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/*
* PVH Option ROM for fw_cfg DMA
*
* 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/>.
*
* Copyright (c) 2019 Red Hat Inc.
* Authors:
* Stefano Garzarella <sgarzare@redhat.com>
*/
asm (".code32"); /* this code will be executed in protected mode */
#include <stddef.h>
#include <stdint.h>
#include "optrom.h"
#include "optrom_fw_cfg.h"
#include "../../include/hw/xen/start_info.h"
#define RSDP_SIGNATURE 0x2052545020445352LL /* "RSD PTR " */
#define RSDP_AREA_ADDR 0x000E0000
#define RSDP_AREA_SIZE 0x00020000
#define EBDA_BASE_ADDR 0x0000040E
#define EBDA_SIZE 1024
#define E820_MAXENTRIES 128
#define CMDLINE_BUFSIZE 4096
/* e820 table filled in pvh.S using int 0x15 */
struct pvh_e820_table {
uint32_t entries;
uint32_t reserved;
struct hvm_memmap_table_entry table[E820_MAXENTRIES];
};
struct pvh_e820_table pvh_e820 asm("pvh_e820") __attribute__ ((aligned));
static struct hvm_start_info start_info;
static struct hvm_modlist_entry ramdisk_mod;
static uint8_t cmdline_buffer[CMDLINE_BUFSIZE];
/* Search RSDP signature. */
static uintptr_t search_rsdp(uint32_t start_addr, uint32_t end_addr)
{
uint64_t *rsdp_p;
/* RSDP signature is always on a 16 byte boundary */
for (rsdp_p = (uint64_t *)start_addr; rsdp_p < (uint64_t *)end_addr;
rsdp_p += 2) {
if (*rsdp_p == RSDP_SIGNATURE) {
return (uintptr_t)rsdp_p;
}
}
return 0;
}
/* Force the asm name without leading underscore, even on Win32. */
extern void pvh_load_kernel(void) asm("pvh_load_kernel");
void pvh_load_kernel(void)
{
void *cmdline_addr = &cmdline_buffer;
void *kernel_entry, *initrd_addr;
uint32_t cmdline_size, initrd_size, fw_cfg_version = bios_cfg_version();
start_info.magic = XEN_HVM_START_MAGIC_VALUE;
start_info.version = 1;
/*
* pvh_e820 is filled in the pvh.S before to switch in protected mode,
* because we can use int 0x15 only in real mode.
*/
start_info.memmap_entries = pvh_e820.entries;
start_info.memmap_paddr = (uintptr_t)pvh_e820.table;
/*
* Search RSDP in the main BIOS area below 1 MB.
* SeaBIOS store the RSDP in this area, so we try it first.
*/
start_info.rsdp_paddr = search_rsdp(RSDP_AREA_ADDR,
RSDP_AREA_ADDR + RSDP_AREA_SIZE);
/* Search RSDP in the EBDA if it is not found */
if (!start_info.rsdp_paddr) {
/*
* Th EBDA address is stored at EBDA_BASE_ADDR. It contains 2 bytes
* segment pointer to EBDA, so we must convert it to a linear address.
*/
uint32_t ebda_paddr = ((uint32_t)*((uint16_t *)EBDA_BASE_ADDR)) << 4;
if (ebda_paddr > 0x400) {
uint32_t *ebda = (uint32_t *)ebda_paddr;
start_info.rsdp_paddr = search_rsdp(*ebda, *ebda + EBDA_SIZE);
}
}
bios_cfg_read_entry(&cmdline_size, FW_CFG_CMDLINE_SIZE, 4, fw_cfg_version);
bios_cfg_read_entry(cmdline_addr, FW_CFG_CMDLINE_DATA, cmdline_size,
fw_cfg_version);
start_info.cmdline_paddr = (uintptr_t)cmdline_addr;
/* Check if we have the initrd to load */
bios_cfg_read_entry(&initrd_size, FW_CFG_INITRD_SIZE, 4, fw_cfg_version);
if (initrd_size) {
bios_cfg_read_entry(&initrd_addr, FW_CFG_INITRD_ADDR, 4,
fw_cfg_version);
bios_cfg_read_entry(initrd_addr, FW_CFG_INITRD_DATA, initrd_size,
fw_cfg_version);
ramdisk_mod.paddr = (uintptr_t)initrd_addr;
ramdisk_mod.size = initrd_size;
/* The first module is always ramdisk. */
start_info.modlist_paddr = (uintptr_t)&ramdisk_mod;
start_info.nr_modules = 1;
}
bios_cfg_read_entry(&kernel_entry, FW_CFG_KERNEL_ENTRY, 4, fw_cfg_version);
asm volatile("jmp *%1" : : "b"(&start_info), "c"(kernel_entry));
}
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