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/*
* QEMU PC System Firmware (OVMF specific)
*
* Copyright (c) 2003-2004 Fabrice Bellard
* Copyright (c) 2011-2012 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "qemu/error-report.h"
#include "hw/i386/pc.h"
#include "cpu.h"
#define OVMF_TABLE_FOOTER_GUID "96b582de-1fb2-45f7-baea-a366c55a082d"
static const int bytes_after_table_footer = 32;
static bool ovmf_flash_parsed;
static uint8_t *ovmf_table;
static int ovmf_table_len;
void pc_system_parse_ovmf_flash(uint8_t *flash_ptr, size_t flash_size)
{
uint8_t *ptr;
QemuUUID guid;
int tot_len;
/* should only be called once */
if (ovmf_flash_parsed) {
return;
}
ovmf_flash_parsed = true;
if (flash_size < TARGET_PAGE_SIZE) {
return;
}
/*
* if this is OVMF there will be a table footer
* guid 48 bytes before the end of the flash file
* (= 32 bytes after the table + 16 bytes the GUID itself).
* If it's not found, silently abort the flash parsing.
*/
qemu_uuid_parse(OVMF_TABLE_FOOTER_GUID, &guid);
guid = qemu_uuid_bswap(guid); /* guids are LE */
ptr = flash_ptr + flash_size - (bytes_after_table_footer + sizeof(guid));
if (!qemu_uuid_is_equal((QemuUUID *)ptr, &guid)) {
return;
}
/* if found, just before is two byte table length */
ptr -= sizeof(uint16_t);
tot_len = le16_to_cpu(*(uint16_t *)ptr) - sizeof(guid) - sizeof(uint16_t);
if (tot_len < 0 || tot_len > (ptr - flash_ptr)) {
error_report("OVMF table has invalid size %d", tot_len);
return;
}
if (tot_len == 0) {
/* no entries in the OVMF table */
return;
}
ovmf_table = g_malloc(tot_len);
ovmf_table_len = tot_len;
/*
* ptr is the foot of the table, so copy it all to the newly
* allocated ovmf_table and then set the ovmf_table pointer
* to the table foot
*/
memcpy(ovmf_table, ptr - tot_len, tot_len);
ovmf_table += tot_len;
}
/**
* pc_system_ovmf_table_find - Find the data associated with an entry in OVMF's
* reset vector GUIDed table.
*
* @entry: GUID string of the entry to lookup
* @data: Filled with a pointer to the entry's value (if not NULL)
* @data_len: Filled with the length of the entry's value (if not NULL). Pass
* NULL here if the length of data is known.
*
* Return: true if the entry was found in the OVMF table; false otherwise.
*/
bool pc_system_ovmf_table_find(const char *entry, uint8_t **data,
int *data_len)
{
uint8_t *ptr = ovmf_table;
int tot_len = ovmf_table_len;
QemuUUID entry_guid;
assert(ovmf_flash_parsed);
if (qemu_uuid_parse(entry, &entry_guid) < 0) {
return false;
}
if (!ptr) {
return false;
}
entry_guid = qemu_uuid_bswap(entry_guid); /* guids are LE */
while (tot_len >= sizeof(QemuUUID) + sizeof(uint16_t)) {
int len;
QemuUUID *guid;
/*
* The data structure is
* arbitrary length data
* 2 byte length of entire entry
* 16 byte guid
*/
guid = (QemuUUID *)(ptr - sizeof(QemuUUID));
len = le16_to_cpu(*(uint16_t *)(ptr - sizeof(QemuUUID) -
sizeof(uint16_t)));
/*
* just in case the table is corrupt, wouldn't want to spin in
* the zero case
*/
if (len < sizeof(QemuUUID) + sizeof(uint16_t)) {
return false;
} else if (len > tot_len) {
return false;
}
ptr -= len;
tot_len -= len;
if (qemu_uuid_is_equal(guid, &entry_guid)) {
if (data) {
*data = ptr;
}
if (data_len) {
*data_len = len - sizeof(QemuUUID) - sizeof(uint16_t);
}
return true;
}
}
return false;
}
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