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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/* See comment with struct hv_vss_msg regarding the max VMbus packet size */
35#define VSS_MAX_PKT_SIZE (HV_HYP_PAGE_SIZE * 2)
36
37/*
38 * Timeout values are based on expecations from host
39 */
40#define VSS_FREEZE_TIMEOUT (15 * 60)
41
42/*
43 * Global state maintained for transaction that is being processed. For a class
44 * of integration services, including the "VSS service", the specified protocol
45 * is a "request/response" protocol which means that there can only be single
46 * outstanding transaction from the host at any given point in time. We use
47 * this to simplify memory management in this driver - we cache and process
48 * only one message at a time.
49 *
50 * While the request/response protocol is guaranteed by the host, we further
51 * ensure this by serializing packet processing in this driver - we do not
52 * read additional packets from the VMBUs until the current packet is fully
53 * handled.
54 */
55
56static struct {
57 int state; /* hvutil_device_state */
58 int recv_len; /* number of bytes received. */
59 struct vmbus_channel *recv_channel; /* chn we got the request */
60 u64 recv_req_id; /* request ID. */
61 struct hv_vss_msg *msg; /* current message */
62} vss_transaction;
63
64
65static void vss_respond_to_host(int error);
66
67/*
68 * This state maintains the version number registered by the daemon.
69 */
70static int dm_reg_value;
71
72static const char vss_devname[] = "vmbus/hv_vss";
73static __u8 *recv_buffer;
74static struct hvutil_transport *hvt;
75
76static void vss_timeout_func(struct work_struct *dummy);
77static void vss_handle_request(struct work_struct *dummy);
78
79static DECLARE_DELAYED_WORK(vss_timeout_work, vss_timeout_func);
80static DECLARE_WORK(vss_handle_request_work, vss_handle_request);
81
82static void vss_poll_wrapper(void *channel)
83{
84 /* Transaction is finished, reset the state here to avoid races. */
85 vss_transaction.state = HVUTIL_READY;
86 tasklet_schedule(&((struct vmbus_channel *)channel)->callback_event);
87}
88
89/*
90 * Callback when data is received from user mode.
91 */
92
93static void vss_timeout_func(struct work_struct *dummy)
94{
95 /*
96 * Timeout waiting for userspace component to reply happened.
97 */
98 pr_warn("VSS: timeout waiting for daemon to reply\n");
99 vss_respond_to_host(HV_E_FAIL);
100
101 hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper);
102}
103
104static void vss_register_done(void)
105{
106 hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper);
107 pr_debug("VSS: userspace daemon registered\n");
108}
109
110static int vss_handle_handshake(struct hv_vss_msg *vss_msg)
111{
112 u32 our_ver = VSS_OP_REGISTER1;
113
114 switch (vss_msg->vss_hdr.operation) {
115 case VSS_OP_REGISTER:
116 /* Daemon doesn't expect us to reply */
117 dm_reg_value = VSS_OP_REGISTER;
118 break;
119 case VSS_OP_REGISTER1:
120 /* Daemon expects us to reply with our own version */
121 if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver),
122 vss_register_done))
123 return -EFAULT;
124 dm_reg_value = VSS_OP_REGISTER1;
125 break;
126 default:
127 return -EINVAL;
128 }
129 pr_info("VSS: userspace daemon ver. %d connected\n", dm_reg_value);
130 return 0;
131}
132
133static int vss_on_msg(void *msg, int len)
134{
135 struct hv_vss_msg *vss_msg = (struct hv_vss_msg *)msg;
136
137 if (len != sizeof(*vss_msg)) {
138 pr_debug("VSS: Message size does not match length\n");
139 return -EINVAL;
140 }
141
142 if (vss_msg->vss_hdr.operation == VSS_OP_REGISTER ||
143 vss_msg->vss_hdr.operation == VSS_OP_REGISTER1) {
144 /*
145 * Don't process registration messages if we're in the middle
146 * of a transaction processing.
