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