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685a6bf8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
a110b7eb GZ |
2 | /* |
3 | * VMware VMCI Driver | |
4 | * | |
5 | * Copyright (C) 2012 VMware, Inc. All rights reserved. | |
a110b7eb GZ |
6 | */ |
7 | ||
8 | #include <linux/vmw_vmci_defs.h> | |
9 | #include <linux/vmw_vmci_api.h> | |
10 | #include <linux/module.h> | |
11 | #include <linux/sched.h> | |
12 | #include <linux/slab.h> | |
13 | #include <linux/bug.h> | |
14 | ||
15 | #include "vmci_datagram.h" | |
16 | #include "vmci_resource.h" | |
17 | #include "vmci_context.h" | |
18 | #include "vmci_driver.h" | |
19 | #include "vmci_event.h" | |
20 | #include "vmci_route.h" | |
21 | ||
22 | /* | |
23 | * struct datagram_entry describes the datagram entity. It is used for datagram | |
24 | * entities created only on the host. | |
25 | */ | |
26 | struct datagram_entry { | |
27 | struct vmci_resource resource; | |
28 | u32 flags; | |
29 | bool run_delayed; | |
30 | vmci_datagram_recv_cb recv_cb; | |
31 | void *client_data; | |
32 | u32 priv_flags; | |
33 | }; | |
34 | ||
35 | struct delayed_datagram_info { | |
36 | struct datagram_entry *entry; | |
a110b7eb GZ |
37 | struct work_struct work; |
38 | bool in_dg_host_queue; | |
347e0899 AK |
39 | /* msg and msg_payload must be together. */ |
40 | struct vmci_datagram msg; | |
41 | u8 msg_payload[]; | |
a110b7eb GZ |
42 | }; |
43 | ||
44 | /* Number of in-flight host->host datagrams */ | |
45 | static atomic_t delayed_dg_host_queue_size = ATOMIC_INIT(0); | |
46 | ||
47 | /* | |
48 | * Create a datagram entry given a handle pointer. | |
49 | */ | |
50 | static int dg_create_handle(u32 resource_id, | |
51 | u32 flags, | |
52 | u32 priv_flags, | |
53 | vmci_datagram_recv_cb recv_cb, | |
54 | void *client_data, struct vmci_handle *out_handle) | |
55 | { | |
56 | int result; | |
57 | u32 context_id; | |
58 | struct vmci_handle handle; | |
59 | struct datagram_entry *entry; | |
60 | ||
61 | if ((flags & VMCI_FLAG_WELLKNOWN_DG_HND) != 0) | |
62 | return VMCI_ERROR_INVALID_ARGS; | |
63 | ||
64 | if ((flags & VMCI_FLAG_ANYCID_DG_HND) != 0) { | |
65 | context_id = VMCI_INVALID_ID; | |
66 | } else { | |
67 | context_id = vmci_get_context_id(); | |
68 | if (context_id == VMCI_INVALID_ID) | |
69 | return VMCI_ERROR_NO_RESOURCES; | |
70 | } | |
71 | ||
72 | handle = vmci_make_handle(context_id, resource_id); | |
73 | ||
74 | entry = kmalloc(sizeof(*entry), GFP_KERNEL); | |
75 | if (!entry) { | |
76 | pr_warn("Failed allocating memory for datagram entry\n"); | |
77 | return VMCI_ERROR_NO_MEM; | |
78 | } | |
79 | ||
80 | entry->run_delayed = (flags & VMCI_FLAG_DG_DELAYED_CB) ? true : false; | |
81 | entry->flags = flags; | |
82 | entry->recv_cb = recv_cb; | |
83 | entry->client_data = client_data; | |
84 | entry->priv_flags = priv_flags; | |
85 | ||
86 | /* Make datagram resource live. */ | |
87 | result = vmci_resource_add(&entry->resource, | |
88 | VMCI_RESOURCE_TYPE_DATAGRAM, | |
89 | handle); | |
90 | if (result != VMCI_SUCCESS) { | |
91 | pr_warn("Failed to add new resource (handle=0x%x:0x%x), error: %d\n", | |
92 | handle.context, handle.resource, result); | |
93 | kfree(entry); | |
94 | return result; | |
95 | } | |
96 | ||
97 | *out_handle = vmci_resource_handle(&entry->resource); | |
98 | return VMCI_SUCCESS; | |
99 | } | |
100 | ||
101 | /* | |
102 | * Internal utility function with the same purpose as | |
103 | * vmci_datagram_get_priv_flags that also takes a context_id. | |
104 | */ | |
105 | static int vmci_datagram_get_priv_flags(u32 context_id, | |
