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1/*
2 * Virtio PCI driver - common functionality for all device versions
3 *
4 * This module allows virtio devices to be used over a virtual PCI device.
5 * This can be used with QEMU based VMMs like KVM or Xen.
6 *
7 * Copyright IBM Corp. 2007
8 * Copyright Red Hat, Inc. 2014
9 *
10 * Authors:
11 * Anthony Liguori <aliguori@us.ibm.com>
12 * Rusty Russell <rusty@rustcorp.com.au>
13 * Michael S. Tsirkin <mst@redhat.com>
14 *
15 * This work is licensed under the terms of the GNU GPL, version 2 or later.
16 * See the COPYING file in the top-level directory.
17 *
18 */
19
20#include "virtio_pci_common.h"
21
22static bool force_legacy = false;
23
24#if IS_ENABLED(CONFIG_VIRTIO_PCI_LEGACY)
25module_param(force_legacy, bool, 0444);
26MODULE_PARM_DESC(force_legacy,
27 "Force legacy mode for transitional virtio 1 devices");
28#endif
29
30/* wait for pending irq handlers */
31void vp_synchronize_vectors(struct virtio_device *vdev)
32{
33 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
34 int i;
35
36 if (vp_dev->intx_enabled)
37 synchronize_irq(vp_dev->pci_dev->irq);
38
39 for (i = 0; i < vp_dev->msix_vectors; ++i)
40 synchronize_irq(pci_irq_vector(vp_dev->pci_dev, i));
41}
42
43/* the notify function used when creating a virt queue */
44bool vp_notify(struct virtqueue *vq)
45{
46 /* we write the queue's selector into the notification register to
47 * signal the other end */
48 iowrite16(vq->index, (void __iomem *)vq->priv);
49 return true;
50}
51
52/* Handle a configuration change: Tell driver if it wants to know. */
53static irqreturn_t vp_config_changed(int irq, void *opaque)
54{
55 struct virtio_pci_device *vp_dev = opaque;
56
57 virtio_config_changed(&vp_dev->vdev);
58 return IRQ_HANDLED;
59}
60
61/* Notify all virtqueues on an interrupt. */
62static irqreturn_t vp_vring_interrupt(int irq, void *opaque)
63{
64 struct virtio_pci_device *vp_dev = opaque;
65 struct virtio_pci_vq_info *info;
66 irqreturn_t ret = IRQ_NONE;
67 unsigned long flags;
68
69 spin_lock_irqsave(&vp_dev->lock, flags);
70 list_for_each_entry(info, &vp_dev->virtqueues, node) {
71 if (vring_interrupt(irq, info->vq) == IRQ_HANDLED)
72 ret = IRQ_HANDLED;
73 }
74 spin_unlock_irqrestore(&vp_dev->lock, flags);
75
76 return ret;
77}
78
79/* A small wrapper to also acknowledge the interrupt when it's handled.
80 * I really need an EIO hook for the vring so I can ack the interrupt once we
81 * know that we'll be handling the IRQ but before we invoke the callback since
82 * the callback may notify the host which results in the host attempting to
83 * raise an interrupt that we would then mask once we acknowledged the
84 * interrupt. */
85static irqreturn_t vp_interrupt(int irq, void *opaque)
86{
87 struct virtio_pci_device *vp_dev = opaque;
88 u8 isr;
89
90 /* reading the ISR has the effect of also clearing it so it's very
91 * important to save off the value. */
92 isr = ioread8(vp_dev->isr);
93
94 /* It's definitely not us if the ISR was not high */
95 if (!isr)
96 return IRQ_NONE;
97
98 /* Configuration change? Tell driver if it wants to know. */
99 if (isr & VIRTIO_PCI_ISR_CONFIG)
100 vp_config_changed(irq, opaque);
101
102 return vp_vring_interrupt(irq, opaque);
103}
104
105static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors,
106 bool per_vq_vectors)
107{
108 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
109 const char *name = dev_name(&vp_dev->vdev.dev);
110 unsigned i, v;
111 int err = -ENOMEM;
112
113 vp_dev->msix_vectors = nvectors;
114
115 vp_dev->msix_names = kmalloc(nvectors * sizeof *vp_dev->msix_names,
116 GFP_KERNEL);
117 if (!vp_dev->msix_names)
118 goto error;
119 vp_dev->msix_affinity_masks
120 = kzalloc(nvectors * sizeof *vp_dev->msix_affinity_masks,
121 GFP_KERNEL);
122 if (!vp_dev->msix_affinity_masks)
123 goto error;
124 for (i = 0; i < nvectors; ++i)
125 if (!alloc_cpumask_var(&vp_dev->msix_affinity_masks[i],
126 GFP_KERNEL))
127 goto error;
128
129 err = pci_alloc_irq_vectors(vp_dev->pci_dev, nvectors, nvectors,
130 PCI_IRQ_MSIX);
131 if (err < 0)
