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 bool __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 false; 37 38 /* 39 * Xen emulates Hyper-V to support enlightened Windows. 40 * Check to see first if we are on a Xen Hypervisor. 41 */ 42 if (xen_cpuid_base()) 43 return false; 44 45 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS, 46 &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]); 47 48 return eax >= HYPERV_CPUID_MIN && 49 eax <= HYPERV_CPUID_MAX && 50 !memcmp("Microsoft Hv", hyp_signature, 12); 51 } 52 53 static cycle_t read_hv_clock(struct clocksource *arg) 54 { 55 cycle_t current_tick; 56 /* 57 * Read the partition counter to get the current tick count. This count 58 * is set to 0 when the partition is created and is incremented in 59 * 100 nanosecond units. 60 */ 61 rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick); 62 return current_tick; 63 } 64 65 static struct clocksource hyperv_cs = { 66 .name = "hyperv_clocksource", 67 .rating = 400, /* use this when running on Hyperv*/ 68 .read = read_hv_clock, 69 .mask = CLOCKSOURCE_MASK(64), 70 }; 71 72 static void __init ms_hyperv_init_platform(void) 73 { 74 /* 75 * Extract the features and hints 76 */ 77 ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES); 78 ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO); 79 80 printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n", 81 ms_hyperv.features, ms_hyperv.hints); 82 83 if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE) 84 clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100); 85 #if IS_ENABLED(CONFIG_HYPERV) 86 /* 87 * Setup the IDT for hypervisor callback. 88 */ 89 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector); 90 #endif 91 } 92 93 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = { 94 .name = "Microsoft HyperV", 95 .detect = ms_hyperv_platform, 96 .init_platform = ms_hyperv_init_platform, 97 }; 98 EXPORT_SYMBOL(x86_hyper_ms_hyperv); 99 100 #if IS_ENABLED(CONFIG_HYPERV) 101 static int vmbus_irq = -1; 102 static irq_handler_t vmbus_isr; 103 104 void hv_register_vmbus_handler(int irq, irq_handler_t handler) 105 { 106 vmbus_irq = irq; 107 vmbus_isr = handler; 108 } 109 110 void hyperv_vector_handler(struct pt_regs *regs) 111 { 112 struct pt_regs *old_regs = set_irq_regs(regs); 113 struct irq_desc *desc; 114 115 irq_enter(); 116 exit_idle(); 117 118 desc = irq_to_desc(vmbus_irq); 119 120 if (desc) 121 generic_handle_irq_desc(vmbus_irq, desc); 122 123 irq_exit(); 124 set_irq_regs(old_regs); 125 } 126 #else 127 void hv_register_vmbus_handler(int irq, irq_handler_t handler) 128 { 129 } 130 #endif 131 EXPORT_SYMBOL_GPL(hv_register_vmbus_handler); 132