1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright 2022-23 IBM Corp.
4 */
5
6#define pr_fmt(fmt) "vas: " fmt
7
8#include <linux/module.h>
9#include <linux/kernel.h>
10#include <linux/miscdevice.h>
11#include <linux/kobject.h>
12#include <linux/slab.h>
13#include <linux/mm.h>
14
15#include "vas.h"
16
17#ifdef CONFIG_SYSFS
18static struct kobject *pseries_vas_kobj;
19static struct kobject *gzip_caps_kobj;
20
21struct vas_caps_entry {
22 struct kobject kobj;
23 struct vas_cop_feat_caps *caps;
24};
25
26#define to_caps_entry(entry) container_of(entry, struct vas_caps_entry, kobj)
27
28/*
29 * This function is used to get the notification from the drmgr when
30 * QoS credits are changed.
31 */
32static ssize_t update_total_credits_store(struct vas_cop_feat_caps *caps,
33 const char *buf, size_t count)
34{
35 int err;
36 u16 creds;
37
38 err = kstrtou16(s: buf, base: 0, res: &creds);
39 /*
40 * The user space interface from the management console
41 * notifies OS with the new QoS credits and then the
42 * hypervisor. So OS has to use this new credits value
43 * and reconfigure VAS windows (close or reopen depends
44 * on the credits available) instead of depending on VAS
45 * QoS capabilities from the hypervisor.
46 */
47 if (!err)
48 err = vas_reconfig_capabilties(type: caps->win_type, new_nr_creds: creds);
49
50 if (err)
51 return -EINVAL;
52
53 pr_info("Set QoS total credits %u\n", creds);
54
55 return count;
56}
57
58#define sysfs_caps_entry_read(_name) \
59static ssize_t _name##_show(struct vas_cop_feat_caps *caps, char *buf) \
60{ \
61 return sprintf(buf, "%d\n", atomic_read(&caps->_name)); \
62}
63
64struct vas_sysfs_entry {
65 struct attribute attr;
66 ssize_t (*show)(struct vas_cop_feat_caps *, char *);
67 ssize_t (*store)(struct vas_cop_feat_caps *, const char *, size_t);
68};
69
70#define VAS_ATTR_RO(_name) \
71 sysfs_caps_entry_read(_name); \
72 static struct vas_sysfs_entry _name##_attribute = __ATTR(_name, \
73 0444, _name##_show, NULL);
74
75/*
76 * Create sysfs interface:
77 * /sys/devices/virtual/misc/vas/vas0/gzip/default_capabilities
78 * This directory contains the following VAS GZIP capabilities
79 * for the default credit type.
80 * /sys/devices/virtual/misc/vas/vas0/gzip/default_capabilities/nr_total_credits
81 * Total number of default credits assigned to the LPAR which
82 * can be changed with DLPAR operation.
83 * /sys/devices/virtual/misc/vas/vas0/gzip/default_capabilities/nr_used_credits
84 * Number of credits used by the user space. One credit will
85 * be assigned for each window open.
86 *
87 * /sys/devices/virtual/misc/vas/vas0/gzip/qos_capabilities
88 * This directory contains the following VAS GZIP capabilities
89 * for the Quality of Service (QoS) credit type.
90 * /sys/devices/virtual/misc/vas/vas0/gzip/qos_capabilities/nr_total_credits
91 * Total number of QoS credits assigned to the LPAR. The user
92 * has to define this value using HMC interface. It can be
93 * changed dynamically by the user.
94 * /sys/devices/virtual/misc/vas/vas0/gzip/qos_capabilities/nr_used_credits
95 * Number of credits used by the user space.
