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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 */ | |
38c06c29 | 56 | void *vss_context; /* for the channel callback */ |
96dd86fa S |
57 | } vss_transaction; |
58 | ||
59 | ||
60 | static void vss_respond_to_host(int error); | |
61 | ||
6472f80a | 62 | static const char vss_devname[] = "vmbus/hv_vss"; |
96dd86fa | 63 | static __u8 *recv_buffer; |
6472f80a | 64 | static struct hvutil_transport *hvt; |
96dd86fa S |
65 | |
66 | static void vss_send_op(struct work_struct *dummy); | |
64914207 VK |
67 | static void vss_timeout_func(struct work_struct *dummy); |
68 | ||
69 | static DECLARE_DELAYED_WORK(vss_timeout_work, vss_timeout_func); | |
96dd86fa S |
70 | static DECLARE_WORK(vss_send_op_work, vss_send_op); |
71 | ||
72 | /* | |
73 | * Callback when data is received from user mode. | |
74 | */ | |
75 | ||
64914207 VK |
76 | static void vss_timeout_func(struct work_struct *dummy) |
77 | { | |
78 | /* | |
79 | * Timeout waiting for userspace component to reply happened. | |
80 | */ | |
81 | pr_warn("VSS: timeout waiting for daemon to reply\n"); | |
82 | vss_respond_to_host(HV_E_FAIL); | |
38c06c29 | 83 | |
086a6f68 VK |
84 | /* Transaction is finished, reset the state. */ |
85 | if (vss_transaction.state > HVUTIL_READY) | |
86 | vss_transaction.state = HVUTIL_READY; | |
87 | ||
38c06c29 VK |
88 | hv_poll_channel(vss_transaction.vss_context, |
89 | hv_vss_onchannelcallback); | |
64914207 VK |
90 | } |
91 | ||
6472f80a | 92 | static int vss_on_msg(void *msg, int len) |
96dd86fa | 93 | { |
6472f80a | 94 | struct hv_vss_msg *vss_msg = (struct hv_vss_msg *)msg; |
96dd86fa | 95 | |
6472f80a VK |
96 | if (len != sizeof(*vss_msg)) |
97 | return -EINVAL; | |
96dd86fa | 98 | |
086a6f68 VK |
99 | /* |
100 | * Don't process registration messages if we're in the middle of | |
101 | * a transaction processing. | |
102 | */ | |
103 | if (vss_transaction.state > HVUTIL_READY && | |
104 | vss_msg->vss_hdr.operation == VSS_OP_REGISTER) | |
6472f80a | 105 | return -EINVAL; |
086a6f68 VK |
106 | |
107 | if (vss_transaction.state == HVUTIL_DEVICE_INIT && | |
108 | vss_msg->vss_hdr.operation == VSS_OP_REGISTER) { | |
96dd86fa | 109 | pr_info("VSS daemon registered\n"); |
086a6f68 VK |
110 | vss_transaction.state = HVUTIL_READY; |
111 | } else if (vss_transaction.state == HVUTIL_USERSPACE_REQ) { | |
112 | vss_transaction.state = HVUTIL_USERSPACE_RECV; | |
113 | if (cancel_delayed_work_sync(&vss_timeout_work)) { | |
114 | vss_respond_to_host(vss_msg->error); | |
115 | /* Transaction is finished, reset the state. */ | |
116 | vss_transaction.state = HVUTIL_READY; | |
117 | hv_poll_channel(vss_transaction.vss_context, | |
118 | hv_vss_onchannelcallback); | |
119 | } | |
120 | } else { | |
121 | /* This is a spurious call! */ | |
122 | pr_warn("VSS: Transaction not active\n"); | |
6472f80a | 123 | return -EINVAL; |
96dd86fa | 124 | } |
6472f80a | 125 | return 0; |
96dd86fa S |
126 | } |
127 | ||
128 | ||
129 | static void vss_send_op(struct work_struct *dummy) | |
130 | { | |
131 | int op = vss_transaction.msg->vss_hdr.operation; | |
8d9560eb | 132 | int rc; |
96dd86fa S |
133 | struct hv_vss_msg *vss_msg; |
134 | ||
086a6f68 VK |
135 | /* The transaction state is wrong. */ |
136 | if (vss_transaction.state != HVUTIL_HOSTMSG_RECEIVED) | |
