xref: /freebsd/usr.sbin/bhyve/mem.c (revision 1323ec571215a77ddd21294f0871979d5ad6b992)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2012 NetApp, Inc.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  * $FreeBSD$
29  */
30 
31 /*
32  * Memory ranges are represented with an RB tree. On insertion, the range
33  * is checked for overlaps. On lookup, the key has the same base and limit
34  * so it can be searched within the range.
35  */
36 
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 #include <sys/types.h>
41 #include <sys/errno.h>
42 #include <sys/tree.h>
43 #include <machine/vmm.h>
44 #include <machine/vmm_instruction_emul.h>
45 
46 #include <assert.h>
47 #include <err.h>
48 #include <pthread.h>
49 #include <stdio.h>
50 #include <stdlib.h>
51 
52 #include "mem.h"
53 
54 struct mmio_rb_range {
55 	RB_ENTRY(mmio_rb_range)	mr_link;	/* RB tree links */
56 	struct mem_range	mr_param;
57 	uint64_t                mr_base;
58 	uint64_t                mr_end;
59 };
60 
61 struct mmio_rb_tree;
62 RB_PROTOTYPE(mmio_rb_tree, mmio_rb_range, mr_link, mmio_rb_range_compare);
63 
64 RB_HEAD(mmio_rb_tree, mmio_rb_range) mmio_rb_root, mmio_rb_fallback;
65 
66 /*
67  * Per-vCPU cache. Since most accesses from a vCPU will be to
68  * consecutive addresses in a range, it makes sense to cache the
69  * result of a lookup.
70  */
71 static struct mmio_rb_range	**mmio_hint;
72 static int mmio_ncpu;
73 
74 static pthread_rwlock_t mmio_rwlock;
75 
76 static int
77 mmio_rb_range_compare(struct mmio_rb_range *a, struct mmio_rb_range *b)
78 {
79 	if (a->mr_end < b->mr_base)
80 		return (-1);
81 	else if (a->mr_base > b->mr_end)
82 		return (1);
83 	return (0);
84 }
85 
86 static int
87 mmio_rb_lookup(struct mmio_rb_tree *rbt, uint64_t addr,
88     struct mmio_rb_range **entry)
89 {
90 	struct mmio_rb_range find, *res;
91 
92 	find.mr_base = find.mr_end = addr;
93 
94 	res = RB_FIND(mmio_rb_tree, rbt, &find);
95 
96 	if (res != NULL) {
97 		*entry = res;
98 		return (0);
99 	}
100 
101 	return (ENOENT);
102 }
103 
104 static int
105 mmio_rb_add(struct mmio_rb_tree *rbt, struct mmio_rb_range *new)
106 {
107 	struct mmio_rb_range *overlap;
108 
109 	overlap = RB_INSERT(mmio_rb_tree, rbt, new);
110 
111 	if (overlap != NULL) {
112 #ifdef RB_DEBUG
113 		printf("overlap detected: new %lx:%lx, tree %lx:%lx, '%s' "
114 		       "claims region already claimed for '%s'\n",
115 		       new->mr_base, new->mr_end,
116 		       overlap->mr_base, overlap->mr_end,
117 		       new->mr_param.name, overlap->mr_param.name);
118 #endif
119 
120 		return (EEXIST);
121 	}
122 
123 	return (0);
124 }
125 
126 #if 0
127 static void
128 mmio_rb_dump(struct mmio_rb_tree *rbt)
129 {
130 	int perror;
131 	struct mmio_rb_range *np;
132 
133 	pthread_rwlock_rdlock(&mmio_rwlock);
134 	RB_FOREACH(np, mmio_rb_tree, rbt) {
135 		printf(" %lx:%lx, %s\n", np->mr_base, np->mr_end,
136 		       np->mr_param.name);
137 	}
138 	perror = pthread_rwlock_unlock(&mmio_rwlock);
139 	assert(perror == 0);
140 }
141 #endif
142 
143 RB_GENERATE(mmio_rb_tree, mmio_rb_range, mr_link, mmio_rb_range_compare);
144 
