// 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/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>#include <asm/svm.h> /* Is Linux running as the root partition? */bool hv_root_partition;/* Is Linux running on nested Microsoft Hypervisor */bool hv_nested;struct ms_hyperv_info ms_hyperv; /* Used in modules via hv_do_hypercall(): see arch/x86/include/asm/mshyperv.h */bool hyperv_paravisor_present __ro_after_init;EXPORT_SYMBOL_GPL(hyperv_paravisor_present); #if IS_ENABLED(CONFIG_HYPERV)static inline unsigned int hv_get_nested_msr(unsigned int reg){ if (hv_is_sint_msr(reg)) return reg - HV_X64_MSR_SINT0 + HV_X64_MSR_NESTED_SINT0; switch (reg) { case HV_X64_MSR_SIMP: return HV_X64_MSR_NESTED_SIMP; case HV_X64_MSR_SIEFP: return HV_X64_MSR_NESTED_SIEFP; case HV_X64_MSR_SVERSION: return HV_X64_MSR_NESTED_SVERSION; case HV_X64_MSR_SCONTROL: return HV_X64_MSR_NESTED_SCONTROL; case HV_X64_MSR_EOM: return HV_X64_MSR_NESTED_EOM; default: return reg; }} u64 hv_get_non_nested_msr(unsigned int reg){ u64 value; if (hv_is_synic_msr(reg) && ms_hyperv.paravisor_present) hv_ivm_msr_read(reg, &value); else rdmsrl(reg, value); return value;}EXPORT_SYMBOL_GPL(hv_get_non_nested_msr); void hv_set_non_nested_msr(unsigned int reg, u64 value){ if (hv_is_synic_msr(reg) && ms_hyperv.paravisor_present) { hv_ivm_msr_write(reg, value); /* Write proxy bit via wrmsl instruction */ if (hv_is_sint_msr(reg)) wrmsrl(reg, value | 1 << 20); } else { wrmsrl(reg, value); }}EXPORT_SYMBOL_GPL(hv_set_non_nested_msr); u64 hv_get_msr(unsigned int reg){ if (hv_nested) reg = hv_get_nested_msr(reg); return hv_get_non_nested_msr(reg);}EXPORT_SYMBOL_GPL(hv_get_msr); void hv_set_msr(unsigned int reg, u64 value){ if (hv_nested) reg = hv_get_nested_msr(reg); hv_set_non_nested_msr(reg, value);}EXPORT_SYMBOL_GPL(hv_set_msr); 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) apic_eoi(); set_irq_regs(old_regs);} void hv_setup_vmbus_handler(void (*handler)(void)){ vmbus_handler = handler;} void hv_remove_vmbus_handler(void){ /* We have no way to deallocate the interrupt gate */ vmbus_handler = NULL;} /* * 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); apic_eoi(); 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;} void hv_remove_kexec_handler(void){ hv_kexec_handler = NULL;} void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs)){ hv_crash_handler = handler;} void hv_remove_crash_handler(void){ hv_crash_handler = NULL;} #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) cpuhp_remove_state(CPUHP_AP_HYPERV_ONLINE); /* 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();}#endif /* CONFIG_KEXEC_CORE */ #ifdef CONFIG_CRASH_DUMPstatic 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_CRASH_DUMP */ static u64 hv_ref_counter_at_suspend;static void (*old_save_sched_clock_state)(void);static void (*old_restore_sched_clock_state)(void); /* * Hyper-V clock counter resets during hibernation. Save and restore clock * offset during suspend/resume, while also considering the time passed * before suspend. This is to make sure that sched_clock using hv tsc page * based clocksource, proceeds from where it left off during suspend and * it shows correct time for the timestamps of kernel messages after resume. */static void save_hv_clock_tsc_state(void){ hv_ref_counter_at_suspend = hv_read_reference_counter();} static void restore_hv_clock_tsc_state(void){ /* * Adjust the offsets used by hv tsc clocksource to * account for the time spent before hibernation. * adjusted value = reference counter (time) at suspend * - reference counter (time) now. */ hv_adj_sched_clock_offset(hv_ref_counter_at_suspend - hv_read_reference_counter());} /* * Functions to override save_sched_clock_state and restore_sched_clock_state * functions of x86_platform. The Hyper-V clock counter is reset during * suspend-resume and the offset used to measure time needs to be * corrected, post resume. */static void hv_save_sched_clock_state(void){ old_save_sched_clock_state(); save_hv_clock_tsc_state();} static void hv_restore_sched_clock_state(void){ restore_hv_clock_tsc_state(); old_restore_sched_clock_state();} static void __init x86_setup_ops_for_tsc_pg_clock(void){ if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE)) return; old_save_sched_clock_state = x86_platform.save_sched_clock_state; x86_platform.save_sched_clock_state = hv_save_sched_clock_state; old_restore_sched_clock_state = x86_platform.restore_sched_clock_state; x86_platform.restore_sched_clock_state = hv_restore_sched_clock_state;}#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 0; /* HYPERCALL and VP_INDEX MSRs are mandatory for all features. */ eax = cpuid_eax(HYPERV_CPUID_FEATURES); if (!