| // 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/efi.h> |
| #include <linux/types.h> |
| #include <linux/bitfield.h> |
| #include <linux/io.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/kexec.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> |
| #include <linux/highmem.h> |
| |
| int hyperv_init_cpuhp; |
| u64 hv_current_partition_id = ~0ull; |
| EXPORT_SYMBOL_GPL(hv_current_partition_id); |
| |
| void *hv_hypercall_pg; |
| EXPORT_SYMBOL_GPL(hv_hypercall_pg); |
| |
| union hv_ghcb __percpu **hv_ghcb_pg; |
| |
| /* Storage to save the hypercall page temporarily for hibernation */ |
| static void *hv_hypercall_pg_saved; |
| |
| struct hv_vp_assist_page **hv_vp_assist_page; |
| EXPORT_SYMBOL_GPL(hv_vp_assist_page); |
| |
| static int hyperv_init_ghcb(void) |
| { |
| u64 ghcb_gpa; |
| void *ghcb_va; |
| void **ghcb_base; |
| |
| if (!hv_isolation_type_snp()) |
| return 0; |
| |
| if (!hv_ghcb_pg) |
| return -EINVAL; |
| |
| /* |
| * GHCB page is allocated by paravisor. The address |
| * returned by MSR_AMD64_SEV_ES_GHCB is above shared |
| * memory boundary and map it here. |
| */ |
| rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa); |
| ghcb_va = memremap(ghcb_gpa, HV_HYP_PAGE_SIZE, MEMREMAP_WB); |
| if (!ghcb_va) |
| return -ENOMEM; |
| |
| ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg); |
| *ghcb_base = ghcb_va; |
| |
| return 0; |
| } |
| |
| static int hv_cpu_init(unsigned int cpu) |
| { |
| union hv_vp_assist_msr_contents msr = { 0 }; |
| struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()]; |
| int ret; |
| |
| ret = hv_common_cpu_init(cpu); |
| if (ret) |
| return ret; |
| |
| if (!hv_vp_assist_page) |
| return 0; |
| |
| if (!*hvp) { |
| if (hv_root_partition) { |
| /* |
| * For root partition we get the hypervisor provided VP assist |
| * page, instead of allocating a new page. |
| */ |
| rdmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64); |
| *hvp = memremap(msr.pfn << |
| HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT, |
| PAGE_SIZE, MEMREMAP_WB); |
| } else { |
| /* |
| * 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. |
| */ |
| *hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL | __GFP_ZERO); |
| if (*hvp) |
| msr.pfn = vmalloc_to_pfn(*hvp); |
| } |
| WARN_ON(!(*hvp)); |
| if (*hvp) { |
| msr.enable = 1; |
| wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64); |
| } |
| } |
| |
| return hyperv_init_ghcb(); |
| } |
| |
| 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 privileges to make TSC frequency |
| * change notifications work. |
| */ |
| return ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS && |
| ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE && |
| ms_hyperv.features & HV_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, |
| }; |
| 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(); |
| |
| re_ctrl.target_vp = hv_vp_index[get_cpu()]; |
| |
| wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl)); |
| wrmsrl(HV_X64_MSR_TSC_EMULATION_CONTROL, *((u64 *)&emu_ctrl)); |
| |
| put_cpu(); |
| } |
| 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; |
| void **ghcb_va; |
| |
| if (hv_ghcb_pg) { |
| ghcb_va = (void **)this_cpu_ptr(hv_ghcb_pg); |
| if (*ghcb_va) |
| memunmap(*ghcb_va); |
| *ghcb_va = NULL; |
| } |
| |
| hv_common_cpu_die(cpu); |
| |
| if (hv_vp_assist_page && hv_vp_assist_page[cpu]) { |
| union hv_vp_assist_msr_contents msr = { 0 }; |
| if (hv_root_partition) { |
| /* |
| * For root partition the VP assist page is mapped to |
| * hypervisor provided page, and thus we unmap the |
| * page here and nullify it, so that in future we have |
| * correct page address mapped in hv_cpu_init. |
| */ |
| memunmap(hv_vp_assist_page[cpu]); |
| hv_vp_assist_page[cpu] = NULL; |
| rdmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64); |
| msr.enable = 0; |
| } |
| wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64); |
| } |
| |
| 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; |
| |
| if (hv_root_partition) |
| return -EPERM; |
| |
| /* |
| * Reset the hypercall page as it is going to be invalidated |
| * across 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, |
| }; |
| |
| static void (* __initdata old_setup_percpu_clockev)(void); |
| |
| static void __init hv_stimer_setup_percpu_clockev(void) |
| { |
| /* |
| * Ignore any errors in setting up stimer clockevents |
| * as we can run with the LAPIC timer as a fallback. |
| */ |
| (void)hv_stimer_alloc(false); |
| |
| /* |
| * Still register the LAPIC timer, because the direct-mode STIMER is |
| * not supported by old versions of Hyper-V. This also allows users |
| * to switch to LAPIC timer via /sys, if they want to. |
| */ |
