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 /* Setup the IDT for hypervisor callback */ 63 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector); 64 } 65 66 void hv_remove_vmbus_irq(void) 67 { 68 /* We have no way to deallocate the interrupt gate */ 69 vmbus_handler = NULL; 70 } 71 EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq); 72 EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq); 73 74 void hv_setup_kexec_handler(void (*handler)(void)) 75 { 76 hv_kexec_handler = handler; 77 } 78 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler); 79 80 void hv_remove_kexec_handler(void) 81 { 82 hv_kexec_handler = NULL; 83 } 84 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler); 85 86 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs)) 87 { 88 hv_crash_handler = handler; 89 } 90 EXPORT_SYMBOL_GPL(hv_setup_crash_handler); 91 92 void hv_remove_crash_handler(void) 93 { 94 hv_crash_handler = NULL; 95 } 96 EXPORT_SYMBOL_GPL(hv_remove_crash_handler); 97 98 #ifdef CONFIG_KEXEC_CORE 99 static void hv_machine_shutdown(void) 100 { 101 if (kexec_in_progress && hv_kexec_handler) 102 hv_kexec_handler(); 103 native_machine_shutdown(); 104 } 105 106 static void hv_machine_crash_shutdown(struct pt_regs *regs) 107 { 108 if (hv_crash_handler) 109 hv_crash_handler(regs); 110 native_machine_crash_shutdown(regs); 111 } 112 #endif /* CONFIG_KEXEC_CORE */ 113 #endif /* CONFIG_HYPERV */ 114 115 static uint32_t __init ms_hyperv_platform(void) 116 { 117 u32 eax; 118 u32 hyp_signature[3]; 119 120 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR)) 121 return 0; 122 123 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS, 124 &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]); 125 126 if (eax >= HYPERV_CPUID_MIN && 127 eax <= HYPERV_CPUID_MAX && 128 !memcmp("Microsoft Hv", hyp_signature, 12)) 129 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS; 130 131 return 0; 132 } 133 134 static unsigned char hv_get_nmi_reason(void) 135 { 136 return 0; 137 } 138 139 #ifdef CONFIG_X86_LOCAL_APIC 140 /* 141 * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes 142 * it dificult to process CHANNELMSG_UNLOAD in case of crash. Handle 143 * unknown NMI on the first CPU which gets it. 144 */ 145 static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs) 146 { 147 static atomic_t nmi_cpu = ATOMIC_INIT(-1); 148 149 if (!unknown_nmi_panic) 150 return NMI_DONE; 151 152 if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1) 153 return NMI_HANDLED; 154 155 return NMI_DONE; 156 } 157 #endif 158 159 static unsigned long hv_get_tsc_khz(void) 160 { 161 unsigned long freq; 162 163 rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq); 164 165 return freq / 1000; 166 } 167 168 static void __init ms_hyperv_init_platform(void) 169 { 170 int hv_host_info_eax; 171 int hv_host_info_ebx; 172 int hv_host_info_ecx; 173 int hv_host_info_edx; 174 175 /* 176 * Extract the features and hints 177 */ 178 ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES); 179 ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES); 180 ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO); 181 182 pr_info("Hyper-V: features 0x%x, hints 0x%x\n", 183 ms_hyperv.features, ms_hyperv.hints); 184 185 ms_hyperv.max_vp_index = cpuid_eax(HVCPUID_IMPLEMENTATION_LIMITS); 186 ms_hyperv.max_lp_index = cpuid_ebx(HVCPUID_IMPLEMENTATION_LIMITS); 187 188 pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n", 189 ms_hyperv.max_vp_index, ms_hyperv.max_lp_index); 190 191 /* 192 * Extract host information. 193 */ 194 if (cpuid_eax(HVCPUID_VENDOR_MAXFUNCTION) >= HVCPUID_VERSION) { 195 hv_host_info_eax = cpuid_eax(HVCPUID_VERSION); 196 hv_host_info_ebx = cpuid_ebx(HVCPUID_VERSION); 197 hv_host_info_ecx = cpuid_ecx(HVCPUID_VERSION); 198 hv_host_info_edx = cpuid_edx(HVCPUID_VERSION); 199 200 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n", 201 hv_host_info_eax, hv_host_info_ebx >> 16, 202 hv_host_info_ebx & 0xFFFF, hv_host_info_ecx, 203 hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF); 204 } 205 206 if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS && 207 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { 208 x86_platform.calibrate_tsc = hv_get_tsc_khz; 209 x86_platform.calibrate_cpu = hv_get_tsc_khz; 210 } 211 212 #ifdef CONFIG_X86_LOCAL_APIC 213 if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS && 214 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { 215 /* 216 * Get the APIC frequency. 217 */ 218 u64 hv_lapic_frequency; 219 220 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency); 221 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ); 222 lapic_timer_frequency = hv_lapic_frequency; 223 pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n", 224 lapic_timer_frequency); 225 } 226 227 register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST, 228 "hv_nmi_unknown"); 229 #endif 230 231 #ifdef CONFIG_X86_IO_APIC 232 no_timer_check = 1; 233 #endif 234 235 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE) 236 machine_ops.shutdown = hv_machine_shutdown; 237 machine_ops.crash_shutdown = hv_machine_crash_shutdown; 238 #endif 239 mark_tsc_unstable("running on Hyper-V"); 240 241 /* 242 * Generation 2 instances don't support reading the NMI status from 243 * 0x61 port. 244 */ 245 if (efi_enabled(EFI_BOOT)) 246 x86_platform.get_nmi_reason = hv_get_nmi_reason; 247 248 #if IS_ENABLED(CONFIG_HYPERV) 249 /* 250 * Setup the hook to get control post apic initialization. 251 */ 252 x86_platform.apic_post_init = hyperv_init; 253 #endif 254 } 255 256 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = { 257 .name = "Microsoft Hyper-V", 258 .detect = ms_hyperv_platform, 259 .init_platform = ms_hyperv_init_platform, 260 }; 261 EXPORT_SYMBOL(x86_hyper_ms_hyperv); 262