/* 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 "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;
/*
* COMMAND_WRITE_POINTER - write the fw_cfg file (originating from
* @dest_file) at @wr_pointer.offset, by adding a pointer to
* @src_offset within the table originating from @src_file.
* 1,2,4 or 8 byte unsigned addition is used depending on
* @wr_pointer.size.
*/
struct {
char dest_file[BIOS_LINKER_LOADER_FILESZ];
char src_file[BIOS_LINKER_LOADER_FILESZ];
uint32_t dst_offset;
uint32_t src_offset;
uint8_t size;
} wr_pointer;
/* 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,
BIOS_LINKER_LOADER_COMMAND_WRITE_POINTER = 0x4,
};
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;
}
/*
* board code must realize fw_cfg first, as a fixed device, before
* another device realize function call bios_linker_loader_can_write_pointer()
*/
bool bios_linker_loader_can_write_pointer(void)
{
FWCfgState *fw_cfg = fw_cfg_find();
return fw_cfg && fw_cfg_dma_enabled(fw_cfg);
}
/*
* 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_file);
assert(source_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);
}
/*
* bios_linker_loader_write_pointer: ask guest to write a pointer to the
* source file into the destination file, and write it back to QEMU via
* fw_cfg DMA.
*
* @linker: linker object instance
* @dest_file: destination file that must be written
* @dst_patched_offset: location within destination file blob to be patched
* with the pointer to @src_file, 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 WRITE_POINTER command
*/
void 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)
{
BiosLinkerLoaderEntry entry;
const BiosLinkerFileEntry *source_file =
bios_linker_find_file(linker, src_file);
assert(source_file);
assert(src_offset < source_file->blob->len);
memset(&entry, 0, sizeof entry);
strncpy(entry.wr_pointer.dest_file, dest_file,
sizeof entry.wr_pointer.dest_file - 1);
strncpy(entry.wr_pointer.src_file, src_file,
sizeof entry.wr_pointer.src_file - 1);
entry.command = cpu_to_le32(BIOS_LINKER_LOADER_COMMAND_WRITE_POINTER);
entry.wr_pointer.dst_offset = cpu_to_le32(dst_patched_offset);
entry.wr_pointer.src_offset = cpu_to_le32(src_offset);
entry.wr_pointer.size = dst_patched_size;
assert(dst_patched_size == 1 || dst_patched_size == 2 ||
dst_patched_size == 4 || dst_patched_size == 8);
g_array_append_vals(linker->cmd_blob, &entry, sizeof entry);
}
