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qemu-irix/hw/acpi/bios-linker-loader.c

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/* 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,
};
/*
* bios_linker_loader_init: allocate a new linker file blob array.
*
* After initialization, linker commands can be added, and will
* be stored in the array.
*/
GArray *bios_linker_loader_init(void)
{
return g_array_new(false, true /* clear */, 1);
}
/* Free linker wrapper and return the linker array. */
void *bios_linker_loader_cleanup(GArray *linker)
{
return g_array_free(linker, false);
}
/*
* bios_linker_loader_alloc: ask guest to load file into guest memory.
*
* @linker: linker file blob array
* @file: file to be loaded
* @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(GArray *linker,
const char *file,
uint32_t alloc_align,
bool alloc_fseg)
{
BiosLinkerLoaderEntry entry;
assert(!(alloc_align & (alloc_align - 1)));
memset(&entry, 0, sizeof entry);
strncpy(entry.alloc.file, file, 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, &entry, sizeof entry);
}
/*
* bios_linker_loader_add_checksum: ask guest to add checksum of file data
* into (same) file at the specified pointer.
*
* Checksum calculation simply sums -X for each byte X in the range
* using 8-bit math (i.e. ACPI checksum).
*
* @linker: linker file blob array
* @file: file that includes the checksum to be calculated
* and the data to be checksummed
* @table: @file blob contents
* @start, @size: range of data to checksum
* @checksum: location of the checksum to be patched within file blob
*
* Notes:
* - checksum byte initial value must have been pushed into @table
* and reside at address @checksum.
* - @size bytes must have been pushed into @table and reside at address
* @start.
* - Guest calculates checksum of specified range of data, result is added to
* initial value at @checksum into copy of @file in Guest memory.
* - Range might include the checksum itself.
* - To avoid confusion, caller must always put 0x0 at @checksum.
* - @file must be loaded into Guest memory using bios_linker_loader_alloc
*/
void bios_linker_loader_add_checksum(GArray *linker, const char *file,
GArray *table,
void *start, unsigned size,
uint8_t *checksum)
{
BiosLinkerLoaderEntry entry;
ptrdiff_t checksum_offset = (gchar *)checksum - table->data;
ptrdiff_t start_offset = (gchar *)start - table->data;
assert(checksum_offset >= 0);
assert(start_offset >= 0);
assert(checksum_offset + 1 <= table->len);
assert(start_offset + size <= table->len);
assert(*checksum == 0x0);
memset(&entry, 0, sizeof entry);
strncpy(entry.cksum.file, file, 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, &entry, sizeof entry);
}
/*
* bios_linker_loader_add_pointer: ask guest to add address of source file
* into destination file at the specified pointer.
*
* @linker: linker file blob array
* @dest_file: destination file that must be changed
* @src_file: source file who's address must be taken
* @table: @dest_file blob contents array
* @pointer: location of the pointer to be patched within destination file blob
* @pointer_size: size of pointer to be patched, in bytes
*
* Notes:
* - @pointer_size bytes must have been pushed into @table
* and reside at address @pointer.
* - Guest address is added to initial value at @pointer
* into copy of @dest_file in Guest memory.
* e.g. to get start of src_file in guest memory, put 0x0 there
* to get address of a field at offset 0x10 in src_file, put 0x10 there
* - Both @dest_file and @src_file must be
* loaded into Guest memory using bios_linker_loader_alloc
*/
void bios_linker_loader_add_pointer(GArray *linker,
const char *dest_file,
const char *src_file,
GArray *table, void *pointer,
uint8_t pointer_size)
{
BiosLinkerLoaderEntry entry;
ptrdiff_t offset = (gchar *)pointer - table->data;
assert(offset >= 0);
assert(offset + pointer_size <= table->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(offset);
entry.pointer.size = pointer_size;
assert(pointer_size == 1 || pointer_size == 2 ||
pointer_size == 4 || pointer_size == 8);
g_array_append_vals(linker, &entry, sizeof entry);
}
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