diff options
Diffstat (limited to 'arch/x86/hyperv/hv_init.c')
| -rw-r--r-- | arch/x86/hyperv/hv_init.c | 650 |
1 files changed, 650 insertions, 0 deletions
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c new file mode 100644 index 000000000..c18e5c764 --- /dev/null +++ b/arch/x86/hyperv/hv_init.c @@ -0,0 +1,650 @@ +// 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/e820/api.h> +#include <asm/sev.h> +#include <asm/ibt.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> +#include <linux/swiotlb.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[cpu]; + int ret; + + ret = hv_common_cpu_init(cpu); + if (ret) + return ret; + + if (!hv_vp_assist_page) + return 0; + + 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. + */ + if (!*hvp) + *hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL | __GFP_ZERO); + if (*hvp) + msr.pfn = vmalloc_to_pfn(*hvp); + + } + if (!WARN_ON(!(*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; + } + + if (!hv_vp_index) + 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) +{ + bool gen2vm = efi_enabled(EFI_BOOT); + + /* + * A Generation-2 VM doesn't support legacy PCI/PCIe, so both + * raw_pci_ops and raw_pci_ext_ops are NULL, and pci_subsys_init() -> + * pcibios_init() doesn't call pcibios_resource_survey() -> + * e820__reserve_resources_late(); as a result, any emulated persistent + * memory of E820_TYPE_PRAM (12) via the kernel parameter + * memmap=nn[KMG]!ss is not added into iomem_resource and hence can't be + * detected by register_e820_pmem(). Fix this by directly calling + * e820__reserve_resources_late() here: e820__reserve_resources_late() + * depends on e820__reserve_resources(), which has been called earlier + * from setup_arch(). Note: e820__reserve_resources_late() also adds + * any memory of E820_TYPE_PMEM (7) into iomem_resource, and + * acpi_nfit_register_region() -> acpi_nfit_insert_resource() -> + * region_intersects() returns REGION_INTERSECTS, so the memory of + * E820_TYPE_PMEM won't get added twice. + * + * We return 0 here so that pci_arch_init() won't print the warning: + * "PCI: Fatal: No config space access function found" + */ + if (gen2vm) { + e820__reserve_resources_late(); + 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; + union hv_x64_msr_hypercall_contents hypercall_msr; + int cpuhp; + + if (x86_hyper_type != X86_HYPER_MS_HYPERV) + 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()) { + /* Negotiate GHCB Version. */ + if (!hv_ghcb_negotiate_protocol()) + hv_ghcb_terminate(SEV_TERM_SET_GEN, + GHCB_SEV_ES_PROT_UNSUPPORTED); + + 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 = hv_generate_guest_id(LINUX_VERSION_CODE); + 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; + + /* + * 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); + src = memremap(hypercall_msr.guest_physical_address << PAGE_SHIFT, PAGE_SIZE, + MEMREMAP_WB); + BUG_ON(!src); + memcpy_to_page(pg, 0, src, HV_HYP_PAGE_SIZE); + memunmap(src); + } else { + hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg); + wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); + } + + /* + * Some versions of Hyper-V that provide IBT in guest VMs have a bug + * in that there's no ENDBR64 instruction at the entry to the + * hypercall page. Because hypercalls are invoked via an indirect call + * to the hypercall page, all hypercall attempts fail when IBT is + * enabled, and Linux panics. For such buggy versions, disable IBT. + * + * Fixed versions of Hyper-V always provide ENDBR64 on the hypercall + * page, so if future Linux kernel versions enable IBT for 32-bit + * builds, additional hypercall page hackery will be required here + * to provide an ENDBR32. + */ +#ifdef CONFIG_X86_KERNEL_IBT + if (cpu_feature_enabled(X86_FEATURE_IBT) && + *(u32 *)hv_hypercall_pg != gen_endbr()) { + setup_clear_cpu_cap(X86_FEATURE_IBT); + pr_warn("Hyper-V: Disabling IBT because of Hyper-V bug\n"); + } +#endif + + /* + * 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); + +#ifdef CONFIG_SWIOTLB + /* + * Swiotlb bounce buffer needs to be mapped in extra address + * space. Map function doesn't work in the early place and so + * call swiotlb_update_mem_attributes() here. + */ + if (hv_is_isolation_supported()) + swiotlb_update_mem_attributes(); +#endif + + 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; + union hv_reference_tsc_msr tsc_msr; + + /* 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 = hv_get_register(HV_X64_MSR_HYPERCALL); + hypercall_msr.enable = 0; + hv_set_register(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); + + /* Reset the TSC page */ + tsc_msr.as_uint64 = hv_get_register(HV_X64_MSR_REFERENCE_TSC); + tsc_msr.enable = 0; + hv_set_register(HV_X64_MSR_REFERENCE_TSC, tsc_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); |