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/idle.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 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 exiting_irq(); 53 set_irq_regs(old_regs); 54 } 55 56 void hv_setup_vmbus_irq(void (*handler)(void)) 57 { 58 vmbus_handler = handler; 59 /* 60 * Setup the IDT for hypervisor callback. Prevent reallocation 61 * at module reload. 62 */ 63 if (!test_bit(HYPERVISOR_CALLBACK_VECTOR, used_vectors)) 64 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, 65 hyperv_callback_vector); 66 } 67 68 void hv_remove_vmbus_irq(void) 69 { 70 /* We have no way to deallocate the interrupt gate */ 71 vmbus_handler = NULL; 72 } 73 EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq); 74 EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq); 75 76 void hv_setup_kexec_handler(void (*handler)(void)) 77 { 78 hv_kexec_handler = handler; 79 } 80 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler); 81 82 void hv_remove_kexec_handler(void) 83 { 84 hv_kexec_handler = NULL; 85 } 86 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler); 87 88 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs)) 89 { 90 hv_crash_handler = handler; 91 } 92 EXPORT_SYMBOL_GPL(hv_setup_crash_handler); 93 94 void hv_remove_crash_handler(void) 95 { 96 hv_crash_handler = NULL; 97 } 98 EXPORT_SYMBOL_GPL(hv_remove_crash_handler); 99 100 #ifdef CONFIG_KEXEC_CORE 101 static void hv_machine_shutdown(void) 102 { 103 if (kexec_in_progress && hv_kexec_handler) 104 hv_kexec_handler(); 105 native_machine_shutdown(); 106 } 107 108 static void hv_machine_crash_shutdown(struct pt_regs *regs) 109 { 110 if (hv_crash_handler) 111 hv_crash_handler(regs); 112 native_machine_crash_shutdown(regs); 113 } 114 #endif /* CONFIG_KEXEC_CORE */ 115 #endif /* CONFIG_HYPERV */ 116 117 static uint32_t __init ms_hyperv_platform(void) 118 { 119 u32 eax; 120 u32 hyp_signature[3]; 121 122 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR)) 123 return 0; 124 125 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS, 126 &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]); 127 128 if (eax >= HYPERV_CPUID_MIN && 129 eax <= HYPERV_CPUID_MAX && 130 !memcmp("Microsoft Hv", hyp_signature, 12)) 131 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS; 132 133 return 0; 134 } 135 136 static cycle_t read_hv_clock(struct clocksource *arg) 137 { 138 cycle_t current_tick; 139 /* 140 * Read the partition counter to get the current tick count. This count 141 * is set to 0 when the partition is created and is incremented in 142 * 100 nanosecond units. 143 */ 144 rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick); 145 return current_tick; 146 } 147 148 static struct clocksource hyperv_cs = { 149 .name = "hyperv_clocksource", 150 .rating = 400, /* use this when running on Hyperv*/ 151 .read = read_hv_clock, 152 .mask = CLOCKSOURCE_MASK(64), 153 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 154 }; 155 156 static unsigned char hv_get_nmi_reason(void) 157 { 158 return 0; 159 } 160 161 static void __init ms_hyperv_init_platform(void) 162 { 163 /* 164 * Extract the features and hints 165 */ 166 ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES); 167 ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES); 168 ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO); 169 170 pr_info("HyperV: features 0x%x, hints 0x%x\n", 171 ms_hyperv.features, ms_hyperv.hints); 172 173 #ifdef CONFIG_X86_LOCAL_APIC 174 if (ms_hyperv.features & HV_X64_MSR_APIC_FREQUENCY_AVAILABLE) { 175 /* 176 * Get the APIC frequency. 177 */ 178 u64 hv_lapic_frequency; 179 180 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency); 181 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ); 182 lapic_timer_frequency = hv_lapic_frequency; 183 pr_info("HyperV: LAPIC Timer Frequency: %#x\n", 184 lapic_timer_frequency); 185 } 186 #endif 187 188 if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE) 189 clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100); 190 191 #ifdef CONFIG_X86_IO_APIC 192 no_timer_check = 1; 193 #endif 194 195 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE) 196 machine_ops.shutdown = hv_machine_shutdown; 197 machine_ops.crash_shutdown = hv_machine_crash_shutdown; 198 #endif 199 mark_tsc_unstable("running on Hyper-V"); 200 201 /* 202 * Generation 2 instances don't support reading the NMI status from 203 * 0x61 port. 204 */ 205 if (efi_enabled(EFI_BOOT)) 206 x86_platform.get_nmi_reason = hv_get_nmi_reason; 207 } 208 209 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = { 210 .name = "Microsoft HyperV", 211 .detect = ms_hyperv_platform, 212 .init_platform = ms_hyperv_init_platform, 213 }; 214 EXPORT_SYMBOL(x86_hyper_ms_hyperv); 215