1 /* 2 * HyperV Detection code. 3 * 4 * Copyright (C) 2010, Novell, Inc. 5 * Author : K. Y. Srinivasan <ksrinivasan@novell.com> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; version 2 of the License. 10 * 11 */ 12 13 #include <linux/types.h> 14 #include <linux/time.h> 15 #include <linux/clocksource.h> 16 #include <linux/init.h> 17 #include <linux/export.h> 18 #include <linux/hardirq.h> 19 #include <linux/efi.h> 20 #include <linux/interrupt.h> 21 #include <linux/irq.h> 22 #include <linux/kexec.h> 23 #include <asm/processor.h> 24 #include <asm/hypervisor.h> 25 #include <asm/hyperv.h> 26 #include <asm/mshyperv.h> 27 #include <asm/desc.h> 28 #include <asm/irq_regs.h> 29 #include <asm/i8259.h> 30 #include <asm/apic.h> 31 #include <asm/timer.h> 32 #include <asm/reboot.h> 33 #include <asm/nmi.h> 34 35 struct ms_hyperv_info ms_hyperv; 36 EXPORT_SYMBOL_GPL(ms_hyperv); 37 38 #if IS_ENABLED(CONFIG_HYPERV) 39 static void (*vmbus_handler)(void); 40 static void (*hv_kexec_handler)(void); 41 static void (*hv_crash_handler)(struct pt_regs *regs); 42 43 void hyperv_vector_handler(struct pt_regs *regs) 44 { 45 struct pt_regs *old_regs = set_irq_regs(regs); 46 47 entering_irq(); 48 inc_irq_stat(irq_hv_callback_count); 49 if (vmbus_handler) 50 vmbus_handler(); 51 52 if (ms_hyperv.hints & HV_X64_DEPRECATING_AEOI_RECOMMENDED) 53 ack_APIC_irq(); 54 55 exiting_irq(); 56 set_irq_regs(old_regs); 57 } 58 59 void hv_setup_vmbus_irq(void (*handler)(void)) 60 { 61 vmbus_handler = handler; 62 /* 63 * Setup the IDT for hypervisor callback. Prevent reallocation 64 * at module reload. 65 */ 66 if (!test_bit(HYPERVISOR_CALLBACK_VECTOR, used_vectors)) 67 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, 68 hyperv_callback_vector); 69 } 70 71 void hv_remove_vmbus_irq(void) 72 { 73 /* We have no way to deallocate the interrupt gate */ 74 vmbus_handler = NULL; 75 } 76 EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq); 77 EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq); 78 79 void hv_setup_kexec_handler(void (*handler)(void)) 80 { 81 hv_kexec_handler = handler; 82 } 83 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler); 84 85 void hv_remove_kexec_handler(void) 86 { 87 hv_kexec_handler = NULL; 88 } 89 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler); 90 91 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs)) 92 { 93 hv_crash_handler = handler; 94 } 95 EXPORT_SYMBOL_GPL(hv_setup_crash_handler); 96 97 void hv_remove_crash_handler(void) 98 { 99 hv_crash_handler = NULL; 100 } 101 EXPORT_SYMBOL_GPL(hv_remove_crash_handler); 102 103 #ifdef CONFIG_KEXEC_CORE 104 static void hv_machine_shutdown(void) 105 { 106 if (kexec_in_progress && hv_kexec_handler) 107 hv_kexec_handler(); 108 native_machine_shutdown(); 109 } 110 111 static void hv_machine_crash_shutdown(struct pt_regs *regs) 112 { 113 if (hv_crash_handler) 114 hv_crash_handler(regs); 115 native_machine_crash_shutdown(regs); 116 } 117 #endif /* CONFIG_KEXEC_CORE */ 118 #endif /* CONFIG_HYPERV */ 119 120 static uint32_t __init ms_hyperv_platform(void) 121 { 122 u32 eax; 123 u32 hyp_signature[3]; 124 125 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR)) 126 return 0; 127 128 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS, 129 &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]); 