diff options
Diffstat (limited to 'drivers/hv/vmbus_drv.c')
| -rw-r--r-- | drivers/hv/vmbus_drv.c | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index b10fe26c4891..05e37283d7c3 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -56,6 +56,8 @@ static struct completion probe_event; static int hyperv_cpuhp_online; +static void *hv_panic_page; + static int hyperv_panic_event(struct notifier_block *nb, unsigned long val, void *args) { @@ -1018,6 +1020,75 @@ static void vmbus_isr(void) add_interrupt_randomness(HYPERVISOR_CALLBACK_VECTOR, 0); } +/* + * 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; + +/* + * 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) +{ + size_t bytes_written; + phys_addr_t panic_pa; + + /* We are only interested in panics. */ + if ((reason != KMSG_DUMP_PANIC) || (!sysctl_record_panic_msg)) + return; + + panic_pa = virt_to_phys(hv_panic_page); + + /* + * Write dump contents to the page. No need to synchronize; panic should + * be single-threaded. + */ + if (!kmsg_dump_get_buffer(dumper, true, hv_panic_page, + PAGE_SIZE, &bytes_written)) { + pr_err("Hyper-V: Unable to get kmsg data for panic\n"); + return; + } + + hyperv_report_panic_msg(panic_pa, bytes_written); +} + +static struct kmsg_dumper hv_kmsg_dumper = { + .dump = hv_kmsg_dump, +}; + +static struct ctl_table_header *hv_ctl_table_hdr; +static int zero; +static int one = 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 = &zero, + .extra2 = &one + }, + {} +}; + +static struct ctl_table hv_root_table[] = { + { + .procname = "kernel", + .mode = 0555, + .child = hv_ctl_table + }, + {} +}; /* * vmbus_bus_init -Main vmbus driver initialization routine. @@ -1065,6 +1136,32 @@ static int vmbus_bus_init(void) * Only register if the crash MSRs are available */ if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) { + u64 hyperv_crash_ctl; + /* + * Sysctl registration is not fatal, since by default + * reporting is enabled. + */ + 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. + */ + rdmsrl(HV_X64_MSR_CRASH_CTL, hyperv_crash_ctl); + if (hyperv_crash_ctl & HV_CRASH_CTL_CRASH_NOTIFY_MSG) { + hv_panic_page = (void *)get_zeroed_page(GFP_KERNEL); + if (hv_panic_page) { + ret = kmsg_dump_register(&hv_kmsg_dumper); + if (ret) + pr_err("Hyper-V: kmsg dump register " + "error 0x%x\n", ret); + } else + pr_err("Hyper-V: panic message page memory " + "allocation failed"); + } + register_die_notifier(&hyperv_die_block); atomic_notifier_chain_register(&panic_notifier_list, &hyperv_panic_block); @@ -1081,6 +1178,11 @@ err_alloc: hv_remove_vmbus_irq(); bus_unregister(&hv_bus); + free_page((unsigned long)hv_panic_page); + if (!hv_ctl_table_hdr) { + unregister_sysctl_table(hv_ctl_table_hdr); + hv_ctl_table_hdr = NULL; + } return ret; } @@ -1785,10 +1887,18 @@ static void __exit vmbus_exit(void) vmbus_free_channels(); if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) { + kmsg_dump_unregister(&hv_kmsg_dumper); unregister_die_notifier(&hyperv_die_block); atomic_notifier_chain_unregister(&panic_notifier_list, &hyperv_panic_block); } + + free_page((unsigned long)hv_panic_page); + if (!hv_ctl_table_hdr) { + unregister_sysctl_table(hv_ctl_table_hdr); + hv_ctl_table_hdr = NULL; + } + bus_unregister(&hv_bus); cpuhp_remove_state(hyperv_cpuhp_online); |