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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
27#include "hyperv_vmbus.h"
28#include "hv_utils_transport.h"
29
30#define VSS_MAJOR 5
31#define VSS_MINOR 0
32#define VSS_VERSION (VSS_MAJOR << 16 | VSS_MINOR)
33
34#define VSS_USERSPACE_TIMEOUT (msecs_to_jiffies(10 * 1000))
35
36/*
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.
43 *
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.
48 */
49
50static struct {
51 int state; /* hvutil_device_state */
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
59static void vss_respond_to_host(int error);
60
61/*
62 * This state maintains the version number registered by the daemon.
63 */
64static int dm_reg_value;
65
66static const char vss_devname[] = "vmbus/hv_vss";
67static __u8 *recv_buffer;
68static struct hvutil_transport *hvt;
69
70static void vss_send_op(struct work_struct *dummy);
71static void vss_timeout_func(struct work_struct *dummy);
72
73static DECLARE_DELAYED_WORK(vss_timeout_work, vss_timeout_func);
74static DECLARE_WORK(vss_send_op_work, vss_send_op);
75
76static 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
83/*
84 * Callback when data is received from user mode.
85 */
86
87static 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);
94
95 hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper);
96}
97
98static 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 }
116 hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper);
117 pr_debug("VSS: userspace daemon ver. %d registered\n", dm_reg_value);
118 return 0;
119}
120
121static int vss_on_msg(void *msg, int len)
122{
123 struct hv_vss_msg *vss_msg = (struct hv_vss_msg *)msg;
124
125 if (len != sizeof(*vss_msg))
126 return -EINVAL;
127
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);
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. */
142 hv_poll_channel(vss_transaction.recv_channel,
143 vss_poll_wrapper);
144 }
145 } else {
146 /* This is a spurious call! */
147 pr_warn("VSS: Transaction not active\n");
148 return -EINVAL;
149 }
150 return 0;
151}
152
153
154static void vss_send_op(struct work_struct *dummy)
155{
156 int op = vss_transaction.msg->vss_hdr.operation;
157 int rc;
158 struct hv_vss_msg *vss_msg;
159
160 /* The transaction state is wrong. */
161 if (vss_transaction.state != HVUTIL_HOSTMSG_RECEIVED)
162 return;
163
164 vss_msg = kzalloc(sizeof(*vss_msg), GFP_KERNEL);
165 if (!vss_msg)
166 return;
167
168 vss_msg->vss_hdr.operation = op;
169
170 vss_transaction.state = HVUTIL_USERSPACE_REQ;
171 rc = hvutil_transport_send(hvt, vss_msg, sizeof(*vss_msg));
172 if (rc) {
173 pr_warn("VSS: failed to communicate to the daemon: %d\n", rc);
174 if (cancel_delayed_work_sync(&vss_timeout_work)) {
175 vss_respond_to_host(HV_E_FAIL);
176 vss_transaction.state = HVUTIL_READY;
177 }
178 }
179
180 kfree(vss_msg);
181
182 return;
183}
184
185/*
186 * Send a response back to the host.
187 */
188
189static void
190vss_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
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;
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
230void 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
241 if (vss_transaction.state > HVUTIL_READY)
242 return;
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,
253 recv_buffer, UTIL_FW_VERSION,
254 VSS_VERSION);
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_req_id = requestid;
267 vss_transaction.msg = (struct hv_vss_msg *)vss_msg;
268
269 switch (vss_msg->vss_hdr.operation) {
270 /*
271 * Initiate a "freeze/thaw"
272 * operation in the guest.
273 * We respond to the host once
274 * the operation is complete.
275 *
276 * We send the message to the
277 * user space daemon and the
278 * operation is performed in
279 * the daemon.
