325 lines
8.3 KiB
C
325 lines
8.3 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Architecture neutral utility routines for interacting with
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* Hyper-V. This file is specifically for code that must be
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* built-in to the kernel image when CONFIG_HYPERV is set
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* (vs. being in a module) because it is called from architecture
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* specific code under arch/.
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*
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* Copyright (C) 2021, Microsoft, Inc.
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*
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* Author : Michael Kelley <mikelley@microsoft.com>
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*/
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#include <linux/types.h>
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#include <linux/acpi.h>
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#include <linux/export.h>
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#include <linux/bitfield.h>
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#include <linux/cpumask.h>
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#include <linux/panic_notifier.h>
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#include <linux/ptrace.h>
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#include <linux/slab.h>
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#include <linux/dma-map-ops.h>
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#include <asm/hyperv-tlfs.h>
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#include <asm/mshyperv.h>
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/*
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* hv_root_partition, ms_hyperv and hv_nested are defined here with other
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* Hyper-V specific globals so they are shared across all architectures and are
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* built only when CONFIG_HYPERV is defined. But on x86,
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* ms_hyperv_init_platform() is built even when CONFIG_HYPERV is not
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* defined, and it uses these three variables. So mark them as __weak
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* here, allowing for an overriding definition in the module containing
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* ms_hyperv_init_platform().
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*/
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bool __weak hv_root_partition;
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EXPORT_SYMBOL_GPL(hv_root_partition);
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bool __weak hv_nested;
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EXPORT_SYMBOL_GPL(hv_nested);
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struct ms_hyperv_info __weak ms_hyperv;
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EXPORT_SYMBOL_GPL(ms_hyperv);
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u32 *hv_vp_index;
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EXPORT_SYMBOL_GPL(hv_vp_index);
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u32 hv_max_vp_index;
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EXPORT_SYMBOL_GPL(hv_max_vp_index);
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void * __percpu *hyperv_pcpu_input_arg;
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EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg);
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void * __percpu *hyperv_pcpu_output_arg;
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EXPORT_SYMBOL_GPL(hyperv_pcpu_output_arg);
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/*
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* Hyper-V specific initialization and shutdown code that is
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* common across all architectures. Called from architecture
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* specific initialization functions.
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*/
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void __init hv_common_free(void)
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{
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kfree(hv_vp_index);
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hv_vp_index = NULL;
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free_percpu(hyperv_pcpu_output_arg);
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hyperv_pcpu_output_arg = NULL;
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free_percpu(hyperv_pcpu_input_arg);
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hyperv_pcpu_input_arg = NULL;
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}
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int __init hv_common_init(void)
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{
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int i;
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/*
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* Hyper-V expects to get crash register data or kmsg when
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* crash enlightment is available and system crashes. Set
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* crash_kexec_post_notifiers to be true to make sure that
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* calling crash enlightment interface before running kdump
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* kernel.
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*/
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if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
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crash_kexec_post_notifiers = true;
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pr_info("Hyper-V: enabling crash_kexec_post_notifiers\n");
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}
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/*
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* Allocate the per-CPU state for the hypercall input arg.
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* If this allocation fails, we will not be able to setup
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* (per-CPU) hypercall input page and thus this failure is
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* fatal on Hyper-V.
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*/
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hyperv_pcpu_input_arg = alloc_percpu(void *);
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BUG_ON(!hyperv_pcpu_input_arg);
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/* Allocate the per-CPU state for output arg for root */
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if (hv_root_partition) {
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hyperv_pcpu_output_arg = alloc_percpu(void *);
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BUG_ON(!hyperv_pcpu_output_arg);
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}
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hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index),
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GFP_KERNEL);
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if (!hv_vp_index) {
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hv_common_free();
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return -ENOMEM;
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}
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for (i = 0; i < num_possible_cpus(); i++)
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hv_vp_index[i] = VP_INVAL;
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return 0;
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}
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/*
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* Hyper-V specific initialization and die code for
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* individual CPUs that is common across all architectures.
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* Called by the CPU hotplug mechanism.
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*/
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int hv_common_cpu_init(unsigned int cpu)
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{
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void **inputarg, **outputarg;
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u64 msr_vp_index;
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gfp_t flags;
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int pgcount = hv_root_partition ? 2 : 1;
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/* hv_cpu_init() can be called with IRQs disabled from hv_resume() */
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flags = irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL;
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inputarg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
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*inputarg = kmalloc(pgcount * HV_HYP_PAGE_SIZE, flags);
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if (!(*inputarg))
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return -ENOMEM;
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if (hv_root_partition) {
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outputarg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
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*outputarg = (char *)(*inputarg) + HV_HYP_PAGE_SIZE;
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}
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msr_vp_index = hv_get_register(HV_REGISTER_VP_INDEX);
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hv_vp_index[cpu] = msr_vp_index;
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if (msr_vp_index > hv_max_vp_index)
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hv_max_vp_index = msr_vp_index;
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return 0;
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}
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int hv_common_cpu_die(unsigned int cpu)
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{
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unsigned long flags;
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void **inputarg, **outputarg;
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void *mem;
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local_irq_save(flags);
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inputarg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
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mem = *inputarg;
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*inputarg = NULL;
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if (hv_root_partition) {
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outputarg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
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*outputarg = NULL;
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}
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local_irq_restore(flags);
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kfree(mem);
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return 0;
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}
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/* Bit mask of the extended capability to query: see HV_EXT_CAPABILITY_xxx */
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bool hv_query_ext_cap(u64 cap_query)
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{
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/*
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* The address of the 'hv_extended_cap' variable will be used as an
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* output parameter to the hypercall below and so it should be
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* compatible with 'virt_to_phys'. Which means, it's address should be
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* directly mapped. Use 'static' to keep it compatible; stack variables
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* can be virtually mapped, making them incompatible with
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* 'virt_to_phys'.
