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