Subject: [PATCH 3/3] Partition migration in the kernel

From: Nathan Fontenot <[email-masked]>
Date: Fri, 10 Sep 2010 14:42:36 -0500

Enable partition migration in the kernel.  To do this a new sysfs file,
/sys/kernel/mobility/migration, is created.  In order to initiate a migration
the stream id (generated by the HMC managing the system) is written to this
file.

After a migration occurs, and what is the majority of this code, the device
tree needs to be updated for the new system the partition is running on. This
is done via the ibm,update-nodes and ibm,update-properties rtas calls which
return information regarding which nodes and properties of the device tree
are to be added/removed/updated.

Signed-off-by: Nathan Fontenot <[email-masked]>
---
 arch/powerpc/platforms/pseries/Makefile   |    2 
 arch/powerpc/platforms/pseries/mobility.c |  362 ++++++++++++++++++++++++++++++
 2 files changed, 363 insertions(+), 1 deletion(-)

Index: linux-next/arch/powerpc/platforms/pseries/Makefile
===================================================================
--- linux-next.orig/arch/powerpc/platforms/pseries/Makefile	2010-09-10 12:38:51.000000000 -0500
+++ linux-next/arch/powerpc/platforms/pseries/Makefile	2010-09-10 12:41:09.000000000 -0500
@@ -8,7 +8,7 @@ endif
 