147 */
148 if (vss_transaction.state > HVUTIL_READY) {
149 pr_debug("VSS: Got unexpected registration request\n");
150 return -EINVAL;
151 }
152
153 return vss_handle_handshake(vss_msg);
154 } else if (vss_transaction.state == HVUTIL_USERSPACE_REQ) {
155 vss_transaction.state = HVUTIL_USERSPACE_RECV;
156
157 if (vss_msg->vss_hdr.operation == VSS_OP_HOT_BACKUP)
158 vss_transaction.msg->vss_cf.flags =
159 VSS_HBU_NO_AUTO_RECOVERY;
160
161 if (cancel_delayed_work_sync(&vss_timeout_work)) {
162 vss_respond_to_host(vss_msg->error);
163 /* Transaction is finished, reset the state. */
164 hv_poll_channel(vss_transaction.recv_channel,
165 vss_poll_wrapper);
166 }
167 } else {
168 /* This is a spurious call! */
169 pr_debug("VSS: Transaction not active\n");
170 return -EINVAL;
171 }
172 return 0;
173}
174
175static void vss_send_op(void)
176{
177 int op = vss_transaction.msg->vss_hdr.operation;
178 int rc;
179 struct hv_vss_msg *vss_msg;
180
181 /* The transaction state is wrong. */
182 if (vss_transaction.state != HVUTIL_HOSTMSG_RECEIVED) {
183 pr_debug("VSS: Unexpected attempt to send to daemon\n");
184 return;
185 }
186
187 vss_msg = kzalloc(sizeof(*vss_msg), GFP_KERNEL);
188 if (!vss_msg)
189 return;
190
191 vss_msg->vss_hdr.operation = op;
192
193 vss_transaction.state = HVUTIL_USERSPACE_REQ;
194
195 schedule_delayed_work(&vss_timeout_work, op == VSS_OP_FREEZE ?
196 VSS_FREEZE_TIMEOUT * HZ : HV_UTIL_TIMEOUT * HZ);
197
198 rc = hvutil_transport_send(hvt, vss_msg, sizeof(*vss_msg), NULL);
199 if (rc) {
200 pr_warn("VSS: failed to communicate to the daemon: %d\n", rc);
201 if (cancel_delayed_work_sync(&vss_timeout_work)) {
202 vss_respond_to_host(HV_E_FAIL);
203 vss_transaction.state = HVUTIL_READY;
204 }
205 }
206
207 kfree(vss_msg);
208}
209
210static void vss_handle_request(struct work_struct *dummy)
211{
212 switch (vss_transaction.msg->vss_hdr.operation) {
213 /*
214 * Initiate a "freeze/thaw" operation in the guest.
215 * We respond to the host once the operation is complete.
216 *
217 * We send the message to the user space daemon and the operation is
218 * performed in the daemon.
219 */
220 case VSS_OP_THAW:
221 case VSS_OP_FREEZE:
222 case VSS_OP_HOT_BACKUP:
223 if (vss_transaction.state < HVUTIL_READY) {
224 /* Userspace is not registered yet */
225 pr_debug("VSS: Not ready for request.\n");
226 vss_respond_to_host(HV_E_FAIL);
227 return;
228 }
229
230 pr_debug("VSS: Received request for op code: %d\n",
231 vss_transaction.msg->vss_hdr.operation);
232 vss_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
233 vss_send_op();
234 return;
235 case VSS_OP_GET_DM_INFO:
236 vss_transaction.msg->dm_info.flags = 0;
237 break;
238 default:
239 break;
240 }
241
242 vss_respond_to_host(0);
243 hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper);
244}
245
246/*
247 * Send a response back to the host.
248 */
249
250static void
251vss_respond_to_host(int error)
252{
253 struct icmsg_hdr *icmsghdrp;
254 u32 buf_len;
255 struct vmbus_channel *channel;
256 u64 req_id;
257
258 /*
259 * Copy the global state for completing the transaction. Note that
260 * only one transaction can be active at a time.
261 */
262
263 buf_len = vss_transaction.recv_len;
264 channel = vss_transaction.recv_channel;
265 req_id = vss_transaction.recv_req_id;
266
267 icmsghdrp = (struct icmsg_hdr *)
268 &recv_buffer[sizeof(struct vmbuspipe_hdr)];
269
270 if (channel->onchannel_callback == NULL)
271 /*
272 * We have raced with util driver being unloaded;
273 * silently return.
274 */
275 return;
276
277 icmsghdrp->status = error;
278
279 icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
280
281 vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
282 VM_PKT_DATA_INBAND, 0);
283
284}
285
286/*
287 * This callback is invoked when we get a VSS message from the host.
288 * The host ensures that only one VSS transaction can be active at a time.
