| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * X86 specific Hyper-V initialization code. |
| * |
| * Copyright (C) 2016, Microsoft, Inc. |
| * |
| * Author : K. Y. Srinivasan <kys@microsoft.com> |
| */ |
| |
| #include <linux/acpi.h> |
| #include <linux/efi.h> |
| #include <linux/types.h> |
| #include <asm/apic.h> |
| #include <asm/desc.h> |
| #include <asm/hypervisor.h> |
| #include <asm/hyperv-tlfs.h> |
| #include <asm/mshyperv.h> |
| #include <asm/idtentry.h> |
| #include <linux/version.h> |
| #include <linux/vmalloc.h> |
| #include <linux/mm.h> |
| #include <linux/hyperv.h> |
| #include <linux/slab.h> |
| #include <linux/kernel.h> |
| #include <linux/cpuhotplug.h> |
| #include <linux/syscore_ops.h> |
| #include <clocksource/hyperv_timer.h> |
| |
| void *hv_hypercall_pg; |
| EXPORT_SYMBOL_GPL(hv_hypercall_pg); |
| |
| /* Storage to save the hypercall page temporarily for hibernation */ |
| static void *hv_hypercall_pg_saved; |
| |
| u32 *hv_vp_index; |
| EXPORT_SYMBOL_GPL(hv_vp_index); |
| |
| struct hv_vp_assist_page **hv_vp_assist_page; |
| EXPORT_SYMBOL_GPL(hv_vp_assist_page); |
| |
| void __percpu **hyperv_pcpu_input_arg; |
| EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg); |
| |
| u32 hv_max_vp_index; |
| EXPORT_SYMBOL_GPL(hv_max_vp_index); |
| |
| void *hv_alloc_hyperv_page(void) |
| { |
| BUILD_BUG_ON(PAGE_SIZE != HV_HYP_PAGE_SIZE); |
| |
| return (void *)__get_free_page(GFP_KERNEL); |
| } |
| EXPORT_SYMBOL_GPL(hv_alloc_hyperv_page); |
| |
| void *hv_alloc_hyperv_zeroed_page(void) |
| { |
| BUILD_BUG_ON(PAGE_SIZE != HV_HYP_PAGE_SIZE); |
| |
| return (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO); |
| } |
| EXPORT_SYMBOL_GPL(hv_alloc_hyperv_zeroed_page); |
| |
| void hv_free_hyperv_page(unsigned long addr) |
| { |
| free_page(addr); |
| } |
| EXPORT_SYMBOL_GPL(hv_free_hyperv_page); |
| |
| static int hv_cpu_init(unsigned int cpu) |
| { |
| u64 msr_vp_index; |
| struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()]; |
| void **input_arg; |
| struct page *pg; |
| |
| input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg); |
| /* hv_cpu_init() can be called with IRQs disabled from hv_resume() */ |
| pg = alloc_page(irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL); |
| if (unlikely(!pg)) |
| return -ENOMEM; |
| *input_arg = page_address(pg); |
| |
| hv_get_vp_index(msr_vp_index); |
| |
| hv_vp_index[smp_processor_id()] = msr_vp_index; |
| |
| if (msr_vp_index > hv_max_vp_index) |
| hv_max_vp_index = msr_vp_index; |
| |
| if (!hv_vp_assist_page) |
| return 0; |
| |
| /* |
| * The VP ASSIST PAGE is an "overlay" page (see Hyper-V TLFS's Section |
| * 5.2.1 "GPA Overlay Pages"). Here it must be zeroed out to make sure |
| * we always write the EOI MSR in hv_apic_eoi_write() *after* the |
| * EOI optimization is disabled in hv_cpu_die(), otherwise a CPU may |
| * not be stopped in the case of CPU offlining and the VM will hang. |
| */ |
| if (!*hvp) { |
| *hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL | __GFP_ZERO); |
| } |
| |
| if (*hvp) { |
| u64 val; |
| |
| val = vmalloc_to_pfn(*hvp); |
| val = (val << HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT) | |
| HV_X64_MSR_VP_ASSIST_PAGE_ENABLE; |
| |
| wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, val); |
| } |
| |
| return 0; |
| } |
| |
| static void (*hv_reenlightenment_cb)(void); |
| |
| static void hv_reenlightenment_notify(struct work_struct *dummy) |
| { |
| struct hv_tsc_emulation_status emu_status; |
| |
| rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status); |
| |
| /* Don't issue the callback if TSC accesses are not emulated */ |
| if (hv_reenlightenment_cb && emu_status.inprogress) |
| hv_reenlightenment_cb(); |
| } |
| static DECLARE_DELAYED_WORK(hv_reenlightenment_work, hv_reenlightenment_notify); |
| |
| void hyperv_stop_tsc_emulation(void) |
| { |
| u64 freq; |