145 typedef int (mem_cb_t)(struct vmctx *ctx, int vcpu, uint64_t gpa,
146     struct mem_range *mr, void *arg);
147 
148 static int
149 mem_read(void *ctx, int vcpu, uint64_t gpa, uint64_t *rval, int size, void *arg)
150 {
151 	int error;
152 	struct mem_range *mr = arg;
153 
154 	error = (*mr->handler)(ctx, vcpu, MEM_F_READ, gpa, size,
155 			       rval, mr->arg1, mr->arg2);
156 	return (error);
157 }
158 
159 static int
160 mem_write(void *ctx, int vcpu, uint64_t gpa, uint64_t wval, int size, void *arg)
161 {
162 	int error;
163 	struct mem_range *mr = arg;
164 
165 	error = (*mr->handler)(ctx, vcpu, MEM_F_WRITE, gpa, size,
166 			       &wval, mr->arg1, mr->arg2);
167 	return (error);
168 }
169 
170 static int
171 access_memory(struct vmctx *ctx, int vcpu, uint64_t paddr, mem_cb_t *cb,
172     void *arg)
173 {
174 	struct mmio_rb_range *entry;
175 	int err, perror, immutable;
176 
177 	pthread_rwlock_rdlock(&mmio_rwlock);
178 	/*
179 	 * First check the per-vCPU cache
180 	 */
181 	if (mmio_hint[vcpu] &&
182 	    paddr >= mmio_hint[vcpu]->mr_base &&
183 	    paddr <= mmio_hint[vcpu]->mr_end) {
184 		entry = mmio_hint[vcpu];
185 	} else
186 		entry = NULL;
187 
188 	if (entry == NULL) {
189 		if (mmio_rb_lookup(&mmio_rb_root, paddr, &entry) == 0) {
190 			/* Update the per-vCPU cache */
191 			mmio_hint[vcpu] = entry;
192 		} else if (mmio_rb_lookup(&mmio_rb_fallback, paddr, &entry)) {
193 			perror = pthread_rwlock_unlock(&mmio_rwlock);
194 			assert(perror == 0);
195 			return (ESRCH);
196 		}
197 	}
198 
199 	assert(entry != NULL);
200 
201 	/*
202 	 * An 'immutable' memory range is guaranteed to be never removed
203 	 * so there is no need to hold 'mmio_rwlock' while calling the
204 	 * handler.
205 	 *
206 	 * XXX writes to the PCIR_COMMAND register can cause register_mem()
207 	 * to be called. If the guest is using PCI extended config space
208 	 * to modify the PCIR_COMMAND register then register_mem() can
209 	 * deadlock on 'mmio_rwlock'. However by registering the extended
210 	 * config space window as 'immutable' the deadlock can be avoided.
211 	 */
212 	immutable = (entry->mr_param.flags & MEM_F_IMMUTABLE);
213 	if (immutable) {
214 		perror = pthread_rwlock_unlock(&mmio_rwlock);
215 		assert(perror == 0);
216 	}
217 
218 	err = cb(ctx, vcpu, paddr, &entry->mr_param, arg);
219 
220 	if (!immutable) {
221 		perror = pthread_rwlock_unlock(&mmio_rwlock);
222 		assert(perror == 0);
223 	}
224 
225 
226 	return (err);
227 }
228 
229 struct emulate_mem_args {
230 	struct vie *vie;
231 	struct vm_guest_paging *paging;
232 };
233 
234 static int
235 emulate_mem_cb(struct vmctx *ctx, int vcpu, uint64_t paddr, struct mem_range *mr,
236     void *arg)
237 {
238 	struct emulate_mem_args *ema;
239 
240 	ema = arg;
241 	return (vmm_emulate_instruction(ctx, vcpu, paddr, ema->vie, ema->paging,
242 	    mem_read, mem_write, mr));
243 }
244 
245 int
246 emulate_mem(struct vmctx *ctx, int vcpu, uint64_t paddr, struct vie *vie,
247     struct vm_guest_paging *paging)
248 
249 {
250 	struct emulate_mem_args ema;
251 
252 	ema.vie = vie;
253 	ema.paging = paging;
