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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * VIRTIO based driver for vDPA device
4 *
5 * Copyright (c) 2020, Red Hat. All rights reserved.
6 * Author: Jason Wang <jasowang@redhat.com>
7 *
8 */
9
10#include <linux/init.h>
11#include <linux/module.h>
12#include <linux/device.h>
13#include <linux/kernel.h>
14#include <linux/slab.h>
15#include <linux/uuid.h>
16#include <linux/virtio.h>
17#include <linux/vdpa.h>
18#include <linux/virtio_config.h>
19#include <linux/virtio_ring.h>
20
21#define MOD_VERSION "0.1"
22#define MOD_AUTHOR "Jason Wang <jasowang@redhat.com>"
23#define MOD_DESC "vDPA bus driver for virtio devices"
24#define MOD_LICENSE "GPL v2"
25
26struct virtio_vdpa_device {
27 struct virtio_device vdev;
28 struct vdpa_device *vdpa;
29 u64 features;
30
31 /* The lock to protect virtqueue list */
32 spinlock_t lock;
33 /* List of virtio_vdpa_vq_info */
34 struct list_head virtqueues;
35};
36
37struct virtio_vdpa_vq_info {
38 /* the actual virtqueue */
39 struct virtqueue *vq;
40
41 /* the list node for the virtqueues list */
42 struct list_head node;
43};
44
45static inline struct virtio_vdpa_device *
46to_virtio_vdpa_device(struct virtio_device *dev)
47{
48 return container_of(dev, struct virtio_vdpa_device, vdev);
49}
50
51static struct vdpa_device *vd_get_vdpa(struct virtio_device *vdev)
52{
53 return to_virtio_vdpa_device(vdev)->vdpa;
54}
55
56static void virtio_vdpa_get(struct virtio_device *vdev, unsigned offset,
57 void *buf, unsigned len)
58{
59 struct vdpa_device *vdpa = vd_get_vdpa(vdev);
60
61 vdpa_get_config(vdpa, offset, buf, len);
62}
63
64static void virtio_vdpa_set(struct virtio_device *vdev, unsigned offset,
65 const void *buf, unsigned len)
66{
67 struct vdpa_device *vdpa = vd_get_vdpa(vdev);
68 const struct vdpa_config_ops *ops = vdpa->config;
69
70 ops->set_config(vdpa, offset, buf, len);
71}
72
73static u32 virtio_vdpa_generation(struct virtio_device *vdev)
74{
75 struct vdpa_device *vdpa = vd_get_vdpa(vdev);
76 const struct vdpa_config_ops *ops = vdpa->config;
77
78 if (ops->get_generation)
79 return ops->get_generation(vdpa);
80
81 return 0;
82}
83
84static u8 virtio_vdpa_get_status(struct virtio_device *vdev)
85{
86 struct vdpa_device *vdpa = vd_get_vdpa(vdev);
87 const struct vdpa_config_ops *ops = vdpa->config;
88
89 return ops->get_status(vdpa);
90}
91
92static void virtio_vdpa_set_status(struct virtio_device *vdev, u8 status)
93{
94 struct vdpa_device *vdpa = vd_get_vdpa(vdev);
95 const struct vdpa_config_ops *ops = vdpa->config;
96
97 return ops->set_status(vdpa, status);
98}
99
100static void virtio_vdpa_reset(struct virtio_device *vdev)
101{
102 struct vdpa_device *vdpa = vd_get_vdpa(vdev);
103
104 vdpa_reset(vdpa);
105}
106
107static bool virtio_vdpa_notify(struct virtqueue *vq)
108{
109 struct vdpa_device *vdpa = vd_get_vdpa(vq->vdev);
110 const struct vdpa_config_ops *ops = vdpa->config;
111
112 ops->kick_vq(vdpa, vq->index);
113
114 return true;
115}
116
117static irqreturn_t virtio_vdpa_config_cb(void *private)
118{
119 struct virtio_vdpa_device *vd_dev = private;
120
121 virtio_config_changed(&vd_dev->vdev);
122
123 return IRQ_HANDLED;
124}
125
126static irqreturn_t virtio_vdpa_virtqueue_cb(void *private)
127{
128 struct virtio_vdpa_vq_info *info = private;
129
130 return vring_interrupt(0, info->vq);
131}
132
133static struct virtqueue *
134virtio_vdpa_setup_vq(struct virtio_device *vdev, unsigned int index,
135 void (*callback)(struct virtqueue *vq),
136 const char *name, bool ctx)
137{
138 struct virtio_vdpa_device *vd_dev = to_virtio_vdpa_device(vdev);
139 struct vdpa_device *vdpa = vd_get_vdpa(vdev);
140 const struct vdpa_config_ops *ops = vdpa->config;
141 struct virtio_vdpa_vq_info *info;
142 struct vdpa_callback cb;
