT_BACKUP: | |
296 | vss_msg->vss_cf.flags = | |
297 | VSS_HBU_NO_AUTO_RECOVERY; | |
298 | vss_respond_to_host(0); | |
299 | return; | |
300 | ||
301 | case VSS_OP_GET_DM_INFO: | |
302 | vss_msg->dm_info.flags = 0; | |
303 | vss_respond_to_host(0); | |
304 | return; | |
305 | ||
306 | default: | |
307 | vss_respond_to_host(0); | |
308 | return; | |
309 | ||
310 | } | |
311 | ||
312 | } | |
313 | ||
314 | icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | |
315 | | ICMSGHDRFLAG_RESPONSE; | |
316 | ||
317 | vmbus_sendpacket(channel, recv_buffer, | |
318 | recvlen, requestid, | |
319 | VM_PKT_DATA_INBAND, 0); | |
320 | } | |
321 | ||
322 | } | |
323 | ||
6472f80a VK |
324 | static void vss_on_reset(void) |
325 | { | |
326 | if (cancel_delayed_work_sync(&vss_timeout_work)) | |
327 | vss_respond_to_host(HV_E_FAIL); | |
328 | vss_transaction.state = HVUTIL_DEVICE_INIT; | |
329 | } | |
330 | ||
96dd86fa S |
331 | int |
332 | hv_vss_init(struct hv_util_service *srv) | |
333 | { | |
ed9ba608 OH |
334 | if (vmbus_proto_version < VERSION_WIN8_1) { |
335 | pr_warn("Integration service 'Backup (volume snapshot)'" | |
336 | " not supported on this host version.\n"); | |
337 | return -ENOTSUPP; | |
338 | } | |
96dd86fa S |
339 | recv_buffer = srv->recv_buffer; |
340 | ||
341 | /* | |
342 | * When this driver loads, the user level daemon that | |
343 | * processes the host requests may not yet be running. | |
344 | * Defer processing channel callbacks until the daemon | |
345 | * has registered. | |
346 | */ | |
086a6f68 VK |
347 | vss_transaction.state = HVUTIL_DEVICE_INIT; |
348 | ||
6472f80a VK |
349 | hvt = hvutil_transport_init(vss_devname, CN_VSS_IDX, CN_VSS_VAL, |
350 | vss_on_msg, vss_on_reset); | |
351 | if (!hvt) | |
352 | return -EFAULT; | |
353 | ||
96dd86fa S |
354 | return 0; |
355 | } | |
356 | ||
357 | void hv_vss_deinit(void) | |
358 | { | |
086a6f68 | 359 | vss_transaction.state = HVUTIL_DEVICE_DYING; |
64914207 | 360 | cancel_delayed_work_sync(&vss_timeout_work); |
96dd86fa | 361 | cancel_work_sync(&vss_send_op_work); |
6472f80a | 362 | hvutil_transport_destroy(hvt); |
96dd86fa | 363 | } |