1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * HyperV Detection code. 4 * 5 * Copyright (C) 2010, Novell, Inc. 6 * Author : K. Y. Srinivasan <ksrinivasan@novell.com> 7 */ 8 9 #include <linux/types.h> 10 #include <linux/time.h> 11 #include <linux/clocksource.h> 12 #include <linux/init.h> 13 #include <linux/export.h> 14 #include <linux/hardirq.h> 15 #include <linux/efi.h> 16 #include <linux/interrupt.h> 17 #include <linux/irq.h> 18 #include <linux/kexec.h> 19 #include <linux/i8253.h> 20 #include <asm/processor.h> 21 #include <asm/hypervisor.h> 22 #include <asm/hyperv-tlfs.h> 23 #include <asm/mshyperv.h> 24 #include <asm/desc.h> 25 #include <asm/irq_regs.h> 26 #include <asm/i8259.h> 27 #include <asm/apic.h> 28 #include <asm/timer.h> 29 #include <asm/reboot.h> 30 #include <asm/nmi.h> 31 32 struct ms_hyperv_info ms_hyperv; 33 EXPORT_SYMBOL_GPL(ms_hyperv); 34 35 #if IS_ENABLED(CONFIG_HYPERV) 36 static void (*vmbus_handler)(void); 37 static void (*hv_stimer0_handler)(void); 38 static void (*hv_kexec_handler)(void); 39 static void (*hv_crash_handler)(struct pt_regs *regs); 40 41 __visible void __irq_entry hyperv_vector_handler(struct pt_regs *regs) 42 { 43 struct pt_regs *old_regs = set_irq_regs(regs); 44 45 entering_irq(); 46 inc_irq_stat(irq_hv_callback_count); 47 if (vmbus_handler) 48 vmbus_handler(); 49 50 if (ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED) 51 ack_APIC_irq(); 52 53 exiting_irq(); 54 set_irq_regs(old_regs); 55 } 56 57 void hv_setup_vmbus_irq(void (*handler)(void)) 58 { 59 vmbus_handler = handler; 60 } 61 62 void hv_remove_vmbus_irq(void) 63 { 64 /* We have no way to deallocate the interrupt gate */ 65 vmbus_handler = NULL; 66 } 67 EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq); 68 EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq); 69 70 /* 71 * Routines to do per-architecture handling of stimer0 72 * interrupts when in Direct Mode 73 */ 74 75 __visible void __irq_entry hv_stimer0_vector_handler(struct pt_regs *regs) 76 { 77 struct pt_regs *old_regs = set_irq_regs(regs); 78 79 entering_irq(); 80 inc_irq_stat(hyperv_stimer0_count); 81 if (hv_stimer0_handler) 82 hv_stimer0_handler(); 83 ack_APIC_irq(); 84 85 exiting_irq(); 86 set_irq_regs(old_regs); 87 } 88 89 int hv_setup_stimer0_irq(int *irq, int *vector, void (*handler)(void)) 90 { 91 *vector = HYPERV_STIMER0_VECTOR; 92 *irq = 0; /* Unused on x86/x64 */ 93 hv_stimer0_handler = handler; 94 return 0; 95 } 96 EXPORT_SYMBOL_GPL(hv_setup_stimer0_irq); 97 98 void hv_remove_stimer0_irq(int irq) 99 { 100 /* We have no way to deallocate the interrupt gate */ 101 hv_stimer0_handler = NULL; 102 } 103 EXPORT_SYMBOL_GPL(hv_remove_stimer0_irq); 104 105 void hv_setup_kexec_handler(void (*handler)(void)) 106 { 107 hv_kexec_handler = handler; 108 } 109 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler); 110 111 void hv_remove_kexec_handler(void) 112 { 113 hv_kexec_handler = NULL; 114 } 115 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler); 116 117 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs)) 118 { 119 hv_crash_handler = handler; 120 } 121 EXPORT_SYMBOL_GPL(hv_setup_crash_handler); 122 123 void hv_remove_crash_handler(void) 124 { 125 hv_crash_handler = NULL; 126 } 127 EXPORT_SYMBOL_GPL(hv_remove_crash_handler); 128 129 #ifdef CONFIG_KEXEC_CORE 130 static void