143 struct virtqueue *vq;
144 u64 desc_addr, driver_addr, device_addr;
145 /* Assume split virtqueue, switch to packed if necessary */
146 struct vdpa_vq_state state = {0};
147 unsigned long flags;
148 u32 align, num;
149 int err;
150
151 if (!name)
152 return NULL;
153
154 if (index >= vdpa->nvqs)
155 return ERR_PTR(-ENOENT);
156
157 /* Queue shouldn't already be set up. */
158 if (ops->get_vq_ready(vdpa, index))
159 return ERR_PTR(-ENOENT);
160
161 /* Allocate and fill out our active queue description */
162 info = kmalloc(sizeof(*info), GFP_KERNEL);
163 if (!info)
164 return ERR_PTR(-ENOMEM);
165
166 num = ops->get_vq_num_max(vdpa);
167 if (num == 0) {
168 err = -ENOENT;
169 goto error_new_virtqueue;
170 }
171
172 /* Create the vring */
173 align = ops->get_vq_align(vdpa);
174 vq = vring_create_virtqueue(index, num, align, vdev,
175 true, true, ctx,
176 virtio_vdpa_notify, callback, name);
177 if (!vq) {
178 err = -ENOMEM;
179 goto error_new_virtqueue;
180 }
181
182 /* Setup virtqueue callback */
183 cb.callback = virtio_vdpa_virtqueue_cb;
184 cb.private = info;
185 ops->set_vq_cb(vdpa, index, &cb);
186 ops->set_vq_num(vdpa, index, virtqueue_get_vring_size(vq));
187
188 desc_addr = virtqueue_get_desc_addr(vq);
189 driver_addr = virtqueue_get_avail_addr(vq);
190 device_addr = virtqueue_get_used_addr(vq);
191
192 if (ops->set_vq_address(vdpa, index,
193 desc_addr, driver_addr,
194 device_addr)) {
195 err = -EINVAL;
196 goto err_vq;
197 }
198
199 /* reset virtqueue state index */
200 if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
201 struct vdpa_vq_state_packed *s = &state.packed;
202
203 s->last_avail_counter = 1;
204 s->last_avail_idx = 0;
205 s->last_used_counter = 1;
206 s->last_used_idx = 0;
207 }
208 err = ops->set_vq_state(vdpa, index, &state);
209 if (err)
210 goto err_vq;
211
212 ops->set_vq_ready(vdpa, index, 1);
213
214 vq->priv = info;
215 info->vq = vq;
216
217 spin_lock_irqsave(&vd_dev->lock, flags);
218 list_add(&info->node, &vd_dev->virtqueues);
219 spin_unlock_irqrestore(&vd_dev->lock, flags);
220
221 return vq;
222
223err_vq:
224 vring_del_virtqueue(vq);
225error_new_virtqueue:
226 ops->set_vq_ready(vdpa, index, 0);
227 /* VDPA driver should make sure vq is stopeed here */
228 WARN_ON(ops->get_vq_ready(vdpa, index));
229 kfree(info);
230 return ERR_PTR(err);
231}
232
233static void virtio_vdpa_del_vq(struct virtqueue *vq)
234{
235 struct virtio_vdpa_device *vd_dev = to_virtio_vdpa_device(vq->vdev);
236 struct vdpa_device *vdpa = vd_dev->vdpa;
237 const struct vdpa_config_ops *ops = vdpa->config;
238 struct virtio_vdpa_vq_info *info = vq->priv;
239 unsigned int index = vq->index;
240 unsigned long flags;
241
242 spin_lock_irqsave(&vd_dev->lock, flags);
243 list_del(&info->node);
244 spin_unlock_irqrestore(&vd_dev->lock, flags);
245
246 /* Select and deactivate the queue (best effort) */
247 ops->set_vq_ready(vdpa, index, 0);
248
249 vring_del_virtqueue(vq);
250
251 kfree(info);
252}
253
254static void virtio_vdpa_del_vqs(struct virtio_device *vdev)
255{
256 struct virtqueue *vq, *n;
257
258 list_for_each_entry_safe(vq, n, &vdev->vqs, list)
259 virtio_vdpa_del_vq(vq);
260}
261
262static int virtio_vdpa_find_vqs(struct virtio_device *vdev, unsigned nvqs,
263 struct virtqueue *vqs[],
264 vq_callback_t *callbacks[],
265 const char * const names[],
266 const bool *ctx,
267 struct irq_affinity *desc)
268{
269 struct virtio_vdpa_device *vd_dev = to_virtio_vdpa_device(vdev);
270 struct vdpa_device *vdpa = vd_get_vdpa(vdev);
271 const struct vdpa_config_ops *ops = vdpa->config;
272 struct vdpa_callback cb;
273 int i, err, queue_idx = 0;
274
275 for (i = 0; i < nvqs; ++i) {
276 if (!names[i]) {
277 vqs[i] = NULL;
278 continue;
279 }
280
281 vqs[i] = virtio_vdpa_setup_vq(vdev, queue_idx++,
282 callbacks[i], names[i], ctx ?