130 131 if (eax >= HYPERV_CPUID_MIN && 132 eax <= HYPERV_CPUID_MAX && 133 !memcmp("Microsoft Hv", hyp_signature, 12)) 134 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS; 135 136 return 0; 137 } 138 139 static unsigned char hv_get_nmi_reason(void) 140 { 141 return 0; 142 } 143 144 #ifdef CONFIG_X86_LOCAL_APIC 145 /* 146 * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes 147 * it dificult to process CHANNELMSG_UNLOAD in case of crash. Handle 148 * unknown NMI on the first CPU which gets it. 149 */ 150 static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs) 151 { 152 static atomic_t nmi_cpu = ATOMIC_INIT(-1); 153 154 if (!unknown_nmi_panic) 155 return NMI_DONE; 156 157 if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1) 158 return NMI_HANDLED; 159 160 return NMI_DONE; 161 } 162 #endif 163 164 static void __init ms_hyperv_init_platform(void) 165 { 166 int hv_host_info_eax; 167 int hv_host_info_ebx; 168 int hv_host_info_ecx; 169 int hv_host_info_edx; 170 171 /* 172 * Extract the features and hints 173 */ 174 ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES); 175 ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES); 176 ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO); 177 178 pr_info("HyperV: features 0x%x, hints 0x%x\n", 179 ms_hyperv.features, ms_hyperv.hints); 180 181 /* 182 * Extract host information. 183 */ 184 if (cpuid_eax(HVCPUID_VENDOR_MAXFUNCTION) >= HVCPUID_VERSION) { 185 hv_host_info_eax = cpuid_eax(HVCPUID_VERSION); 186 hv_host_info_ebx = cpuid_ebx(HVCPUID_VERSION); 187 hv_host_info_ecx = cpuid_ecx(HVCPUID_VERSION); 188 hv_host_info_edx = cpuid_edx(HVCPUID_VERSION); 189 190 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n", 191 hv_host_info_eax, hv_host_info_ebx >> 16, 192 hv_host_info_ebx & 0xFFFF, hv_host_info_ecx, 193 hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF); 194 } 195 196 #ifdef CONFIG_X86_LOCAL_APIC 197 if (ms_hyperv.features & HV_X64_MSR_APIC_FREQUENCY_AVAILABLE) { 198 /* 199 * Get the APIC frequency. 200 */ 201 u64 hv_lapic_frequency; 202 203 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency); 204 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ); 205 lapic_timer_frequency = hv_lapic_frequency; 206 pr_info("HyperV: LAPIC Timer Frequency: %#x\n", 207 lapic_timer_frequency); 208 } 209 210 register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST, 211 "hv_nmi_unknown"); 212 #endif 213 214 #ifdef CONFIG_X86_IO_APIC 215 no_timer_check = 1; 216 #endif 217 218 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE) 219 machine_ops.shutdown = hv_machine_shutdown; 220 machine_ops.crash_shutdown = hv_machine_crash_shutdown; 221 #endif 222 mark_tsc_unstable("running on Hyper-V"); 223 224 /* 225 * Generation 2 instances don't support reading the NMI status from 226 * 0x61 port. 227 */ 228 if (efi_enabled(EFI_BOOT)) 229 x86_platform.get_nmi_reason = hv_get_nmi_reason; 230 231 #if IS_ENABLED(CONFIG_HYPERV) 232 /* 233 * Setup the hook to get control post apic initialization. 234 */ 235 x86_platform.apic_post_init = hyperv_init; 236 #endif 237 } 238 239 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = { 240 .name = "Microsoft HyperV", 241 .detect = ms_hyperv_platform, 242 .init_platform = ms_hyperv_init_platform, 243 }; 244 EXPORT_SYMBOL(x86_hyper_ms_hyperv); 245