(eax & HV_MSR_HYPERCALL_AVAILABLE)) { pr_warn("x86/hyperv: HYPERCALL MSR not available.\n"); return 0; } if (!(eax & HV_MSR_VP_INDEX_AVAILABLE)) { pr_warn("x86/hyperv: VP_INDEX MSR not available.\n"); return 0; } return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS;} #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); unsigned int old_cpu, this_cpu; if (!unknown_nmi_panic) return NMI_DONE; old_cpu = -1; this_cpu = raw_smp_processor_id(); if (!atomic_try_cmpxchg(&nmi_cpu, &old_cpu, this_cpu)) 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); /* * Override wakeup_secondary_cpu_64 callback for SEV-SNP * enlightened guest. */ if (!ms_hyperv.paravisor_present && hv_isolation_type_snp()) { apic->wakeup_secondary_cpu_64 = hv_snp_boot_ap; return; } #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 /* * When a fully enlightened TDX VM runs on Hyper-V, the firmware sets the * HW_REDUCED flag: refer to acpi_tb_create_local_fadt(). Consequently ttyS0 * interrupts can't work because request_irq() -> ... -> irq_to_desc() returns * NULL for ttyS0. This happens because mp_config_acpi_legacy_irqs() sees a * nr_legacy_irqs() of 0, so it doesn't initialize the array 'mp_irqs[]', and * later setup_IO_APIC_irqs() -> find_irq_entry() fails to find the legacy irqs * from the array and hence doesn't create the necessary irq description info. * * Clone arch/x86/kernel/acpi/boot.c: acpi_generic_reduced_hw_init() here, * except don't change 'legacy_pic', which keeps its default value * 'default_legacy_pic'. This way, mp_config_acpi_legacy_irqs() sees a non-zero * nr_legacy_irqs() and eventually serial console interrupts works properly. */static void __init reduced_hw_init(void){ x86_init.timers.timer_init = x86_init_noop; x86_init.irqs.pre_vector_init = x86_init_noop;} int hv_get_hypervisor_version(union hv_hypervisor_version_info *info){ unsigned int hv_max_functions; hv_max_functions = cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS); if (hv_max_functions < HYPERV_CPUID_VERSION) { pr_err("%s: Could not detect Hyper-V version\n", __func__); return -ENODEV; } cpuid(HYPERV_CPUID_VERSION, &info->eax, &info->ebx, &info->ecx, &info->edx); return 0;} static void __init ms_hyperv_init_platform(void){ int hv_max_functions_eax; #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); hv_max_functions_eax = cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS); 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. * * Hyper-V should never specify running as root and as a Confidential * VM. But to protect against a compromised/malicious Hyper-V trying * to exploit root behavior to expose Confidential VM memory, ignore * the root partition setting if also a Confidential VM. */ if ((ms_hyperv.priv_high & HV_CPU_MANAGEMENT) && !(ms_hyperv.priv_high & HV_ISOLATION)) { hv_root_partition = true; pr_info("Hyper-V: running as root partition\n"); } if (ms_hyperv.hints & HV_X64_HYPERV_NESTED) { hv_nested = true; pr_info("Hyper-V: running on a nested hypervisor\n"); } 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; setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); } 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); if (ms_hyperv.shared_gpa_boundary_active) ms_hyperv.shared_gpa_boundary = BIT_ULL(ms_hyperv.shared_gpa_boundary_bits); hyperv_paravisor_present = !!ms_hyperv.paravisor_present; 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 (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP) {Lines 1–500 of 714. 