| if (old_setup_percpu_clockev) |
| old_setup_percpu_clockev(); |
| } |
| |
| static void __init hv_get_partition_id(void) |
| { |
| struct hv_get_partition_id *output_page; |
| u64 status; |
| unsigned long flags; |
| |
| local_irq_save(flags); |
| output_page = *this_cpu_ptr(hyperv_pcpu_output_arg); |
| status = hv_do_hypercall(HVCALL_GET_PARTITION_ID, NULL, output_page); |
| if (!hv_result_success(status)) { |
| /* No point in proceeding if this failed */ |
| pr_err("Failed to get partition ID: %lld\n", status); |
| BUG(); |
| } |
| hv_current_partition_id = output_page->partition_id; |
| local_irq_restore(flags); |
| } |
| |
| /* |
| * 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; |
| |
| if (x86_hyper_type != X86_HYPER_MS_HYPERV) |
| return; |
| |
| /* Absolutely required MSRs */ |
| required_msrs = HV_MSR_HYPERCALL_AVAILABLE | |
| HV_MSR_VP_INDEX_AVAILABLE; |
| |
| if ((ms_hyperv.features & required_msrs) != required_msrs) |
| return; |
| |
| if (hv_common_init()) |
| return; |
| |
| 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 common_free; |
| } |
| |
| if (hv_isolation_type_snp()) { |
| hv_ghcb_pg = alloc_percpu(union hv_ghcb *); |
| if (!hv_ghcb_pg) |
| goto free_vp_assist_page; |
| } |
| |
| cpuhp = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online", |
| hv_cpu_init, hv_cpu_die); |
| if (cpuhp < 0) |
| goto free_ghcb_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); |
| |
| /* Hyper-V requires to write guest os id via ghcb in SNP IVM. */ |
| hv_ghcb_msr_write(HV_X64_MSR_GUEST_OS_ID, guest_id); |
| |
| hv_hypercall_pg = __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START, |
| VMALLOC_END, GFP_KERNEL, PAGE_KERNEL_ROX, |
| VM_FLUSH_RESET_PERMS, NUMA_NO_NODE, |
| __builtin_return_address(0)); |
| if (hv_hypercall_pg == NULL) |
| goto clean_guest_os_id; |
| |
| rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); |
| hypercall_msr.enable = 1; |
| |
| if (hv_root_partition) { |
| struct page *pg; |
| void *src, *dst; |
| |
| /* |
| * For the root partition, the hypervisor will set up its |
| * hypercall page. The hypervisor guarantees it will not show |
| * up in the root's address space. The root can't change the |
| * location of the hypercall page. |
| * |
| * Order is important here. We must enable the hypercall page |
| * so it is populated with code, then copy the code to an |
| * executable page. |
| */ |
| wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); |
| |
| pg = vmalloc_to_page(hv_hypercall_pg); |
| dst = kmap(pg); |
| src = memremap(hypercall_msr.guest_physical_address << PAGE_SHIFT, PAGE_SIZE, |
| MEMREMAP_WB); |
| BUG_ON(!(src && dst)); |
| memcpy(dst, src, HV_HYP_PAGE_SIZE); |
| memunmap(src); |
| kunmap(pg); |
| } else { |
| hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg); |
| wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); |
| } |
| |
| /* |
| * hyperv_init() is called before LAPIC is initialized: see |
| * apic_intr_mode_init() -> x86_platform.apic_post_init() and |
| * apic_bsp_setup() -> setup_local_APIC(). The direct-mode STIMER |
| * depends on LAPIC, so hv_stimer_alloc() should be called from |
| * x86_init.timers.setup_percpu_clockev. |
| */ |
| old_setup_percpu_clockev = x86_init.timers.setup_percpu_clockev; |
| x86_init.timers.setup_percpu_clockev = hv_stimer_setup_percpu_clockev; |
| |
| hv_apic_init(); |
| |
| x86_init.pci.arch_init = hv_pci_init; |
| |
| register_syscore_ops(&hv_syscore_ops); |
| |
| hyperv_init_cpuhp = cpuhp; |
| |
| if (cpuid_ebx(HYPERV_CPUID_FEATURES) & HV_ACCESS_PARTITION_ID) |
| hv_get_partition_id(); |
| |
| BUG_ON(hv_root_partition && hv_current_partition_id == ~0ull); |
| |
| #ifdef CONFIG_PCI_MSI |
| /* |
| * If we're running as root, we want to create our own PCI MSI domain. |
| * We can't set this in hv_pci_init because that would be too late. |
| */ |
| if (hv_root_partition) |
| x86_init.irqs.create_pci_msi_domain = hv_create_pci_msi_domain; |
| #endif |
| |
| /* Query the VMs extended capability once, so that it can be cached. */ |
| hv_query_ext_cap(0); |
| return; |
| |
| clean_guest_os_id: |
| wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0); |
| hv_ghcb_msr_write(HV_X64_MSR_GUEST_OS_ID, 0); |
| cpuhp_remove_state(cpuhp); |
| free_ghcb_page: |
| free_percpu(hv_ghcb_pg); |
| free_vp_assist_page: |
| kfree(hv_vp_assist_page); |
| hv_vp_assist_page = NULL; |
| common_free: |
| hv_common_free(); |
| } |
| |
| /* |
| * 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); |
| hv_ghcb_msr_write(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); |
| } |
| |
| 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); |
| |
| 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); |