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/interrupt.h> 19 #include <asm/processor.h> 20 #include <asm/hypervisor.h> 21 #include <asm/hyperv.h> 22 #include <asm/mshyperv.h> 23 #include <asm/desc.h> 24 #include <asm/idle.h> 25 #include <asm/irq_regs.h> 26 27 struct ms_hyperv_info ms_hyperv; 28 EXPORT_SYMBOL_GPL(ms_hyperv); 29 30 static uint32_t __init ms_hyperv_platform(void) 31 { 32 u32 eax; 33 u32 hyp_signature[3]; 34 35 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR)) 36 return 0; 37 38 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS, 39 &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]); 40 41 if (eax >= HYPERV_CPUID_MIN && 42 eax <= HYPERV_CPUID_MAX && 43 !memcmp("Microsoft Hv", hyp_signature, 12)) 44 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS; 45 46 return 0; 47 } 48 49 static cycle_t read_hv_clock(struct clocksource *arg) 50 { 51 cycle_t current_tick; 52 /* 53 * Read the partition counter to get the current tick count. This count 54 * is set to 0 when the partition is created and is incremented in 55 * 100 nanosecond units. 56 */ 57 rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick); 58 return current_tick; 59 } 60 61 static struct clocksource hyperv_cs = { 62 .name = "hyperv_clocksource", 63 .rating = 400, /* use this when running on Hyperv*/ 64 .read = read_hv_clock, 65 .mask = CLOCKSOURCE_MASK(64), 66 }; 67 68 static void __init ms_hyperv_init_platform(void) 69 { 70 /* 71 * Extract the features and hints 72 */ 73 ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES); 74 ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO); 75 76 printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n", 77 ms_hyperv.features, ms_hyperv.hints); 78 79 if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE) 80 clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100); 81 } 82 83 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = { 84 .name = "Microsoft HyperV", 85 .detect = ms_hyperv_platform, 86 .init_platform = ms_hyperv_init_platform, 87 }; 88 EXPORT_SYMBOL(x86_hyper_ms_hyperv); 89 90 #if IS_ENABLED(CONFIG_HYPERV) 91 static int vmbus_irq = -1; 92 static irq_handler_t vmbus_isr; 93 94 void hv_register_vmbus_handler(int irq, irq_handler_t handler) 95 { 96 /* 97 * Setup the IDT for hypervisor callback. 98 */ 99 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector); 100 101 vmbus_irq = irq; 102 vmbus_isr = handler; 103 } 104 105 void hyperv_vector_handler(struct pt_regs *regs) 106 { 107 struct pt_regs *old_regs = set_irq_regs(regs); 108 struct irq_desc *desc; 109 110 irq_enter(); 111 exit_idle(); 112 113 desc = irq_to_desc(vmbus_irq); 114 115 if (desc) 116 generic_handle_irq_desc(vmbus_irq, desc); 117 118 irq_exit(); 119 set_irq_regs(old_regs); 120 } 121 #else 122 void hv_register_vmbus_handler(int irq, irq_handler_t handler) 123 { 124 } 125 #endif 126 EXPORT_SYMBOL_GPL(hv_register_vmbus_handler); 127