289 */
290
291void hv_vss_onchannelcallback(void *context)
292{
293 struct vmbus_channel *channel = context;
294 u32 recvlen;
295 u64 requestid;
296 struct hv_vss_msg *vss_msg;
297 int vss_srv_version;
298
299 struct icmsg_hdr *icmsghdrp;
300
301 if (vss_transaction.state > HVUTIL_READY)
302 return;
303
304 if (vmbus_recvpacket(channel, recv_buffer, VSS_MAX_PKT_SIZE, &recvlen, &requestid)) {
305 pr_err_ratelimited("VSS request received. Could not read into recv buf\n");
306 return;
307 }
308
309 if (!recvlen)
310 return;
311
312 /* Ensure recvlen is big enough to read header data */
313 if (recvlen < ICMSG_HDR) {
314 pr_err_ratelimited("VSS request received. Packet length too small: %d\n",
315 recvlen);
316 return;
317 }
318
319 icmsghdrp = (struct icmsg_hdr *)&recv_buffer[sizeof(struct vmbuspipe_hdr)];
320
321 if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
322 if (vmbus_prep_negotiate_resp(icmsghdrp,
323 recv_buffer, recvlen,
324 fw_versions, FW_VER_COUNT,
325 vss_versions, VSS_VER_COUNT,
326 NULL, &vss_srv_version)) {
327
328 pr_info("VSS IC version %d.%d\n",
329 vss_srv_version >> 16,
330 vss_srv_version & 0xFFFF);
331 }
332 } else if (icmsghdrp->icmsgtype == ICMSGTYPE_VSS) {
333 /* Ensure recvlen is big enough to contain hv_vss_msg */
334 if (recvlen < ICMSG_HDR + sizeof(struct hv_vss_msg)) {
335 pr_err_ratelimited("Invalid VSS msg. Packet length too small: %u\n",
336 recvlen);
337 return;
338 }
339 vss_msg = (struct hv_vss_msg *)&recv_buffer[ICMSG_HDR];
340
341 /*
342 * Stash away this global state for completing the
343 * transaction; note transactions are serialized.
344 */
345
346 vss_transaction.recv_len = recvlen;
347 vss_transaction.recv_req_id = requestid;
348 vss_transaction.msg = (struct hv_vss_msg *)vss_msg;
349
350 schedule_work(&vss_handle_request_work);
351 return;
352 } else {
353 pr_err_ratelimited("VSS request received. Invalid msg type: %d\n",
354 icmsghdrp->icmsgtype);
355 return;
356 }
357
358 icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION |
359 ICMSGHDRFLAG_RESPONSE;
360 vmbus_sendpacket(channel, recv_buffer, recvlen, requestid,
361 VM_PKT_DATA_INBAND, 0);
362}
363
364static void vss_on_reset(void)
365{
366 if (cancel_delayed_work_sync(&vss_timeout_work))
367 vss_respond_to_host(HV_E_FAIL);
368 vss_transaction.state = HVUTIL_DEVICE_INIT;
369}
370
371int
372hv_vss_init(struct hv_util_service *srv)
373{
374 if (vmbus_proto_version < VERSION_WIN8_1) {
375 pr_warn("Integration service 'Backup (volume snapshot)'"
376 " not supported on this host version.\n");
377 return -ENOTSUPP;
378 }
379 recv_buffer = srv->recv_buffer;
380 vss_transaction.recv_channel = srv->channel;
381 vss_transaction.recv_channel->max_pkt_size = VSS_MAX_PKT_SIZE;
382
383 /*
384 * When this driver loads, the user level daemon that
385 * processes the host requests may not yet be running.
386 * Defer processing channel callbacks until the daemon
387 * has registered.
388 */
389 vss_transaction.state = HVUTIL_DEVICE_INIT;
390
391 hvt = hvutil_transport_init(vss_devname, CN_VSS_IDX, CN_VSS_VAL,
392 vss_on_msg, vss_on_reset);
393 if (!hvt) {
394 pr_warn("VSS: Failed to initialize transport\n");
395 return -EFAULT;
396 }
397
398 return 0;
399}
400
401static void hv_vss_cancel_work(void)
402{
403 cancel_delayed_work_sync(&vss_timeout_work);
404 cancel_work_sync(&vss_handle_request_work);
405}
406
407int hv_vss_pre_suspend(void)
408{
409 struct vmbus_channel *channel = vss_transaction.recv_channel;
410 struct hv_vss_msg *vss_msg;
411
412 /*
413 * Fake a THAW message for the user space daemon in case the daemon
414 * has frozen the file systems. It doesn't matter if there is already
415 * a message pending to be delivered to the user space since we force
416 * vss_transaction.state to be HVUTIL_READY, so the user space daemon's
417 * write() will fail with EINVAL (see vss_on_msg()), and the daemon
418 * will reset the device by closing and re-opening it.
