diff options
Diffstat (limited to 'pc-bios/optionrom/pvh_main.c')
| -rw-r--r-- | pc-bios/optionrom/pvh_main.c | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/pc-bios/optionrom/pvh_main.c b/pc-bios/optionrom/pvh_main.c new file mode 100644 index 0000000000..1dcc5c9256 --- /dev/null +++ b/pc-bios/optionrom/pvh_main.c @@ -0,0 +1,116 @@ +/* + * 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 2048 +#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 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; + uint32_t cmdline_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; + + bios_cfg_read_entry(&kernel_entry, FW_CFG_KERNEL_ENTRY, 4, fw_cfg_version); + + asm volatile("jmp *%1" : : "b"(&start_info), "c"(kernel_entry)); +} |