106 | struct vmci_handle handle, | |
107 | u32 *priv_flags) | |
108 | { | |
109 | if (context_id == VMCI_INVALID_ID) | |
110 | return VMCI_ERROR_INVALID_ARGS; | |
111 | ||
112 | if (context_id == VMCI_HOST_CONTEXT_ID) { | |
113 | struct datagram_entry *src_entry; | |
114 | struct vmci_resource *resource; | |
115 | ||
116 | resource = vmci_resource_by_handle(handle, | |
117 | VMCI_RESOURCE_TYPE_DATAGRAM); | |
118 | if (!resource) | |
119 | return VMCI_ERROR_INVALID_ARGS; | |
120 | ||
121 | src_entry = container_of(resource, struct datagram_entry, | |
122 | resource); | |
123 | *priv_flags = src_entry->priv_flags; | |
124 | vmci_resource_put(resource); | |
125 | } else if (context_id == VMCI_HYPERVISOR_CONTEXT_ID) | |
126 | *priv_flags = VMCI_MAX_PRIVILEGE_FLAGS; | |
127 | else | |
128 | *priv_flags = vmci_context_get_priv_flags(context_id); | |
129 | ||
130 | return VMCI_SUCCESS; | |
131 | } | |
132 | ||
133 | /* | |
134 | * Calls the specified callback in a delayed context. | |
135 | */ | |
136 | static void dg_delayed_dispatch(struct work_struct *work) | |
137 | { | |
138 | struct delayed_datagram_info *dg_info = | |
139 | container_of(work, struct delayed_datagram_info, work); | |
140 | ||
141 | dg_info->entry->recv_cb(dg_info->entry->client_data, &dg_info->msg); | |
142 | ||
143 | vmci_resource_put(&dg_info->entry->resource); | |
144 | ||
145 | if (dg_info->in_dg_host_queue) | |
146 | atomic_dec(&delayed_dg_host_queue_size); | |
147 | ||
148 | kfree(dg_info); | |
149 | } | |
150 | ||
151 | /* | |
152 | * Dispatch datagram as a host, to the host, or other vm context. This | |
153 | * function cannot dispatch to hypervisor context handlers. This should | |
154 | * have been handled before we get here by vmci_datagram_dispatch. | |
155 | * Returns number of bytes sent on success, error code otherwise. | |
156 | */ | |
157 | static int dg_dispatch_as_host(u32 context_id, struct vmci_datagram *dg) | |
158 | { | |
159 | int retval; | |
160 | size_t dg_size; | |
161 | u32 src_priv_flags; | |
162 | ||
163 | dg_size = VMCI_DG_SIZE(dg); | |
164 | ||
165 | /* Host cannot send to the hypervisor. */ | |
166 | if (dg->dst.context == VMCI_HYPERVISOR_CONTEXT_ID) | |
167 | return VMCI_ERROR_DST_UNREACHABLE; | |
168 | ||
169 | /* Check that source handle matches sending context. */ | |
170 | if (dg->src.context != context_id) { | |
171 | pr_devel("Sender context (ID=0x%x) is not owner of src datagram entry (handle=0x%x:0x%x)\n", | |
172 | context_id, dg->src.context, dg->src.resource); | |
173 | return VMCI_ERROR_NO_ACCESS; | |
174 | } | |
175 | ||
176 | /* Get hold of privileges of sending endpoint. */ | |
177 | retval = vmci_datagram_get_priv_flags(context_id, dg->src, | |
178 | &src_priv_flags); | |
179 | if (retval != VMCI_SUCCESS) { | |
180 | pr_warn("Couldn't get privileges (handle=0x%x:0x%x)\n", | |
181 | dg->src.context, dg->src.resource); | |
182 | return retval; | |
183 | } | |
184 | ||
185 | /* Determine if we should route to host or guest destination. */ | |
186 | if (dg->dst.context == VMCI_HOST_CONTEXT_ID) { | |
187 | /* Route to host datagram entry. */ | |
188 | struct datagram_entry *dst_entry; | |
189 | struct vmci_resource *resource; | |
190 | ||
191 | if (dg->src.context == VMCI_HYPERVISOR_CONTEXT_ID && | |
192 | dg->dst.resource == VMCI_EVENT_HANDLER) { | |
193 | return vmci_event_dispatch(dg); | |
194 | } | |
195 | ||
196 | resource = vmci_resource_by_handle(dg->dst, | |
197 | VMCI_RESOURCE_TYPE_DATAGRAM); | |
198 | if (!resource) { | |
199 | pr_devel("Sending to invalid destination (handle=0x%x:0x%x)\n", | |