| struct hv_tsc_emulation_status emu_status; |
| |
| rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status); |
| emu_status.inprogress = 0; |
| wrmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status); |
| |
| rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq); |
| tsc_khz = div64_u64(freq, 1000); |
| } |
| EXPORT_SYMBOL_GPL(hyperv_stop_tsc_emulation); |
| |
| static inline bool hv_reenlightenment_available(void) |
| { |
| /* |
| * Check for required features and priviliges to make TSC frequency |
| * change notifications work. |
| */ |
| return ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS && |
| ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE && |
| ms_hyperv.features & HV_X64_ACCESS_REENLIGHTENMENT; |
| } |
| |
| DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_reenlightenment) |
| { |
| ack_APIC_irq(); |
| inc_irq_stat(irq_hv_reenlightenment_count); |
| schedule_delayed_work(&hv_reenlightenment_work, HZ/10); |
| } |
| |
| void set_hv_tscchange_cb(void (*cb)(void)) |
| { |
| struct hv_reenlightenment_control re_ctrl = { |
| .vector = HYPERV_REENLIGHTENMENT_VECTOR, |
| .enabled = 1, |
| .target_vp = hv_vp_index[smp_processor_id()] |
| }; |
| struct hv_tsc_emulation_control emu_ctrl = {.enabled = 1}; |
| |
| if (!hv_reenlightenment_available()) { |
| pr_warn("Hyper-V: reenlightenment support is unavailable\n"); |
| return; |
| } |
| |
| hv_reenlightenment_cb = cb; |
| |
| /* Make sure callback is registered before we write to MSRs */ |
| wmb(); |
| |
| wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl)); |
| wrmsrl(HV_X64_MSR_TSC_EMULATION_CONTROL, *((u64 *)&emu_ctrl)); |
| } |
| EXPORT_SYMBOL_GPL(set_hv_tscchange_cb); |
| |
| void clear_hv_tscchange_cb(void) |
| { |
| struct hv_reenlightenment_control re_ctrl; |
| |
| if (!hv_reenlightenment_available()) |
| return; |
| |
| rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl); |
| re_ctrl.enabled = 0; |
| wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl); |
| |
| hv_reenlightenment_cb = NULL; |
| } |
| EXPORT_SYMBOL_GPL(clear_hv_tscchange_cb); |
| |
| static int hv_cpu_die(unsigned int cpu) |
| { |
| struct hv_reenlightenment_control re_ctrl; |
| unsigned int new_cpu; |
| unsigned long flags; |
| void **input_arg; |
| void *input_pg = NULL; |
| |
| local_irq_save(flags); |
| input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg); |
| input_pg = *input_arg; |
| *input_arg = NULL; |
| local_irq_restore(flags); |
| free_page((unsigned long)input_pg); |
| |
| if (hv_vp_assist_page && hv_vp_assist_page[cpu]) |
| wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, 0); |
| |
| if (hv_reenlightenment_cb == NULL) |
| return 0; |
| |
| rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl)); |
| if (re_ctrl.target_vp == hv_vp_index[cpu]) { |
| /* |
| * Reassign reenlightenment notifications to some other online |
| * CPU or just disable the feature if there are no online CPUs |
| * left (happens on hibernation). |
| */ |
| new_cpu = cpumask_any_but(cpu_online_mask, cpu); |
| |
| if (new_cpu < nr_cpu_ids) |
| re_ctrl.target_vp = hv_vp_index[new_cpu]; |
| else |
| re_ctrl.enabled = 0; |
| |
| wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl)); |
| } |
| |
| return 0; |
| } |
| |
| static int __init hv_pci_init(void) |
| { |
| int gen2vm = efi_enabled(EFI_BOOT); |
| |
| /* |
| * For Generation-2 VM, we exit from pci_arch_init() by returning 0. |
| * The purpose is to suppress the harmless warning: |
| * "PCI: Fatal: No config space access function found" |
| */ |
| if (gen2vm) |
| return 0; |
| |
| /* For Generation-1 VM, we'll proceed in pci_arch_init(). */ |
| return 1; |
| } |
| |
| static int hv_suspend(void) |
| { |
| union hv_x64_msr_hypercall_contents hypercall_msr; |
| int ret; |
| |
| /* |
| * Reset the hypercall page as it is going to be invalidated |
