1 /* Dynamic linker/loader of ACPI tables
2 *
3 * Copyright (C) 2013 Red Hat Inc
4 *
5 * Author: Michael S. Tsirkin <mst@redhat.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16
17 * You should have received a copy of the GNU General Public License along
18 * with this program; if not, see <http://www.gnu.org/licenses/>.
19 */
20
21 #include "qemu/osdep.h"
22 #include "hw/acpi/bios-linker-loader.h"
23 #include "hw/nvram/fw_cfg.h"
24
25 /*
26 * Linker/loader is a paravirtualized interface that passes commands to guest.
27 * The commands can be used to request guest to
28 * - allocate memory chunks and initialize them from QEMU FW CFG files
29 * - link allocated chunks by storing pointer to one chunk into another
30 * - calculate ACPI checksum of part of the chunk and store into same chunk
31 */
32 #define BIOS_LINKER_LOADER_FILESZ FW_CFG_MAX_FILE_PATH
33
34 struct BiosLinkerLoaderEntry {
35 uint32_t command;
36 union {
37 /*
38 * COMMAND_ALLOCATE - allocate a table from @alloc.file
39 * subject to @alloc.align alignment (must be power of 2)
40 * and @alloc.zone (can be HIGH or FSEG) requirements.
41 *
42 * Must appear exactly once for each file, and before
43 * this file is referenced by any other command.
44 */
45 struct {
46 char file[BIOS_LINKER_LOADER_FILESZ];
47 uint32_t align;
48 uint8_t zone;
49 } alloc;
50
51 /*
52 * COMMAND_ADD_POINTER - patch the table (originating from
53 * @dest_file) at @pointer.offset, by adding a pointer to the table
54 * originating from @src_file. 1,2,4 or 8 byte unsigned
55 * addition is used depending on @pointer.size.
56 */
57 struct {
58 char dest_file[BIOS_LINKER_LOADER_FILESZ];
59 char src_file[BIOS_LINKER_LOADER_FILESZ];
60 uint32_t offset;
61 uint8_t size;
62 } pointer;
63
64 /*
65 * COMMAND_ADD_CHECKSUM - calculate checksum of the range specified by
66 * @cksum_start and @cksum_length fields,
67 * and then add the value at @cksum.offset.
68 * Checksum simply sums -X for each byte X in the range
69 * using 8-bit math.
70 */
71 struct {
72 char file[BIOS_LINKER_LOADER_FILESZ];
73 uint32_t offset;
74 uint32_t start;
75 uint32_t length;
76 } cksum;
77
78 /*
79 * COMMAND_WRITE_POINTER - write the fw_cfg file (originating from
80 * @dest_file) at @wr_pointer.offset, by adding a pointer to
81 * @src_offset within the table originating from @src_file.
82 * 1,2,4 or 8 byte unsigned addition is used depending on
83 * @wr_pointer.size.
84 */
85 struct {
86 char dest_file[BIOS_LINKER_LOADER_FILESZ];
87 char src_file[BIOS_LINKER_LOADER_FILESZ];
88 uint32_t dst_offset;
89 uint32_t src_offset;
90 uint8_t size;
91 } wr_pointer;
92
93 /* padding */
94 char pad[124];
95 };
96 } QEMU_PACKED;
97 typedef struct BiosLinkerLoaderEntry BiosLinkerLoaderEntry;
98
99 enum {
100 BIOS_LINKER_LOADER_COMMAND_ALLOCATE = 0x1,
101 BIOS_LINKER_LOADER_COMMAND_ADD_POINTER = 0x2,
102 BIOS_LINKER_LOADER_COMMAND_ADD_CHECKSUM = 0x3,
103 BIOS_LINKER_LOADER_COMMAND_WRITE_POINTER = 0x4,
104 };
105
106 enum {
107 BIOS_LINKER_LOADER_ALLOC_ZONE_HIGH = 0x1,
108 BIOS_LINKER_LOADER_ALLOC_ZONE_FSEG = 0x2,
109 };
110
111 /*
112 * BiosLinkerFileEntry:
113 *
114 * An internal type used for book-keeping file entries
115 */
116 typedef struct BiosLinkerFileEntry {
117 char *name; /* file name */
118 GArray *blob; /* data accosiated with @name */
119 } BiosLinkerFileEntry;
120
121 /*
122 * bios_linker_loader_init: allocate a new linker object instance.
123 *
124 * After initialization, linker commands can be added, and will
125 * be stored in the linker.cmd_blob array.