280 */
281 case VSS_OP_FREEZE:
282 case VSS_OP_THAW:
283 if (vss_transaction.state < HVUTIL_READY) {
284 /* Userspace is not registered yet */
285 vss_respond_to_host(HV_E_FAIL);
286 return;
287 }
288 vss_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
289 schedule_work(&vss_send_op_work);
290 schedule_delayed_work(&vss_timeout_work,
291 VSS_USERSPACE_TIMEOUT);
292 return;
293
294 case VSS_OP_HOT_BACKUP:
295 vss_msg->vss_cf.flags =
296 VSS_HBU_NO_AUTO_RECOVERY;
297 vss_respond_to_host(0);
298 return;
299
300 case VSS_OP_GET_DM_INFO:
301 vss_msg->dm_info.flags = 0;
302 vss_respond_to_host(0);
303 return;
304
305 default:
306 vss_respond_to_host(0);
307 return;
308
309 }
310
311 }
312
313 icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
314 | ICMSGHDRFLAG_RESPONSE;
315
316 vmbus_sendpacket(channel, recv_buffer,
317 recvlen, requestid,
318 VM_PKT_DATA_INBAND, 0);
319 }
320
321}
322
323static void vss_on_reset(void)
324{
325 if (cancel_delayed_work_sync(&vss_timeout_work))
326 vss_respond_to_host(HV_E_FAIL);
327 vss_transaction.state = HVUTIL_DEVICE_INIT;
328}
329
330int
331hv_vss_init(struct hv_util_service *srv)
332{
333 if (vmbus_proto_version < VERSION_WIN8_1) {
334 pr_warn("Integration service 'Backup (volume snapshot)'"
335 " not supported on this host version.\n");
336 return -ENOTSUPP;
337 }
338 recv_buffer = srv->recv_buffer;
339 vss_transaction.recv_channel = srv->channel;
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 */
347 vss_transaction.state = HVUTIL_DEVICE_INIT;
348
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
354 return 0;
355}
356
357void hv_vss_deinit(void)
358{
359 vss_transaction.state = HVUTIL_DEVICE_DYING;
360 cancel_delayed_work_sync(&vss_timeout_work);
361 cancel_work_sync(&vss_send_op_work);
362 hvutil_transport_destroy(hvt);
363}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * An implementation of host initiated guest snapshot.
4 *
5 * Copyright (C) 2013, Microsoft, Inc.
6 * Author : K. Y. Srinivasan <kys@microsoft.com>
7 */
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/net.h>
11#include <linux/nls.h>
12#include <linux/connector.h>
13#include <linux/workqueue.h>
14#include <linux/hyperv.h>
15#include <asm/hyperv-tlfs.h>
16
17#include "hyperv_vmbus.h"
18#include "hv_utils_transport.h"
19
20#define VSS_MAJOR 5
21#define VSS_MINOR 0
22#define VSS_VERSION (VSS_MAJOR << 16 | VSS_MINOR)
23
24#define VSS_VER_COUNT 1
25static const int vss_versions[] = {
26 VSS_VERSION
27};
28
29#define FW_VER_COUNT 1
30static const int fw_versions[] = {
31 UTIL_FW_VERSION
32};
33
34/*
35 * Timeout values are based on expecations from host
36 */
37#define VSS_FREEZE_TIMEOUT (15 * 60)
38
39/*
40 * Global state maintained for transaction that is being processed. For a class
41 * of integration services, including the "VSS service", the specified protocol
42 * is a "request/response" protocol which means that there can only be single
43 * outstanding transaction from the host at any given point in time. We use
44 * this to simplify memory management in this driver - we cache and process
45 * only one message at a time.
46 *
47 * While the request/response protocol is guaranteed by the host, we further
48 * ensure this by serializing packet processing in this driver - we do not
49 * read additional packets from the VMBUs until the current packet is fully
50 * handled.
51 */
52
53static struct {
54 int state; /* hvutil_device_state */
55 int recv_len; /* number of bytes received. */
56 struct vmbus_channel *recv_channel; /* chn we got the request */
57 u64 recv_req_id; /* request ID. */
58 struct hv_vss_msg *msg; /* current message */
59} vss_transaction;
60
61
62static void vss_respond_to_host(int error);
63
64/*
65 * This state maintains the version number registered by the daemon.
66 */
67static int dm_reg_value;
68
69static const char vss_devname[] = "vmbus/hv_vss";
70static __u8 *recv_buffer;
71static struct hvutil_transport *hvt;
72
73static void vss_timeout_func(struct work_struct *dummy);
74static void vss_handle_request(struct work_struct *dummy);
75
76static DECLARE_DELAYED_WORK(vss_timeout_work, vss_timeout_func);
77static DECLARE_WORK(vss_handle_request_work, vss_handle_request);
78
79static void vss_poll_wrapper(void *channel)
80{
81 /* Transaction is finished, reset the state here to avoid races. */
82 vss_transaction.state = HVUTIL_READY;
83 tasklet_schedule(&((struct vmbus_channel *)channel)->callback_event);
84}
85
86/*
87 * Callback when data is received from user mode.
