1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2015 Neel Natu <neel@freebsd.org>
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 THE AUTHOR ``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 THE AUTHOR 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
29 #include <sys/param.h>
30
31 #include <sys/types.h>
32 #include <sys/mman.h>
33 #include <sys/stat.h>
34
35 #include <machine/vmm.h>
36
37 #include <err.h>
38 #include <errno.h>
39 #include <fcntl.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <string.h>
43 #include <unistd.h>
44 #include <stdbool.h>
45
46 #include <vmmapi.h>
47
48 #include "bhyverun.h"
49 #include "bootrom.h"
50 #include "debug.h"
51 #include "mem.h"
52
53 #define BOOTROM_SIZE (16 * 1024 * 1024) /* 16 MB */
54
55 /*
56 * ROM region is 16 MB at the top of 4GB ("low") memory.
57 *
58 * The size is limited so it doesn't encroach into reserved MMIO space (e.g.,
59 * APIC, HPET, MSI).
60 *
61 * It is allocated in page-multiple blocks on a first-come first-serve basis,
62 * from high to low, during initialization, and does not change at runtime.
63 */
64 static char *romptr; /* Pointer to userspace-mapped bootrom region. */
65 static vm_paddr_t gpa_base; /* GPA of low end of region. */
66 static vm_paddr_t gpa_allocbot; /* Low GPA of free region. */
67 static vm_paddr_t gpa_alloctop; /* High GPA, minus 1, of free region. */
68
69 #define CFI_BCS_WRITE_BYTE 0x10
70 #define CFI_BCS_CLEAR_STATUS 0x50
71 #define CFI_BCS_READ_STATUS 0x70
72 #define CFI_BCS_READ_ARRAY 0xff
73
74 static struct bootrom_var_state {
75 uint8_t *mmap;
76 uint64_t gpa;
77 off_t size;
78 uint8_t cmd;
79 } var = { NULL, 0, 0, CFI_BCS_READ_ARRAY };
80
81 /*
82 * Emulate just those CFI basic commands that will convince EDK II
83 * that the Firmware Volume area is writable and persistent.
84 */
85 static int
bootrom_var_mem_handler(struct vcpu * vcpu __unused,int dir,uint64_t addr,int size,uint64_t * val,void * arg1 __unused,long arg2 __unused)86 bootrom_var_mem_handler(struct vcpu *vcpu __unused, int dir, uint64_t addr,
87 int size, uint64_t *val, void *arg1 __unused, long arg2 __unused)
88 {
89 off_t offset;
90
91 offset = addr - var.gpa;
92 if (offset + size > var.size || offset < 0 || offset + size <= offset)
93 return (EINVAL);
94
95 if (dir == MEM_F_WRITE) {
96 switch (var.cmd) {
97 case CFI_BCS_WRITE_BYTE:
98 memcpy(var.mmap + offset, val, size);
99 var.cmd = CFI_BCS_READ_ARRAY;
100 break;
101 default:
102 var.cmd = *(uint8_t *)val;
103 }
104 } else {
105 switch (var.cmd) {
106 case CFI_BCS_CLEAR_STATUS:
107 case CFI_BCS_READ_STATUS:
108 memset(val, 0, size);
109 var.cmd = CFI_BCS_READ_ARRAY;
110 break;
111 default:
112 memcpy(val, var.mmap + offset, size);
113 break;
114 }
115 }
116 return (0);
117 }
118
119 void
init_bootrom(struct vmctx * ctx)120 init_bootrom(struct vmctx *ctx)
121 {
122 vm_paddr_t highmem;
123
124 romptr = vm_create_devmem(ctx, VM_BOOTROM, "bootrom", BOOTROM_SIZE);
125 if (romptr == MAP_FAILED)
126 err(4, "%s: vm_create_devmem", __func__);
127 highmem = vm_get_highmem_base(ctx);
128 gpa_base = highmem - BOOTROM_SIZE;
129 gpa_allocbot = gpa_base;
130 gpa_alloctop = highmem - 1;
131 }
132
133 int
bootrom_alloc(struct vmctx * ctx,size_t len,int prot,int flags,char ** region_out,uint64_t * gpa_out)134 bootrom_alloc(struct vmctx *ctx, size_t len, int prot, int flags,
135 char **region_out, uint64_t *gpa_out)
136 {
137 static const int bootrom_valid_flags = BOOTROM_ALLOC_TOP;
138
139 vm_paddr_t gpa;
140 vm_ooffset_t segoff;
141
142 if (flags & ~bootrom_valid_flags) {
143 warnx("%s: Invalid flags: %x", __func__,
144 flags & ~bootrom_valid_flags);
145 return (EINVAL);
146 }
147 if (prot & ~_PROT_ALL) {
148 warnx("%s: Invalid protection: %x", __func__,
149 prot & ~_PROT_ALL);
150 return (EINVAL);
151 }
152
153 if (len == 0 || len > BOOTROM_SIZE) {
154 warnx("ROM size %zu is invalid", len);
155 return (EINVAL);
156 }
157 if (len & PAGE_MASK) {
158 warnx("ROM size %zu is not a multiple of the page size",
159 len);
160 return (EINVAL);
161 }
162
163 if (flags & BOOTROM_ALLOC_TOP) {
