1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * VFIO based Physical Subchannel device driver
4 *
5 * Copyright IBM Corp. 2017
6 * Copyright Red Hat, Inc. 2019
7 *
8 * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
9 * Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
10 * Cornelia Huck <cohuck@redhat.com>
11 */
12
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/device.h>
16 #include <linux/slab.h>
17 #include <linux/uuid.h>
18 #include <linux/mdev.h>
19
20 #include <asm/isc.h>
21
22 #include "ioasm.h"
23 #include "css.h"
24 #include "vfio_ccw_private.h"
25
26 struct workqueue_struct *vfio_ccw_work_q;
27 static struct kmem_cache *vfio_ccw_io_region;
28 static struct kmem_cache *vfio_ccw_cmd_region;
29
30 debug_info_t *vfio_ccw_debug_msg_id;
31 debug_info_t *vfio_ccw_debug_trace_id;
32
33 /*
34 * Helpers
35 */
vfio_ccw_sch_quiesce(struct subchannel * sch)36 int vfio_ccw_sch_quiesce(struct subchannel *sch)
37 {
38 struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
39 DECLARE_COMPLETION_ONSTACK(completion);
40 int iretry, ret = 0;
41
42 spin_lock_irq(sch->lock);
43 if (!sch->schib.pmcw.ena)
44 goto out_unlock;
45 ret = cio_disable_subchannel(sch);
46 if (ret != -EBUSY)
47 goto out_unlock;
48
49 iretry = 255;
50 do {
51
52 ret = cio_cancel_halt_clear(sch, &iretry);
53
54 if (ret == -EIO) {
55 pr_err("vfio_ccw: could not quiesce subchannel 0.%x.%04x!\n",
56 sch->schid.ssid, sch->schid.sch_no);
57 break;
58 }
59
60 /*
61 * Flush all I/O and wait for
62 * cancel/halt/clear completion.
63 */
64 private->completion = &completion;
65 spin_unlock_irq(sch->lock);
66
67 if (ret == -EBUSY)
68 wait_for_completion_timeout(&completion, 3*HZ);
69
70 private->completion = NULL;
71 flush_workqueue(vfio_ccw_work_q);
72 spin_lock_irq(sch->lock);
73 ret = cio_disable_subchannel(sch);
74 } while (ret == -EBUSY);
75 out_unlock:
76 private->state = VFIO_CCW_STATE_NOT_OPER;
77 spin_unlock_irq(sch->lock);
78 return ret;
79 }
80
vfio_ccw_sch_io_todo(struct work_struct * work)81 static void vfio_ccw_sch_io_todo(struct work_struct *work)
82 {
83 struct vfio_ccw_private *private;
84 struct irb *irb;
85 bool is_final;
86 bool cp_is_finished = false;
87
88 private = container_of(work, struct vfio_ccw_private, io_work);
89 irb = &private->irb;
90
91 is_final = !(scsw_actl(&irb->scsw) &
92 (SCSW_ACTL_DEVACT | SCSW_ACTL_SCHACT));
93 if (scsw_is_solicited(&irb->scsw)) {
94 cp_update_scsw(&private->cp, &irb->scsw);
95 if (is_final && private->state == VFIO_CCW_STATE_CP_PENDING) {
96 cp_free(&private->cp);
97 cp_is_finished = true;
98 }
99 }
100 mutex_lock(&private->io_mutex);
101 memcpy(private->io_region->irb_area, irb, sizeof(*irb));
102 mutex_unlock(&private->io_mutex);
103
104 /*
105 * Reset to IDLE only if processing of a channel program
106 * has finished. Do not overwrite a possible processing
107 * state if the final interrupt was for HSCH or CSCH.