132 goto error;
133 vp_dev->msix_enabled = 1;
134
135 /* Set the vector used for configuration */
136 v = vp_dev->msix_used_vectors;
137 snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names,
138 "%s-config", name);
139 err = request_irq(pci_irq_vector(vp_dev->pci_dev, v),
140 vp_config_changed, 0, vp_dev->msix_names[v],
141 vp_dev);
142 if (err)
143 goto error;
144 ++vp_dev->msix_used_vectors;
145
146 v = vp_dev->config_vector(vp_dev, v);
147 /* Verify we had enough resources to assign the vector */
148 if (v == VIRTIO_MSI_NO_VECTOR) {
149 err = -EBUSY;
150 goto error;
151 }
152
153 if (!per_vq_vectors) {
154 /* Shared vector for all VQs */
155 v = vp_dev->msix_used_vectors;
156 snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names,
157 "%s-virtqueues", name);
158 err = request_irq(pci_irq_vector(vp_dev->pci_dev, v),
159 vp_vring_interrupt, 0, vp_dev->msix_names[v],
160 vp_dev);
161 if (err)
162 goto error;
163 ++vp_dev->msix_used_vectors;
164 }
165 return 0;
166error:
167 return err;
168}
169
170static struct virtqueue *vp_setup_vq(struct virtio_device *vdev, unsigned index,
171 void (*callback)(struct virtqueue *vq),
172 const char *name,
173 u16 msix_vec)
174{
175 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
176 struct virtio_pci_vq_info *info = kmalloc(sizeof *info, GFP_KERNEL);
177 struct virtqueue *vq;
178 unsigned long flags;
179
180 /* fill out our structure that represents an active queue */
181 if (!info)
182 return ERR_PTR(-ENOMEM);
183
184 vq = vp_dev->setup_vq(vp_dev, info, index, callback, name, msix_vec);
185 if (IS_ERR(vq))
186 goto out_info;
187
188 info->vq = vq;
189 if (callback) {
190 spin_lock_irqsave(&vp_dev->lock, flags);
191 list_add(&info->node, &vp_dev->virtqueues);
192 spin_unlock_irqrestore(&vp_dev->lock, flags);
193 } else {
194 INIT_LIST_HEAD(&info->node);
195 }
196
197 vp_dev->vqs[index] = info;
198 return vq;
199
200out_info:
201 kfree(info);
202 return vq;
203}
204
205static void vp_del_vq(struct virtqueue *vq)
206{
207 struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
208 struct virtio_pci_vq_info *info = vp_dev->vqs[vq->index];
209 unsigned long flags;
210
211 spin_lock_irqsave(&vp_dev->lock, flags);
212 list_del(&info->node);
213 spin_unlock_irqrestore(&vp_dev->lock, flags);
214
215 vp_dev->del_vq(info);
216 kfree(info);
217}
218
219/* the config->del_vqs() implementation */
220void vp_del_vqs(struct virtio_device *vdev)
221{
222 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
223 struct virtqueue *vq, *n;
224 int i;
225
226 list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
227 if (vp_dev->per_vq_vectors) {
228 int v = vp_dev->vqs[vq->index]->msix_vector;
229
230 if (v != VIRTIO_MSI_NO_VECTOR)
231 free_irq(pci_irq_vector(vp_dev->pci_dev, v),
232 vq);
233 }
234 vp_del_vq(vq);
235 }
236 vp_dev->per_vq_vectors = false;
237
238 if (vp_dev->intx_enabled) {
239 free_irq(vp_dev->pci_dev->irq, vp_dev);
240 vp_dev->intx_enabled = 0;
241 }
242
243 for (i = 0; i < vp_dev->msix_used_vectors; ++i)
244 free_irq(pci_irq_vector(vp_dev->pci_dev, i), vp_dev);
245
246 for (i = 0; i < vp_dev->msix_vectors; i++)
247 if (vp_dev->msix_affinity_masks[i])
248 free_cpumask_var(vp_dev->msix_affinity_masks[i]);
249
250 if (vp_dev->msix_enabled) {
251 /* Disable the vector used for configuration */
252 vp_dev->config_vector(vp_dev, VIRTIO_MSI_NO_VECTOR);
253
254 pci_free_irq_vectors(vp_dev->pci_dev);
255 vp_dev->msix_enabled = 0;
256 }
257
258 vp_dev->msix_vectors = 0;
259 vp_dev->msix_used_vectors = 0;
260 kfree(vp_dev->msix_names);
261 vp_dev->msix_names = NULL;
262 kfree(vp_dev->msix_affinity_masks);
263 vp_dev->msix_affinity_masks = NULL;
264 kfree(vp_dev->vqs);
265 vp_dev->vqs = NULL;
266}
267
268static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
269 struct virtqueue *vqs[],
270 vq_callback_t *callbacks[],
271 const char * const names[],
272 bool per_vq_vectors)
273{
274 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
275 u16 msix_vec;
276 int i, err, nvectors, allocated_vectors;
277
278 vp_dev->vqs = kcalloc(nvqs, sizeof(*vp_dev->vqs), GFP_KERNEL);
