1 | /* |
2 | * PVH Option ROM for fw_cfg DMA |
3 | * |
4 | * This program is free software; you can redistribute it and/or modify |
5 | * it under the terms of the GNU General Public License as published by |
6 | * the Free Software Foundation; either version 2 of the License, or |
7 | * (at your option) any later version. |
8 | * |
9 | * This program is distributed in the hope that it will be useful, |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
12 | * GNU General Public License for more details. |
13 | * |
14 | * You should have received a copy of the GNU General Public License |
15 | * along with this program; if not, see <http://www.gnu.org/licenses/>. |
16 | * |
17 | * Copyright (c) 2019 Red Hat Inc. |
18 | * Authors: |
19 | * Stefano Garzarella <sgarzare@redhat.com> |
20 | */ |
21 | |
22 | asm (".code32" ); /* this code will be executed in protected mode */ |
23 | |
24 | #include <stddef.h> |
25 | #include <stdint.h> |
26 | #include "optrom.h" |
27 | #include "optrom_fw_cfg.h" |
28 | #include "../../include/hw/xen/start_info.h" |
29 | |
30 | #define RSDP_SIGNATURE 0x2052545020445352LL /* "RSD PTR " */ |
31 | #define RSDP_AREA_ADDR 0x000E0000 |
32 | #define RSDP_AREA_SIZE 2048 |
33 | #define EBDA_BASE_ADDR 0x0000040E |
34 | #define EBDA_SIZE 1024 |
35 | |
36 | #define E820_MAXENTRIES 128 |
37 | #define CMDLINE_BUFSIZE 4096 |
38 | |
39 | /* e820 table filled in pvh.S using int 0x15 */ |
40 | struct pvh_e820_table { |
41 | uint32_t entries; |
42 | uint32_t reserved; |
43 | struct hvm_memmap_table_entry table[E820_MAXENTRIES]; |
44 | }; |
45 | |
46 | struct pvh_e820_table pvh_e820 asm("pvh_e820" ) __attribute__ ((aligned)); |
47 | |
48 | static struct hvm_start_info start_info; |
49 | static struct hvm_modlist_entry ramdisk_mod; |
50 | static uint8_t cmdline_buffer[CMDLINE_BUFSIZE]; |
51 | |
52 | |
53 | /* Search RSDP signature. */ |
54 | static uintptr_t search_rsdp(uint32_t start_addr, uint32_t end_addr) |
55 | { |
56 | uint64_t *rsdp_p; |
57 | |
58 | /* RSDP signature is always on a 16 byte boundary */ |
59 | for (rsdp_p = (uint64_t *)start_addr; rsdp_p < (uint64_t *)end_addr; |
60 | rsdp_p += 2) { |
61 | if (*rsdp_p == RSDP_SIGNATURE) { |
62 | return (uintptr_t)rsdp_p; |
63 | } |
64 | } |
65 | |
66 | return 0; |
67 | } |
68 | |
69 | /* Force the asm name without leading underscore, even on Win32. */ |
70 | extern void pvh_load_kernel(void) asm("pvh_load_kernel" ); |
71 | |
72 | void pvh_load_kernel(void) |
73 | { |
74 | void *cmdline_addr = &cmdline_buffer; |
75 | void *kernel_entry, *initrd_addr; |
76 | uint32_t cmdline_size, initrd_size, fw_cfg_version = bios_cfg_version(); |
77 | |
78 | start_info.magic = XEN_HVM_START_MAGIC_VALUE; |
79 | start_info.version = 1; |
80 | |
81 | /* |
82 | * pvh_e820 is filled in the pvh.S before to switch in protected mode, |
83 | * because we can use int 0x15 only in real mode. |
84 | */ |
85 | start_info.memmap_entries = pvh_e820.entries; |
86 | start_info.memmap_paddr = (uintptr_t)pvh_e820.table; |
87 | |
88 | /* |
89 | * Search RSDP in the main BIOS area below 1 MB. |
90 | * SeaBIOS store the RSDP in this area, so we try it first. |
91 | */ |
92 | start_info.rsdp_paddr = search_rsdp(RSDP_AREA_ADDR, |
93 | RSDP_AREA_ADDR + RSDP_AREA_SIZE); |
94 | |
95 | /* Search RSDP in the EBDA if it is not found */ |
96 | if (!start_info.rsdp_paddr) { |
97 | /* |
98 | * Th EBDA address is stored at EBDA_BASE_ADDR. It contains 2 bytes |
99 | * segment pointer to EBDA, so we must convert it to a linear address. |
100 | */ |
101 | uint32_t ebda_paddr = ((uint32_t)*((uint16_t *)EBDA_BASE_ADDR)) << 4; |
102 | if (ebda_paddr > 0x400) { |
103 | uint32_t *ebda = (uint32_t *)ebda_paddr; |
104 | |
105 | start_info.rsdp_paddr = search_rsdp(*ebda, *ebda + EBDA_SIZE); |
106 | } |
107 | } |
108 | |
109 | bios_cfg_read_entry(&cmdline_size, FW_CFG_CMDLINE_SIZE, 4, fw_cfg_version); |
110 | bios_cfg_read_entry(cmdline_addr, FW_CFG_CMDLINE_DATA, cmdline_size, |
111 | fw_cfg_version); |
112 | start_info.cmdline_paddr = (uintptr_t)cmdline_addr; |
113 | |
114 | /* Check if we have the initrd to load */ |
115 | bios_cfg_read_entry(&initrd_size, FW_CFG_INITRD_SIZE, 4, fw_cfg_version); |
116 | if (initrd_size) { |
117 | bios_cfg_read_entry(&initrd_addr, FW_CFG_INITRD_ADDR, 4, |
118 | fw_cfg_version); |
119 | bios_cfg_read_entry(initrd_addr, FW_CFG_INITRD_DATA, initrd_size, |
120 | fw_cfg_version); |
121 | |
122 | ramdisk_mod.paddr = (uintptr_t)initrd_addr; |
123 | ramdisk_mod.size = initrd_size; |
124 | |
125 | /* The first module is always ramdisk. */ |
126 | start_info.modlist_paddr = (uintptr_t)&ramdisk_mod; |
127 | start_info.nr_modules = 1; |
128 | } |
129 | |
130 | bios_cfg_read_entry(&kernel_entry, FW_CFG_KERNEL_ENTRY, 4, fw_cfg_version); |
131 | |
132 | asm volatile("jmp *%1" : : "b" (&start_info), "c" (kernel_entry)); |
133 | } |
134 | |