/* Dynamic linker/loader of ACPI tables * * Copyright (C) 2013 Red Hat Inc * * Author: Michael S. Tsirkin <mst@redhat.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * You should have received a copy of the GNU General Public License along * with this program; if not, see <http://www.gnu.org/licenses/>. */ #include "qemu/osdep.h" #include "qemu-common.h" #include "hw/acpi/bios-linker-loader.h" #include "hw/nvram/fw_cfg.h" #include "qemu/bswap.h" /* * Linker/loader is a paravirtualized interface that passes commands to guest. * The commands can be used to request guest to * - allocate memory chunks and initialize them from QEMU FW CFG files * - link allocated chunks by storing pointer to one chunk into another * - calculate ACPI checksum of part of the chunk and store into same chunk */ #define BIOS_LINKER_LOADER_FILESZ FW_CFG_MAX_FILE_PATH struct BiosLinkerLoaderEntry { uint32_t command; union { /* * COMMAND_ALLOCATE - allocate a table from @alloc.file * subject to @alloc.align alignment (must be power of 2) * and @alloc.zone (can be HIGH or FSEG) requirements. * * Must appear exactly once for each file, and before * this file is referenced by any other command. */ struct { char file[BIOS_LINKER_LOADER_FILESZ]; uint32_t align; uint8_t zone; } alloc; /* * COMMAND_ADD_POINTER - patch the table (originating from * @dest_file) at @pointer.offset, by adding a pointer to the table * originating from @src_file. 1,2,4 or 8 byte unsigned * addition is used depending on @pointer.size. */ struct { char dest_file[BIOS_LINKER_LOADER_FILESZ]; char src_file[BIOS_LINKER_LOADER_FILESZ]; uint32_t offset; uint8_t size; } pointer; /* * COMMAND_ADD_CHECKSUM - calculate checksum of the range specified by * @cksum_start and @cksum_length fields, * and then add the value at @cksum.offset. * Checksum simply sums -X for each byte X in the range * using 8-bit math. */ struct { char file[BIOS_LINKER_LOADER_FILESZ]; uint32_t offset; uint32_t start; uint32_t length; } cksum; /* padding */ char pad[124]; }; } QEMU_PACKED; typedef struct BiosLinkerLoaderEntry BiosLinkerLoaderEntry; enum { BIOS_LINKER_LOADER_COMMAND_ALLOCATE = 0x1, BIOS_LINKER_LOADER_COMMAND_ADD_POINTER = 0x2, BIOS_LINKER_LOADER_COMMAND_ADD_CHECKSUM = 0x3, }; enum { BIOS_LINKER_LOADER_ALLOC_ZONE_HIGH = 0x1, BIOS_LINKER_LOADER_ALLOC_ZONE_FSEG = 0x2, }; /* * BiosLinkerFileEntry: * * An internal type used for book-keeping file entries */ typedef struct BiosLinkerFileEntry { char *name; /* file name */ GArray *blob; /* data accosiated with @name */ } BiosLinkerFileEntry; /* * bios_linker_loader_init: allocate a new linker object instance. * * After initialization, linker commands can be added, and will * be stored in the linker.cmd_blob array. */ BIOSLinker *bios_linker_loader_init(void) { BIOSLinker *linker = g_new(BIOSLinker, 1); linker->cmd_blob = g_array_new(false, true /* clear */, 1); linker->file_list = g_array_new(false, true /* clear */, sizeof(BiosLinkerFileEntry)); return linker; } /* Free linker wrapper */ void bios_linker_loader_cleanup(BIOSLinker *linker) { int i; BiosLinkerFileEntry *entry; g_array_free(linker->cmd_blob, true); for (i = 0; i < linker->file_list->len; i++) { entry = &g_array_index(linker->file_list, BiosLinkerFileEntry, i); g_free(entry->name); } g_array_free(linker->file_list, true); g_free(linker); } static const BiosLinkerFileEntry * bios_linker_find_file(const BIOSLinker *linker, const char *name) { int i; BiosLinkerFileEntry *entry; for (i = 0; i < linker->file_list->len; i++) { entry = &g_array_index(linker->file_list, BiosLinkerFileEntry, i); if (!strcmp(entry->name, name)) { return entry; } } return NULL; } /* * bios_linker_loader_alloc: ask guest to load file into guest memory. * * @linker: linker object instance * @file_name: name of the file blob to be loaded * @file_blob: pointer to blob corresponding to @file_name * @alloc_align: required minimal alignment in bytes. Must be a power of 2. * @alloc_fseg: request allocation in FSEG zone (useful for the RSDP ACPI table) * * Note: this command must precede any other linker command using this file. */ void bios_linker_loader_alloc(BIOSLinker *linker, const char *file_name, GArray *file_blob, uint32_t alloc_align, bool alloc_fseg) { BiosLinkerLoaderEntry entry; BiosLinkerFileEntry file = { g_strdup(file_name), file_blob}; assert(!