hv_machine_shutdown(void) 131 { 132 if (kexec_in_progress && hv_kexec_handler) 133 hv_kexec_handler(); 134 native_machine_shutdown(); 135 } 136 137 static void hv_machine_crash_shutdown(struct pt_regs *regs) 138 { 139 if (hv_crash_handler) 140 hv_crash_handler(regs); 141 native_machine_crash_shutdown(regs); 142 } 143 #endif /* CONFIG_KEXEC_CORE */ 144 #endif /* CONFIG_HYPERV */ 145 146 static uint32_t __init ms_hyperv_platform(void) 147 { 148 u32 eax; 149 u32 hyp_signature[3]; 150 151 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR)) 152 return 0; 153 154 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS, 155 &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]); 156 157 if (eax >= HYPERV_CPUID_MIN && 158 eax <= HYPERV_CPUID_MAX && 159 !memcmp("Microsoft Hv", hyp_signature, 12)) 160 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS; 161 162 return 0; 163 } 164 165 static unsigned char hv_get_nmi_reason(void) 166 { 167 return 0; 168 } 169 170 #ifdef CONFIG_X86_LOCAL_APIC 171 /* 172 * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes 173 * it dificult to process CHANNELMSG_UNLOAD in case of crash. Handle 174 * unknown NMI on the first CPU which gets it. 175 */ 176 static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs) 177 { 178 static atomic_t nmi_cpu = ATOMIC_INIT(-1); 179 180 if (!unknown_nmi_panic) 181 return NMI_DONE; 182 183 if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1) 184 return NMI_HANDLED; 185 186 return NMI_DONE; 187 } 188 #endif 189 190 static unsigned long hv_get_tsc_khz(void) 191 { 192 unsigned long freq; 193 194 rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq); 195 196 return freq / 1000; 197 } 198 199 #if defined(CONFIG_SMP) && IS_ENABLED(CONFIG_HYPERV) 200 static void __init hv_smp_prepare_boot_cpu(void) 201 { 202 native_smp_prepare_boot_cpu(); 203 #if defined(CONFIG_X86_64) && defined(CONFIG_PARAVIRT_SPINLOCKS) 204 hv_init_spinlocks(); 205 #endif 206 } 207 #endif 208 209 static void __init ms_hyperv_init_platform(void) 210 { 211 int hv_host_info_eax; 212 int hv_host_info_ebx; 213 int hv_host_info_ecx; 214 int hv_host_info_edx; 215 216 /* 217 * Extract the features and hints 218 */ 219 ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES); 220 ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES); 221 ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO); 222 223 pr_info("Hyper-V: features 0x%x, hints 0x%x\n", 224 ms_hyperv.features, ms_hyperv.hints); 225 226 ms_hyperv.max_vp_index = cpuid_eax(HYPERV_CPUID_IMPLEMENT_LIMITS); 227 ms_hyperv.max_lp_index = cpuid_ebx(HYPERV_CPUID_IMPLEMENT_LIMITS); 228 229 pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n", 230 ms_hyperv.max_vp_index, ms_hyperv.max_lp_index); 231 232 /* 233 * Extract host information. 234 */ 235 if (cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS) >= 236 HYPERV_CPUID_VERSION) { 237 hv_host_info_eax = cpuid_eax(HYPERV_CPUID_VERSION); 238 hv_host_info_ebx = cpuid_ebx(HYPERV_CPUID_VERSION); 239 hv_host_info_ecx = cpuid_ecx(HYPERV_CPUID_VERSION); 240 hv_host_info_edx = cpuid_edx(HYPERV_CPUID_VERSION); 241 242 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n", 243 hv_host_info_eax, hv_host_info_ebx >> 16, 244 hv_host_info_ebx & 0xFFFF, hv_host_info_ecx, 245 hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF); 246 } 