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/module.h> 17 #include <linux/hardirq.h> 18 #include <linux/efi.h> 19 #include <linux/interrupt.h> 20 #include <linux/irq.h> 21 #include <asm/processor.h> 22 #include <asm/hypervisor.h> 23 #include <asm/hyperv.h> 24 #include <asm/mshyperv.h> 25 #include <asm/desc.h> 26 #include <asm/idle.h> 27 #include <asm/irq_regs.h> 28 #include <asm/i8259.h> 29 #include <asm/apic.h> 30 #include <asm/timer.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 38 void hyperv_vector_handler(struct pt_regs *regs) 39 { 40 struct pt_regs *old_regs = set_irq_regs(regs); 41 42 irq_enter(); 43 exit_idle(); 44 45 inc_irq_stat(irq_hv_callback_count); 46 if (vmbus_handler) 47 vmbus_handler(); 48 49 irq_exit(); 50 set_irq_regs(old_regs); 51 } 52 53 void hv_setup_vmbus_irq(void (*handler)(void)) 54 { 55 vmbus_handler = handler; 56 /* 57 * Setup the IDT for hypervisor callback. Prevent reallocation 58 * at module reload. 59 */ 60 if (!test_bit(HYPERVISOR_CALLBACK_VECTOR, used_vectors)) 61 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, 62 hyperv_callback_vector); 63 } 64 65 void hv_remove_vmbus_irq(void) 66 { 67 /* We have no way to deallocate the interrupt gate */ 68 vmbus_handler = NULL; 69 } 70 EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq); 71 EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq); 72 #endif 73 74 static uint32_t __init ms_hyperv_platform(void) 75 { 76 u32 eax; 77 u32 hyp_signature[3]; 78 79 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR)) 80 return 0; 81 82 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS, 83 &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]); 84 85 if (eax >= HYPERV_CPUID_MIN && 86 eax <= HYPERV_CPUID_MAX && 87 !memcmp("Microsoft Hv", hyp_signature, 12)) 88 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS; 89 90 return 0; 91 } 92 93 static cycle_t read_hv_clock(struct clocksource *arg) 94 { 95 cycle_t current_tick; 96 /* 97 * Read the partition counter to get the current tick count. This count 98 * is set to 0 when the partition is created and is incremented in 99 * 100 nanosecond units. 100 */ 101 rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick); 102 return current_tick; 103 } 104 105 static struct clocksource hyperv_cs = { 106 .name = "hyperv_clocksource", 107 .rating = 400, /* use this when running on Hyperv*/ 108 .read = read_hv_clock, 109 .mask = CLOCKSOURCE_MASK(64), 110 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 111 }; 112 113 static void __init ms_hyperv_init_platform(void) 114 { 115 /* 116 * Extract the features and hints 117 */ 118 ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES); 119 ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO); 120 121 printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n", 122 ms_hyperv.features, ms_hyperv.hints); 123 124 #ifdef CONFIG_X86_LOCAL_APIC 125 if (ms_hyperv.features & HV_X64_MSR_APIC_FREQUENCY_AVAILABLE) { 126 /* 127 * Get the APIC frequency. 128 */ 129 u64 hv_lapic_frequency; 130 131 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency); 132 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ); 133 lapic_timer_frequency = hv_lapic_frequency; 134 printk(KERN_INFO "HyperV: LAPIC Timer Frequency: %#x\n", 135 lapic_timer_frequency); 136 } 137 #endif 138 139 if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE) 140 clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100); 141 142 #ifdef CONFIG_X86_IO_APIC 143 no_timer_check = 1; 144 #endif 145 146 } 147 148 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = { 149 .name = "Microsoft HyperV", 150 .detect = ms_hyperv_platform, 151 .init_platform = ms_hyperv_init_platform, 152 }; 153 EXPORT_SYMBOL(x86_hyper_ms_hyperv); 154