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 <asm/processor.h> 21 #include <asm/hypervisor.h> 22 #include <asm/hyperv.h> 23 #include <asm/mshyperv.h> 24 #include <asm/desc.h> 25 #include <asm/idle.h> 26 #include <asm/irq_regs.h> 27 #include <asm/i8259.h> 28 #include <asm/apic.h> 29 30 struct ms_hyperv_info ms_hyperv; 31 EXPORT_SYMBOL_GPL(ms_hyperv); 32 33 static uint32_t __init ms_hyperv_platform(void) 34 { 35 u32 eax; 36 u32 hyp_signature[3]; 37 38 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR)) 39 return 0; 40 41 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS, 42 &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]); 43 44 if (eax >= HYPERV_CPUID_MIN && 45 eax <= HYPERV_CPUID_MAX && 46 !memcmp("Microsoft Hv", hyp_signature, 12)) 47 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS; 48 49 return 0; 50 } 51 52 static cycle_t read_hv_clock(struct clocksource *arg) 53 { 54 cycle_t current_tick; 55 /* 56 * Read the partition counter to get the current tick count. This count 57 * is set to 0 when the partition is created and is incremented in 58 * 100 nanosecond units. 59 */ 60 rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick); 61 return current_tick; 62 } 63 64 static struct clocksource hyperv_cs = { 65 .name = "hyperv_clocksource", 66 .rating = 400, /* use this when running on Hyperv*/ 67 .read = read_hv_clock, 68 .mask = CLOCKSOURCE_MASK(64), 69 }; 70 71 static void __init ms_hyperv_init_platform(void) 72 { 73 /* 74 * Extract the features and hints 75 */ 76 ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES); 77 ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO); 78 79 printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n", 80 ms_hyperv.features, ms_hyperv.hints); 81 82 #ifdef CONFIG_X86_LOCAL_APIC 83 if (ms_hyperv.features & HV_X64_MSR_APIC_FREQUENCY_AVAILABLE) { 84 /* 85 * Get the APIC frequency. 86 */ 87 u64 hv_lapic_frequency; 88 89 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency); 90 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ); 91 lapic_timer_frequency = hv_lapic_frequency; 92 printk(KERN_INFO "HyperV: LAPIC Timer Frequency: %#x\n", 93 lapic_timer_frequency); 94 95 /* 96 * On Hyper-V, when we are booting off an EFI firmware stack, 97 * we do not have many legacy devices including PIC, PIT etc. 98 */ 99 if (efi_enabled(EFI_BOOT)) { 100 printk(KERN_INFO "HyperV: Using null_legacy_pic\n"); 101 legacy_pic = &null_legacy_pic; 102 } 103 } 104 #endif 105 106 if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE) 107 clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100); 108 } 109 110 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = { 111 .name = "Microsoft HyperV", 112 .detect = ms_hyperv_platform, 113 .init_platform = ms_hyperv_init_platform, 114 }; 115 EXPORT_SYMBOL(x86_hyper_ms_hyperv); 116 117 #if IS_ENABLED(CONFIG_HYPERV) 118 static int vmbus_irq = -1; 119 static irq_handler_t vmbus_isr; 120 121 void hv_register_vmbus_handler(int irq, irq_handler_t handler) 122 { 123 /* 124 * Setup the IDT for hypervisor callback. 125 */ 126 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector); 127 128 vmbus_irq = irq; 129 vmbus_isr = handler; 130 } 131 132 void hyperv_vector_handler(struct pt_regs *regs) 133 { 134 struct pt_regs *old_regs = set_irq_regs(regs); 135 struct irq_desc *desc; 136 137 irq_enter(); 138 exit_idle(); 139 140 desc = irq_to_desc(vmbus_irq); 141 142 if (desc) 143 generic_handle_irq_desc(vmbus_irq, desc); 144 145 irq_exit(); 146 set_irq_regs(old_regs); 147 } 148 #else 149 void hv_register_vmbus_handler(int irq, irq_handler_t handler) 150 { 151 } 152 #endif 153 EXPORT_SYMBOL_GPL(hv_register_vmbus_handler); 154