1 files changed, 119 insertions, 1 deletions

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index b10fe26c4891..b1b548a21f91 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)
 {
@@ -208,6 +210,20 @@ static ssize_t modalias_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(modalias);
 
+#ifdef CONFIG_NUMA
+static ssize_t numa_node_show(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct hv_device *hv_dev = device_to_hv_device(dev);
+
+	if (!hv_dev->channel)
+		return -ENODEV;
+
+	return sprintf(buf, "%d\n", hv_dev->channel->numa_node);
+}
+static DEVICE_ATTR_RO(numa_node);
+#endif
+
 static ssize_t server_monitor_pending_show(struct device *dev,
 					   struct device_attribute *dev_attr,
 					   char *buf)
@@ -490,6 +506,9 @@ static struct attribute *vmbus_dev_attrs[] = {
 	&dev_attr_class_id.attr,
 	&dev_attr_device_id.attr,
 	&dev_attr_modalias.attr,
+#ifdef CONFIG_NUMA
+	&dev_attr_numa_node.attr,
+#endif
 	&dev_attr_server_monitor_pending.attr,
 	&dev_attr_client_monitor_pending.attr,
 	&dev_attr_server_monitor_latency.attr,
@@ -1018,6 +1037,72 @@ 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.
+	 */
+	kmsg_dump_get_buffer(dumper, true, hv_panic_page, PAGE_SIZE,
+			     &bytes_written);
+	if (bytes_written)
+		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 +1150,32 @@ 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.
+		 */
+		hv_get_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);
@@ -1081,7 +1192,9 @@ err_alloc:
 	hv_remove_vmbus_irq();
 
 	bus_unregister(&hv_bus);
-
+	free_page((unsigned long)hv_panic_page);
+	unregister_sysctl_table(hv_ctl_table_hdr);
+	hv_ctl_table_hdr = NULL;
 	return ret;
 }
 
@@ -1785,10 +1898,15 @@ 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);
+	unregister_sysctl_table(hv_ctl_table_hdr);
+	hv_ctl_table_hdr = NULL;
 	bus_unregister(&hv_bus);
 
 	cpuhp_remove_state(hyperv_cpuhp_online);