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* Hypercall input/output addresses should also be 8-byte aligned.
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*/
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static u64 hv_extended_cap __aligned(8);
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static bool hv_extended_cap_queried;
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u64 status;
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/*
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* Querying extended capabilities is an extended hypercall. Check if the
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* partition supports extended hypercall, first.
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*/
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if (!(ms_hyperv.priv_high & HV_ENABLE_EXTENDED_HYPERCALLS))
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return false;
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/* Extended capabilities do not change at runtime. */
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if (hv_extended_cap_queried)
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return hv_extended_cap & cap_query;
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status = hv_do_hypercall(HV_EXT_CALL_QUERY_CAPABILITIES, NULL,
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&hv_extended_cap);
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/*
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* The query extended capabilities hypercall should not fail under
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* any normal circumstances. Avoid repeatedly making the hypercall, on
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* error.
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*/
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hv_extended_cap_queried = true;
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if (!hv_result_success(status)) {
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pr_err("Hyper-V: Extended query capabilities hypercall failed 0x%llx\n",
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status);
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return false;
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}
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return hv_extended_cap & cap_query;
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}
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EXPORT_SYMBOL_GPL(hv_query_ext_cap);
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void hv_setup_dma_ops(struct device *dev, bool coherent)
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{
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/*
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* Hyper-V does not offer a vIOMMU in the guest
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* VM, so pass 0/NULL for the IOMMU settings
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*/
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arch_setup_dma_ops(dev, 0, 0, NULL, coherent);
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}
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EXPORT_SYMBOL_GPL(hv_setup_dma_ops);
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bool hv_is_hibernation_supported(void)
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{
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return !hv_root_partition && acpi_sleep_state_supported(ACPI_STATE_S4);
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}
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EXPORT_SYMBOL_GPL(hv_is_hibernation_supported);
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/*
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* Default function to read the Hyper-V reference counter, independent
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* of whether Hyper-V enlightened clocks/timers are being used. But on
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* architectures where it is used, Hyper-V enlightenment code in
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* hyperv_timer.c may override this function.
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*/
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static u64 __hv_read_ref_counter(void)
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{
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return hv_get_register(HV_REGISTER_TIME_REF_COUNT);
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}
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u64 (*hv_read_reference_counter)(void) = __hv_read_ref_counter;
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EXPORT_SYMBOL_GPL(hv_read_reference_counter);
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/* These __weak functions provide default "no-op" behavior and
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* may be overridden by architecture specific versions. Architectures
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* for which the default "no-op" behavior is sufficient can leave
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* them unimplemented and not be cluttered with a bunch of stub
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* functions in arch-specific code.
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*/
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bool __weak hv_is_isolation_supported(void)
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{
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return false;
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}
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EXPORT_SYMBOL_GPL(hv_is_isolation_supported);
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bool __weak hv_isolation_type_snp(void)
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{
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return false;
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}
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EXPORT_SYMBOL_GPL(hv_isolation_type_snp);
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void __weak hv_setup_vmbus_handler(void (*handler)(void))
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{
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}
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EXPORT_SYMBOL_GPL(hv_setup_vmbus_handler);
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void __weak hv_remove_vmbus_handler(void)
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{
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}
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EXPORT_SYMBOL_GPL(hv_remove_vmbus_handler);
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void __weak hv_setup_kexec_handler(void (*handler)(void))
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{
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}
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EXPORT_SYMBOL_GPL(hv_setup_kexec_handler);
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void __weak hv_remove_kexec_handler(void)
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{
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}
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EXPORT_SYMBOL_GPL(hv_remove_kexec_handler);
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void __weak hv_setup_crash_handler(void (*handler)(struct pt_regs *regs))
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{
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}
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EXPORT_SYMBOL_GPL(hv_setup_crash_handler);
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void __weak hv_remove_crash_handler(void)
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{
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}
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EXPORT_SYMBOL_GPL(hv_remove_crash_handler);
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void __weak hyperv_cleanup(void)
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{
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}
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EXPORT_SYMBOL_GPL(hyperv_cleanup);
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u64 __weak hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size)
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{
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return HV_STATUS_INVALID_PARAMETER;
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}
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EXPORT_SYMBOL_GPL(hv_ghcb_hypercall);
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void __weak *hv_map_memory(void *addr, unsigned long size)
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{
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return NULL;
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}
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EXPORT_SYMBOL_GPL(hv_map_memory);
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void __weak hv_unmap_memory(void *addr)
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{
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}
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EXPORT_SYMBOL_GPL(hv_unmap_memory);
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