 obj-y			:= lpar.o hvCall.o nvram.o reconfig.o \
 			   setup.o iommu.o event_sources.o ras.o \
-			   firmware.o power.o dlpar.o
+			   firmware.o power.o dlpar.o mobility.o
 obj-$(CONFIG_SMP)	+= smp.o
 obj-$(CONFIG_XICS)	+= xics.o
 obj-$(CONFIG_SCANLOG)	+= scanlog.o
Index: linux-next/arch/powerpc/platforms/pseries/mobility.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-next/arch/powerpc/platforms/pseries/mobility.c	2010-09-10 12:41:09.000000000 -0500
@@ -0,0 +1,362 @@
+/*
+ * Support for Partition Mobility/Migration
+ *
+ * Copyright (C) 2010 Nathan Fontenot
+ * Copyright (C) 2010 IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/kobject.h>
+#include <linux/smp.h>
+#include <linux/completion.h>
+#include <linux/device.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+
+#include <asm/rtas.h>
+#include "pseries.h"
+
+static struct kobject *mobility_kobj;
+
+struct update_props_workarea {
+	u32 phandle;
+	u32 state;
+	u64 reserved;
+	u32 nprops;
+};
+
+#define NODE_ACTION_MASK	0xff000000
+#define NODE_COUNT_MASK		0x00ffffff
+
+#define DELETE_DT_NODE	0x01000000
+#define UPDATE_DT_NODE	0x02000000
+#define ADD_DT_NODE	0x03000000
+
+static int mobility_rtas_call(int token, char *buf)
+{
+	int rc;
+
+	spin_lock(&rtas_data_buf_lock);
+
+	memcpy(rtas_data_buf, buf, RTAS_DATA_BUF_SIZE);
+	rc = rtas_call(token, 2, 1, NULL, rtas_data_buf, 1);
+	memcpy(buf, rtas_data_buf, RTAS_DATA_BUF_SIZE);
+
+	spin_unlock(&rtas_data_buf_lock);
+	return rc;
+}
+
+static int delete_dt_node(u32 phandle)
+{
+	struct device_node *dn;
+
+	dn = of_find_node_by_phandle(phandle);
+	if (!dn)
+		return -ENOENT;
+
+	dlpar_detach_node(dn);
+	return 0;
+}
+
+static int update_dt_property(struct device_node *dn, struct property **prop,
+			      const char *name, u32 vd, char *value)
+{
+	struct property *new_prop = *prop;
+	struct property *old_prop;
+	int more = 0;
+
+	/* A negative 'vd' value indicates that only part of the new property
+	 * value is contained in the buffer and we need to call
+	 * ibm,update-properties again to get the rest of the value.
+	 *
+	 * A negative value is also the two's compliment of the actual value.
+	 */
+	if (vd & 0x80000000) {
+		vd = ~vd + 1;
+		more = 1;
+	}
+
+	if (new_prop) {
+		/* partial property fixup */
+		char *new_data = kzalloc(new_prop->length + vd, GFP_KERNEL);
+		if (!new_data)
+			return -ENOMEM;
+
+		memcpy(new_data, new_prop->value, new_prop->length);
+		memcpy(new_data + new_prop->length, value, vd);
+
+		kfree(new_prop->value);
+		new_prop->value = new_data;
+		new_prop->length += vd;
+	} else {
+		new_prop = kzalloc(sizeof(*new_prop), GFP_KERNEL);
+		if (!new_prop)
+			return -ENOMEM;
+
+		new_prop->name = kstrdup(name, GFP_KERNEL);
+		if (!new_prop->name) {
+			kfree(new_prop);
+			return -ENOMEM;
+		}
+
+		new_prop->length = vd;
+		new_prop->value = kzalloc(new_prop->length, GFP_KERNEL);
+		if (!new_prop->value) {
+			kfree(new_prop->name);
+			kfree(new_prop);
+			return -ENOMEM;
+		}
+
+		memcpy(new_prop->value, value, vd);
+		*prop = new_prop;
+	}
+
+	if (!more) {
+		old_prop = of_find_property(dn, new_prop->name, NULL);
+		if (old_prop)
+			prom_update_property(dn, new_prop, old_prop);
+		else
+			prom_add_property(dn, new_prop);
+
+		new_prop = NULL;
+	}
+
+	return 0;
+}
+
+static int update_dt_node(u32 phandle)
+{
+	struct update_props_workarea *upwa;
+	struct device_node *dn;
+	struct property *prop = NULL;
+	int i, rc;
+	char *prop_data;
+	char *rtas_buf;
+	int update_properties_token;
+
+	update_properties_token = rtas_token("ibm,update-properties");
+	if (update_properties_token == RTAS_UNKNOWN_SERVICE)
+		return -EINVAL;
+
+	rtas_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
+	if (!rtas_buf)
+		return -ENOMEM;
+
+	dn = of_find_node_by_phandle(phandle);
+	if (!dn) {
+		kfree(rtas_buf);
+		return -ENOENT;
+	}
+
+	upwa = (struct update_props_workarea *)&rtas_buf[0];
+	upwa->phandle = phandle;
+
+	do {
+		rc = mobility_rtas_call(update_properties_token, rtas_buf);
+		if (rc < 0)
+			break;
+
+		prop_data = rtas_buf + sizeof(*upwa);
+
+		for (i = 0; i < upwa->nprops; i++) {
+			char *prop_name;