200 | dg->dst.context, dg->dst.resource); | |
201 | return VMCI_ERROR_INVALID_RESOURCE; | |
202 | } | |
203 | dst_entry = container_of(resource, struct datagram_entry, | |
204 | resource); | |
205 | if (vmci_deny_interaction(src_priv_flags, | |
206 | dst_entry->priv_flags)) { | |
207 | vmci_resource_put(resource); | |
208 | return VMCI_ERROR_NO_ACCESS; | |
209 | } | |
210 | ||
211 | /* | |
212 | * If a VMCI datagram destined for the host is also sent by the | |
213 | * host, we always run it delayed. This ensures that no locks | |
214 | * are held when the datagram callback runs. | |
215 | */ | |
216 | if (dst_entry->run_delayed || | |
217 | dg->src.context == VMCI_HOST_CONTEXT_ID) { | |
218 | struct delayed_datagram_info *dg_info; | |
219 | ||
220 | if (atomic_add_return(1, &delayed_dg_host_queue_size) | |
221 | == VMCI_MAX_DELAYED_DG_HOST_QUEUE_SIZE) { | |
222 | atomic_dec(&delayed_dg_host_queue_size); | |
223 | vmci_resource_put(resource); | |
224 | return VMCI_ERROR_NO_MEM; | |
225 | } | |
226 | ||
227 | dg_info = kmalloc(sizeof(*dg_info) + | |
228 | (size_t) dg->payload_size, GFP_ATOMIC); | |
229 | if (!dg_info) { | |
230 | atomic_dec(&delayed_dg_host_queue_size); | |
231 | vmci_resource_put(resource); | |
232 | return VMCI_ERROR_NO_MEM; | |
233 | } | |
234 | ||
235 | dg_info->in_dg_host_queue = true; | |
236 | dg_info->entry = dst_entry; | |
237 | memcpy(&dg_info->msg, dg, dg_size); | |
238 | ||
239 | INIT_WORK(&dg_info->work, dg_delayed_dispatch); | |
240 | schedule_work(&dg_info->work); | |
241 | retval = VMCI_SUCCESS; | |
242 | ||
243 | } else { | |
244 | retval = dst_entry->recv_cb(dst_entry->client_data, dg); | |
245 | vmci_resource_put(resource); | |
246 | if (retval < VMCI_SUCCESS) | |
247 | return retval; | |
248 | } | |
249 | } else { | |
250 | /* Route to destination VM context. */ | |
251 | struct vmci_datagram *new_dg; | |
252 | ||
253 | if (context_id != dg->dst.context) { | |
254 | if (vmci_deny_interaction(src_priv_flags, | |
255 | vmci_context_get_priv_flags | |
256 | (dg->dst.context))) { | |
257 | return VMCI_ERROR_NO_ACCESS; | |
258 | } else if (VMCI_CONTEXT_IS_VM(context_id)) { | |
259 | /* | |
260 | * If the sending context is a VM, it | |
261 | * cannot reach another VM. | |
262 | */ | |
263 | ||
264 | pr_devel("Datagram communication between VMs not supported (src=0x%x, dst=0x%x)\n", | |
265 | context_id, dg->dst.context); | |
266 | return VMCI_ERROR_DST_UNREACHABLE; | |
267 | } | |
268 | } | |
269 | ||
270 | /* We make a copy to enqueue. */ | |
bf84b140 | 271 | new_dg = kmemdup(dg, dg_size, GFP_KERNEL); |
a110b7eb GZ |
272 | if (new_dg == NULL) |
273 | return VMCI_ERROR_NO_MEM; | |
274 | ||
a110b7eb GZ |
275 | retval = vmci_ctx_enqueue_datagram(dg->dst.context, new_dg); |
276 | if (retval < VMCI_SUCCESS) { | |
277 | kfree(new_dg); | |
278 | return retval; | |
279 | } | |
280 | } | |
281 | ||
282 | /* | |
283 | * We currently truncate the size to signed 32 bits. This doesn't | |
284 | * matter for this handler as it only support 4Kb messages. | |
285 | */ | |
286 | return (int)dg_size; | |
287 | } | |
288 | ||
289 | /* | |
290 | * Dispatch datagram as a guest, down through the VMX and potentially to | |
291 | * the host. | |
292 | * Returns number of bytes sent on success, error code otherwise. | |
293 | */ | |
294 | static int dg_dispatch_as_guest(struct vmci_datagram *dg) | |
295 | { | |
296 | int retval; | |
297 | struct vmci_resource *resource; | |
298 | ||
299 | resource = vmci_resource_by_handle(dg->src, | |
300 | VMCI_RESOURCE_TYPE_DATAGRAM); | |