164 gpa = (gpa_alloctop - len) + 1;
165 if (gpa < gpa_allocbot) {
166 warnx("No room for %zu ROM in bootrom region", len);
167 return (ENOMEM);
168 }
169 } else {
170 gpa = gpa_allocbot;
171 if (gpa > (gpa_alloctop - len) + 1) {
172 warnx("No room for %zu ROM in bootrom region", len);
173 return (ENOMEM);
174 }
175 }
176
177 segoff = gpa - gpa_base;
178 if (vm_mmap_memseg(ctx, gpa, VM_BOOTROM, segoff, len, prot) != 0) {
179 int serrno = errno;
180 warn("%s: vm_mmap_mapseg", __func__);
181 return (serrno);
182 }
183
184 if (flags & BOOTROM_ALLOC_TOP)
185 gpa_alloctop = gpa - 1;
186 else
187 gpa_allocbot = gpa + len;
188
189 *region_out = romptr + segoff;
190 if (gpa_out != NULL)
191 *gpa_out = gpa;
192 return (0);
193 }
194
195 int
bootrom_loadrom(struct vmctx * ctx)196 bootrom_loadrom(struct vmctx *ctx)
197 {
198 struct stat sbuf;
199 ssize_t rlen;
200 off_t rom_size, var_size, total_size;
201 char *ptr, *romfile;
202 int fd, varfd, i, rv;
203 const char *bootrom, *varfile;
204
205 rv = -1;
206 varfd = -1;
207
208 bootrom = get_config_value("bootrom");
209 if (bootrom == NULL) {
210 return (0);
211 }
212
213 /*
214 * get_config_value_node may use a thread local buffer to return
215 * variables. So, when we query the second variable, the first variable
216 * might get overwritten. For that reason, the bootrom should be
217 * duplicated.
218 */
219 romfile = strdup(bootrom);
220 if (romfile == NULL) {
221 return (-1);
222 }
223
224 fd = open(romfile, O_RDONLY);
225 if (fd < 0) {
226 EPRINTLN("Error opening bootrom \"%s\": %s",
227 romfile, strerror(errno));
228 goto done;
229 }
230
231 if (fstat(fd, &sbuf) < 0) {
232 EPRINTLN("Could not fstat bootrom file \"%s\": %s", romfile,
233 strerror(errno));
234 goto done;
235 }
236
237 rom_size = sbuf.st_size;
238
239 varfile = get_config_value("bootvars");
240 var_size = 0;
241 if (varfile != NULL) {
242 varfd = open(varfile, O_RDWR);
243 if (varfd < 0) {
244 EPRINTLN("Error opening bootrom variable file "
245 "\"%s\": %s", varfile, strerror(errno));
246 goto done;
247 }
248
249 if (fstat(varfd, &sbuf) < 0) {
250 EPRINTLN(
251 "Could not fstat bootrom variable file \"%s\": %s",
252 varfile, strerror(errno));
253 goto done;
254 }
255
256 var_size = sbuf.st_size;
257 }
258
259 if (var_size > BOOTROM_SIZE ||
260 (var_size != 0 && var_size < PAGE_SIZE)) {
261 EPRINTLN("Invalid bootrom variable size %ld",
262 var_size);
263 goto done;
264 }
265
266 total_size = rom_size + var_size;
267
268 if (total_size > BOOTROM_SIZE) {
269 EPRINTLN("Invalid bootrom and variable aggregate size %ld",
270 total_size);
271 goto done;
272 }
273
274 /* Map the bootrom into the guest address space */
275 if (bootrom_alloc(ctx, rom_size, PROT_READ | PROT_EXEC,
276 BOOTROM_ALLOC_TOP, &ptr, NULL) != 0) {
277 goto done;
278 }
279
280 /* Read 'romfile' into the guest address space */
281 for (i = 0; i < rom_size / PAGE_SIZE; i++) {
282 rlen = read(fd, ptr + i * PAGE_SIZE, PAGE_SIZE);
283 if (rlen != PAGE_SIZE) {
284 EPRINTLN("Incomplete read of page %d of bootrom "
285 "file %s: %ld bytes", i, romfile, rlen);
286 goto done;
287 }
288 }
289
290 if (varfd >= 0) {
291 #ifdef __FreeBSD__
292 var.mmap = mmap(NULL, var_size, PROT_READ | PROT_WRITE,
293 MAP_SHARED, varfd, 0);
294 #else
295 var.mmap = (uint8_t *)mmap(NULL, var_size,
296 PROT_READ | PROT_WRITE, MAP_SHARED, varfd, 0);
297 #endif
298 if (var.mmap == MAP_FAILED)
299 goto done;
300 var.size = var_size;
301 var.gpa = (gpa_alloctop - var_size) + 1;
302 gpa_alloctop = var.gpa - 1;
303 rv = register_mem(&(struct mem_range){
304 .name = "bootrom variable",
305 .flags = MEM_F_RW,
306 .handler = bootrom_var_mem_handler,
307 .base = var.gpa,
308 .size = var.size,
309 });
310 if (rv != 0)
311 goto done;
312 }
313
314 rv = 0;
315 done:
316 if (varfd >= 0)
317 close(varfd);
318 if (fd >= 0)
319 close(fd);
320 free(romfile);
321 return (rv);
322 }
323
324 /*
325 * Are we relying on a bootrom to initialize the guest's CPU context?
326 */
327 bool
bootrom_boot(void)328 bootrom_boot(void)
329 {
330 return (get_config_value("bootrom") != NULL);
331 }
332