6.1-stable review patch. If anyone has any objections, please let me know.
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From: Long Li longli@microsoft.com
[ Upstream commit 9c318a1d9b5000c77527011f158a75c5483510f5 ]
The panic reporting code was added in commit 81b18bce48af ("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@linuxonhyp... Signed-off-by: Wei Liu wei.liu@kernel.org Stable-dep-of: 09eea7ad0b8e ("Drivers: hv: Allocate interrupt and monitor pages aligned to system page boundary") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/hv/hv.c | 36 ------- drivers/hv/hv_common.c | 231 +++++++++++++++++++++++++++++++++++++++++ drivers/hv/vmbus_drv.c | 199 ----------------------------------- 3 files changed, 231 insertions(+), 235 deletions(-)
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c index 4d6480d57546d..d1a3be24396f0 100644 --- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -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. * diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c index ae68298c0dcac..07338f6ec1e2c 100644 --- a/drivers/hv/hv_common.c +++ b/drivers/hv/hv_common.c @@ -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> @@ -51,6 +54,10 @@ 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 @@ -59,6 +66,12 @@ 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;
@@ -69,10 +82,203 @@ 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 @@ -81,8 +287,33 @@ 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); }
/* diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 5f6415214a1e4..074168f34afd7 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -28,7 +28,6 @@ #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> @@ -47,26 +46,12 @@ static struct acpi_device *hv_acpi_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. @@ -87,54 +72,6 @@ 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; @@ -1376,98 +1313,6 @@ 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. * @@ -1531,38 +1376,6 @@ 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. @@ -1586,8 +1399,6 @@ static int vmbus_bus_init(void) } err_setup: bus_unregister(&hv_bus); - unregister_sysctl_table(hv_ctl_table_hdr); - hv_ctl_table_hdr = NULL; return ret; }
@@ -2833,13 +2644,6 @@ 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. @@ -2847,9 +2651,6 @@ 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);