419 */
420 vss_msg = kzalloc(sizeof(*vss_msg), GFP_KERNEL);
421 if (!vss_msg)
422 return -ENOMEM;
423
424 tasklet_disable(&channel->callback_event);
425
426 vss_msg->vss_hdr.operation = VSS_OP_THAW;
427
428 /* Cancel any possible pending work. */
429 hv_vss_cancel_work();
430
431 /* We don't care about the return value. */
432 hvutil_transport_send(hvt, vss_msg, sizeof(*vss_msg), NULL);
433
434 kfree(vss_msg);
435
436 vss_transaction.state = HVUTIL_READY;
437
438 /* tasklet_enable() will be called in hv_vss_pre_resume(). */
439 return 0;
440}
441
442int hv_vss_pre_resume(void)
443{
444 struct vmbus_channel *channel = vss_transaction.recv_channel;
445
446 tasklet_enable(&channel->callback_event);
447
448 return 0;
449}
450
451void hv_vss_deinit(void)
452{
453 vss_transaction.state = HVUTIL_DEVICE_DYING;
454
455 hv_vss_cancel_work();
456
457 hvutil_transport_destroy(hvt);
458}
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
16#include "hyperv_vmbus.h"
17#include "hv_utils_transport.h"
18
19#define VSS_MAJOR 5
20#define VSS_MINOR 0
21#define VSS_VERSION (VSS_MAJOR << 16 | VSS_MINOR)
22
23#define VSS_VER_COUNT 1
24static const int vss_versions[] = {
25 VSS_VERSION
26};
27
28#define FW_VER_COUNT 1
29static const int fw_versions[] = {
30 UTIL_FW_VERSION
31};
32
33/*
34 * Timeout values are based on expecations from host
35 */
36#define VSS_FREEZE_TIMEOUT (15 * 60)
37
38/*
39 * Global state maintained for transaction that is being processed. For a class
40 * of integration services, including the "VSS service", the specified protocol
41 * is a "request/response" protocol which means that there can only be single
42 * outstanding transaction from the host at any given point in time. We use
43 * this to simplify memory management in this driver - we cache and process
44 * only one message at a time.
45 *
46 * While the request/response protocol is guaranteed by the host, we further
47 * ensure this by serializing packet processing in this driver - we do not
48 * read additional packets from the VMBUs until the current packet is fully
49 * handled.
50 */
51
52static struct {
53 int state; /* hvutil_device_state */
54 int recv_len; /* number of bytes received. */
55 struct vmbus_channel *recv_channel; /* chn we got the request */
56 u64 recv_req_id; /* request ID. */
57 struct hv_vss_msg *msg; /* current message */
58} vss_transaction;
59
60
61static void vss_respond_to_host(int error);
62
63/*
64 * This state maintains the version number registered by the daemon.
65 */
66static int dm_reg_value;
67
68static const char vss_devname[] = "vmbus/hv_vss";
69static __u8 *recv_buffer;
70static struct hvutil_transport *hvt;
71
72static void vss_timeout_func(struct work_struct *dummy);
73static void vss_handle_request(struct work_struct *dummy);
74
75static DECLARE_DELAYED_WORK(vss_timeout_work, vss_timeout_func);
76static DECLARE_WORK(vss_handle_request_work, vss_handle_request);
77
78static void vss_poll_wrapper(void *channel)
79{
80 /* Transaction is finished, reset the state here to avoid races. */
81 vss_transaction.state = HVUTIL_READY;
82 hv_vss_onchannelcallback(channel);
83}
84
85/*
86 * Callback when data is received from user mode.
87 */
88
89static void vss_timeout_func(struct work_struct *dummy)
90{
91 /*
92 * Timeout waiting for userspace component to reply happened.
