/* * HyperV  Detection code. * * Copyright (C) 2010, Novell, Inc. * Author : K. Y. Srinivasan <ksrinivasan@novell.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; version 2 of the License. * */ #include <linux/types.h>#include <linux/time.h>#include <linux/clocksource.h>#include <linux/module.h>#include <linux/hardirq.h>#include <linux/efi.h>#include <linux/interrupt.h>#include <linux/irq.h>#include <asm/processor.h>#include <asm/hypervisor.h>#include <asm/hyperv.h>#include <asm/mshyperv.h>#include <asm/desc.h>#include <asm/idle.h>#include <asm/irq_regs.h>#include <asm/i8259.h>#include <asm/apic.h>#include <asm/timer.h> struct ms_hyperv_info ms_hyperv;EXPORT_SYMBOL_GPL(ms_hyperv); #if IS_ENABLED(CONFIG_HYPERV)static void (*vmbus_handler)(void); void hyperv_vector_handler(struct pt_regs *regs){	struct pt_regs *old_regs = set_irq_regs(regs); 	entering_irq();	inc_irq_stat(irq_hv_callback_count);	if (vmbus_handler)		vmbus_handler(); 	exiting_irq();	set_irq_regs(old_regs);} void hv_setup_vmbus_irq(void (*handler)(void)){	vmbus_handler = handler;	/*	 * Setup the IDT for hypervisor callback. Prevent reallocation	 * at module reload.	 */	if (!test_bit(HYPERVISOR_CALLBACK_VECTOR, used_vectors))		alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR,				hyperv_callback_vector);} void hv_remove_vmbus_irq(void){	/* We have no way to deallocate the interrupt gate */	vmbus_handler = NULL;}EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq);EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq);#endif static uint32_t  __init ms_hyperv_platform(void){	u32 eax;	u32 hyp_signature[3]; 	if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))		return 0; 	cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,	      &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]); 	if (eax >= HYPERV_CPUID_MIN &&	    eax <= HYPERV_CPUID_MAX &&	    !memcmp("Microsoft Hv", hyp_signature, 12))		return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS; 	return 0;} static cycle_t read_hv_clock(struct clocksource *arg){	cycle_t current_tick;	/*	 * Read the partition counter to get the current tick count. This count	 * is set to 0 when the partition is created and is incremented in	 * 100 nanosecond units.	 */	rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);	return current_tick;} static struct clocksource hyperv_cs = {	.name		= "hyperv_clocksource",	.rating		= 400, /* use this when running on Hyperv*/	.read		= read_hv_clock,	.mask		= CLOCKSOURCE_MASK(64),	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,}; static void __init ms_hyperv_init_platform(void){	/*	 * Extract the features and hints	 */	ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);	ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO); 	printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n",	       ms_hyperv.features, ms_hyperv.hints); #ifdef CONFIG_X86_LOCAL_APIC	if (ms_hyperv.features & HV_X64_MSR_APIC_FREQUENCY_AVAILABLE) {		/*		 * Get the APIC frequency.		 */		u64	hv_lapic_frequency; 		rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency);		hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ);		lapic_timer_frequency = hv_lapic_frequency;		printk(KERN_INFO "HyperV: LAPIC Timer Frequency: %#x\n",				lapic_timer_frequency);	}#endif 	if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)		clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100); #ifdef CONFIG_X86_IO_APIC	no_timer_check = 1;#endif } const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {	.name			= "Microsoft HyperV",	.detect			= ms_hyperv_platform,	.init_platform		= ms_hyperv_init_platform,};EXPORT_SYMBOL(x86_hyper_ms_hyperv);