108 */
109 if (private->mdev && cp_is_finished)
110 private->state = VFIO_CCW_STATE_IDLE;
111
112 if (private->io_trigger)
113 eventfd_signal(private->io_trigger, 1);
114 }
115
116 /*
117 * Css driver callbacks
118 */
vfio_ccw_sch_irq(struct subchannel * sch)119 static void vfio_ccw_sch_irq(struct subchannel *sch)
120 {
121 struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
122
123 inc_irq_stat(IRQIO_CIO);
124 vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_INTERRUPT);
125 }
126
vfio_ccw_sch_probe(struct subchannel * sch)127 static int vfio_ccw_sch_probe(struct subchannel *sch)
128 {
129 struct pmcw *pmcw = &sch->schib.pmcw;
130 struct vfio_ccw_private *private;
131 int ret = -ENOMEM;
132
133 if (pmcw->qf) {
134 dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n",
135 dev_name(&sch->dev));
136 return -ENODEV;
137 }
138
139 private = kzalloc(sizeof(*private), GFP_KERNEL | GFP_DMA);
140 if (!private)
141 return -ENOMEM;
142
143 private->cp.guest_cp = kcalloc(CCWCHAIN_LEN_MAX, sizeof(struct ccw1),
144 GFP_KERNEL);
145 if (!private->cp.guest_cp)
146 goto out_free;
147
148 private->io_region = kmem_cache_zalloc(vfio_ccw_io_region,
149 GFP_KERNEL | GFP_DMA);
150 if (!private->io_region)
151 goto out_free;
152
153 private->cmd_region = kmem_cache_zalloc(vfio_ccw_cmd_region,
154 GFP_KERNEL | GFP_DMA);
155 if (!private->cmd_region)
156 goto out_free;
157
158 private->sch = sch;
159 dev_set_drvdata(&sch->dev, private);
160 mutex_init(&private->io_mutex);
161
162 spin_lock_irq(sch->lock);
163 private->state = VFIO_CCW_STATE_NOT_OPER;
164 sch->isc = VFIO_CCW_ISC;
165 ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
166 spin_unlock_irq(sch->lock);
167 if (ret)
168 goto out_free;
169
170 INIT_WORK(&private->io_work, vfio_ccw_sch_io_todo);
171 atomic_set(&private->avail, 1);
172 private->state = VFIO_CCW_STATE_STANDBY;
173
174 ret = vfio_ccw_mdev_reg(sch);
175 if (ret)
176 goto out_disable;
177
178 if (dev_get_uevent_suppress(&sch->dev)) {
179 dev_set_uevent_suppress(&sch->dev, 0);
180 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
181 }
182
183 VFIO_CCW_MSG_EVENT(4, "bound to subchannel %x.%x.%04x\n",
184 sch->schid.cssid, sch->schid.ssid,
185 sch->schid.sch_no);
186 return 0;
187
188 out_disable:
189 cio_disable_subchannel(sch);
190 out_free:
191 dev_set_drvdata(&sch->dev, NULL);
192 if (private->cmd_region)
193 kmem_cache_free(vfio_ccw_cmd_region, private->cmd_region);
194 if (private->io_region)
195 kmem_cache_free(vfio_ccw_io_region, private->io_region);
196 kfree(private->cp.guest_cp);
197 kfree(private);
198 return ret;
199 }
200
vfio_ccw_sch_remove(struct subchannel * sch)201 static int vfio_ccw_sch_remove(struct subchannel *sch)
202 {
203 struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
204
205 vfio_ccw_sch_quiesce(sch);
206
207 vfio_ccw_mdev_unreg(sch);
208
209 dev_set_drvdata(&sch->dev, NULL);
210
211 kmem_cache_free(vfio_ccw_cmd_region, private->cmd_region);
212 kmem_cache_free(vfio_ccw_io_region, private->io_region);
213 kfree(private->cp.guest_cp);
214 kfree(private);
215
216 VFIO_CCW_MSG_EVENT(4, "unbound from subchannel %x.%x.%04x\n",
217 sch->schid.cssid, sch->schid.ssid,
218 sch->schid.sch_no);
219 return 0;
220 }
221
vfio_ccw_sch_shutdown(struct subchannel * sch)222 static void vfio_ccw_sch_shutdown(struct subchannel *sch)
223 {
224 vfio_ccw_sch_quiesce(sch);
225 }
226
227 /**
228 * vfio_ccw_sch_event - process subchannel event
229 * @sch: subchannel
230 * @process: non-zero if function is called in process context
231 *
232 * An unspecified event occurred for this subchannel. Adjust data according
233 * to the current operational state of the subchannel. Return zero when the
234 * event has been handled sufficiently or -EAGAIN when this function should
235 * be called again in process context.