254 	return (access_memory(ctx, vcpu, paddr, emulate_mem_cb, &ema));
255 }
256 
257 struct rw_mem_args {
258 	uint64_t *val;
259 	int size;
260 	int operation;
261 };
262 
263 static int
264 rw_mem_cb(struct vmctx *ctx, int vcpu, uint64_t paddr, struct mem_range *mr,
265     void *arg)
266 {
267 	struct rw_mem_args *rma;
268 
269 	rma = arg;
270 	return (mr->handler(ctx, vcpu, rma->operation, paddr, rma->size,
271 	    rma->val, mr->arg1, mr->arg2));
272 }
273 
274 int
275 read_mem(struct vmctx *ctx, int vcpu, uint64_t gpa, uint64_t *rval, int size)
276 {
277 	struct rw_mem_args rma;
278 
279 	rma.val = rval;
280 	rma.size = size;
281 	rma.operation = MEM_F_READ;
282 	return (access_memory(ctx, vcpu, gpa, rw_mem_cb, &rma));
283 }
284 
285 int
286 write_mem(struct vmctx *ctx, int vcpu, uint64_t gpa, uint64_t wval, int size)
287 {
288 	struct rw_mem_args rma;
289 
290 	rma.val = &wval;
291 	rma.size = size;
292 	rma.operation = MEM_F_WRITE;
293 	return (access_memory(ctx, vcpu, gpa, rw_mem_cb, &rma));
294 }
295 
296 static int
297 register_mem_int(struct mmio_rb_tree *rbt, struct mem_range *memp)
298 {
299 	struct mmio_rb_range *entry, *mrp;
300 	int err, perror;
301 
302 	err = 0;
303 
304 	mrp = malloc(sizeof(struct mmio_rb_range));
305 	if (mrp == NULL) {
306 		warn("%s: couldn't allocate memory for mrp\n",
307 		     __func__);
308 		err = ENOMEM;
309 	} else {
310 		mrp->mr_param = *memp;
311 		mrp->mr_base = memp->base;
312 		mrp->mr_end = memp->base + memp->size - 1;
313 		pthread_rwlock_wrlock(&mmio_rwlock);
314 		if (mmio_rb_lookup(rbt, memp->base, &entry) != 0)
315 			err = mmio_rb_add(rbt, mrp);
316 		perror = pthread_rwlock_unlock(&mmio_rwlock);
317 		assert(perror == 0);
318 		if (err)
319 			free(mrp);
320 	}
321 
322 	return (err);
323 }
324 
325 int
326 register_mem(struct mem_range *memp)
327 {
328 
329 	return (register_mem_int(&mmio_rb_root, memp));
330 }
331 
332 int
333 register_mem_fallback(struct mem_range *memp)
334 {
335 
336 	return (register_mem_int(&mmio_rb_fallback, memp));
337 }
338 
339 int
340 unregister_mem(struct mem_range *memp)
341 {
342 	struct mem_range *mr;
343 	struct mmio_rb_range *entry = NULL;
344 	int err, perror, i;
345 
346 	pthread_rwlock_wrlock(&mmio_rwlock);
347 	err = mmio_rb_lookup(&mmio_rb_root, memp->base, &entry);
348 	if (err == 0) {
349 		mr = &entry->mr_param;
350 		assert(mr->name == memp->name);
351 		assert(mr->base == memp->base && mr->size == memp->size);
352 		assert((mr->flags & MEM_F_IMMUTABLE) == 0);
353 		RB_REMOVE(mmio_rb_tree, &mmio_rb_root, entry);
354 
355 		/* flush Per-vCPU cache */
356 		for (i = 0; i < mmio_ncpu; i++) {
357 			if (mmio_hint[i] == entry)
358 				mmio_hint[i] = NULL;
359 		}
360 	}
361 	perror = pthread_rwlock_unlock(&mmio_rwlock);
362 	assert(perror == 0);
363 
364 	if (entry)
365 		free(entry);
366 
367 	return (err);
368 }
369 
370 void
371 init_mem(int ncpu)
372 {
373 
374 	mmio_ncpu = ncpu;
375 	mmio_hint = calloc(ncpu, sizeof(*mmio_hint));
376 	RB_INIT(&mmio_rb_root);
377 	RB_INIT(&mmio_rb_fallback);
378 	pthread_rwlock_init(&mmio_rwlock, NULL);
379 }
380