123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633 |
- // SPDX-License-Identifier: GPL-2.0-only
- /*
- * X86 specific Hyper-V initialization code.
- *
- * Copyright (C) 2016, Microsoft, Inc.
- *
- * Author : K. Y. Srinivasan <[email protected]>
- */
- #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/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)
- {
- 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;
- 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);
|