| * accross hibernation. Setting hv_hypercall_pg to NULL ensures |
| * that any subsequent hypercall operation fails safely instead of |
| * crashing due to an access of an invalid page. The hypercall page |
| * pointer is restored on resume. |
| */ |
| hv_hypercall_pg_saved = hv_hypercall_pg; |
| hv_hypercall_pg = NULL; |
| |
| /* Disable the hypercall page in the hypervisor */ |
| rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); |
| hypercall_msr.enable = 0; |
| wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); |
| |
| ret = hv_cpu_die(0); |
| return ret; |
| } |
| |
| static void hv_resume(void) |
| { |
| union hv_x64_msr_hypercall_contents hypercall_msr; |
| int ret; |
| |
| ret = hv_cpu_init(0); |
| WARN_ON(ret); |
| |
| /* Re-enable the hypercall page */ |
| rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); |
| hypercall_msr.enable = 1; |
| hypercall_msr.guest_physical_address = |
| vmalloc_to_pfn(hv_hypercall_pg_saved); |
| wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); |
| |
| hv_hypercall_pg = hv_hypercall_pg_saved; |
| hv_hypercall_pg_saved = NULL; |
| |
| /* |
| * Reenlightenment notifications are disabled by hv_cpu_die(0), |
| * reenable them here if hv_reenlightenment_cb was previously set. |
| */ |
| if (hv_reenlightenment_cb) |
| set_hv_tscchange_cb(hv_reenlightenment_cb); |
| } |
| |
| /* Note: when the ops are called, only CPU0 is online and IRQs are disabled. */ |
| static struct syscore_ops hv_syscore_ops = { |
| .suspend = hv_suspend, |
| .resume = hv_resume, |
| }; |
| |
| /* |
| * This function is to be invoked early in the boot sequence after the |
| * hypervisor has been detected. |
| * |
| * 1. Setup the hypercall page. |
| * 2. Register Hyper-V specific clocksource. |
| * 3. Setup Hyper-V specific APIC entry points. |
| */ |
| void __init hyperv_init(void) |
| { |
| u64 guest_id, required_msrs; |
| union hv_x64_msr_hypercall_contents hypercall_msr; |
| int cpuhp, i; |
| |
| if (x86_hyper_type != X86_HYPER_MS_HYPERV) |
| return; |
| |
| /* Absolutely required MSRs */ |
| required_msrs = HV_X64_MSR_HYPERCALL_AVAILABLE | |
| HV_X64_MSR_VP_INDEX_AVAILABLE; |
| |
| if ((ms_hyperv.features & required_msrs) != required_msrs) |
| return; |
| |
| /* |
| * Allocate the per-CPU state for the hypercall input arg. |
| * If this allocation fails, we will not be able to setup |
| * (per-CPU) hypercall input page and thus this failure is |
| * fatal on Hyper-V. |
| */ |
| hyperv_pcpu_input_arg = alloc_percpu(void *); |
| |
| BUG_ON(hyperv_pcpu_input_arg == NULL); |
| |
| /* Allocate percpu VP index */ |
| hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index), |
| GFP_KERNEL); |
| if (!hv_vp_index) |
| return; |
| |
| for (i = 0; i < num_possible_cpus(); i++) |
| hv_vp_index[i] = VP_INVAL; |
| |
| hv_vp_assist_page = kcalloc(num_possible_cpus(), |
| sizeof(*hv_vp_assist_page), GFP_KERNEL); |
| if (!hv_vp_assist_page) { |
| ms_hyperv.hints &= ~HV_X64_ENLIGHTENED_VMCS_RECOMMENDED; |
| goto free_vp_index; |
| } |
| |
| cpuhp = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online", |
| hv_cpu_init, hv_cpu_die); |
| if (cpuhp < 0) |
| goto free_vp_assist_page; |
| |
| /* |
| * Setup the hypercall page and enable hypercalls. |
| * 1. Register the guest ID |
| * 2. Enable the hypercall and register the hypercall page |
| */ |
| guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0); |
| wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id); |
| |
| hv_hypercall_pg = vmalloc_exec(PAGE_SIZE); |
| if (hv_hypercall_pg == NULL) { |
| wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0); |
| goto remove_cpuhp_state; |
| } |
| |
| rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); |
| hypercall_msr.enable = 1; |
| hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg); |
| wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); |
| |
| /* |
| * Ignore any errors in setting up stimer clockevents |
