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