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