| * as we can run with the LAPIC timer as a fallback. |
| */ |
| (void)hv_stimer_alloc(); |
| |
| hv_apic_init(); |
| |
| x86_init.pci.arch_init = hv_pci_init; |
| |
| register_syscore_ops(&hv_syscore_ops); |
| |
| return; |
| |
| remove_cpuhp_state: |
| cpuhp_remove_state(cpuhp); |
| free_vp_assist_page: |
| kfree(hv_vp_assist_page); |
| hv_vp_assist_page = NULL; |
| free_vp_index: |
| kfree(hv_vp_index); |
| hv_vp_index = NULL; |
| } |
| |
| /* |
| * This routine is called before kexec/kdump, it does the required cleanup. |
| */ |
| void hyperv_cleanup(void) |
| { |
| union hv_x64_msr_hypercall_contents hypercall_msr; |
| |
| unregister_syscore_ops(&hv_syscore_ops); |
| |
| /* Reset our OS id */ |
| wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0); |
| |
| /* |
| * Reset hypercall page reference before reset the page, |
| * let hypercall operations fail safely rather than |
| * panic the kernel for using invalid hypercall page |
| */ |
| hv_hypercall_pg = NULL; |
| |
| /* Reset the hypercall page */ |
| hypercall_msr.as_uint64 = 0; |
| wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); |
| |
| /* Reset the TSC page */ |
| hypercall_msr.as_uint64 = 0; |
| wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64); |
| } |
| EXPORT_SYMBOL_GPL(hyperv_cleanup); |
| |
| void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die) |
| { |
| static bool panic_reported; |
| u64 guest_id; |
| |
| if (in_die && !panic_on_oops) |
| return; |
| |
| /* |
| * We prefer to report panic on 'die' chain as we have proper |
| * registers to report, but if we miss it (e.g. on BUG()) we need |
| * to report it on 'panic'. |
| */ |
| if (panic_reported) |
| return; |
| panic_reported = true; |
| |
| rdmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id); |
| |
| wrmsrl(HV_X64_MSR_CRASH_P0, err); |
| wrmsrl(HV_X64_MSR_CRASH_P1, guest_id); |
| wrmsrl(HV_X64_MSR_CRASH_P2, regs->ip); |
| wrmsrl(HV_X64_MSR_CRASH_P3, regs->ax); |
| wrmsrl(HV_X64_MSR_CRASH_P4, regs->sp); |
| |
| /* |
| * Let Hyper-V know there is crash data available |
| */ |
| wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY); |
| } |
| EXPORT_SYMBOL_GPL(hyperv_report_panic); |
| |
| /** |
| * hyperv_report_panic_msg - report panic message to Hyper-V |
| * @pa: physical address of the panic page containing the message |
| * @size: size of the message in the page |
| */ |
| void hyperv_report_panic_msg(phys_addr_t pa, size_t size) |
| { |
| /* |
| * P3 to contain the physical address of the panic page & P4 to |
| * contain the size of the panic data in that page. Rest of the |
| * registers are no-op when the NOTIFY_MSG flag is set. |
| */ |
| wrmsrl(HV_X64_MSR_CRASH_P0, 0); |
| wrmsrl(HV_X64_MSR_CRASH_P1, 0); |
| wrmsrl(HV_X64_MSR_CRASH_P2, 0); |
| wrmsrl(HV_X64_MSR_CRASH_P3, pa); |
| wrmsrl(HV_X64_MSR_CRASH_P4, size); |
| |
| /* |
| * Let Hyper-V know there is crash data available along with |
| * the panic message. |
| */ |
| wrmsrl(HV_X64_MSR_CRASH_CTL, |
| (HV_CRASH_CTL_CRASH_NOTIFY | HV_CRASH_CTL_CRASH_NOTIFY_MSG)); |
| } |
| EXPORT_SYMBOL_GPL(hyperv_report_panic_msg); |
| |
| bool hv_is_hyperv_initialized(void) |
| { |
| union hv_x64_msr_hypercall_contents hypercall_msr; |
| |
| /* |
| * Ensure that we're really on Hyper-V, and not a KVM or Xen |
| * emulation of Hyper-V |
| */ |
| if (x86_hyper_type != X86_HYPER_MS_HYPERV) |
| return false; |
| |
| /* |
| * Verify that earlier initialization succeeded by checking |
| * that the hypercall page is setup |
| */ |
| hypercall_msr.as_uint64 = 0; |
| rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); |
| |
| return hypercall_msr.enable; |
| } |
| EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized); |
| |
| bool hv_is_hibernation_supported(void) |
| { |
| return acpi_sleep_state_supported(ACPI_STATE_S4); |
| } |
| EXPORT_SYMBOL_GPL(hv_is_hibernation_supported); |