diff options
Diffstat (limited to 'arch/x86/kernel/cpu/mshyperv.c')
| -rw-r--r-- | arch/x86/kernel/cpu/mshyperv.c | 502 |
1 files changed, 502 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c new file mode 100644 index 000000000..34d9e899e --- /dev/null +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -0,0 +1,502 @@ +// 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; +struct ms_hyperv_info 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; +} + +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. + * + * 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"); + } + + /* + * 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, 0x1); + 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. + */ +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, +}; |