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 <linux/i8253.h> 24 #include <asm/processor.h> 25 #include <asm/hypervisor.h> 26 #include <asm/hyperv-tlfs.h> 27 #include <asm/mshyperv.h> 28 #include <asm/desc.h> 29 #include <asm/irq_regs.h> 30 #include <asm/i8259.h> 31 #include <asm/apic.h> 32 #include <asm/timer.h> 33 #include <asm/reboot.h> 34 #include <asm/nmi.h> 35 36 struct ms_hyperv_info ms_hyperv; 37 EXPORT_SYMBOL_GPL(ms_hyperv); 38 39 #if IS_ENABLED(CONFIG_HYPERV) 40 static void (*vmbus_handler)(void); 41 static void (*hv_stimer0_handler)(void); 42 static void (*hv_kexec_handler)(void); 43 static void (*hv_crash_handler)(struct pt_regs *regs); 44 45 __visible void __irq_entry hyperv_vector_handler(struct pt_regs *regs) 46 { 47 struct pt_regs *old_regs = set_irq_regs(regs); 48 49 entering_irq(); 50 inc_irq_stat(irq_hv_callback_count); 51 if (vmbus_handler) 52 vmbus_handler(); 53 54 if (ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED) 55 ack_APIC_irq(); 56 57 exiting_irq(); 58 set_irq_regs(old_regs); 59 } 60 61 void hv_setup_vmbus_irq(void (*handler)(void)) 62 { 63 vmbus_handler = handler; 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 /* 75 * Routines to do per-architecture handling of stimer0 76 * interrupts when in Direct Mode 77 */ 78 79 __visible void __irq_entry hv_stimer0_vector_handler(struct pt_regs *regs) 80 { 81 struct pt_regs *old_regs = set_irq_regs(regs); 82 83 entering_irq(); 84 inc_irq_stat(hyperv_stimer0_count); 85 if (hv_stimer0_handler) 86 hv_stimer0_handler(); 87 ack_APIC_irq(); 88 89 exiting_irq(); 90 set_irq_regs(old_regs); 91 } 92 93 int hv_setup_stimer0_irq(int *irq, int *vector, void (*handler)(void)) 94 { 95 *vector = HYPERV_STIMER0_VECTOR; 96 *irq = 0; /* Unused on x86/x64 */ 97 hv_stimer0_handler = handler; 98 return 0; 99 } 100 EXPORT_SYMBOL_GPL(hv_setup_stimer0_irq); 101 102 void hv_remove_stimer0_irq(int irq) 103 { 104 /* We have no way to deallocate the interrupt gate */ 105 hv_stimer0_handler = NULL; 106 } 107 EXPORT_SYMBOL_GPL(hv_remove_stimer0_irq); 108 109 void hv_setup_kexec_handler(void (*handler)(void)) 110 { 111 hv_kexec_handler = handler; 112 } 113 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler); 114 115 void hv_remove_kexec_handler(void) 116 { 117 hv_kexec_handler = NULL; 118 } 119 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler); 120 121 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs)) 122 { 123 hv_crash_handler = handler; 124 } 125 EXPORT_SYMBOL_GPL(hv_setup_crash_handler); 126 127 void hv_remove_crash_handler(void) 128 { 129 hv_crash_handler = NULL; 130 } 131 EXPORT_SYMBOL_GPL(hv_remove_crash_handler); 132 133 #ifdef CONFIG_KEXEC_CORE 134 static void hv_machine_shutdown(void) 135 { 136 if (kexec_in_progress && hv_kexec_handler) 137 hv_kexec_handler(); 138 native_machine_shutdown(); 139 } 140 141 static void hv_machine_crash_shutdown(struct pt_regs *regs) 142 { 143 if (hv_crash_handler) 144 hv_crash_handler(regs); 145 native_machine_crash_shutdown(regs); 146 } 147 #endif /* CONFIG_KEXEC_CORE */ 148 #endif /* CONFIG_HYPERV */ 149 150 static uint32_t __init ms_hyperv_platform(void) 151 { 152 u32 eax; 153 u32 hyp_signature[3]; 154 155 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR)) 156 return 0; 157 158 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS, 159 &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]); 160 161 if (eax >= HYPERV_CPUID_MIN && 162 eax <= HYPERV_CPUID_MAX && 163 !memcmp("Microsoft Hv", hyp_signature, 12)) 164 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS; 165 166 return 0; 167 } 168 169 static unsigned char hv_get_nmi_reason(void) 170 { 171 return 0; 172 } 173 174 #ifdef CONFIG_X86_LOCAL_APIC 175 /* 176 * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes 177 * it dificult to process CHANNELMSG_UNLOAD in case of crash. Handle 178 * unknown NMI on the first CPU which gets it. 179 */ 180 static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs) 181 { 182 static atomic_t nmi_cpu = ATOMIC_INIT(-1); 183 184 if (!unknown_nmi_panic) 185 return NMI_DONE; 186 187 if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1) 188 return NMI_HANDLED; 189 190 return NMI_DONE; 191 } 192 #endif 193 194 static unsigned long hv_get_tsc_khz(void) 195 { 196 unsigned long freq; 197 198 rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq); 199 200 return freq / 1000; 201 } 202 203 #if defined(CONFIG_SMP) && IS_ENABLED(CONFIG_HYPERV) 204 static void __init hv_smp_prepare_boot_cpu(void) 205 { 206 native_smp_prepare_boot_cpu(); 207 #if defined(CONFIG_X86_64) && defined(CONFIG_PARAVIRT_SPINLOCKS) 208 hv_init_spinlocks(); 209 #endif 210 } 211 #endif 212 213 static void __init ms_hyperv_init_platform(void) 214 { 215 int hv_host_info_eax; 216 int hv_host_info_ebx; 217 int hv_host_info_ecx; 218 int hv_host_info_edx; 219 220 /* 221 * Extract the features and hints 222 */ 223 ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES); 224 ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES); 225 ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO); 226 227 pr_info("Hyper-V: features 0x%x, hints 0x%x\n", 228 ms_hyperv.features, ms_hyperv.hints); 229 230 ms_hyperv.max_vp_index = cpuid_eax(HYPERV_CPUID_IMPLEMENT_LIMITS); 231 ms_hyperv.max_lp_index = cpuid_ebx(HYPERV_CPUID_IMPLEMENT_LIMITS); 232 233 pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n", 234 ms_hyperv.max_vp_index, ms_hyperv.max_lp_index); 235 236 /* 237 * Extract host information. 238 */ 239 if (cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS) >= 240 HYPERV_CPUID_VERSION) { 241 hv_host_info_eax = cpuid_eax(HYPERV_CPUID_VERSION); 242 hv_host_info_ebx = cpuid_ebx(HYPERV_CPUID_VERSION); 243 hv_host_info_ecx = cpuid_ecx(HYPERV_CPUID_VERSION); 244 hv_host_info_edx = cpuid_edx(HYPERV_CPUID_VERSION); 245 246 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n", 247 hv_host_info_eax, hv_host_info_ebx >> 16, 248 hv_host_info_ebx & 0xFFFF, hv_host_info_ecx, 249 hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF); 250 } 251 252 if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS && 253 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { 254 x86_platform.calibrate_tsc = hv_get_tsc_khz; 255 x86_platform.calibrate_cpu = hv_get_tsc_khz; 256 } 257 258 if (ms_hyperv.hints & HV_X64_ENLIGHTENED_VMCS_RECOMMENDED) { 259 ms_hyperv.nested_features = 260 cpuid_eax(HYPERV_CPUID_NESTED_FEATURES); 261 } 262 263 #ifdef CONFIG_X86_LOCAL_APIC 264 if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS && 265 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { 266 /* 267 * Get the APIC frequency. 268 */ 269 u64 hv_lapic_frequency; 270 271 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency); 272 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ); 273 lapic_timer_frequency = hv_lapic_frequency; 274 pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n", 275 lapic_timer_frequency); 276 } 277 278 register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST, 279 "hv_nmi_unknown"); 280 #endif 281 282 #ifdef CONFIG_X86_IO_APIC 283 no_timer_check = 1; 284 #endif 285 286 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE) 287 machine_ops.shutdown = hv_machine_shutdown; 288 machine_ops.crash_shutdown = hv_machine_crash_shutdown; 289 #endif 290 mark_tsc_unstable("running on Hyper-V"); 291 292 /* 293 * Generation 2 instances don't support reading the NMI status from 294 * 0x61 port. 295 */ 296 if (efi_enabled(EFI_BOOT)) 297 x86_platform.get_nmi_reason = hv_get_nmi_reason; 298 299 /* 300 * Hyper-V VMs have a PIT emulation quirk such that zeroing the 301 * counter register during PIT shutdown restarts the PIT. So it 302 * continues to interrupt @18.2 HZ. Setting i8253_clear_counter 303 * to false tells pit_shutdown() not to zero the counter so that 304 * the PIT really is shutdown. Generation 2 VMs don't have a PIT, 305 * and setting this value has no effect. 306 */ 307 i8253_clear_counter_on_shutdown = false; 308 309 #if IS_ENABLED(CONFIG_HYPERV) 310 /* 311 * Setup the hook to get control post apic initialization. 312 */ 313 x86_platform.apic_post_init = hyperv_init; 314 hyperv_setup_mmu_ops(); 315 /* Setup the IDT for hypervisor callback */ 316 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector); 317 318 /* Setup the IDT for reenlightenment notifications */ 319 if (ms_hyperv.features & HV_X64_ACCESS_REENLIGHTENMENT) 320 alloc_intr_gate(HYPERV_REENLIGHTENMENT_VECTOR, 321 hyperv_reenlightenment_vector); 322 323 /* Setup the IDT for stimer0 */ 324 if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE) 325 alloc_intr_gate(HYPERV_STIMER0_VECTOR, 326 hv_stimer0_callback_vector); 327 328 # ifdef CONFIG_SMP 329 smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu; 330 # endif 331 332 /* 333 * Hyper-V doesn't provide irq remapping for IO-APIC. To enable x2apic, 334 * set x2apic destination mode to physcial mode when x2apic is available 335 * and Hyper-V IOMMU driver makes sure cpus assigned with IO-APIC irqs 336 * have 8-bit APIC id. 337 */ 338 # ifdef CONFIG_X86_X2APIC 339 if (x2apic_supported()) 340 x2apic_phys = 1; 341 # endif 342 343 #endif 344 } 345 346 const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = { 347 .name = "Microsoft Hyper-V", 348 .detect = ms_hyperv_platform, 349 .type = X86_HYPER_MS_HYPERV, 350 .init.init_platform = ms_hyperv_init_platform, 351 }; 352