// SPDX-License-Identifier: GPL-2.0-only/* * HyperV  Detection code. * * Copyright (C) 2010, Novell, Inc. * Author : K. Y. Srinivasan <ksrinivasan@novell.com> */ #include <linux/types.h>#include <linux/time.h>#include <linux/clocksource.h>#include <linux/init.h>#include <linux/export.h>#include <linux/hardirq.h>#include <linux/efi.h>#include <linux/interrupt.h>#include <linux/irq.h>#include <linux/kexec.h>#include <linux/i8253.h>#include <linux/random.h>#include <asm/processor.h>#include <asm/hypervisor.h>#include <asm/hyperv-tlfs.h>#include <asm/mshyperv.h>#include <asm/desc.h>#include <asm/idtentry.h>#include <asm/irq_regs.h>#include <asm/i8259.h>#include <asm/apic.h>#include <asm/timer.h>#include <asm/reboot.h>#include <asm/nmi.h>#include <clocksource/hyperv_timer.h>#include <asm/numa.h> /* Is Linux running as the root partition? */bool hv_root_partition;EXPORT_SYMBOL_GPL(hv_root_partition); struct ms_hyperv_info ms_hyperv;EXPORT_SYMBOL_GPL(ms_hyperv); #if IS_ENABLED(CONFIG_HYPERV)static void (*vmbus_handler)(void);static void (*hv_stimer0_handler)(void);static void (*hv_kexec_handler)(void);static void (*hv_crash_handler)(struct pt_regs *regs); DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_callback){	struct pt_regs *old_regs = set_irq_regs(regs); 	inc_irq_stat(irq_hv_callback_count);	if (vmbus_handler)		vmbus_handler(); 	if (ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED)		ack_APIC_irq(); 	set_irq_regs(old_regs);} void hv_setup_vmbus_handler(void (*handler)(void)){	vmbus_handler = handler;}EXPORT_SYMBOL_GPL(hv_setup_vmbus_handler); void hv_remove_vmbus_handler(void){	/* We have no way to deallocate the interrupt gate */	vmbus_handler = NULL;}EXPORT_SYMBOL_GPL(hv_remove_vmbus_handler); /* * Routines to do per-architecture handling of stimer0 * interrupts when in Direct Mode */DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_stimer0){	struct pt_regs *old_regs = set_irq_regs(regs); 	inc_irq_stat(hyperv_stimer0_count);	if (hv_stimer0_handler)		hv_stimer0_handler();	add_interrupt_randomness(HYPERV_STIMER0_VECTOR, 0);	ack_APIC_irq(); 	set_irq_regs(old_regs);} /* For x86/x64, override weak placeholders in hyperv_timer.c */void hv_setup_stimer0_handler(void (*handler)(void)){	hv_stimer0_handler = handler;} void hv_remove_stimer0_handler(void){	/* We have no way to deallocate the interrupt gate */	hv_stimer0_handler = NULL;} void hv_setup_kexec_handler(void (*handler)(void)){	hv_kexec_handler = handler;}EXPORT_SYMBOL_GPL(hv_setup_kexec_handler); void hv_remove_kexec_handler(void){	hv_kexec_handler = NULL;}EXPORT_SYMBOL_GPL(hv_remove_kexec_handler); void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs)){	hv_crash_handler = handler;}EXPORT_SYMBOL_GPL(hv_setup_crash_handler); void hv_remove_crash_handler(void){	hv_crash_handler = NULL;}EXPORT_SYMBOL_GPL(hv_remove_crash_handler); #ifdef CONFIG_KEXEC_COREstatic void hv_machine_shutdown(void){	if (kexec_in_progress && hv_kexec_handler)		hv_kexec_handler(); 	/*	 * Call hv_cpu_die() on all the CPUs, otherwise later the hypervisor	 * corrupts the old VP Assist Pages and can crash the kexec kernel.	 */	if (kexec_in_progress && hyperv_init_cpuhp > 0)		cpuhp_remove_state(hyperv_init_cpuhp); 	/* The function calls stop_other_cpus(). */	native_machine_shutdown(); 	/* Disable the hypercall page when there is only 1 active CPU. */	if (kexec_in_progress)		hyperv_cleanup();} static void hv_machine_crash_shutdown(struct pt_regs *regs){	if (hv_crash_handler)		hv_crash_handler(regs); 	/* The function calls crash_smp_send_stop(). */	native_machine_crash_shutdown(regs); 	/* Disable the hypercall page when there is only 1 active CPU. */	hyperv_cleanup();}#endif /* CONFIG_KEXEC_CORE */#endif /* CONFIG_HYPERV */ 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 unsigned char hv_get_nmi_reason(void){	return 0;} #ifdef CONFIG_X86_LOCAL_APIC/* * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes * it difficult to