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("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(&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("Warning: Can fit ISA range into e820\n");
77
78	if (xen_guest)
79		xen_reserve_extra_memory(&pvh_bootparams);
80
81	pvh_bootparams.hdr.cmd_line_ptr =
82		pvh_start_info.cmdline_paddr;
83
84	/* The first module is always ramdisk. */
85	if (pvh_start_info.nr_modules) {
86		struct hvm_modlist_entry *modaddr =
87			__va(pvh_start_info.modlist_paddr);
88		pvh_bootparams.hdr.ramdisk_image = modaddr->paddr;
89		pvh_bootparams.hdr.ramdisk_size = modaddr->size;
90	}
91
92	/*
93	 * See Documentation/arch/x86/boot.rst.
94	 *
95	 * Version 2.12 supports Xen entry point but we will use default x86/PC
96	 * environment (i.e. hardware_subarch 0).
97	 */
98	pvh_bootparams.hdr.version = (2 << 8) | 12;
99	pvh_bootparams.hdr.type_of_loader = ((xen_guest ? 0x9 : 0xb) << 4) | 0;
100
101	x86_init.acpi.get_root_pointer = pvh_get_root_pointer;
102}
103
104/*
105 * If we are trying to boot a Xen PVH guest, it is expected that the kernel
106 * will have been configured to provide the required override for this routine.
107 */
108void __init __weak xen_pvh_init(struct boot_params *boot_params)
109{
110	xen_raw_printk("Error: Missing xen PVH initialization\n");
111	BUG();
112}
113
114static void __init hypervisor_specific_init(bool xen_guest)
115{
116	if (xen_guest)
117		xen_pvh_init(&pvh_bootparams);
118}
119
120/*
121 * This routine (and those that it might call) should not use
122 * anything that lives in .bss since that segment will be cleared later.
123 */
124void __init xen_prepare_pvh(void)
125{
126
127	u32 msr = xen_cpuid_base();
128	bool xen_guest = !!msr;
129
130	if (pvh_start_info.magic != XEN_HVM_START_MAGIC_VALUE) {
131		xen_raw_printk("Error: Unexpected magic value (0x%08x)\n",
132				pvh_start_info.magic);
133		BUG();
134	}
135
136	memset(&pvh_bootparams, 0, sizeof(pvh_bootparams));
137
138	hypervisor_specific_init(xen_guest);
139
140	init_pvh_bootparams(xen_guest);
141}
142