137 | return; | |
138 | ||
6472f80a VK |
139 | vss_msg = kzalloc(sizeof(*vss_msg), GFP_KERNEL); |
140 | if (!vss_msg) | |
96dd86fa S |
141 | return; |
142 | ||
96dd86fa | 143 | vss_msg->vss_hdr.operation = op; |
96dd86fa | 144 | |
086a6f68 | 145 | vss_transaction.state = HVUTIL_USERSPACE_REQ; |
6472f80a | 146 | rc = hvutil_transport_send(hvt, vss_msg, sizeof(*vss_msg)); |
8d9560eb VK |
147 | if (rc) { |
148 | pr_warn("VSS: failed to communicate to the daemon: %d\n", rc); | |
086a6f68 | 149 | if (cancel_delayed_work_sync(&vss_timeout_work)) { |
8d9560eb | 150 | vss_respond_to_host(HV_E_FAIL); |
086a6f68 VK |
151 | vss_transaction.state = HVUTIL_READY; |
152 | } | |
8d9560eb | 153 | } |
086a6f68 | 154 | |
6472f80a | 155 | kfree(vss_msg); |
96dd86fa S |
156 | |
157 | return; | |
158 | } | |
159 | ||
160 | /* | |
161 | * Send a response back to the host. | |
162 | */ | |
163 | ||
164 | static void | |
165 | vss_respond_to_host(int error) | |
166 | { | |
167 | struct icmsg_hdr *icmsghdrp; | |
168 | u32 buf_len; | |
169 | struct vmbus_channel *channel; | |
170 | u64 req_id; | |
171 | ||
96dd86fa S |
172 | /* |
173 | * Copy the global state for completing the transaction. Note that | |
174 | * only one transaction can be active at a time. | |
175 | */ | |
176 | ||
177 | buf_len = vss_transaction.recv_len; | |
178 | channel = vss_transaction.recv_channel; | |
179 | req_id = vss_transaction.recv_req_id; | |
96dd86fa S |
180 | |
181 | icmsghdrp = (struct icmsg_hdr *) | |
182 | &recv_buffer[sizeof(struct vmbuspipe_hdr)]; | |
183 | ||
184 | if (channel->onchannel_callback == NULL) | |
185 | /* | |
186 | * We have raced with util driver being unloaded; | |
187 | * silently return. | |
188 | */ | |
189 | return; | |
190 | ||
191 | icmsghdrp->status = error; | |
192 | ||
193 | icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE; | |
194 | ||
195 | vmbus_sendpacket(channel, recv_buffer, buf_len, req_id, | |
196 | VM_PKT_DATA_INBAND, 0); | |
197 | ||
198 | } | |
199 | ||
200 | /* | |
201 | * This callback is invoked when we get a VSS message from the host. | |
202 | * The host ensures that only one VSS transaction can be active at a time. | |
203 | */ | |
204 | ||
205 | void hv_vss_onchannelcallback(void *context) | |
206 | { | |
207 | struct vmbus_channel *channel = context; | |
208 | u32 recvlen; | |
209 | u64 requestid; | |
210 | struct hv_vss_msg *vss_msg; | |
211 | ||
212 | ||
213 | struct icmsg_hdr *icmsghdrp; | |
214 | struct icmsg_negotiate *negop = NULL; | |
215 | ||
086a6f68 | 216 | if (vss_transaction.state > HVUTIL_READY) { |
96dd86fa S |
217 | /* |
218 | * We will defer processing this callback once | |
219 | * the current transaction is complete. | |
220 | */ | |
38c06c29 | 221 | vss_transaction.vss_context = context; |
96dd86fa S |
222 | return; |
223 | } | |
38c06c29 | 224 | vss_transaction.vss_context = NULL; |
96dd86fa S |
225 | |
226 | vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen, | |
227 | &requestid); | |
228 | ||
229 | if (recvlen > 0) { | |
230 | icmsghdrp = (struct icmsg_hdr *)&recv_buffer[ | |
231 | sizeof(struct vmbuspipe_hdr)]; | |
232 | ||
233 | if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) { | |
234 | vmbus_prep_negotiate_resp(icmsghdrp, negop, | |
3a491605 S |
235 | recv_buffer, UTIL_FW_VERSION, |
236 | VSS_VERSION); | |
96dd86fa S |