126 */
bios_linker_loader_init(void)127 BIOSLinker *bios_linker_loader_init(void)
128 {
129 BIOSLinker *linker = g_new(BIOSLinker, 1);
130
131 linker->cmd_blob = g_array_new(false, true /* clear */, 1);
132 linker->file_list = g_array_new(false, true /* clear */,
133 sizeof(BiosLinkerFileEntry));
134 return linker;
135 }
136
137 /* Free linker wrapper */
bios_linker_loader_cleanup(BIOSLinker * linker)138 void bios_linker_loader_cleanup(BIOSLinker *linker)
139 {
140 int i;
141 BiosLinkerFileEntry *entry;
142
143 g_array_free(linker->cmd_blob, true);
144
145 for (i = 0; i < linker->file_list->len; i++) {
146 entry = &g_array_index(linker->file_list, BiosLinkerFileEntry, i);
147 g_free(entry->name);
148 }
149 g_array_free(linker->file_list, true);
150 g_free(linker);
151 }
152
153 static const BiosLinkerFileEntry *
bios_linker_find_file(const BIOSLinker * linker,const char * name)154 bios_linker_find_file(const BIOSLinker *linker, const char *name)
155 {
156 int i;
157 BiosLinkerFileEntry *entry;
158
159 for (i = 0; i < linker->file_list->len; i++) {
160 entry = &g_array_index(linker->file_list, BiosLinkerFileEntry, i);
161 if (!strcmp(entry->name, name)) {
162 return entry;
163 }
164 }
165 return NULL;
166 }
167
168 /*
169 * board code must realize fw_cfg first, as a fixed device, before
170 * another device realize function call bios_linker_loader_can_write_pointer()
171 */
bios_linker_loader_can_write_pointer(void)172 bool bios_linker_loader_can_write_pointer(void)
173 {
174 FWCfgState *fw_cfg = fw_cfg_find();
175 return fw_cfg && fw_cfg_dma_enabled(fw_cfg);
176 }
177
178 /*
179 * bios_linker_loader_alloc: ask guest to load file into guest memory.
180 *
181 * @linker: linker object instance
182 * @file_name: name of the file blob to be loaded
183 * @file_blob: pointer to blob corresponding to @file_name
184 * @alloc_align: required minimal alignment in bytes. Must be a power of 2.
185 * @alloc_fseg: request allocation in FSEG zone (useful for the RSDP ACPI table)
186 *
187 * Note: this command must precede any other linker command using this file.
188 */
bios_linker_loader_alloc(BIOSLinker * linker,const char * file_name,GArray * file_blob,uint32_t alloc_align,bool alloc_fseg)189 void bios_linker_loader_alloc(BIOSLinker *linker,
190 const char *file_name,
191 GArray *file_blob,
192 uint32_t alloc_align,
193 bool alloc_fseg)
194 {
195 BiosLinkerLoaderEntry entry;
196 BiosLinkerFileEntry file = { g_strdup(file_name), file_blob};
197
198 assert(!(alloc_align & (alloc_align - 1)));
199
200 assert(!bios_linker_find_file(linker, file_name));
201 g_array_append_val(linker->file_list, file);
202
203 memset(&entry, 0, sizeof entry);
204 strncpy(entry.alloc.file, file_name, sizeof entry.alloc.file - 1);
205 entry.command = cpu_to_le32(BIOS_LINKER_LOADER_COMMAND_ALLOCATE);
206 entry.alloc.align = cpu_to_le32(alloc_align);
207 entry.alloc.zone = alloc_fseg ? BIOS_LINKER_LOADER_ALLOC_ZONE_FSEG :
208 BIOS_LINKER_LOADER_ALLOC_ZONE_HIGH;
209
210 /* Alloc entries must come first, so prepend them */
211 g_array_prepend_vals(linker->cmd_blob, &entry, sizeof entry);
212 }
213
214 /*
215 * bios_linker_loader_add_checksum: ask guest to add checksum of ACPI
216 * table in the specified file at the specified offset.
217 *
218 * Checksum calculation simply sums -X for each byte X in the range
219 * using 8-bit math (i.e. ACPI checksum).
220 *
221 * @linker: linker object instance
222 * @file: file that includes the checksum to be calculated
223 * and the data to be checksummed
224 * @start_offset, @size: range of data in the file to checksum,
225 * relative to the start of file blob
226 * @checksum_offset: location of the checksum to be patched within file blob,
227 * relative to the start of file blob
228 */
bios_linker_loader_add_checksum(BIOSLinker * linker,const char * file_name,unsigned start_offset,unsigned size,unsigned checksum_offset)229 void bios_linker_loader_add_checksum(BIOSLinker *linker, const char *file_name,
230 unsigned start_offset, unsigned size,
231 unsigned checksum_offset)
232 {
233 BiosLinkerLoaderEntry entry;
234 const BiosLinkerFileEntry *file = bios_linker_find_file(linker, file_name);
235
236 assert(file);
237 assert(start_offset < file->blob->len);
238 assert(start_offset + size <= file->blob->len);
239 assert(checksum_offset >= start_offset);
240 assert(checksum_offset + 1 <= start_offset + size);
241
242 *(file->blob->data + checksum_offset) = 0;
243 memset(&entry, 0, sizeof entry);
244 strncpy(entry.cksum.file, file_name, sizeof entry.cksum.file - 1);
245 entry.command = cpu_to_le32(BIOS_LINKER_LOADER_COMMAND_ADD_CHECKSUM);
