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 */ 23 struct boot_params __initdata pvh_bootparams; 24 struct hvm_start_info __initdata pvh_start_info; 25 26 const unsigned int __initconst pvh_start_info_sz = sizeof(pvh_start_info); 27 28 static 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 */ 40 void __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 46 static 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 */ 108 void __init __weak xen_pvh_init(struct boot_params *boot_params) 109 { 110 xen_raw_printk("Error: Missing xen PVH initialization\n"); 111 BUG(); 112 } 113 114 static 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 */ 124 void __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