283 ctx[i] : false);
284 if (IS_ERR(vqs[i])) {
285 err = PTR_ERR(vqs[i]);
286 goto err_setup_vq;
287 }
288 }
289
290 cb.callback = virtio_vdpa_config_cb;
291 cb.private = vd_dev;
292 ops->set_config_cb(vdpa, &cb);
293
294 return 0;
295
296err_setup_vq:
297 virtio_vdpa_del_vqs(vdev);
298 return err;
299}
300
301static u64 virtio_vdpa_get_features(struct virtio_device *vdev)
302{
303 struct vdpa_device *vdpa = vd_get_vdpa(vdev);
304 const struct vdpa_config_ops *ops = vdpa->config;
305
306 return ops->get_features(vdpa);
307}
308
309static int virtio_vdpa_finalize_features(struct virtio_device *vdev)
310{
311 struct vdpa_device *vdpa = vd_get_vdpa(vdev);
312
313 /* Give virtio_ring a chance to accept features. */
314 vring_transport_features(vdev);
315
316 return vdpa_set_features(vdpa, vdev->features);
317}
318
319static const char *virtio_vdpa_bus_name(struct virtio_device *vdev)
320{
321 struct virtio_vdpa_device *vd_dev = to_virtio_vdpa_device(vdev);
322 struct vdpa_device *vdpa = vd_dev->vdpa;
323
324 return dev_name(&vdpa->dev);
325}
326
327static const struct virtio_config_ops virtio_vdpa_config_ops = {
328 .get = virtio_vdpa_get,
329 .set = virtio_vdpa_set,
330 .generation = virtio_vdpa_generation,
331 .get_status = virtio_vdpa_get_status,
332 .set_status = virtio_vdpa_set_status,
333 .reset = virtio_vdpa_reset,
334 .find_vqs = virtio_vdpa_find_vqs,
335 .del_vqs = virtio_vdpa_del_vqs,
336 .get_features = virtio_vdpa_get_features,
337 .finalize_features = virtio_vdpa_finalize_features,
338 .bus_name = virtio_vdpa_bus_name,
339};
340
341static void virtio_vdpa_release_dev(struct device *_d)
342{
343 struct virtio_device *vdev =
344 container_of(_d, struct virtio_device, dev);
345 struct virtio_vdpa_device *vd_dev =
346 container_of(vdev, struct virtio_vdpa_device, vdev);
347
348 kfree(vd_dev);
349}
350
351static int virtio_vdpa_probe(struct vdpa_device *vdpa)
352{
353 const struct vdpa_config_ops *ops = vdpa->config;
354 struct virtio_vdpa_device *vd_dev, *reg_dev = NULL;
355 int ret = -EINVAL;
356
357 vd_dev = kzalloc(sizeof(*vd_dev), GFP_KERNEL);
358 if (!vd_dev)
359 return -ENOMEM;
360
361 vd_dev->vdev.dev.parent = vdpa_get_dma_dev(vdpa);
362 vd_dev->vdev.dev.release = virtio_vdpa_release_dev;
363 vd_dev->vdev.config = &virtio_vdpa_config_ops;
364 vd_dev->vdpa = vdpa;
365 INIT_LIST_HEAD(&vd_dev->virtqueues);
366 spin_lock_init(&vd_dev->lock);
367
368 vd_dev->vdev.id.device = ops->get_device_id(vdpa);
369 if (vd_dev->vdev.id.device == 0)
370 goto err;
371
372 vd_dev->vdev.id.vendor = ops->get_vendor_id(vdpa);
373 ret = register_virtio_device(&vd_dev->vdev);
374 reg_dev = vd_dev;
375 if (ret)
376 goto err;
377
378 vdpa_set_drvdata(vdpa, vd_dev);
379
380 return 0;
381
382err:
383 if (reg_dev)
384 put_device(&vd_dev->vdev.dev);
385 else
386 kfree(vd_dev);
387 return ret;
388}
389
390static void virtio_vdpa_remove(struct vdpa_device *vdpa)
391{
392 struct virtio_vdpa_device *vd_dev = vdpa_get_drvdata(vdpa);
393
394 unregister_virtio_device(&vd_dev->vdev);
395}
396
397static struct vdpa_driver virtio_vdpa_driver = {
398 .driver = {
399 .name = "virtio_vdpa",
400 },
401 .probe = virtio_vdpa_probe,
402 .remove = virtio_vdpa_remove,
403};
404
405module_vdpa_driver(virtio_vdpa_driver);
406
407MODULE_VERSION(MOD_VERSION);
408MODULE_LICENSE(MOD_LICENSE);
409MODULE_AUTHOR(MOD_AUTHOR);
410MODULE_DESCRIPTION(MOD_DESC);