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Drivers: hv: move panic report code from vmbus to hv early init code 

The panic reporting code was added in commit 81b18bce48
("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during panic")

It was added to the vmbus driver. The panic reporting has no dependence
on vmbus, and can be enabled at an earlier boot time when Hyper-V is
initialized.

This patch moves the panic reporting code out of vmbus. There is no
functionality changes. During moving, also refactored some cleanup
functions into hv_kmsg_dump_unregister().

Signed-off-by: Long Li <longli@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1682030946-6372-1-git-send-email-longli@linuxonhyperv.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
This commit is contained in:
Long Li 2023-04-20 15:49:06 -07:00 коммит произвёл Wei Liu
Родитель 3be1bc2fe9
Коммит 9c318a1d9b
3 изменённых файлов: 231 добавлений и 235 удалений
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36
drivers/hv/hv.c
Просмотреть файл

@ -38,42 +38,6 @@ int hv_init(void)
return 0;
}
/*
* 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);
}
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);
}
void hv_free_hyperv_page(unsigned long addr)
{
if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
free_page(addr);
else
kfree((void *)addr);
}
/*
* hv_post_message - Post a message using the hypervisor message IPC.
*

231
drivers/hv/hv_common.c
Просмотреть файл

@ -17,8 +17,11 @@
#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>
@ -54,6 +57,10 @@ 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
@ -62,6 +69,12 @@ EXPORT_SYMBOL_GPL(hyperv_pcpu_output_arg);
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;
@ -72,10 +85,203 @@ void __init hv_common_free(void)
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
@ -84,8 +290,33 @@ int __init hv_common_init(void)
* 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);
}
/*

199
drivers/hv/vmbus_drv.c
Просмотреть файл

@ -30,7 +30,6 @@
#include <linux/panic_notifier.h>
#include <linux/ptrace.h>
#include <linux/screen_info.h>
#include <linux/kdebug.h>
#include <linux/efi.h>
#include <linux/random.h>
#include <linux/kernel.h>
@ -50,26 +49,12 @@ static struct device *hv_dev;
static int hyperv_cpuhp_online;
static void *hv_panic_page;
static long __percpu *vmbus_evt;
/* Values parsed from ACPI DSDT */
int vmbus_irq;
int vmbus_interrupt;
/*
* 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;
static int hyperv_report_reg(void)
{
return !sysctl_record_panic_msg || !hv_panic_page;
}
/*
* The panic notifier below is responsible solely for unloading the
* vmbus connection, which is necessary in a panic event.
@ -90,54 +75,6 @@ static struct notifier_block hyperv_panic_vmbus_unload_block = {
.priority = INT_MIN + 1, /* almost the latest one to execute */
};
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 (hyperv_report_reg())
hyperv_report_panic(regs, val, is_die);
return NOTIFY_DONE;
}
static const char *fb_mmio_name = "fb_range";
static struct resource *fb_mmio;
static struct resource *hyperv_mmio;
@ -1379,98 +1316,6 @@ static irqreturn_t vmbus_percpu_isr(int irq, void *dev_id)
return IRQ_HANDLED;
}
/*
* 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_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;
}
}
static struct ctl_table_header *hv_ctl_table_hdr;
/*
* 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 struct ctl_table hv_root_table[] = {
{
.procname = "kernel",
.mode = 0555,
.child = hv_ctl_table
},
{}
};
/*
* vmbus_bus_init -Main vmbus driver initialization routine.
*
@ -1534,38 +1379,6 @@ static int vmbus_bus_init(void)
if (ret)
goto err_connect;
if (hv_is_isolation_supported())
sysctl_record_panic_msg = 0;
/*
* Only register if the crash MSRs are available
*/
if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
u64 hyperv_crash_ctl;
/*
* 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_table(hv_root_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);
}
/*
* Always register the vmbus unload panic notifier because we
* need to shut the VMbus channel connection on panic.
@ -1590,8 +1403,6 @@ err_alloc:
}
err_setup:
bus_unregister(&hv_bus);
unregister_sysctl_table(hv_ctl_table_hdr);
hv_ctl_table_hdr = NULL;
return ret;
}
@ -2887,13 +2698,6 @@ static void __exit vmbus_exit(void)
vmbus_free_channels();
kfree(vmbus_connection.channels);
if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
kmsg_dump_unregister(&hv_kmsg_dumper);
unregister_die_notifier(&hyperv_die_report_block);
atomic_notifier_chain_unregister(&panic_notifier_list,
&hyperv_panic_report_block);
}
/*
* The vmbus panic notifier is always registered, hence we should
* also unconditionally unregister it here as well.
@ -2901,9 +2705,6 @@ static void __exit vmbus_exit(void)
atomic_notifier_chain_unregister(&panic_notifier_list,
&hyperv_panic_vmbus_unload_block);
free_page((unsigned long)hv_panic_page);
unregister_sysctl_table(hv_ctl_table_hdr);
hv_ctl_table_hdr = NULL;
bus_unregister(&hv_bus);
cpuhp_remove_state(hyperv_cpuhp_online);