93 */
94 pr_warn("VSS: timeout waiting for daemon to reply\n");
95 vss_respond_to_host(HV_E_FAIL);
96
97 hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper);
98}
99
100static void vss_register_done(void)
101{
102 hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper);
103 pr_debug("VSS: userspace daemon registered\n");
104}
105
106static int vss_handle_handshake(struct hv_vss_msg *vss_msg)
107{
108 u32 our_ver = VSS_OP_REGISTER1;
109
110 switch (vss_msg->vss_hdr.operation) {
111 case VSS_OP_REGISTER:
112 /* Daemon doesn't expect us to reply */
113 dm_reg_value = VSS_OP_REGISTER;
114 break;
115 case VSS_OP_REGISTER1:
116 /* Daemon expects us to reply with our own version */
117 if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver),
118 vss_register_done))
119 return -EFAULT;
120 dm_reg_value = VSS_OP_REGISTER1;
121 break;
122 default:
123 return -EINVAL;
124 }
125 pr_info("VSS: userspace daemon ver. %d connected\n", dm_reg_value);
126 return 0;
127}
128
129static int vss_on_msg(void *msg, int len)
130{
131 struct hv_vss_msg *vss_msg = (struct hv_vss_msg *)msg;
132
133 if (len != sizeof(*vss_msg)) {
134 pr_debug("VSS: Message size does not match length\n");
135 return -EINVAL;
136 }
137
138 if (vss_msg->vss_hdr.operation == VSS_OP_REGISTER ||
139 vss_msg->vss_hdr.operation == VSS_OP_REGISTER1) {
140 /*
141 * Don't process registration messages if we're in the middle
142 * of a transaction processing.
143 */
144 if (vss_transaction.state > HVUTIL_READY) {
145 pr_debug("VSS: Got unexpected registration request\n");
146 return -EINVAL;
147 }
148
149 return vss_handle_handshake(vss_msg);
150 } else if (vss_transaction.state == HVUTIL_USERSPACE_REQ) {
151 vss_transaction.state = HVUTIL_USERSPACE_RECV;
152
153 if (vss_msg->vss_hdr.operation == VSS_OP_HOT_BACKUP)
154 vss_transaction.msg->vss_cf.flags =
155 VSS_HBU_NO_AUTO_RECOVERY;
156
157 if (cancel_delayed_work_sync(&vss_timeout_work)) {
158 vss_respond_to_host(vss_msg->error);
159 /* Transaction is finished, reset the state. */
160 hv_poll_channel(vss_transaction.recv_channel,
161 vss_poll_wrapper);
162 }
163 } else {
164 /* This is a spurious call! */
165 pr_debug("VSS: Transaction not active\n");
166 return -EINVAL;
167 }
168 return 0;
169}
170
171static void vss_send_op(void)
172{
173 int op = vss_transaction.msg->vss_hdr.operation;
174 int rc;
175 struct hv_vss_msg *vss_msg;
176
177 /* The transaction state is wrong. */
178 if (vss_transaction.state != HVUTIL_HOSTMSG_RECEIVED) {
179 pr_debug("VSS: Unexpected attempt to send to daemon\n");
180 return;
181 }
182
183 vss_msg = kzalloc(sizeof(*vss_msg), GFP_KERNEL);
184 if (!vss_msg)
185 return;
186
187 vss_msg->vss_hdr.operation = op;
188
189 vss_transaction.state = HVUTIL_USERSPACE_REQ;
190
191 schedule_delayed_work(&vss_timeout_work, op == VSS_OP_FREEZE ?
192 VSS_FREEZE_TIMEOUT * HZ : HV_UTIL_TIMEOUT * HZ);
193
194 rc = hvutil_transport_send(hvt, vss_msg, sizeof(*vss_msg), NULL);
195 if (rc) {
196 pr_warn("VSS: failed to communicate to the daemon: %d\n", rc);
197 if (cancel_delayed_work_sync(&vss_timeout_work)) {
198 vss_respond_to_host(HV_E_FAIL);
199 vss_transaction.state = HVUTIL_READY;
200 }
201 }
202
203 kfree(vss_msg);
204}
205
206static void vss_handle_request(struct work_struct *dummy)
207{
208 switch (vss_transaction.msg->vss_hdr.operation) {
209 /*
210 * Initiate a "freeze/thaw" operation in the guest.
211 * We respond to the host once the operation is complete.
212 *
213 * We send the message to the user space daemon and the operation is
214 * performed in the daemon.
215 */
216 case VSS_OP_THAW:
217 case VSS_OP_FREEZE:
218 case VSS_OP_HOT_BACKUP:
219 if (vss_transaction.state < HVUTIL_READY) {
220 /* Userspace is not registered yet */
221 pr_debug("VSS: Not ready for request.\n");
222 vss_respond_to_host(HV_E_FAIL);
223 return;
224 }
225
226 pr_debug("VSS: Received request for op code: %d\n",
227 vss_transaction.msg->vss_hdr.operation);
228 vss_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
229 vss_send_op();
230 return;
231 case VSS_OP_GET_DM_INFO:
232 vss_transaction.msg->dm_info.flags = 0;
233 break;
234 default:
235 break;
236 }
237
238 vss_respond_to_host(0);
239 hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper);
240}
241
242/*
243 * Send a response back to the host.