96 * /sys/devices/virtual/misc/vas/vas0/gzip/qos_capabilities/update_total_credits
97 * Update total QoS credits dynamically
98 */
99
100VAS_ATTR_RO(nr_total_credits);
101VAS_ATTR_RO(nr_used_credits);
102
103static struct vas_sysfs_entry update_total_credits_attribute =
104 __ATTR(update_total_credits, 0200, NULL, update_total_credits_store);
105
106static struct attribute *vas_def_capab_attrs[] = {
107 &nr_total_credits_attribute.attr,
108 &nr_used_credits_attribute.attr,
109 NULL,
110};
111ATTRIBUTE_GROUPS(vas_def_capab);
112
113static struct attribute *vas_qos_capab_attrs[] = {
114 &nr_total_credits_attribute.attr,
115 &nr_used_credits_attribute.attr,
116 &update_total_credits_attribute.attr,
117 NULL,
118};
119ATTRIBUTE_GROUPS(vas_qos_capab);
120
121static ssize_t vas_type_show(struct kobject *kobj, struct attribute *attr,
122 char *buf)
123{
124 struct vas_caps_entry *centry;
125 struct vas_cop_feat_caps *caps;
126 struct vas_sysfs_entry *entry;
127
128 centry = to_caps_entry(kobj);
129 caps = centry->caps;
130 entry = container_of(attr, struct vas_sysfs_entry, attr);
131
132 if (!entry->show)
133 return -EIO;
134
135 return entry->show(caps, buf);
136}
137
138static ssize_t vas_type_store(struct kobject *kobj, struct attribute *attr,
139 const char *buf, size_t count)
140{
141 struct vas_caps_entry *centry;
142 struct vas_cop_feat_caps *caps;
143 struct vas_sysfs_entry *entry;
144
145 centry = to_caps_entry(kobj);
146 caps = centry->caps;
147 entry = container_of(attr, struct vas_sysfs_entry, attr);
148 if (!entry->store)
149 return -EIO;
150
151 return entry->store(caps, buf, count);
152}
153
154static void vas_type_release(struct kobject *kobj)
155{
156 struct vas_caps_entry *centry = to_caps_entry(kobj);
157 kfree(objp: centry);
158}
159
160static const struct sysfs_ops vas_sysfs_ops = {
161 .show = vas_type_show,
162 .store = vas_type_store,
163};
164
165static struct kobj_type vas_def_attr_type = {
166 .release = vas_type_release,
167 .sysfs_ops = &vas_sysfs_ops,
168 .default_groups = vas_def_capab_groups,
169};
170
171static struct kobj_type vas_qos_attr_type = {
172 .release = vas_type_release,
173 .sysfs_ops = &vas_sysfs_ops,
174 .default_groups = vas_qos_capab_groups,
175};
176
177static char *vas_caps_kobj_name(struct vas_caps_entry *centry,
178 struct kobject **kobj)
179{
180 struct vas_cop_feat_caps *caps = centry->caps;
181
182 if (caps->descriptor == VAS_GZIP_QOS_CAPABILITIES) {
183 kobject_init(kobj: &centry->kobj, ktype: &vas_qos_attr_type);
184 *kobj = gzip_caps_kobj;
185 return "qos_capabilities";
186 } else if (caps->descriptor == VAS_GZIP_DEFAULT_CAPABILITIES) {
187 kobject_init(kobj: &centry->kobj, ktype: &vas_def_attr_type);
188 *kobj = gzip_caps_kobj;
189 return "default_capabilities";
190 } else
191 return "Unknown";
192}
193
194/*
195 * Add feature specific capability dir entry.
196 * Ex: VDefGzip or VQosGzip
197 */
198int sysfs_add_vas_caps(struct vas_cop_feat_caps *caps)
199{
200 struct vas_caps_entry *centry;
201 struct kobject *kobj = NULL;
202 int ret = 0;
203 char *name;
204
205 centry = kzalloc(size: sizeof(*centry), GFP_KERNEL);
206 if (!centry)
207 return -ENOMEM;
208
209 centry->caps = caps;
210 name = vas_caps_kobj_name(centry, kobj: &kobj);
211
212 if (kobj) {
213 ret = kobject_add(kobj: &centry->kobj, parent: kobj, fmt: "%s", name);
214
215 if (ret) {
216 pr_err("VAS: sysfs kobject add / event failed %d\n",
217 ret);
218 kobject_put(kobj: &centry->kobj);
219 }
220 }
221
222 return ret;
223}
224
225static struct miscdevice vas_miscdev = {
226 .minor = MISC_DYNAMIC_MINOR,
227 .name = "vas",
228};
229
230/*
231 * Add VAS and VasCaps (overall capabilities) dir entries.
232 */
233int __init sysfs_pseries_vas_init(struct vas_all_caps *vas_caps)
234{
235 int ret;
236
237 ret = misc_register(misc: &vas_miscdev);
238 if (ret < 0) {
239 pr_err("%s: register vas misc device failed\n", __func__);
240 return ret;
241 }
242
243 /*
244 * The hypervisor does not expose multiple VAS instances, but can
245 * see multiple VAS instances on PowerNV. So create 'vas0' directory
246 * on pseries.
247 */
248 pseries_vas_kobj = kobject_create_and_add(name: "vas0",
249 parent: &vas_miscdev.this_device->kobj);
250 if (!pseries_vas_kobj) {
251 misc_deregister(misc: &vas_miscdev);
252 pr_err("Failed to create VAS sysfs entry\n");
253 return -ENOMEM;
254 }
255
256 if ((vas_caps->feat_type & VAS_GZIP_QOS_FEAT_BIT) ||
257 (vas_caps->feat_type & VAS_GZIP_DEF_FEAT_BIT)) {
258 gzip_caps_kobj = kobject_create_and_add(name: "gzip",
259 parent: pseries_vas_kobj);
260 if (!gzip_caps_kobj) {
261 pr_err("Failed to create VAS GZIP capability entry\n");
262 kobject_put(kobj: pseries_vas_kobj);
263 misc_deregister(misc: &vas_miscdev);
264 return -ENOMEM;
265 }
266 }
267
268 return 0;
269}
270
271#else
272int sysfs_add_vas_caps(struct vas_cop_feat_caps *caps)
273{
274 return 0;
275}
276
277int __init sysfs_pseries_vas_init(struct vas_all_caps *vas_caps)
278{
279 return 0;
280}
281#endif
282

source code of linux/arch/powerpc/platforms/pseries/vas-sysfs.c