88 */
89
90static void vss_timeout_func(struct work_struct *dummy)
91{
92 /*
93 * Timeout waiting for userspace component to reply happened.
94 */
95 pr_warn("VSS: timeout waiting for daemon to reply\n");
96 vss_respond_to_host(HV_E_FAIL);
97
98 hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper);
99}
100
101static void vss_register_done(void)
102{
103 hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper);
104 pr_debug("VSS: userspace daemon registered\n");
105}
106
107static int vss_handle_handshake(struct hv_vss_msg *vss_msg)
108{
109 u32 our_ver = VSS_OP_REGISTER1;
110
111 switch (vss_msg->vss_hdr.operation) {
112 case VSS_OP_REGISTER:
113 /* Daemon doesn't expect us to reply */
114 dm_reg_value = VSS_OP_REGISTER;
115 break;
116 case VSS_OP_REGISTER1:
117 /* Daemon expects us to reply with our own version */
118 if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver),
119 vss_register_done))
120 return -EFAULT;
121 dm_reg_value = VSS_OP_REGISTER1;
122 break;
123 default:
124 return -EINVAL;
125 }
126 pr_info("VSS: userspace daemon ver. %d connected\n", dm_reg_value);
127 return 0;
128}
129
130static int vss_on_msg(void *msg, int len)
131{
132 struct hv_vss_msg *vss_msg = (struct hv_vss_msg *)msg;
133
134 if (len != sizeof(*vss_msg)) {
135 pr_debug("VSS: Message size does not match length\n");
136 return -EINVAL;
137 }
138
139 if (vss_msg->vss_hdr.operation == VSS_OP_REGISTER ||
140 vss_msg->vss_hdr.operation == VSS_OP_REGISTER1) {
141 /*
142 * Don't process registration messages if we're in the middle
143 * of a transaction processing.
144 */
145 if (vss_transaction.state > HVUTIL_READY) {
146 pr_debug("VSS: Got unexpected registration request\n");
147 return -EINVAL;
148 }
149
150 return vss_handle_handshake(vss_msg);
151 } else if (vss_transaction.state == HVUTIL_USERSPACE_REQ) {
152 vss_transaction.state = HVUTIL_USERSPACE_RECV;
153
154 if (vss_msg->vss_hdr.operation == VSS_OP_HOT_BACKUP)
155 vss_transaction.msg->vss_cf.flags =
156 VSS_HBU_NO_AUTO_RECOVERY;
157
158 if (cancel_delayed_work_sync(&vss_timeout_work)) {
159 vss_respond_to_host(vss_msg->error);
160 /* Transaction is finished, reset the state. */
161 hv_poll_channel(vss_transaction.recv_channel,
162 vss_poll_wrapper);
163 }
164 } else {
165 /* This is a spurious call! */
166 pr_debug("VSS: Transaction not active\n");
167 return -EINVAL;
168 }
169 return 0;
170}
171
172static void vss_send_op(void)
173{
174 int op = vss_transaction.msg->vss_hdr.operation;
175 int rc;
176 struct hv_vss_msg *vss_msg;
177
178 /* The transaction state is wrong. */
179 if (vss_transaction.state != HVUTIL_HOSTMSG_RECEIVED) {
180 pr_debug("VSS: Unexpected attempt to send to daemon\n");
181 return;
182 }
183
184 vss_msg = kzalloc(sizeof(*vss_msg), GFP_KERNEL);
185 if (!vss_msg)
186 return;
187
188 vss_msg->vss_hdr.operation = op;
189
190 vss_transaction.state = HVUTIL_USERSPACE_REQ;
191
192 schedule_delayed_work(&vss_timeout_work, op == VSS_OP_FREEZE ?
