summaryrefslogtreecommitdiff
path: root/arch/x86/platform/pvh/enlighten.c
blob: ed0442e354344fad84fce7fcc29c67934828a9f9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
// SPDX-License-Identifier: GPL-2.0
#include <linux/acpi.h>

#include <xen/hvc-console.h>

#include <asm/io_apic.h>
#include <asm/hypervisor.h>
#include <asm/e820/api.h>
#include <asm/x86_init.h>

#include <asm/xen/interface.h>

#include <xen/xen.h>
#include <xen/interface/hvm/start_info.h>

/*
 * PVH variables.
 *
 * pvh_bootparams and pvh_start_info need to live in a data segment since
 * they are used after startup_{32|64}, which clear .bss, are invoked.
 */
struct boot_params __initdata pvh_bootparams;
struct hvm_start_info __initdata pvh_start_info;

const unsigned int __initconst pvh_start_info_sz = sizeof(pvh_start_info);

static u64 __init pvh_get_root_pointer(void)
{
	return pvh_start_info.rsdp_paddr;
}

/*
 * Xen guests are able to obtain the memory map from the hypervisor via the
 * HYPERVISOR_memory_op hypercall.
 * If we are trying to boot a Xen PVH guest, it is expected that the kernel
 * will have been configured to provide an override for this routine to do
 * just that.
 */
void __init __weak mem_map_via_hcall(struct boot_params *ptr __maybe_unused)
{
	xen_raw_printk("Error: Could not find memory map\n");
	BUG();
}

static void __init init_pvh_bootparams(bool xen_guest)
{
	if ((pvh_start_info.version > 0) && (pvh_start_info.memmap_entries)) {
		struct hvm_memmap_table_entry *ep;
		int i;

		ep = __va(pvh_start_info.memmap_paddr);
		pvh_bootparams.e820_entries = pvh_start_info.memmap_entries;

		for (i = 0; i < pvh_bootparams.e820_entries ; i++, ep++) {
			pvh_bootparams.e820_table[i].addr = ep->addr;
			pvh_bootparams.e820_table[i].size = ep->size;
			pvh_bootparams.e820_table[i].type = ep->type;
		}
	} else if (xen_guest) {
		mem_map_via_hcall(&pvh_bootparams);
	} else {
		/* Non-xen guests are not supported by version 0 */
		BUG();
	}

	if (pvh_bootparams.e820_entries < E820_MAX_ENTRIES_ZEROPAGE - 1) {
		pvh_bootparams.e820_table[pvh_bootparams.e820_entries].addr =
			ISA_START_ADDRESS;
		pvh_bootparams.e820_table[pvh_bootparams.e820_entries].size =
			ISA_END_ADDRESS - ISA_START_ADDRESS;
		pvh_bootparams.e820_table[pvh_bootparams.e820_entries].type =
			E820_TYPE_RESERVED;
		pvh_bootparams.e820_entries++;
	} else
		xen_raw_printk("Warning: Can fit ISA range into e820\n");

	pvh_bootparams.hdr.cmd_line_ptr =
		pvh_start_info.cmdline_paddr;

	/* The first module is always ramdisk. */
	if (pvh_start_info.nr_modules) {
		struct hvm_modlist_entry *modaddr =
			__va(pvh_start_info.modlist_paddr);
		pvh_bootparams.hdr.ramdisk_image = modaddr->paddr;
		pvh_bootparams.hdr.ramdisk_size = modaddr->size;
	}

	/*
	 * See Documentation/x86/boot.rst.
	 *
	 * Version 2.12 supports Xen entry point but we will use default x86/PC
	 * environment (i.e. hardware_subarch 0).
	 */
	pvh_bootparams.hdr.version = (2 << 8) | 12;
	pvh_bootparams.hdr.type_of_loader = ((xen_guest ? 0x9 : 0xb) << 4) | 0;

	x86_init.acpi.get_root_pointer = pvh_get_root_pointer;
}

/*
 * If we are trying to boot a Xen PVH guest, it is expected that the kernel
 * will have been configured to provide the required override for this routine.
 */
void __init __weak xen_pvh_init(struct boot_params *boot_params)
{
	xen_raw_printk("Error: Missing xen PVH initialization\n");
	BUG();
}

static void __init hypervisor_specific_init(bool xen_guest)
{
	if (xen_guest)
		xen_pvh_init(&pvh_bootparams);
}

/*
 * This routine (and those that it might call) should not use
 * anything that lives in .bss since that segment will be cleared later.
 */
void __init xen_prepare_pvh(void)
{

	u32 msr = xen_cpuid_base();
	bool xen_guest = !!msr;

	if (pvh_start_info.magic != XEN_HVM_START_MAGIC_VALUE) {
		xen_raw_printk("Error: Unexpected magic value (0x%08x)\n",
				pvh_start_info.magic);
		BUG();
	}

	memset(&pvh_bootparams, 0, sizeof(pvh_bootparams));

	hypervisor_specific_init(xen_guest);

	init_pvh_bootparams(xen_guest);
}