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// 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/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> #include <asm/svm.h> /* Is Linux running as the root partition? */ bool hv_root_partition; /* Is Linux running on nested Microsoft Hypervisor */ bool hv_nested; struct ms_hyperv_info ms_hyperv; /* Used in modules via hv_do_hypercall(): see arch/x86/include/asm/mshyperv.h */ bool hyperv_paravisor_present __ro_after_init; EXPORT_SYMBOL_GPL(hyperv_paravisor_present); #if IS_ENABLED(CONFIG_HYPERV) static inline unsigned int hv_get_nested_msr(unsigned int reg) { if (hv_is_sint_msr(reg)) return reg - HV_X64_MSR_SINT0 + HV_X64_MSR_NESTED_SINT0; switch (reg) { case HV_X64_MSR_SIMP: return HV_X64_MSR_NESTED_SIMP; case HV_X64_MSR_SIEFP: return HV_X64_MSR_NESTED_SIEFP; case HV_X64_MSR_SVERSION: return HV_X64_MSR_NESTED_SVERSION; case HV_X64_MSR_SCONTROL: return HV_X64_MSR_NESTED_SCONTROL; case HV_X64_MSR_EOM: return HV_X64_MSR_NESTED_EOM; default: return reg; } } u64 hv_get_non_nested_msr(unsigned int reg) { u64 value; if (hv_is_synic_msr(reg) && ms_hyperv.paravisor_present) hv_ivm_msr_read(reg, &value); else rdmsrl(reg, value); return value; } EXPORT_SYMBOL_GPL(hv_get_non_nested_msr); void hv_set_non_nested_msr(unsigned int reg, u64 value) { if (hv_is_synic_msr(reg) && ms_hyperv.paravisor_present) { hv_ivm_msr_write(reg, value); /* Write proxy bit via wrmsl instruction */ if (hv_is_sint_msr(reg)) wrmsrl(reg, value | 1 << 20); } else { wrmsrl(reg, value); } } EXPORT_SYMBOL_GPL(hv_set_non_nested_msr); u64 hv_get_msr(unsigned int reg) { if (hv_nested) reg = hv_get_nested_msr(reg); return hv_get_non_nested_msr(reg); } EXPORT_SYMBOL_GPL(hv_get_msr); void hv_set_msr(unsigned int reg, u64 value) { if (hv_nested) reg = hv_get_nested_msr(reg); hv_set_non_nested_msr(reg, value); } EXPORT_SYMBOL_GPL(hv_set_msr); 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) apic_eoi(); set_irq_regs(old_regs); } void hv_setup_vmbus_handler(void (*handler)(void)) { vmbus_handler = handler; } void hv_remove_vmbus_handler(void) { /* We have no way to deallocate the interrupt gate */ vmbus_handler = NULL; } /* * 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); apic_eoi(); 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; } void hv_remove_kexec_handler(void) { hv_kexec_handler = NULL; } void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs)) { hv_crash_handler = handler; } void hv_remove_crash_handler(void) { hv_crash_handler = NULL; } #ifdef CONFIG_KEXEC_CORE static 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) cpuhp_remove_state(CPUHP_AP_HYPERV_ONLINE); /* 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(); } #endif /* CONFIG_KEXEC_CORE */ #ifdef CONFIG_CRASH_DUMP 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_CRASH_DUMP */ static u64 hv_ref_counter_at_suspend; static void (*old_save_sched_clock_state)(void); static void (*old_restore_sched_clock_state)(void); /* * Hyper-V clock counter resets during hibernation. Save and restore clock * offset during suspend/resume, while also considering the time passed * before suspend. This is to make sure that sched_clock using hv tsc page * based clocksource, proceeds from where it left off during suspend and * it shows correct time for the timestamps of kernel messages after resume. */ static void save_hv_clock_tsc_state(void) { hv_ref_counter_at_suspend = hv_read_reference_counter(); } static void restore_hv_clock_tsc_state(void) { /* * Adjust the offsets used by hv tsc clocksource to * account for the time spent before hibernation. * adjusted value = reference counter (time) at suspend * - reference counter (time) now. */ hv_adj_sched_clock_offset(hv_ref_counter_at_suspend - hv_read_reference_counter()); } /* * Functions to override save_sched_clock_state and restore_sched_clock_state * functions of x86_platform. The Hyper-V clock counter is reset during * suspend-resume and the offset used to measure time needs to be * corrected, post resume. */ static void hv_save_sched_clock_state(void) { old_save_sched_clock_state(); save_hv_clock_tsc_state(); } static void