244 */
245
246static void
247vss_respond_to_host(int error)
248{
249 struct icmsg_hdr *icmsghdrp;
250 u32 buf_len;
251 struct vmbus_channel *channel;
252 u64 req_id;
253
254 /*
255 * Copy the global state for completing the transaction. Note that
256 * only one transaction can be active at a time.
257 */
258
259 buf_len = vss_transaction.recv_len;
260 channel = vss_transaction.recv_channel;
261 req_id = vss_transaction.recv_req_id;
262
263 icmsghdrp = (struct icmsg_hdr *)
264 &recv_buffer[sizeof(struct vmbuspipe_hdr)];
265
266 if (channel->onchannel_callback == NULL)
267 /*
268 * We have raced with util driver being unloaded;
269 * silently return.
270 */
271 return;
272
273 icmsghdrp->status = error;
274
275 icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
276
277 vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
278 VM_PKT_DATA_INBAND, 0);
279
280}
281
282/*
283 * This callback is invoked when we get a VSS message from the host.
284 * The host ensures that only one VSS transaction can be active at a time.
285 */
286
287void hv_vss_onchannelcallback(void *context)
288{
289 struct vmbus_channel *channel = context;
290 u32 recvlen;
291 u64 requestid;
292 struct hv_vss_msg *vss_msg;
293 int vss_srv_version;
294
295 struct icmsg_hdr *icmsghdrp;
296
297 if (vss_transaction.state > HVUTIL_READY)
298 return;
299
300 vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
301 &requestid);
302
303 if (recvlen > 0) {
304 icmsghdrp = (struct icmsg_hdr *)&recv_buffer[
305 sizeof(struct vmbuspipe_hdr)];
306
307 if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
308 if (vmbus_prep_negotiate_resp(icmsghdrp,
309 recv_buffer, fw_versions, FW_VER_COUNT,
310 vss_versions, VSS_VER_COUNT,
311 NULL, &vss_srv_version)) {
312
313 pr_info("VSS IC version %d.%d\n",
314 vss_srv_version >> 16,
315 vss_srv_version & 0xFFFF);
316 }
317 } else {
318 vss_msg = (struct hv_vss_msg *)&recv_buffer[
319 sizeof(struct vmbuspipe_hdr) +
320 sizeof(struct icmsg_hdr)];
321
322 /*
323 * Stash away this global state for completing the
324 * transaction; note transactions are serialized.
325 */
326
327 vss_transaction.recv_len = recvlen;
328 vss_transaction.recv_req_id = requestid;
329 vss_transaction.msg = (struct hv_vss_msg *)vss_msg;
330
331 schedule_work(&vss_handle_request_work);
332 return;
333 }
334
335 icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
336 | ICMSGHDRFLAG_RESPONSE;
337
338 vmbus_sendpacket(channel, recv_buffer,
339 recvlen, requestid,
340 VM_PKT_DATA_INBAND, 0);
341 }
342
343}
344
345static void vss_on_reset(void)
346{
347 if (cancel_delayed_work_sync(&vss_timeout_work))
348 vss_respond_to_host(HV_E_FAIL);
349 vss_transaction.state = HVUTIL_DEVICE_INIT;
350}
351
352int
353hv_vss_init(struct hv_util_service *srv)
354{
355 if (vmbus_proto_version < VERSION_WIN8_1) {
356 pr_warn("Integration service 'Backup (volume snapshot)'"
357 " not supported on this host version.\n");
358 return -ENOTSUPP;
359 }
360 recv_buffer = srv->recv_buffer;
361 vss_transaction.recv_channel = srv->channel;
362
363 /*
364 * When this driver loads, the user level daemon that
365 * processes the host requests may not yet be running.
366 * Defer processing channel callbacks until the daemon
367 * has registered.
368 */
369 vss_transaction.state = HVUTIL_DEVICE_INIT;
370
371 hvt = hvutil_transport_init(vss_devname, CN_VSS_IDX, CN_VSS_VAL,
372 vss_on_msg, vss_on_reset);
373 if (!hvt) {
374 pr_warn("VSS: Failed to initialize transport\n");
375 return -EFAULT;
376 }
377
378 return 0;
379}
380
381void hv_vss_deinit(void)
382{
383 vss_transaction.state = HVUTIL_DEVICE_DYING;
384 cancel_delayed_work_sync(&vss_timeout_work);
385 cancel_work_sync(&vss_handle_request_work);
386 hvutil_transport_destroy(hvt);
387}