(alloc_align & (alloc_align - 1))); assert(!bios_linker_find_file(linker, file_name)); g_array_append_val(linker->file_list, file); memset(&entry, 0, sizeof entry); strncpy(entry.alloc.file, file_name, sizeof entry.alloc.file - 1); entry.command = cpu_to_le32(BIOS_LINKER_LOADER_COMMAND_ALLOCATE); entry.alloc.align = cpu_to_le32(alloc_align); entry.alloc.zone = alloc_fseg ? BIOS_LINKER_LOADER_ALLOC_ZONE_FSEG : BIOS_LINKER_LOADER_ALLOC_ZONE_HIGH; /* Alloc entries must come first, so prepend them */ g_array_prepend_vals(linker->cmd_blob, &entry, sizeof entry); } /* * bios_linker_loader_add_checksum: ask guest to add checksum of ACPI * table in the specified file at the specified offset. * * Checksum calculation simply sums -X for each byte X in the range * using 8-bit math (i.e. ACPI checksum). * * @linker: linker object instance * @file: file that includes the checksum to be calculated * and the data to be checksummed * @start_offset, @size: range of data in the file to checksum, * relative to the start of file blob * @checksum_offset: location of the checksum to be patched within file blob, * relative to the start of file blob */ void bios_linker_loader_add_checksum(BIOSLinker *linker, const char *file_name, unsigned start_offset, unsigned size, unsigned checksum_offset) { BiosLinkerLoaderEntry entry; const BiosLinkerFileEntry *file = bios_linker_find_file(linker, file_name); assert(file); assert(start_offset < file->blob->len); assert(start_offset + size <= file->blob->len); assert(checksum_offset >= start_offset); assert(checksum_offset + 1 <= start_offset + size); *(file->blob->data + checksum_offset) = 0; memset(&entry, 0, sizeof entry); strncpy(entry.cksum.file, file_name, sizeof entry.cksum.file - 1); entry.command = cpu_to_le32(BIOS_LINKER_LOADER_COMMAND_ADD_CHECKSUM); entry.cksum.offset = cpu_to_le32(checksum_offset); entry.cksum.start = cpu_to_le32(start_offset); entry.cksum.length = cpu_to_le32(size); g_array_append_vals(linker->cmd_blob, &entry, sizeof entry); } /* * bios_linker_loader_add_pointer: ask guest to patch address in * destination file with a pointer to source file * * @linker: linker object instance * @dest_file: destination file that must be changed * @dst_patched_offset: location within destination file blob to be patched * with the pointer to @src_file+@src_offset (i.e. source * blob allocated in guest memory + @src_offset), in bytes * @dst_patched_offset_size: size of the pointer to be patched * at @dst_patched_offset in @dest_file blob, in bytes * @src_file: source file who's address must be taken * @src_offset: location within source file blob to which * @dest_file+@dst_patched_offset will point to after * firmware's executed ADD_POINTER command */ void 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) { uint64_t le_src_offset; BiosLinkerLoaderEntry entry; const BiosLinkerFileEntry *dst_file = bios_linker_find_file(linker, dest_file); const BiosLinkerFileEntry *source_file = bios_linker_find_file(linker, src_file); assert(dst_patched_offset < dst_file->blob->len); assert(dst_patched_offset + dst_patched_size <= dst_file->blob->len); assert(src_offset < source_file->blob->len); memset(&entry, 0, sizeof entry); strncpy(entry.pointer.dest_file, dest_file, sizeof entry.pointer.dest_file - 1); strncpy(entry.pointer.src_file, src_file, sizeof entry.pointer.src_file - 1); entry.command = cpu_to_le32(BIOS_LINKER_LOADER_COMMAND_ADD_POINTER); entry.pointer.offset = cpu_to_le32(dst_patched_offset); entry.pointer.size = dst_patched_size; assert(dst_patched_size == 1 || dst_patched_size == 2 || dst_patched_size == 4 || dst_patched_size == 8); le_src_offset = cpu_to_le64(src_offset); memcpy(dst_file->blob->data + dst_patched_offset, &le_src_offset, dst_patched_size); g_array_append_vals(linker->cmd_blob, &entry, sizeof entry); }