301 | if (!resource) | |
302 | return VMCI_ERROR_NO_HANDLE; | |
303 | ||
304 | retval = vmci_send_datagram(dg); | |
305 | vmci_resource_put(resource); | |
306 | return retval; | |
307 | } | |
308 | ||
309 | /* | |
310 | * Dispatch datagram. This will determine the routing for the datagram | |
311 | * and dispatch it accordingly. | |
312 | * Returns number of bytes sent on success, error code otherwise. | |
313 | */ | |
314 | int vmci_datagram_dispatch(u32 context_id, | |
315 | struct vmci_datagram *dg, bool from_guest) | |
316 | { | |
317 | int retval; | |
318 | enum vmci_route route; | |
319 | ||
320 | BUILD_BUG_ON(sizeof(struct vmci_datagram) != 24); | |
321 | ||
2e453546 DC |
322 | if (dg->payload_size > VMCI_MAX_DG_SIZE || |
323 | VMCI_DG_SIZE(dg) > VMCI_MAX_DG_SIZE) { | |
a110b7eb GZ |
324 | pr_devel("Payload (size=%llu bytes) too big to send\n", |
325 | (unsigned long long)dg->payload_size); | |
326 | return VMCI_ERROR_INVALID_ARGS; | |
327 | } | |
328 | ||
329 | retval = vmci_route(&dg->src, &dg->dst, from_guest, &route); | |
330 | if (retval < VMCI_SUCCESS) { | |
331 | pr_devel("Failed to route datagram (src=0x%x, dst=0x%x, err=%d)\n", | |
332 | dg->src.context, dg->dst.context, retval); | |
333 | return retval; | |
334 | } | |
335 | ||
336 | if (VMCI_ROUTE_AS_HOST == route) { | |
337 | if (VMCI_INVALID_ID == context_id) | |
338 | context_id = VMCI_HOST_CONTEXT_ID; | |
339 | return dg_dispatch_as_host(context_id, dg); | |
340 | } | |
341 | ||
342 | if (VMCI_ROUTE_AS_GUEST == route) | |
343 | return dg_dispatch_as_guest(dg); | |
344 | ||
345 | pr_warn("Unknown route (%d) for datagram\n", route); | |
346 | return VMCI_ERROR_DST_UNREACHABLE; | |
347 | } | |
348 | ||
349 | /* | |
350 | * Invoke the handler for the given datagram. This is intended to be | |
351 | * called only when acting as a guest and receiving a datagram from the | |
352 | * virtual device. | |
353 | */ | |
354 | int vmci_datagram_invoke_guest_handler(struct vmci_datagram *dg) | |
355 | { | |
356 | struct vmci_resource *resource; | |
357 | struct datagram_entry *dst_entry; | |
358 | ||
359 | resource = vmci_resource_by_handle(dg->dst, | |
360 | VMCI_RESOURCE_TYPE_DATAGRAM); | |
361 | if (!resource) { | |
362 | pr_devel("destination (handle=0x%x:0x%x) doesn't exist\n", | |
363 | dg->dst.context, dg->dst.resource); | |
364 | return VMCI_ERROR_NO_HANDLE; | |
365 | } | |
366 | ||
367 | dst_entry = container_of(resource, struct datagram_entry, resource); | |
368 | if (dst_entry->run_delayed) { | |
369 | struct delayed_datagram_info *dg_info; | |
370 | ||
371 | dg_info = kmalloc(sizeof(*dg_info) + (size_t)dg->payload_size, | |
372 | GFP_ATOMIC); | |
373 | if (!dg_info) { | |
374 | vmci_resource_put(resource); | |
375 | return VMCI_ERROR_NO_MEM; | |
376 | } | |
377 | ||
378 | dg_info->in_dg_host_queue = false; | |
379 | dg_info->entry = dst_entry; | |
380 | memcpy(&dg_info->msg, dg, VMCI_DG_SIZE(dg)); | |
381 | ||
382 | INIT_WORK(&dg_info->work, dg_delayed_dispatch); | |
383 | schedule_work(&dg_info->work); | |
384 | } else { | |
385 | dst_entry->recv_cb(dst_entry->client_data, dg); | |
386 | vmci_resource_put(resource); | |
387 | } | |
388 | ||
389 | return VMCI_SUCCESS; | |
390 | } | |
391 | ||
392 | /* | |
393 | * vmci_datagram_create_handle_priv() - Create host context datagram endpoint | |
394 | * @resource_id: The resource ID. | |
395 | * @flags: Datagram Flags. | |
396 | * @priv_flags: Privilege Flags. | |
397 | * @recv_cb: Callback when receiving datagrams. | |
398 | * @client_data: Pointer for a datagram_entry struct | |