193 VSS_FREEZE_TIMEOUT * HZ : HV_UTIL_TIMEOUT * HZ);
194
195 rc = hvutil_transport_send(hvt, vss_msg, sizeof(*vss_msg), NULL);
196 if (rc) {
197 pr_warn("VSS: failed to communicate to the daemon: %d\n", rc);
198 if (cancel_delayed_work_sync(&vss_timeout_work)) {
199 vss_respond_to_host(HV_E_FAIL);
200 vss_transaction.state = HVUTIL_READY;
201 }
202 }
203
204 kfree(vss_msg);
205}
206
207static void vss_handle_request(struct work_struct *dummy)
208{
209 switch (vss_transaction.msg->vss_hdr.operation) {
210 /*
211 * Initiate a "freeze/thaw" operation in the guest.
212 * We respond to the host once the operation is complete.
213 *
214 * We send the message to the user space daemon and the operation is
215 * performed in the daemon.
216 */
217 case VSS_OP_THAW:
218 case VSS_OP_FREEZE:
219 case VSS_OP_HOT_BACKUP:
220 if (vss_transaction.state < HVUTIL_READY) {
221 /* Userspace is not registered yet */
222 pr_debug("VSS: Not ready for request.\n");
223 vss_respond_to_host(HV_E_FAIL);
224 return;
225 }
226
227 pr_debug("VSS: Received request for op code: %d\n",
228 vss_transaction.msg->vss_hdr.operation);
229 vss_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
230 vss_send_op();
231 return;
232 case VSS_OP_GET_DM_INFO:
233 vss_transaction.msg->dm_info.flags = 0;
234 break;
235 default:
236 break;
237 }
238
239 vss_respond_to_host(0);
240 hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper);
241}
242
243/*
244 * Send a response back to the host.
245 */
246
247static void
248vss_respond_to_host(int error)
249{
250 struct icmsg_hdr *icmsghdrp;
251 u32 buf_len;
252 struct vmbus_channel *channel;
253 u64 req_id;
254
255 /*
256 * Copy the global state for completing the transaction. Note that
257 * only one transaction can be active at a time.
258 */
259
260 buf_len = vss_transaction.recv_len;
261 channel = vss_transaction.recv_channel;
262 req_id = vss_transaction.recv_req_id;
263
264 icmsghdrp = (struct icmsg_hdr *)
265 &recv_buffer[sizeof(struct vmbuspipe_hdr)];
266
267 if (channel->onchannel_callback == NULL)
268 /*
269 * We have raced with util driver being unloaded;
270 * silently return.
271 */
272 return;
273
274 icmsghdrp->status = error;
275
276 icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
277
278 vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
279 VM_PKT_DATA_INBAND, 0);
280
281}
282
283/*
284 * This callback is invoked when we get a VSS message from the host.
285 * The host ensures that only one VSS transaction can be active at a time.
286 */
287
288void hv_vss_onchannelcallback(void *context)
289{
290 struct vmbus_channel *channel = context;
291 u32 recvlen;
292 u64 requestid;
293 struct hv_vss_msg *vss_msg;
294 int vss_srv_version;
295
296 struct icmsg_hdr *icmsghdrp;
297
298 if (vss_transaction.state > HVUTIL_READY)
299 return;
300
301 if (vmbus_recvpacket(channel, recv_buffer, HV_HYP_PAGE_SIZE * 2, &recvlen, &requestid)) {
302 pr_err_ratelimited("VSS request received. Could not read into recv buf\n");
303 return;
304 }
305
306 if (!recvlen)
307 return;
308
309 /* Ensure recvlen is big enough to read header data */
310 if (recvlen < ICMSG_HDR) {
311 pr_err_ratelimited("VSS request received. Packet length too small: %d\n",
312 recvlen);
313 return;
314 }
315
316 icmsghdrp = (struct icmsg_hdr *)&recv_buffer[sizeof(struct vmbuspipe_hdr)];
317
318 if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
319 if (vmbus_prep_negotiate_resp(icmsghdrp,
320 recv_buffer, recvlen,
321 fw_versions, FW_VER_COUNT,
322 vss_versions, VSS_VER_COUNT,
323 NULL, &vss_srv_version)) {
324
325 pr_info("VSS IC version %d.%d\n",
326 vss_srv_version >> 16,
327 vss_srv_version & 0xFFFF);
328 }
329 } else if (icmsghdrp->icmsgtype == ICMSGTYPE_VSS) {
330 /* Ensure recvlen is big enough to contain hv_vss_msg */
331 if (recvlen < ICMSG_HDR + sizeof(struct hv_vss_msg)) {
332 pr_err_ratelimited("Invalid VSS msg. Packet length too small: %u\n",
333 recvlen);
334 return;
335 }
336 vss_msg = (struct hv_vss_msg *)&recv_buffer[ICMSG_HDR];
337
338 /*
339 * Stash away this global state for completing the
340 * transaction; note transactions are serialized.
