OpenCloudOS-Kernel/drivers/hv/hv_common.c

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// 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/sched/task_stack.h>
#include <linux/panic_notifier.h>
#include <linux/ptrace.h>
#include <linux/kdebug.h>
#include <linux/kmsg_dump.h>
#include <linux/slab.h>
#include <linux/dma-map-ops.h>
#include <asm/hyperv-tlfs.h>
#include <asm/mshyperv.h>
/*
* hv_root_partition, ms_hyperv and hv_nested 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 three 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);
bool __weak hv_nested;
EXPORT_SYMBOL_GPL(hv_nested);
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);
static void hv_kmsg_dump_unregister(void);
static struct ctl_table_header *hv_ctl_table_hdr;
/*
* 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)
{
unregister_sysctl_table(hv_ctl_table_hdr);
hv_ctl_table_hdr = NULL;
if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE)
hv_kmsg_dump_unregister();
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;
}
/*
* Functions for allocating and freeing memory with size and
* alignment HV_HYP_PAGE_SIZE. These functions are needed because
* the guest page size may not be the same as the Hyper-V page
* size. We depend upon kmalloc() aligning power-of-two size
* allocations to the allocation size boundary, so that the
* allocated memory appears to Hyper-V as a page of the size
* it expects.
*/
void *hv_alloc_hyperv_page(void)
{
BUILD_BUG_ON(PAGE_SIZE < HV_HYP_PAGE_SIZE);
if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
return (void *)__get_free_page(GFP_KERNEL);
else
return kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
}
EXPORT_SYMBOL_GPL(hv_alloc_hyperv_page);
void *hv_alloc_hyperv_zeroed_page(void)
{
if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
return (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
else
return kzalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
}
EXPORT_SYMBOL_GPL(hv_alloc_hyperv_zeroed_page);
void hv_free_hyperv_page(unsigned long addr)
{
if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
free_page(addr);
else
kfree((void *)addr);
}
EXPORT_SYMBOL_GPL(hv_free_hyperv_page);
static void *hv_panic_page;
/*
* Boolean to control whether to report panic messages over Hyper-V.
*
* It can be set via /proc/sys/kernel/hyperv_record_panic_msg
*/
static int sysctl_record_panic_msg = 1;
/*
* sysctl option to allow the user to control whether kmsg data should be
* reported to Hyper-V on panic.
*/
static struct ctl_table hv_ctl_table[] = {
{
.procname = "hyperv_record_panic_msg",
.data = &sysctl_record_panic_msg,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE
},
{}
};
static int hv_die_panic_notify_crash(struct notifier_block *self,
unsigned long val, void *args);
static struct notifier_block hyperv_die_report_block = {
.notifier_call = hv_die_panic_notify_crash,
};
static struct notifier_block hyperv_panic_report_block = {
.notifier_call = hv_die_panic_notify_crash,
};
/*
* The following callback works both as die and panic notifier; its
* goal is to provide panic information to the hypervisor unless the
* kmsg dumper is used [see hv_kmsg_dump()], which provides more
* information but isn't always available.
*
* Notice that both the panic/die report notifiers are registered only
* if we have the capability HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE set.
*/
static int hv_die_panic_notify_crash(struct notifier_block *self,
unsigned long val, void *args)
{
struct pt_regs *regs;
bool is_die;
/* Don't notify Hyper-V unless we have a die oops event or panic. */
if (self == &hyperv_panic_report_block) {
is_die = false;
regs = current_pt_regs();
} else { /* die event */
if (val != DIE_OOPS)
return NOTIFY_DONE;
is_die = true;
regs = ((struct die_args *)args)->regs;
}
/*
* Hyper-V should be notified only once about a panic/die. If we will
* be calling hv_kmsg_dump() later with kmsg data, don't do the
* notification here.
*/
if (!sysctl_record_panic_msg || !hv_panic_page)
hyperv_report_panic(regs, val, is_die);
return NOTIFY_DONE;
}
/*
* Callback from kmsg_dump. Grab as much as possible from the end of the kmsg
* buffer and call into Hyper-V to transfer the data.
*/
static void hv_kmsg_dump(struct kmsg_dumper *dumper,
enum kmsg_dump_reason reason)
{
struct kmsg_dump_iter iter;
size_t bytes_written;
/* We are only interested in panics. */
if (reason != KMSG_DUMP_PANIC || !sysctl_record_panic_msg)
return;
/*
* Write dump contents to the page. No need to synchronize; panic should
* be single-threaded.