+			u32 vd;
+
+			prop_name = prop_data + 1;
+			prop_data += strlen(prop_name) + 1;
+			vd = *prop_data++;
+
+			switch (vd) {
+			case 0x00000000:
+				/* name only property, nothing to do */
+				break;
+
+			case 0x80000000:
+				prop = of_find_property(dn, prop_name, NULL);
+				prom_remove_property(dn, prop);
+				prop = NULL;
+				break;
+
+			default:
+				rc = update_dt_property(dn, &prop, prop_name,
+							vd, prop_data);
+				if (rc) {
+					printk(KERN_ERR "Could not update %s"
+					       " property\n", prop_name);
+				}
+
+				prop_data += vd;
+			}
+		}
+	} while (rc == 1);
+
+	of_node_put(dn);
+	kfree(rtas_buf);
+	return 0;
+}
+
+static int add_dt_node(u32 parent_phandle, u32 drc_index)
+{
+	struct device_node *dn;
+	struct device_node *parent_dn;
+	int rc;
+
+	dn = dlpar_configure_connector(drc_index);
+	if (!dn)
+		return -ENOENT;
+
+	parent_dn = of_find_node_by_phandle(parent_phandle);
+	if (!parent_dn) {
+		dlpar_free_cc_nodes(dn);
+		return -ENOENT;
+	}
+
+	dn->parent = parent_dn;
+	rc = dlpar_attach_node(dn);
+	if (rc)
+		dlpar_free_cc_nodes(dn);
+
+	of_node_put(parent_dn);
+	return rc;
+}
+
+static int pseries_devicetree_update(void)
+{
+	char *rtas_buf;
+	u32 *data;
+	int update_nodes_token;
+	int rc;
+
+	update_nodes_token = rtas_token("ibm,update-nodes");
+	if (update_nodes_token == RTAS_UNKNOWN_SERVICE)
+		return -EINVAL;
+
+	rtas_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
+	if (!rtas_buf)
+		return -ENOMEM;
+
+	do {
+		rc = mobility_rtas_call(update_nodes_token, rtas_buf);
+		if (rc && rc != 1)
+			break;
+
+		data = (u32 *)rtas_buf + 4;
+		while (*data & NODE_ACTION_MASK) {
+			int i;
+			u32 action = *data & NODE_ACTION_MASK;
+			int node_count = *data & NODE_COUNT_MASK;
+
+			data++;
+
+			for (i = 0; i < node_count; i++) {
+				u32 phandle = *data++;
+				u32 drc_index;
+
+				switch (action) {
+				case DELETE_DT_NODE:
+					delete_dt_node(phandle);
+					break;
+				case UPDATE_DT_NODE:
+					update_dt_node(phandle);
+					break;
+				case ADD_DT_NODE:
+					drc_index = *data++;
+					add_dt_node(phandle, drc_index);
+					break;
+				}
+			}
+		}
+	} while (rc == 1);
+
+	kfree(rtas_buf);
+	return rc;
+}
+
+void post_mobility_fixup(void)
+{
+	int rc;
+	int activate_fw_token;
+
+	rc = pseries_devicetree_update();
+	if (rc) {
+		printk(KERN_ERR "Initial post-mobility device tree update "
+		       "failed: %d\n", rc);
+		return;
+	}
+
+	activate_fw_token = rtas_token("ibm,activate-firmware");
+	if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
+		printk(KERN_ERR "Could not make post-mobility "
+		       "activate-fw call.\n");
+		return;
+	}
+
+	rc = rtas_call(activate_fw_token, 0, 1, NULL);
+	if (!rc) {
+		rc = pseries_devicetree_update();
+		if (rc)
+			printk(KERN_ERR "Secondary post-mobility device tree "
+			       "update failed: %d\n", rc);
+	} else {
+		printk(KERN_ERR "Post-mobility activate-fw failed: %d\n", rc);
+		return;
+	}
+
+	return;
+}
+
+static ssize_t migrate_store(struct class *class, struct class_attribute *attr,
+			     const char *buf, size_t count)
+{
+	struct rtas_args args;
+	u64 streamid;
+	int rc;
+
+	rc = strict_strtoull(buf, 0, &streamid);
+	if (rc)
+		return rc;
+
+	memset(&args, 0, sizeof(args));
+	args.token = rtas_token("ibm,suspend-me");
+	args.nargs = 2;
+	args.nret = 1;
+
+	args.args[0] = streamid >> 32 ;
+	args.args[1] = streamid & 0xffffffff;
+	args.rets = &args.args[args.nargs];
+
+	do {
+		args.rets[0] = 0;
+		rc = rtas_ibm_suspend_me(&args);
+		if (!rc && args.rets[0] == RTAS_NOT_SUSPENDABLE)
+			ssleep(1);
+	} while (!rc && args.rets[0] == RTAS_NOT_SUSPENDABLE);
+
+	if (rc)
+		return rc;
+	else if (args.rets[0])
+		return args.rets[0];
+
+	post_mobility_fixup();
+	return count;
+}
+
+static CLASS_ATTR(migration, S_IWUSR, NULL, migrate_store);
+
+static int __init mobility_sysfs_init(void)
+{
+	int rc;
+
+	mobility_kobj = kobject_create_and_add("mobility", kernel_kobj);
+	if (!mobility_kobj)
+		return -ENOMEM;
+
+	rc = sysfs_create_file(mobility_kobj, &class_attr_migration.attr);
+
+	return rc;
+}
+device_initcall(mobility_sysfs_init);