341 */
342
343 vss_transaction.recv_len = recvlen;
344 vss_transaction.recv_req_id = requestid;
345 vss_transaction.msg = (struct hv_vss_msg *)vss_msg;
346
347 schedule_work(&vss_handle_request_work);
348 return;
349 } else {
350 pr_err_ratelimited("VSS request received. Invalid msg type: %d\n",
351 icmsghdrp->icmsgtype);
352 return;
353 }
354
355 icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION |
356 ICMSGHDRFLAG_RESPONSE;
357 vmbus_sendpacket(channel, recv_buffer, recvlen, requestid,
358 VM_PKT_DATA_INBAND, 0);
359}
360
361static void vss_on_reset(void)
362{
363 if (cancel_delayed_work_sync(&vss_timeout_work))
364 vss_respond_to_host(HV_E_FAIL);
365 vss_transaction.state = HVUTIL_DEVICE_INIT;
366}
367
368int
369hv_vss_init(struct hv_util_service *srv)
370{
371 if (vmbus_proto_version < VERSION_WIN8_1) {
372 pr_warn("Integration service 'Backup (volume snapshot)'"
373 " not supported on this host version.\n");
374 return -ENOTSUPP;
375 }
376 recv_buffer = srv->recv_buffer;
377 vss_transaction.recv_channel = srv->channel;
378 vss_transaction.recv_channel->max_pkt_size = HV_HYP_PAGE_SIZE * 2;
379
380 /*
381 * When this driver loads, the user level daemon that
382 * processes the host requests may not yet be running.
383 * Defer processing channel callbacks until the daemon
384 * has registered.
385 */
386 vss_transaction.state = HVUTIL_DEVICE_INIT;
387
388 hvt = hvutil_transport_init(vss_devname, CN_VSS_IDX, CN_VSS_VAL,
389 vss_on_msg, vss_on_reset);
390 if (!hvt) {
391 pr_warn("VSS: Failed to initialize transport\n");
392 return -EFAULT;
393 }
394
395 return 0;
396}
397
398static void hv_vss_cancel_work(void)
399{
400 cancel_delayed_work_sync(&vss_timeout_work);
401 cancel_work_sync(&vss_handle_request_work);
402}
403
404int hv_vss_pre_suspend(void)
405{
406 struct vmbus_channel *channel = vss_transaction.recv_channel;
407 struct hv_vss_msg *vss_msg;
408
409 /*
410 * Fake a THAW message for the user space daemon in case the daemon
411 * has frozen the file systems. It doesn't matter if there is already
412 * a message pending to be delivered to the user space since we force
413 * vss_transaction.state to be HVUTIL_READY, so the user space daemon's
414 * write() will fail with EINVAL (see vss_on_msg()), and the daemon
415 * will reset the device by closing and re-opening it.
416 */
417 vss_msg = kzalloc(sizeof(*vss_msg), GFP_KERNEL);
418 if (!vss_msg)
419 return -ENOMEM;
420
421 tasklet_disable(&channel->callback_event);
422
423 vss_msg->vss_hdr.operation = VSS_OP_THAW;
424
425 /* Cancel any possible pending work. */
426 hv_vss_cancel_work();
427
428 /* We don't care about the return value. */
429 hvutil_transport_send(hvt, vss_msg, sizeof(*vss_msg), NULL);
430
431 kfree(vss_msg);
432
433 vss_transaction.state = HVUTIL_READY;
434
435 /* tasklet_enable() will be called in hv_vss_pre_resume(). */
436 return 0;
437}
438
439int hv_vss_pre_resume(void)
440{
441 struct vmbus_channel *channel = vss_transaction.recv_channel;
442
443 tasklet_enable(&channel->callback_event);
444
445 return 0;
446}
447
448void hv_vss_deinit(void)
449{
450 vss_transaction.state = HVUTIL_DEVICE_DYING;
451
452 hv_vss_cancel_work();
453
454 hvutil_transport_destroy(hvt);
455}