237 | } else { |
238 | vss_msg = (struct hv_vss_msg *)&recv_buffer[ | |
239 | sizeof(struct vmbuspipe_hdr) + | |
240 | sizeof(struct icmsg_hdr)]; | |
241 | ||
242 | /* | |
243 | * Stash away this global state for completing the | |
244 | * transaction; note transactions are serialized. | |
245 | */ | |
246 | ||
247 | vss_transaction.recv_len = recvlen; | |
248 | vss_transaction.recv_channel = channel; | |
249 | vss_transaction.recv_req_id = requestid; | |
96dd86fa S |
250 | vss_transaction.msg = (struct hv_vss_msg *)vss_msg; |
251 | ||
252 | switch (vss_msg->vss_hdr.operation) { | |
253 | /* | |
254 | * Initiate a "freeze/thaw" | |
255 | * operation in the guest. | |
256 | * We respond to the host once | |
257 | * the operation is complete. | |
258 | * | |
259 | * We send the message to the | |
260 | * user space daemon and the | |
261 | * operation is performed in | |
262 | * the daemon. | |
263 | */ | |
264 | case VSS_OP_FREEZE: | |
265 | case VSS_OP_THAW: | |
086a6f68 VK |
266 | if (vss_transaction.state < HVUTIL_READY) { |
267 | /* Userspace is not registered yet */ | |
268 | vss_respond_to_host(HV_E_FAIL); | |
269 | return; | |
270 | } | |
271 | vss_transaction.state = HVUTIL_HOSTMSG_RECEIVED; | |
96dd86fa | 272 | schedule_work(&vss_send_op_work); |
64914207 VK |
273 | schedule_delayed_work(&vss_timeout_work, |
274 | VSS_USERSPACE_TIMEOUT); | |
96dd86fa S |
275 | return; |
276 | ||
277 | case VSS_OP_HOT_BACKUP: | |
278 | vss_msg->vss_cf.flags = | |
279 | VSS_HBU_NO_AUTO_RECOVERY; | |
280 | vss_respond_to_host(0); | |
281 | return; | |
282 | ||
283 | case VSS_OP_GET_DM_INFO: | |
284 | vss_msg->dm_info.flags = 0; | |
285 | vss_respond_to_host(0); | |
286 | return; | |
287 | ||
288 | default: | |
289 | vss_respond_to_host(0); | |
290 | return; | |
291 | ||
292 | } | |
293 | ||
294 | } | |
295 | ||
296 | icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | |
297 | | ICMSGHDRFLAG_RESPONSE; | |
298 | ||
299 | vmbus_sendpacket(channel, recv_buffer, | |
300 | recvlen, requestid, | |
301 | VM_PKT_DATA_INBAND, 0); | |
302 | } | |
303 | ||
304 | } | |
305 | ||
6472f80a VK |
306 | static void vss_on_reset(void) |
307 | { | |
308 | if (cancel_delayed_work_sync(&vss_timeout_work)) | |
309 | vss_respond_to_host(HV_E_FAIL); | |
310 | vss_transaction.state = HVUTIL_DEVICE_INIT; | |
311 | } | |
312 | ||
96dd86fa S |
313 | int |
314 | hv_vss_init(struct hv_util_service *srv) | |
315 | { | |
96dd86fa S |
316 | recv_buffer = srv->recv_buffer; |
317 | ||
318 | /* | |
319 | * When this driver loads, the user level daemon that | |
320 | * processes the host requests may not yet be running. | |
321 | * Defer processing channel callbacks until the daemon | |
322 | * has registered. | |
323 | */ | |
086a6f68 VK |
324 | vss_transaction.state = HVUTIL_DEVICE_INIT; |
325 | ||
6472f80a VK |
326 | hvt = hvutil_transport_init(vss_devname, CN_VSS_IDX, CN_VSS_VAL, |
327 | vss_on_msg, vss_on_reset); | |
328 | if (!hvt) | |
329 | return -EFAULT; | |
330 | ||
96dd86fa S |
331 | return 0; |
332 | } | |
333 | ||
334 | void hv_vss_deinit(void) | |
335 | { | |
086a6f68 | 336 | vss_transaction.state = HVUTIL_DEVICE_DYING; |
64914207 | 337 | cancel_delayed_work_sync(&vss_timeout_work); |
96dd86fa | 338 | cancel_work_sync(&vss_send_op_work); |
6472f80a | 339 | hvutil_transport_destroy(hvt); |
96dd86fa | 340 | } |