process CHANNELMSG_UNLOAD in case of crash. Handle * unknown NMI on the first CPU which gets it. */static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs){	static atomic_t nmi_cpu = ATOMIC_INIT(-1); 	if (!unknown_nmi_panic)		return NMI_DONE; 	if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1)		return NMI_HANDLED; 	return NMI_DONE;}#endif static unsigned long hv_get_tsc_khz(void){	unsigned long freq; 	rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq); 	return freq / 1000;} #if defined(CONFIG_SMP) && IS_ENABLED(CONFIG_HYPERV)static void __init hv_smp_prepare_boot_cpu(void){	native_smp_prepare_boot_cpu();#if defined(CONFIG_X86_64) && defined(CONFIG_PARAVIRT_SPINLOCKS)	hv_init_spinlocks();#endif} static void __init hv_smp_prepare_cpus(unsigned int max_cpus){#ifdef CONFIG_X86_64	int i;	int ret;#endif 	native_smp_prepare_cpus(max_cpus); #ifdef CONFIG_X86_64	for_each_present_cpu(i) {		if (i == 0)			continue;		ret = hv_call_add_logical_proc(numa_cpu_node(i), i, cpu_physical_id(i));		BUG_ON(ret);	} 	for_each_present_cpu(i) {		if (i == 0)			continue;		ret = hv_call_create_vp(numa_cpu_node(i), hv_current_partition_id, i, i);		BUG_ON(ret);	}#endif}#endif static void __init ms_hyperv_init_platform(void){	int hv_host_info_eax;	int hv_host_info_ebx;	int hv_host_info_ecx;	int hv_host_info_edx; #ifdef CONFIG_PARAVIRT	pv_info.name = "Hyper-V";#endif 	/*	 * Extract the features and hints	 */	ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);	ms_hyperv.priv_high = cpuid_ebx(HYPERV_CPUID_FEATURES);	ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);	ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO); 	pr_info("Hyper-V: privilege flags low 0x%x, high 0x%x, hints 0x%x, misc 0x%x\n",		ms_hyperv.features, ms_hyperv.priv_high, ms_hyperv.hints,		ms_hyperv.misc_features); 	ms_hyperv.max_vp_index = cpuid_eax(HYPERV_CPUID_IMPLEMENT_LIMITS);	ms_hyperv.max_lp_index = cpuid_ebx(HYPERV_CPUID_IMPLEMENT_LIMITS); 	pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n",		 ms_hyperv.max_vp_index, ms_hyperv.max_lp_index); 	/*	 * Check CPU management privilege.	 *	 * To mirror what Windows does we should extract CPU management	 * features and use the ReservedIdentityBit to detect if Linux is the	 * root partition. But that requires negotiating CPU management	 * interface (a process to be finalized).	 *	 * For now, use the privilege flag as the indicator for running as	 * root.	 */	if (cpuid_ebx(HYPERV_CPUID_FEATURES) & HV_CPU_MANAGEMENT) {		hv_root_partition = true;		pr_info("Hyper-V: running as root partition\n");	} 	/*	 * Extract host information.	 */	if (cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS) >=	    HYPERV_CPUID_VERSION) {		hv_host_info_eax = cpuid_eax(HYPERV_CPUID_VERSION);		hv_host_info_ebx = cpuid_ebx(HYPERV_CPUID_VERSION);		hv_host_info_ecx = cpuid_ecx(HYPERV_CPUID_VERSION);		hv_host_info_edx = cpuid_edx(HYPERV_CPUID_VERSION); 		pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n",			hv_host_info_eax, hv_host_info_ebx >> 16,			hv_host_info_ebx & 0xFFFF, hv_host_info_ecx,			hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF);	} 	if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&	    ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {		x86_platform.calibrate_tsc = hv_get_tsc_khz;		x86_platform.calibrate_cpu = hv_get_tsc_khz;	} 	if (ms_hyperv.priv_high & HV_ISOLATION) {		ms_hyperv.isolation_config_a = cpuid_eax(HYPERV_CPUID_ISOLATION_CONFIG);		ms_hyperv.isolation_config_b = cpuid_ebx(HYPERV_CPUID_ISOLATION_CONFIG); 		pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B 0x%x\n",			ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b);	} 	if (ms_hyperv.hints & HV_X64_ENLIGHTENED_VMCS_RECOMMENDED) {		ms_hyperv.nested_features =			cpuid_eax(HYPERV_CPUID_NESTED_FEATURES);	} 	/*	 * Hyper-V expects to get crash register data or kmsg when	 * crash enlightment is available and system crashes. Set	 * crash_kexec_post_notifiers to be true to make sure that	 * calling crash enlightment interface before running kdump	 * kernel.	 */	if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE)		crash_kexec_post_notifiers = true; #ifdef CONFIG_X86_LOCAL_APIC	if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&	    ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_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_period = hv_lapic_frequency;		pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n",			lapic_timer_period);	} 	register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST,			     "hv_nmi_unknown");#endif #ifdef CONFIG_X86_IO_APIC	no_timer_check = 1;#endif #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE)	machine_ops.shutdown = hv_machine_shutdown;	machine_ops.crash_shutdown = hv_machine_crash_shutdown;#endif	if (ms_hyperv.features & HV_ACCESS_TSC_INVARIANT) {		wrmsrl(HV_X64_MSR_TSC_INVARIANT_CONTROL, 0x1);		setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);	} else {		mark_tsc_unstable("running on Hyper-V");	} 	/*	 * Generation 2 instances don't support reading the NMI status from	 * 0x61 port.	 */	if (efi_enabled(EFI_BOOT))		x86_platform.get_nmi_reason = hv_get_nmi_reason; 	/*	 * Hyper-V VMs have a PIT emulation quirk such that zeroing the	 * counter register during PIT shutdown restarts the PIT. So it	 * continues to interrupt @18.2 HZ. Setting i8253_clear_counter	 * to false tells pit_shutdown() not to zero the counter so that	 * the PIT really is shutdown. Generation 2 VMs don't have a PIT,	 * and setting this value has no effect.	 */	i8253_clear_counter_on_shutdown = false; #if IS_ENABLED(CONFIG_HYPERV)	/*	 * Setup the hook to get control post apic initialization.	 */	x86_platform.apic_post_init = hyperv_init;	hyperv_setup_mmu_ops();	/* Setup the IDT for hypervisor callback */	alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_hyperv_callback); 	/* Setup the IDT for reenlightenment notifications */	if (ms_hyperv.features & HV_ACCESS_REENLIGHTENMENT) {		alloc_intr_gate(HYPERV_REENLIGHTENMENT_VECTOR,				asm_sysvec_hyperv_reenlightenment);	} 	/* Setup the IDT for stimer0 */	if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE) {		alloc_intr_gate(HYPERV_STIMER0_VECTOR,				asm_sysvec_hyperv_stimer0);	} # ifdef CONFIG_SMP	smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu;	if (hv_root_partition)		smp_ops.smp_prepare_cpus = hv_smp_prepare_cpus;# endif 	/*	 * Hyper-V doesn't provide irq remapping for IO-APIC. To enable x2apic,	 * set x2apic destination mode to physical mode when x2apic is available	 * and Hyper-V IOMMU driver makes sure cpus assigned with IO-APIC irqs	 * have 8-bit APIC id.	 */# ifdef CONFIG_X86_X2APIC	if (x2apic_supported())		x2apic_phys = 1;# endif 	/* Register Hyper-V specific clocksource */	hv_init_clocksource();#endif} static bool __init ms_hyperv_x2apic_available(void){	return x2apic_supported();} /* * If ms_hyperv_msi_ext_dest_id() returns true, hyperv_prepare_irq_remapping() * returns -ENODEV and the Hyper-V IOMMU driver is not used; instead, the * generic support of the 15-bit APIC ID is used: see __irq_msi_compose_msg(). * * Note: for a VM on Hyper-V, the I/O-APIC is the only device which * (logically) generates MSIs directly to the system APIC irq domain. * There is no HPET, and PCI MSI/MSI-X interrupts are remapped by the * pci-hyperv host bridge. */static bool __init ms_hyperv_msi_ext_dest_id(void){	u32 eax; 	eax = cpuid_eax(HYPERV_CPUID_VIRT_STACK_INTERFACE);	if (eax != HYPERV_VS_INTERFACE_EAX_SIGNATURE)		return false; 	eax = cpuid_eax(HYPERV_CPUID_VIRT_STACK_PROPERTIES);	return eax & HYPERV_VS_PROPERTIES_EAX_EXTENDED_IOAPIC_RTE;} const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {	.name			= "Microsoft Hyper-V",	.detect			= ms_hyperv_platform,	.type			= X86_HYPER_MS_HYPERV,	.init.x2apic_available	= ms_hyperv_x2apic_available,	.init.msi_ext_dest_id	= ms_hyperv_msi_ext_dest_id,	.init.init_platform	= ms_hyperv_init_platform,};