247 248 if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS && 249 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { 250 x86_platform.calibrate_tsc = hv_get_tsc_khz; 251 x86_platform.calibrate_cpu = hv_get_tsc_khz; 252 } 253 254 if (ms_hyperv.hints & HV_X64_ENLIGHTENED_VMCS_RECOMMENDED) { 255 ms_hyperv.nested_features = 256 cpuid_eax(HYPERV_CPUID_NESTED_FEATURES); 257 } 258 259 #ifdef CONFIG_X86_LOCAL_APIC 260 if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS && 261 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { 262 /* 263 * Get the APIC frequency. 264 */ 265 u64 hv_lapic_frequency; 266 267 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency); 268 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ); 269 lapic_timer_frequency = hv_lapic_frequency; 270 pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n", 271 lapic_timer_frequency); 272 } 273 274 register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST, 275 "hv_nmi_unknown"); 276 #endif 277 278 #ifdef CONFIG_X86_IO_APIC 279 no_timer_check = 1; 280 #endif 281 282 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE) 283 machine_ops.shutdown = hv_machine_shutdown; 284 machine_ops.crash_shutdown = hv_machine_crash_shutdown; 285 #endif 286 mark_tsc_unstable("running on Hyper-V"); 287 288 /* 289 * Generation 2 instances don't support reading the NMI status from 290 * 0x61 port. 291 */ 292 if (efi_enabled(EFI_BOOT)) 293 x86_platform.get_nmi_reason = hv_get_nmi_reason; 294 295 /* 296 * Hyper-V VMs have a PIT emulation quirk such that zeroing the 297 * counter register during PIT shutdown restarts the PIT. So it 298 * continues to interrupt @18.2 HZ. Setting i8253_clear_counter 299 * to false tells pit_shutdown() not to zero the counter so that 300 * the PIT really is shutdown. Generation 2 VMs don't have a PIT, 301 * and setting this value has no effect. 302 */ 303 i8253_clear_counter_on_shutdown = false; 304 305 #if IS_ENABLED(CONFIG_HYPERV) 306 /* 307 * Setup the hook to get control post apic initialization. 308 */ 309 x86_platform.apic_post_init = hyperv_init; 310 hyperv_setup_mmu_ops(); 311 /* Setup the IDT for hypervisor callback */ 312 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector); 313 314 /* Setup the IDT for reenlightenment notifications */ 315 if (ms_hyperv.features & HV_X64_ACCESS_REENLIGHTENMENT) 316 alloc_intr_gate(HYPERV_REENLIGHTENMENT_VECTOR, 317 hyperv_reenlightenment_vector); 318 319 /* Setup the IDT for stimer0 */ 320 if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE) 321 alloc_intr_gate(HYPERV_STIMER0_VECTOR, 322 hv_stimer0_callback_vector); 323 324 # ifdef CONFIG_SMP 325 smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu; 326 # endif 327 328 /* 329 * Hyper-V doesn't provide irq remapping for IO-APIC. To enable x2apic, 330 * set x2apic destination mode to physcial mode when x2apic is available 331 * and Hyper-V IOMMU driver makes sure cpus assigned with IO-APIC irqs 332 * have 8-bit APIC id. 333 */ 334 # ifdef CONFIG_X86_X2APIC 335 if (x2apic_supported()) 336 x2apic_phys = 1; 337 # endif 338 339 #endif 340 } 341 342 const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = { 343 .name = "Microsoft Hyper-V", 344 .detect = ms_hyperv_platform, 345 .type = X86_HYPER_MS_HYPERV, 346 .init.init_platform = ms_hyperv_init_platform, 347 }; 348