LXR linux/arch/x86/platform/pvh/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/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 the data segment since
  20 * they are used after startup_{32|64}, which clear .bss, are invoked.
  21 */
  22struct boot_params pvh_bootparams __attribute__((section(".data")));
  23struct hvm_start_info pvh_start_info __attribute__((section(".data")));
  24
  25unsigned int pvh_start_info_sz = sizeof(pvh_start_info);
  26
  27static u64 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/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 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