hv_restore_sched_clock_state(void) { restore_hv_clock_tsc_state(); old_restore_sched_clock_state(); } static void __init x86_setup_ops_for_tsc_pg_clock(void) { if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE)) return; old_save_sched_clock_state = x86_platform.save_sched_clock_state; x86_platform.save_sched_clock_state = hv_save_sched_clock_state; old_restore_sched_clock_state = x86_platform.restore_sched_clock_state; x86_platform.restore_sched_clock_state = hv_restore_sched_clock_state; } #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 0; /* HYPERCALL and VP_INDEX MSRs are mandatory for all features. */ eax = cpuid_eax(HYPERV_CPUID_FEATURES); if (!(eax & HV_MSR_HYPERCALL_AVAILABLE)) { pr_warn("x86/hyperv: HYPERCALL MSR not available.\n"); return 0; } if (!(eax & HV_MSR_VP_INDEX_AVAILABLE)) { pr_warn("x86/hyperv: VP_INDEX MSR not available.\n"); return 0; } return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS; } #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); unsigned int old_cpu, this_cpu; if (!unknown_nmi_panic) return NMI_DONE; old_cpu = -1; this_cpu = raw_smp_processor_id(); if (!atomic_try_cmpxchg(&nmi_cpu, &old_cpu, this_cpu)) 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); /* * Override wakeup_secondary_cpu_64 callback for SEV-SNP * enlightened guest. */ if (!ms_hyperv.paravisor_present && hv_isolation_type_snp()) { apic->wakeup_secondary_cpu_64 = hv_snp_boot_ap; return; } #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 /* * When a fully enlightened TDX VM runs on Hyper-V, the firmware sets the * HW_REDUCED flag: refer to acpi_tb_create_local_fadt(). Consequently ttyS0 * interrupts can't work because request_irq() -> ... -> irq_to_desc() returns * NULL for ttyS0. This happens because mp_config_acpi_legacy_irqs() sees a * nr_legacy_irqs() of 0, so it doesn't initialize the array 'mp_irqs[]', and * later setup_IO_APIC_irqs() -> find_irq_entry() fails to find the legacy irqs * from the array and hence doesn't create the necessary irq description info. * * Clone arch/x86/kernel/acpi/boot.c: acpi_generic_reduced_hw_init() here, * except don't change 'legacy_pic', which keeps its default value * 'default_legacy_pic'. This way, mp_config_acpi_legacy_irqs() sees a non-zero * nr_legacy_irqs() and eventually serial console interrupts works properly. */ static void __init reduced_hw_init(void) { x86_init.timers.timer_init = x86_init_noop; x86_init.irqs.pre_vector_init = x86_init_noop; } int hv_get_hypervisor_version(union hv_hypervisor_version_info *info) { unsigned int hv_max_functions; hv_max_functions = cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS); if (hv_max_functions < HYPERV_CPUID_VERSION) { pr_err("%s: Could not detect Hyper-V version\n", __func__); return -ENODEV; } cpuid(HYPERV_CPUID_VERSION, &info->eax, &info->ebx, &info->ecx, &info->edx); return 0; } static void __init ms_hyperv_init_platform(void) { int hv_max_functions_eax; #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); hv_max_functions_eax = cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS); 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. * * Hyper-V should never specify running as root and as a Confidential * VM. But to protect against a compromised/malicious Hyper-V trying * to exploit root behavior to expose Confidential VM memory, ignore * the root partition setting if also a Confidential VM. */ if ((ms_hyperv.priv_high & HV_CPU_MANAGEMENT) && !(ms_hyperv.priv_high & HV_ISOLATION)) { hv_root_partition = true; pr_info("Hyper-V: running as root partition\n"); } if (ms_hyperv.hints & HV_X64_HYPERV_NESTED) { hv_nested = true; pr_info("Hyper-V: running on a nested hypervisor\n"); } 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; setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); } 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); if (ms_hyperv.shared_gpa_boundary_active) ms_hyperv.shared_gpa_boundary = BIT_ULL(ms_hyperv.shared_gpa_boundary_bits); hyperv_paravisor_present = !!ms_hyperv.paravisor_present; 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 (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP) {