enlighten.c

  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	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("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(&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("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}