*/
kmsg_dump_rewind(&iter);
kmsg_dump_get_buffer(&iter, false, hv_panic_page, HV_HYP_PAGE_SIZE,
&bytes_written);
if (!bytes_written)
return;
/*
* P3 to contain the physical address of the panic page & P4 to
* contain the size of the panic data in that page. Rest of the
* registers are no-op when the NOTIFY_MSG flag is set.
*/
hv_set_register(HV_REGISTER_CRASH_P0, 0);
hv_set_register(HV_REGISTER_CRASH_P1, 0);
hv_set_register(HV_REGISTER_CRASH_P2, 0);
hv_set_register(HV_REGISTER_CRASH_P3, virt_to_phys(hv_panic_page));
hv_set_register(HV_REGISTER_CRASH_P4, bytes_written);
/*
* Let Hyper-V know there is crash data available along with
* the panic message.
*/
hv_set_register(HV_REGISTER_CRASH_CTL,
(HV_CRASH_CTL_CRASH_NOTIFY |
HV_CRASH_CTL_CRASH_NOTIFY_MSG));
}
static struct kmsg_dumper hv_kmsg_dumper = {
.dump = hv_kmsg_dump,
};
static void hv_kmsg_dump_unregister(void)
{
kmsg_dump_unregister(&hv_kmsg_dumper);
unregister_die_notifier(&hyperv_die_report_block);
atomic_notifier_chain_unregister(&panic_notifier_list,
&hyperv_panic_report_block);
hv_free_hyperv_page((unsigned long)hv_panic_page);
hv_panic_page = NULL;
}
static void hv_kmsg_dump_register(void)
{
int ret;
hv_panic_page = hv_alloc_hyperv_zeroed_page();
if (!hv_panic_page) {
pr_err("Hyper-V: panic message page memory allocation failed\n");
return;
}
ret = kmsg_dump_register(&hv_kmsg_dumper);
if (ret) {
pr_err("Hyper-V: kmsg dump register error 0x%x\n", ret);
hv_free_hyperv_page((unsigned long)hv_panic_page);
hv_panic_page = NULL;
}
}
int __init hv_common_init(void)
{
int i;
if (hv_is_isolation_supported())
sysctl_record_panic_msg = 0;
/*
* 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) {
u64 hyperv_crash_ctl;
crash_kexec_post_notifiers = true;
pr_info("Hyper-V: enabling crash_kexec_post_notifiers\n");
/*
* Panic message recording (sysctl_record_panic_msg)
* is enabled by default in non-isolated guests and
* disabled by default in isolated guests; the panic
* message recording won't be available in isolated
* guests should the following registration fail.
*/
hv_ctl_table_hdr = register_sysctl("kernel", hv_ctl_table);
if (!hv_ctl_table_hdr)
pr_err("Hyper-V: sysctl table register error");
/*
* Register for panic kmsg callback only if the right
* capability is supported by the hypervisor.