246 entry.cksum.offset = cpu_to_le32(checksum_offset);
247 entry.cksum.start = cpu_to_le32(start_offset);
248 entry.cksum.length = cpu_to_le32(size);
249
250 g_array_append_vals(linker->cmd_blob, &entry, sizeof entry);
251 }
252
253 /*
254 * bios_linker_loader_add_pointer: ask guest to patch address in
255 * destination file with a pointer to source file
256 *
257 * @linker: linker object instance
258 * @dest_file: destination file that must be changed
259 * @dst_patched_offset: location within destination file blob to be patched
260 * with the pointer to @src_file+@src_offset (i.e. source
261 * blob allocated in guest memory + @src_offset), in bytes
262 * @dst_patched_offset_size: size of the pointer to be patched
263 * at @dst_patched_offset in @dest_file blob, in bytes
264 * @src_file: source file who's address must be taken
265 * @src_offset: location within source file blob to which
266 * @dest_file+@dst_patched_offset will point to after
267 * firmware's executed ADD_POINTER command
268 */
bios_linker_loader_add_pointer(BIOSLinker * linker,const char * dest_file,uint32_t dst_patched_offset,uint8_t dst_patched_size,const char * src_file,uint32_t src_offset)269 void bios_linker_loader_add_pointer(BIOSLinker *linker,
270 const char *dest_file,
271 uint32_t dst_patched_offset,
272 uint8_t dst_patched_size,
273 const char *src_file,
274 uint32_t src_offset)
275 {
276 uint64_t le_src_offset;
277 BiosLinkerLoaderEntry entry;
278 const BiosLinkerFileEntry *dst_file =
279 bios_linker_find_file(linker, dest_file);
280 const BiosLinkerFileEntry *source_file =
281 bios_linker_find_file(linker, src_file);
282
283 assert(dst_file);
284 assert(source_file);
285 assert(dst_patched_offset < dst_file->blob->len);
286 assert(dst_patched_offset + dst_patched_size <= dst_file->blob->len);
287 assert(src_offset < source_file->blob->len);
288
289 memset(&entry, 0, sizeof entry);
290 strncpy(entry.pointer.dest_file, dest_file,
291 sizeof entry.pointer.dest_file - 1);
292 strncpy(entry.pointer.src_file, src_file,
293 sizeof entry.pointer.src_file - 1);
294 entry.command = cpu_to_le32(BIOS_LINKER_LOADER_COMMAND_ADD_POINTER);
295 entry.pointer.offset = cpu_to_le32(dst_patched_offset);
296 entry.pointer.size = dst_patched_size;
297 assert(dst_patched_size == 1 || dst_patched_size == 2 ||
298 dst_patched_size == 4 || dst_patched_size == 8);
299
300 le_src_offset = cpu_to_le64(src_offset);
301 memcpy(dst_file->blob->data + dst_patched_offset,
302 &le_src_offset, dst_patched_size);
303
304 g_array_append_vals(linker->cmd_blob, &entry, sizeof entry);
305 }
306
307 /*
308 * bios_linker_loader_write_pointer: ask guest to write a pointer to the
309 * source file into the destination file, and write it back to QEMU via
310 * fw_cfg DMA.
311 *
312 * @linker: linker object instance
313 * @dest_file: destination file that must be written
314 * @dst_patched_offset: location within destination file blob to be patched
315 * with the pointer to @src_file, in bytes
316 * @dst_patched_offset_size: size of the pointer to be patched
317 * at @dst_patched_offset in @dest_file blob, in bytes
318 * @src_file: source file who's address must be taken
319 * @src_offset: location within source file blob to which
320 * @dest_file+@dst_patched_offset will point to after
321 * firmware's executed WRITE_POINTER command
322 */
bios_linker_loader_write_pointer(BIOSLinker * linker,const char * dest_file,uint32_t dst_patched_offset,uint8_t dst_patched_size,const char * src_file,uint32_t src_offset)323 void bios_linker_loader_write_pointer(BIOSLinker *linker,
324 const char *dest_file,
325 uint32_t dst_patched_offset,
326 uint8_t dst_patched_size,
327 const char *src_file,
328 uint32_t src_offset)
329 {
330 BiosLinkerLoaderEntry entry;
331 const BiosLinkerFileEntry *source_file =
332 bios_linker_find_file(linker, src_file);
333
334 assert(source_file);
335 assert(src_offset < source_file->blob->len);
336 memset(&entry, 0, sizeof entry);
337 strncpy(entry.wr_pointer.dest_file, dest_file,
338 sizeof entry.wr_pointer.dest_file - 1);
339 strncpy(entry.wr_pointer.src_file, src_file,
340 sizeof entry.wr_pointer.src_file - 1);
341 entry.command = cpu_to_le32(BIOS_LINKER_LOADER_COMMAND_WRITE_POINTER);
342 entry.wr_pointer.dst_offset = cpu_to_le32(dst_patched_offset);
343 entry.wr_pointer.src_offset = cpu_to_le32(src_offset);
344 entry.wr_pointer.size = dst_patched_size;
345 assert(dst_patched_size == 1 || dst_patched_size == 2 ||
346 dst_patched_size == 4 || dst_patched_size == 8);
347
348 g_array_append_vals(linker->cmd_blob, &entry, sizeof entry);
349 }
350