399 | * @out_handle: vmci_handle that is populated as a result of this function. | |
400 | * | |
401 | * Creates a host context datagram endpoint and returns a handle to it. | |
402 | */ | |
403 | int vmci_datagram_create_handle_priv(u32 resource_id, | |
404 | u32 flags, | |
405 | u32 priv_flags, | |
406 | vmci_datagram_recv_cb recv_cb, | |
407 | void *client_data, | |
408 | struct vmci_handle *out_handle) | |
409 | { | |
410 | if (out_handle == NULL) | |
411 | return VMCI_ERROR_INVALID_ARGS; | |
412 | ||
413 | if (recv_cb == NULL) { | |
414 | pr_devel("Client callback needed when creating datagram\n"); | |
415 | return VMCI_ERROR_INVALID_ARGS; | |
416 | } | |
417 | ||
418 | if (priv_flags & ~VMCI_PRIVILEGE_ALL_FLAGS) | |
419 | return VMCI_ERROR_INVALID_ARGS; | |
420 | ||
421 | return dg_create_handle(resource_id, flags, priv_flags, recv_cb, | |
422 | client_data, out_handle); | |
423 | } | |
424 | EXPORT_SYMBOL_GPL(vmci_datagram_create_handle_priv); | |
425 | ||
426 | /* | |
427 | * vmci_datagram_create_handle() - Create host context datagram endpoint | |
428 | * @resource_id: Resource ID. | |
429 | * @flags: Datagram Flags. | |
430 | * @recv_cb: Callback when receiving datagrams. | |
431 | * @client_ata: Pointer for a datagram_entry struct | |
432 | * @out_handle: vmci_handle that is populated as a result of this function. | |
433 | * | |
434 | * Creates a host context datagram endpoint and returns a handle to | |
435 | * it. Same as vmci_datagram_create_handle_priv without the priviledge | |
436 | * flags argument. | |
437 | */ | |
438 | int vmci_datagram_create_handle(u32 resource_id, | |
439 | u32 flags, | |
440 | vmci_datagram_recv_cb recv_cb, | |
441 | void *client_data, | |
442 | struct vmci_handle *out_handle) | |
443 | { | |
444 | return vmci_datagram_create_handle_priv( | |
445 | resource_id, flags, | |
446 | VMCI_DEFAULT_PROC_PRIVILEGE_FLAGS, | |
447 | recv_cb, client_data, | |
448 | out_handle); | |
449 | } | |
450 | EXPORT_SYMBOL_GPL(vmci_datagram_create_handle); | |
451 | ||
452 | /* | |
453 | * vmci_datagram_destroy_handle() - Destroys datagram handle | |
454 | * @handle: vmci_handle to be destroyed and reaped. | |
455 | * | |
456 | * Use this function to destroy any datagram handles created by | |
457 | * vmci_datagram_create_handle{,Priv} functions. | |
458 | */ | |
459 | int vmci_datagram_destroy_handle(struct vmci_handle handle) | |
460 | { | |
461 | struct datagram_entry *entry; | |
462 | struct vmci_resource *resource; | |
463 | ||
464 | resource = vmci_resource_by_handle(handle, VMCI_RESOURCE_TYPE_DATAGRAM); | |
465 | if (!resource) { | |
466 | pr_devel("Failed to destroy datagram (handle=0x%x:0x%x)\n", | |
467 | handle.context, handle.resource); | |
468 | return VMCI_ERROR_NOT_FOUND; | |
469 | } | |
470 | ||
471 | entry = container_of(resource, struct datagram_entry, resource); | |
472 | ||
473 | vmci_resource_put(&entry->resource); | |
474 | vmci_resource_remove(&entry->resource); | |
475 | kfree(entry); | |
476 | ||
477 | return VMCI_SUCCESS; | |
478 | } | |
479 | EXPORT_SYMBOL_GPL(vmci_datagram_destroy_handle); | |
480 | ||
481 | /* | |
482 | * vmci_datagram_send() - Send a datagram | |
483 | * @msg: The datagram to send. | |
484 | * | |
485 | * Sends the provided datagram on its merry way. | |
486 | */ | |
487 | int vmci_datagram_send(struct vmci_datagram *msg) | |
488 | { | |
489 | if (msg == NULL) | |
490 | return VMCI_ERROR_INVALID_ARGS; | |
491 | ||
492 | return vmci_datagram_dispatch(VMCI_INVALID_ID, msg, false); | |
493 | } | |
494 | EXPORT_SYMBOL_GPL(vmci_datagram_send); |