*/
hyperv_crash_ctl = hv_get_register(HV_REGISTER_CRASH_CTL);
if (hyperv_crash_ctl & HV_CRASH_CTL_CRASH_NOTIFY_MSG)
hv_kmsg_dump_register();
register_die_notifier(&hyperv_die_report_block);
atomic_notifier_chain_register(&panic_notifier_list,
&hyperv_panic_report_block);
}
/*
* 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);
x86/hyperv: Fix hyperv_pcpu_input_arg handling when CPUs go online/offline These commits a494aef23dfc ("PCI: hv: Replace retarget_msi_interrupt_params with hyperv_pcpu_input_arg") 2c6ba4216844 ("PCI: hv: Enable PCI pass-thru devices in Confidential VMs") update the Hyper-V virtual PCI driver to use the hyperv_pcpu_input_arg because that memory will be correctly marked as decrypted or encrypted for all VM types (CoCo or normal). But problems ensue when CPUs in the VM go online or offline after virtual PCI devices have been configured. When a CPU is brought online, the hyperv_pcpu_input_arg for that CPU is initialized by hv_cpu_init() running under state CPUHP_AP_ONLINE_DYN. But this state occurs after state CPUHP_AP_IRQ_AFFINITY_ONLINE, which may call the virtual PCI driver and fault trying to use the as yet uninitialized hyperv_pcpu_input_arg. A similar problem occurs in a CoCo VM if the MMIO read and write hypercalls are used from state CPUHP_AP_IRQ_AFFINITY_ONLINE. When a CPU is taken offline, IRQs may be reassigned in state CPUHP_TEARDOWN_CPU. Again, the virtual PCI driver may fault trying to use the hyperv_pcpu_input_arg that has already been freed by a higher state. Fix the onlining problem by adding state CPUHP_AP_HYPERV_ONLINE immediately after CPUHP_AP_ONLINE_IDLE (similar to CPUHP_AP_KVM_ONLINE) and before CPUHP_AP_IRQ_AFFINITY_ONLINE. Use this new state for Hyper-V initialization so that hyperv_pcpu_input_arg is allocated early enough. Fix the offlining problem by not freeing hyperv_pcpu_input_arg when a CPU goes offline. Retain the allocated memory, and reuse it if the CPU comes back online later. Signed-off-by: Michael Kelley <mikelley@microsoft.com> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Acked-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Dexuan Cui <decui@microsoft.com> Link: https://lore.kernel.org/r/1684862062-51576-1-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2023-05-24 01:14:21 +08:00
/*
* hyperv_pcpu_input_arg and hyperv_pcpu_output_arg memory is already
* allocated if this CPU was previously online and then taken offline
*/
if (!*inputarg) {
*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)
{
x86/hyperv: Fix hyperv_pcpu_input_arg handling when CPUs go online/offline These commits a494aef23dfc ("PCI: hv: Replace retarget_msi_interrupt_params with hyperv_pcpu_input_arg") 2c6ba4216844 ("PCI: hv: Enable PCI pass-thru devices in Confidential VMs") update the Hyper-V virtual PCI driver to use the hyperv_pcpu_input_arg because that memory will be correctly marked as decrypted or encrypted for all VM types (CoCo or normal). But problems ensue when CPUs in the VM go online or offline after virtual PCI devices have been configured. When a CPU is brought online, the hyperv_pcpu_input_arg for that CPU is initialized by hv_cpu_init() running under state CPUHP_AP_ONLINE_DYN. But this state occurs after state CPUHP_AP_IRQ_AFFINITY_ONLINE, which may call the virtual PCI driver and fault trying to use the as yet uninitialized hyperv_pcpu_input_arg. A similar problem occurs in a CoCo VM if the MMIO read and write hypercalls are used from state CPUHP_AP_IRQ_AFFINITY_ONLINE. When a CPU is taken offline, IRQs may be reassigned in state CPUHP_TEARDOWN_CPU. Again, the virtual PCI driver may fault trying to use the hyperv_pcpu_input_arg that has already been freed by a higher state. Fix the onlining problem by adding state CPUHP_AP_HYPERV_ONLINE immediately after CPUHP_AP_ONLINE_IDLE (similar to CPUHP_AP_KVM_ONLINE) and before CPUHP_AP_IRQ_AFFINITY_ONLINE. Use this new state for Hyper-V initialization so that hyperv_pcpu_input_arg is allocated early enough. Fix the offlining problem by not freeing hyperv_pcpu_input_arg when a CPU goes offline. Retain the allocated memory, and reuse it if the CPU comes back online later. Signed-off-by: Michael Kelley <mikelley@microsoft.com> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Acked-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Dexuan Cui <decui@microsoft.com> Link: https://lore.kernel.org/r/1684862062-51576-1-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2023-05-24 01:14:21 +08:00
/*
* The hyperv_pcpu_input_arg and hyperv_pcpu_output_arg memory
* is not freed when the CPU goes offline as the hyperv_pcpu_input_arg
* may be used by the Hyper-V vPCI driver in reassigning interrupts
* as part of the offlining process. The interrupt reassignment
* happens *after* the CPUHP_AP_HYPERV_ONLINE state has run and
* called this function.
*
* If a previously offlined CPU is brought back online again, the
* originally allocated memory is reused in hv_common_cpu_init().
*/
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);
bool __weak hv_isolation_type_en_snp(void)
{
return false;
}
EXPORT_SYMBOL_GPL(hv_isolation_type_en_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);