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 64 void hv_remove_vmbus_irq(void) 65 { 66 /* We have no way to deallocate the interrupt gate */ 67 vmbus_handler = NULL; 68 } 69 EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq); 70 EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq); 71 72 void hv_setup_kexec_handler(void (*handler)(void)) 73 { 74 hv_kexec_handler = handler; 75 } 76 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler); 77 78 void hv_remove_kexec_handler(void) 79 { 80 hv_kexec_handler = NULL; 81 } 82 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler); 83 84 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs)) 85 { 86 hv_crash_handler = handler; 87 } 88 EXPORT_SYMBOL_GPL(hv_setup_crash_handler); 89 90 void hv_remove_crash_handler(void) 91 { 92 hv_crash_handler = NULL; 93 } 94 EXPORT_SYMBOL_GPL(hv_remove_crash_handler); 95 96 #ifdef CONFIG_KEXEC_CORE 97 static void hv_machine_shutdown(void) 98 { 99 if (kexec_in_progress && hv_kexec_handler) 100 hv_kexec_handler(); 101 native_machine_shutdown(); 102 } 103 104 static void hv_machine_crash_shutdown(struct pt_regs *regs) 105 { 106 if (hv_crash_handler) 107 hv_crash_handler(regs); 108 native_machine_crash_shutdown(regs); 109 } 110 #endif /* CONFIG_KEXEC_CORE */ 111 #endif /* CONFIG_HYPERV */ 112 113 static uint32_t __init ms_hyperv_platform(void) 114 { 115 u32 eax; 116 u32 hyp_signature[3]; 117 118 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR)) 119 return 0; 120 121 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS, 122 &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]); 123 124 if (eax >= HYPERV_CPUID_MIN && 125 eax <= HYPERV_CPUID_MAX && 126 !memcmp("Microsoft Hv", hyp_signature, 12)) 127 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS; 128 129 return 0; 130 } 131 132 static unsigned char hv_get_nmi_reason(void) 133 { 134 return 0; 135 } 136 137 #ifdef CONFIG_X86_LOCAL_APIC 138 /* 139 * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes 140 * it dificult to process CHANNELMSG_UNLOAD in case of crash. Handle 141 * unknown NMI on the first CPU which gets it. 142 */ 143 static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs) 144 { 145 static atomic_t nmi_cpu = ATOMIC_INIT(-1); 146 147 if (!unknown_nmi_panic) 148 return NMI_DONE; 149 150 if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1) 151 return NMI_HANDLED; 152 153 return NMI_DONE; 154 } 155 #endif 156 157 static unsigned long hv_get_tsc_khz(void) 158 { 159 unsigned long freq; 160 161 rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq); 162 163 return freq / 1000; 164 } 165 166 static void __init ms_hyperv_init_platform(void) 167 { 168 int hv_host_info_eax; 169 int hv_host_info_ebx; 170 int hv_host_info_ecx; 171 int hv_host_info_edx; 172 173 /* 174 * Extract the features and hints 175 */ 176 ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES); 177 ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES); 178 ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO); 179 180 pr_info("Hyper-V: features 0x%x, hints 0x%x\n", 181 ms_hyperv.features, ms_hyperv.hints); 182 183 ms_hyperv.max_vp_index = cpuid_eax(HVCPUID_IMPLEMENTATION_LIMITS); 184 ms_hyperv.max_lp_index = cpuid_ebx(HVCPUID_IMPLEMENTATION_LIMITS); 185 186 pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n", 187 ms_hyperv.max_vp_index, ms_hyperv.max_lp_index); 188 189 /* 190 * Extract host information. 191 */ 192 if (cpuid_eax(HVCPUID_VENDOR_MAXFUNCTION) >= HVCPUID_VERSION) { 193 hv_host_info_eax = cpuid_eax(HVCPUID_VERSION); 194 hv_host_info_ebx = cpuid_ebx(HVCPUID_VERSION); 195 hv_host_info_ecx = cpuid_ecx(HVCPUID_VERSION); 196 hv_host_info_edx = cpuid_edx(HVCPUID_VERSION); 197 198 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n", 199 hv_host_info_eax, hv_host_info_ebx >> 16, 200 hv_host_info_ebx & 0xFFFF, hv_host_info_ecx, 201 hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF); 202 } 203 204 if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS && 205 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { 206 x86_platform.calibrate_tsc = hv_get_tsc_khz; 207 x86_platform.calibrate_cpu = hv_get_tsc_khz; 208 } 209 210 #ifdef CONFIG_X86_LOCAL_APIC 211 if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS && 212 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { 213 /* 214 * Get the APIC frequency. 215 */ 216 u64 hv_lapic_frequency; 217 218 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency); 219 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ); 220 lapic_timer_frequency = hv_lapic_frequency; 221 pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n", 222 lapic_timer_frequency); 223 } 224 225 register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST, 226 "hv_nmi_unknown"); 227 #endif 228 229 #ifdef CONFIG_X86_IO_APIC 230 no_timer_check = 1; 231 #endif 232 233 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE) 234 machine_ops.shutdown = hv_machine_shutdown; 235 machine_ops.crash_shutdown = hv_machine_crash_shutdown; 236 #endif 237 mark_tsc_unstable("running on Hyper-V"); 238 239 /* 240 * Generation 2 instances don't support reading the NMI status from 241 * 0x61 port. 242 */ 243 if (efi_enabled(EFI_BOOT)) 244 x86_platform.get_nmi_reason = hv_get_nmi_reason; 245 246 #if IS_ENABLED(CONFIG_HYPERV) 247 /* 248 * Setup the hook to get control post apic initialization. 249 */ 250 x86_platform.apic_post_init = hyperv_init; 251 hyperv_setup_mmu_ops(); 252 /* Setup the IDT for hypervisor callback */ 253 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector); 254 #endif 255 } 256 257 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = { 258 .name = "Microsoft Hyper-V", 259 .detect = ms_hyperv_platform, 260 .init_platform = ms_hyperv_init_platform, 261 }; 262 EXPORT_SYMBOL(x86_hyper_ms_hyperv); 263