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