| // 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 <linux/swiotlb.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/coco.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; |
| |
| #if IS_ENABLED(CONFIG_HYPERV) |
| static inline unsigned int hv_get_nested_reg(unsigned int reg) |
| { |
| if (hv_is_sint_reg(reg)) |
| return reg - HV_REGISTER_SINT0 + HV_REGISTER_NESTED_SINT0; |
| |
| switch (reg) { |
| case HV_REGISTER_SIMP: |
| return HV_REGISTER_NESTED_SIMP; |
| case HV_REGISTER_SIEFP: |
| return HV_REGISTER_NESTED_SIEFP; |
| case HV_REGISTER_SVERSION: |
| return HV_REGISTER_NESTED_SVERSION; |
| case HV_REGISTER_SCONTROL: |
| return HV_REGISTER_NESTED_SCONTROL; |
| case HV_REGISTER_EOM: |
| return HV_REGISTER_NESTED_EOM; |
| default: |
| return reg; |
| } |
| } |
| |
| u64 hv_get_non_nested_register(unsigned int reg) |
| { |
| u64 value; |
| |
| if (hv_is_synic_reg(reg) && hv_isolation_type_snp()) |
| hv_ghcb_msr_read(reg, &value); |
| else |
| rdmsrl(reg, value); |
| return value; |
| } |
| EXPORT_SYMBOL_GPL(hv_get_non_nested_register); |
| |
| void hv_set_non_nested_register(unsigned int reg, u64 value) |
| { |
| if (hv_is_synic_reg(reg) && hv_isolation_type_snp()) { |
| hv_ghcb_msr_write(reg, value); |
| |
| /* Write proxy bit via wrmsl instruction */ |
| if (hv_is_sint_reg(reg)) |
| wrmsrl(reg, value | 1 << 20); |
| } else { |
| wrmsrl(reg, value); |
| } |
| } |
| EXPORT_SYMBOL_GPL(hv_set_non_nested_register); |
| |
| u64 hv_get_register(unsigned int reg) |
| { |
| if (hv_nested) |
| reg = hv_get_nested_reg(reg); |
| |
| return hv_get_non_nested_register(reg); |
| } |
| EXPORT_SYMBOL_GPL(hv_get_register); |
| |
| void hv_set_register(unsigned int reg, u64 value) |
| { |
| if (hv_nested) |
| reg = hv_get_nested_reg(reg); |
| |
| hv_set_non_nested_register(reg, value); |
| } |
| EXPORT_SYMBOL_GPL(hv_set_register); |
| |
| 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; |
| } |
| |
| 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); |
| 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; |
| } |
| |
| 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 && 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 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; |
| } |
| |
| 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_max_functions_eax; |
| 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); |
| |
| 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. |
| */ |
| if (cpuid_ebx(HYPERV_CPUID_FEATURES) & HV_CPU_MANAGEMENT) { |
| 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"); |
| } |
| |
| /* |
| * Extract host information. |
| */ |
| if (hv_max_functions_eax >= 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_ebx >> 16, hv_host_info_ebx & 0xFFFF, |
| hv_host_info_eax, hv_host_info_edx & 0xFFFFFF, |
| hv_host_info_ecx, hv_host_info_edx >> 24); |
| } |
| |
| 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); |
| ms_hyperv.shared_gpa_boundary = |
| BIT_ULL(ms_hyperv.shared_gpa_boundary_bits); |
| |
| 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) { |
| static_branch_enable(&isolation_type_snp); |
| #ifdef CONFIG_SWIOTLB |
| swiotlb_unencrypted_base = ms_hyperv.shared_gpa_boundary; |
| #endif |
| } |
| /* Isolation VMs are unenlightened SEV-based VMs, thus this check: */ |
| if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) { |
| if (hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE) |
| cc_set_vendor(CC_VENDOR_HYPERV); |
| } |
| } |
| |
| if (hv_max_functions_eax >= HYPERV_CPUID_NESTED_FEATURES) { |
| ms_hyperv.nested_features = |
| cpuid_eax(HYPERV_CPUID_NESTED_FEATURES); |
| pr_info("Hyper-V: Nested features: 0x%x\n", |
| ms_hyperv.nested_features); |
| } |
| |
| #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) { |
| /* |
| * Writing to synthetic MSR 0x40000118 updates/changes the |
| * guest visible CPUIDs. Setting bit 0 of this MSR enables |
| * guests to report invariant TSC feature through CPUID |
| * instruction, CPUID 0x800000007/EDX, bit 8. See code in |
| * early_init_intel() where this bit is examined. The |
| * setting of this MSR bit should happen before init_intel() |
| * is called. |
| */ |
| wrmsrl(HV_X64_MSR_TSC_INVARIANT_CONTROL, HV_EXPOSE_INVARIANT_TSC); |
| setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE); |
| } |
| |
| /* |
| * 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 |
| /* |
| * TSC should be marked as unstable only after Hyper-V |
| * clocksource has been initialized. This ensures that the |
| * stability of the sched_clock is not altered. |
| */ |
| if (!(ms_hyperv.features & HV_ACCESS_TSC_INVARIANT)) |
| mark_tsc_unstable("running on Hyper-V"); |
| |
| hardlockup_detector_disable(); |
| } |
| |
| 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. |
| * |
| * Note: for a Hyper-V root partition, this will always return false. |
| * The hypervisor doesn't expose these HYPERV_CPUID_VIRT_STACK_* cpuids by |
| * default, they are implemented as intercepts by the Windows Hyper-V stack. |
| * Even a nested root partition (L2 root) will not get them because the |
| * nested (L1) hypervisor filters them out. |
| */ |
| 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, |
| }; |