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