1// SPDX-License-Identifier: GPL-2.0
2#include <linux/acpi.h>
3
4#include <xen/hvc-console.h>
5
6#include <asm/bootparam.h>
7#include <asm/io_apic.h>
8#include <asm/hypervisor.h>
9#include <asm/e820/api.h>
10#include <asm/x86_init.h>
11
12#include <asm/xen/interface.h>
13
14#include <xen/xen.h>
15#include <xen/interface/hvm/start_info.h>
16
17/*
18 * PVH variables.
19 *
20 * pvh_bootparams and pvh_start_info need to live in a data segment since
21 * they are used after startup_{32|64}, which clear .bss, are invoked.
22 */
23struct boot_params __initdata pvh_bootparams;
24struct hvm_start_info __initdata pvh_start_info;
25
26const unsigned int __initconst pvh_start_info_sz = sizeof(pvh_start_info);
27
28static u64 __init pvh_get_root_pointer(void)
29{
30 return pvh_start_info.rsdp_paddr;
31}
32
33/*
34 * Xen guests are able to obtain the memory map from the hypervisor via the
35 * HYPERVISOR_memory_op hypercall.
36 * If we are trying to boot a Xen PVH guest, it is expected that the kernel
37 * will have been configured to provide an override for this routine to do
38 * just that.
39 */
40void __init __weak mem_map_via_hcall(struct boot_params *ptr __maybe_unused)
41{
42 xen_raw_printk(fmt: "Error: Could not find memory map\n");
43 BUG();
44}
45
46static void __init init_pvh_bootparams(bool xen_guest)
47{
48 if ((pvh_start_info.version > 0) && (pvh_start_info.memmap_entries)) {
49 struct hvm_memmap_table_entry *ep;
50 int i;
51
52 ep = __va(pvh_start_info.memmap_paddr);
53 pvh_bootparams.e820_entries = pvh_start_info.memmap_entries;
54
55 for (i = 0; i < pvh_bootparams.e820_entries ; i++, ep++) {
56 pvh_bootparams.e820_table[i].addr = ep->addr;
57 pvh_bootparams.e820_table[i].size = ep->size;
58 pvh_bootparams.e820_table[i].type = ep->type;
59 }
60 } else if (xen_guest) {
61 mem_map_via_hcall(ptr: &pvh_bootparams);
62 } else {
63 /* Non-xen guests are not supported by version 0 */
64 BUG();
65 }
66
67 if (pvh_bootparams.e820_entries < E820_MAX_ENTRIES_ZEROPAGE - 1) {
68 pvh_bootparams.e820_table[pvh_bootparams.e820_entries].addr =
69 ISA_START_ADDRESS;
70 pvh_bootparams.e820_table[pvh_bootparams.e820_entries].size =
71 ISA_END_ADDRESS - ISA_START_ADDRESS;
72 pvh_bootparams.e820_table[pvh_bootparams.e820_entries].type =
73 E820_TYPE_RESERVED;
74 pvh_bootparams.e820_entries++;
75 } else
76 xen_raw_printk(fmt: "Warning: Can fit ISA range into e820\n");
77
78 pvh_bootparams.hdr.cmd_line_ptr =
79 pvh_start_info.cmdline_paddr;
80
81 /* The first module is always ramdisk. */
82 if (pvh_start_info.nr_modules) {
83 struct hvm_modlist_entry *modaddr =
84 __va(pvh_start_info.modlist_paddr);
85 pvh_bootparams.hdr.ramdisk_image = modaddr->paddr;
86 pvh_bootparams.hdr.ramdisk_size = modaddr->size;
87 }
88
89 /*
90 * See Documentation/arch/x86/boot.rst.
91 *
92 * Version 2.12 supports Xen entry point but we will use default x86/PC
93 * environment (i.e. hardware_subarch 0).
94 */
95 pvh_bootparams.hdr.version = (2 << 8) | 12;
96 pvh_bootparams.hdr.type_of_loader = ((xen_guest ? 0x9 : 0xb) << 4) | 0;
97
98 x86_init.acpi.get_root_pointer = pvh_get_root_pointer;
99}
100
101/*
102 * If we are trying to boot a Xen PVH guest, it is expected that the kernel
103 * will have been configured to provide the required override for this routine.
104 */
105void __init __weak xen_pvh_init(struct boot_params *boot_params)
106{
107 xen_raw_printk(fmt: "Error: Missing xen PVH initialization\n");
108 BUG();
109}
110
111static void __init hypervisor_specific_init(bool xen_guest)
112{
113 if (xen_guest)
114 xen_pvh_init(boot_params: &pvh_bootparams);
115}
116
117/*
118 * This routine (and those that it might call) should not use
119 * anything that lives in .bss since that segment will be cleared later.
120 */
121void __init xen_prepare_pvh(void)
122{
123
124 u32 msr = xen_cpuid_base();
125 bool xen_guest = !!msr;
126
127 if (pvh_start_info.magic != XEN_HVM_START_MAGIC_VALUE) {
128 xen_raw_printk(fmt: "Error: Unexpected magic value (0x%08x)\n",
129 pvh_start_info.magic);
130 BUG();
131 }
132
133 /*
134 * This must not compile to "call memset" because memset() may be
135 * instrumented.
136 */
137 __builtin_memset(&pvh_bootparams, 0, sizeof(pvh_bootparams));
138
139 hypervisor_specific_init(xen_guest);
140
141 init_pvh_bootparams(xen_guest);
142}
143

source code of linux/arch/x86/platform/pvh/enlighten.c