236 */
vfio_ccw_sch_event(struct subchannel * sch,int process)237 static int vfio_ccw_sch_event(struct subchannel *sch, int process)
238 {
239 struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
240 unsigned long flags;
241 int rc = -EAGAIN;
242
243 spin_lock_irqsave(sch->lock, flags);
244 if (!device_is_registered(&sch->dev))
245 goto out_unlock;
246
247 if (work_pending(&sch->todo_work))
248 goto out_unlock;
249
250 rc = 0;
251
252 if (cio_update_schib(sch))
253 vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
254
255 out_unlock:
256 spin_unlock_irqrestore(sch->lock, flags);
257
258 return rc;
259 }
260
261 static struct css_device_id vfio_ccw_sch_ids[] = {
262 { .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
263 { /* end of list */ },
264 };
265 MODULE_DEVICE_TABLE(css, vfio_ccw_sch_ids);
266
267 static struct css_driver vfio_ccw_sch_driver = {
268 .drv = {
269 .name = "vfio_ccw",
270 .owner = THIS_MODULE,
271 },
272 .subchannel_type = vfio_ccw_sch_ids,
273 .irq = vfio_ccw_sch_irq,
274 .probe = vfio_ccw_sch_probe,
275 .remove = vfio_ccw_sch_remove,
276 .shutdown = vfio_ccw_sch_shutdown,
277 .sch_event = vfio_ccw_sch_event,
278 };
279
vfio_ccw_debug_init(void)280 static int __init vfio_ccw_debug_init(void)
281 {
282 vfio_ccw_debug_msg_id = debug_register("vfio_ccw_msg", 16, 1,
283 11 * sizeof(long));
284 if (!vfio_ccw_debug_msg_id)
285 goto out_unregister;
286 debug_register_view(vfio_ccw_debug_msg_id, &debug_sprintf_view);
287 debug_set_level(vfio_ccw_debug_msg_id, 2);
288 vfio_ccw_debug_trace_id = debug_register("vfio_ccw_trace", 16, 1, 16);
289 if (!vfio_ccw_debug_trace_id)
290 goto out_unregister;
291 debug_register_view(vfio_ccw_debug_trace_id, &debug_hex_ascii_view);
292 debug_set_level(vfio_ccw_debug_trace_id, 2);
293 return 0;
294
295 out_unregister:
296 debug_unregister(vfio_ccw_debug_msg_id);
297 debug_unregister(vfio_ccw_debug_trace_id);
298 return -1;
299 }
300
vfio_ccw_debug_exit(void)301 static void vfio_ccw_debug_exit(void)
302 {
303 debug_unregister(vfio_ccw_debug_msg_id);
304 debug_unregister(vfio_ccw_debug_trace_id);
305 }
306
vfio_ccw_sch_init(void)307 static int __init vfio_ccw_sch_init(void)
308 {
309 int ret;
310
311 ret = vfio_ccw_debug_init();
312 if (ret)
313 return ret;
314
315 vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw");
316 if (!vfio_ccw_work_q) {
317 ret = -ENOMEM;
318 goto out_err;
319 }
320
321 vfio_ccw_io_region = kmem_cache_create_usercopy("vfio_ccw_io_region",
322 sizeof(struct ccw_io_region), 0,
323 SLAB_ACCOUNT, 0,
324 sizeof(struct ccw_io_region), NULL);
325 if (!vfio_ccw_io_region) {
326 ret = -ENOMEM;
327 goto out_err;
328 }
329
330 vfio_ccw_cmd_region = kmem_cache_create_usercopy("vfio_ccw_cmd_region",
331 sizeof(struct ccw_cmd_region), 0,
332 SLAB_ACCOUNT, 0,
333 sizeof(struct ccw_cmd_region), NULL);
334 if (!vfio_ccw_cmd_region) {
335 ret = -ENOMEM;
336 goto out_err;
337 }
338
339 isc_register(VFIO_CCW_ISC);
340 ret = css_driver_register(&vfio_ccw_sch_driver);
341 if (ret) {
342 isc_unregister(VFIO_CCW_ISC);
343 goto out_err;
344 }
345
346 return ret;
347
348 out_err:
349 kmem_cache_destroy(vfio_ccw_cmd_region);
350 kmem_cache_destroy(vfio_ccw_io_region);
351 destroy_workqueue(vfio_ccw_work_q);
352 vfio_ccw_debug_exit();
353 return ret;
354 }
355
vfio_ccw_sch_exit(void)356 static void __exit vfio_ccw_sch_exit(void)
357 {
358 css_driver_unregister(&vfio_ccw_sch_driver);
359 isc_unregister(VFIO_CCW_ISC);
360 kmem_cache_destroy(vfio_ccw_io_region);
361 kmem_cache_destroy(vfio_ccw_cmd_region);
362 destroy_workqueue(vfio_ccw_work_q);
363 vfio_ccw_debug_exit();
364 }
365 module_init(vfio_ccw_sch_init);
366 module_exit(vfio_ccw_sch_exit);
367
368 MODULE_LICENSE("GPL v2");
369