279 if (!vp_dev->vqs)
280 return -ENOMEM;
281
282 if (per_vq_vectors) {
283 /* Best option: one for change interrupt, one per vq. */
284 nvectors = 1;
285 for (i = 0; i < nvqs; ++i)
286 if (callbacks[i])
287 ++nvectors;
288 } else {
289 /* Second best: one for change, shared for all vqs. */
290 nvectors = 2;
291 }
292
293 err = vp_request_msix_vectors(vdev, nvectors, per_vq_vectors);
294 if (err)
295 goto error_find;
296
297 vp_dev->per_vq_vectors = per_vq_vectors;
298 allocated_vectors = vp_dev->msix_used_vectors;
299 for (i = 0; i < nvqs; ++i) {
300 if (!names[i]) {
301 vqs[i] = NULL;
302 continue;
303 }
304
305 if (!callbacks[i])
306 msix_vec = VIRTIO_MSI_NO_VECTOR;
307 else if (vp_dev->per_vq_vectors)
308 msix_vec = allocated_vectors++;
309 else
310 msix_vec = VP_MSIX_VQ_VECTOR;
311 vqs[i] = vp_setup_vq(vdev, i, callbacks[i], names[i], msix_vec);
312 if (IS_ERR(vqs[i])) {
313 err = PTR_ERR(vqs[i]);
314 goto error_find;
315 }
316
317 if (!vp_dev->per_vq_vectors || msix_vec == VIRTIO_MSI_NO_VECTOR)
318 continue;
319
320 /* allocate per-vq irq if available and necessary */
321 snprintf(vp_dev->msix_names[msix_vec],
322 sizeof *vp_dev->msix_names,
323 "%s-%s",
324 dev_name(&vp_dev->vdev.dev), names[i]);
325 err = request_irq(pci_irq_vector(vp_dev->pci_dev, msix_vec),
326 vring_interrupt, 0,
327 vp_dev->msix_names[msix_vec],
328 vqs[i]);
329 if (err)
330 goto error_find;
331 }
332 return 0;
333
334error_find:
335 vp_del_vqs(vdev);
336 return err;
337}
338
339static int vp_find_vqs_intx(struct virtio_device *vdev, unsigned nvqs,
340 struct virtqueue *vqs[], vq_callback_t *callbacks[],
341 const char * const names[])
342{
343 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
344 int i, err;
345
346 vp_dev->vqs = kcalloc(nvqs, sizeof(*vp_dev->vqs), GFP_KERNEL);
347 if (!vp_dev->vqs)
348 return -ENOMEM;
349
350 err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, IRQF_SHARED,
351 dev_name(&vdev->dev), vp_dev);
352 if (err)
353 goto out_del_vqs;
354
355 vp_dev->intx_enabled = 1;
356 vp_dev->per_vq_vectors = false;
357 for (i = 0; i < nvqs; ++i) {
358 if (!names[i]) {
359 vqs[i] = NULL;
360 continue;
361 }
362 vqs[i] = vp_setup_vq(vdev, i, callbacks[i], names[i],
363 VIRTIO_MSI_NO_VECTOR);
364 if (IS_ERR(vqs[i])) {
365 err = PTR_ERR(vqs[i]);
366 goto out_del_vqs;
367 }
368 }
369
370 return 0;
371out_del_vqs:
372 vp_del_vqs(vdev);
373 return err;
374}
375
376/* the config->find_vqs() implementation */
377int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs,
378 struct virtqueue *vqs[],
379 vq_callback_t *callbacks[],
380 const char * const names[])
381{
382 int err;
383
384 /* Try MSI-X with one vector per queue. */
385 err = vp_find_vqs_msix(vdev, nvqs, vqs, callbacks, names, true);
386 if (!err)
387 return 0;
388 /* Fallback: MSI-X with one vector for config, one shared for queues. */
389 err = vp_find_vqs_msix(vdev, nvqs, vqs, callbacks, names, false);
390 if (!err)
391 return 0;
392 /* Finally fall back to regular interrupts. */
393 return vp_find_vqs_intx(vdev, nvqs, vqs, callbacks, names);
394}
395
396const char *vp_bus_name(struct virtio_device *vdev)
397{
398 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
399
400 return pci_name(vp_dev->pci_dev);
401}
402
403/* Setup the affinity for a virtqueue:
404 * - force the affinity for per vq vector
405 * - OR over all affinities for shared MSI
406 * - ignore the affinity request if we're using INTX
407 */
408int vp_set_vq_affinity(struct virtqueue *vq, int cpu)
409{
410 struct virtio_device *vdev = vq->vdev;
411 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
412 struct virtio_pci_vq_info *info = vp_dev->vqs[vq->index];
413 struct cpumask *mask;
414 unsigned int irq;
415
416 if (!vq->callback)
417 return -EINVAL;
418
419 if (vp_dev->msix_enabled) {
420 mask = vp_dev->msix_affinity_masks[info->msix_vector];
421 irq = pci_irq_vector(vp_dev->pci_dev, info->msix_vector);
422 if (cpu == -1)
423 irq_set_affinity_hint(irq, NULL);
424 else {
425 cpumask_clear(mask);
426 cpumask_set_cpu(cpu, mask);
427 irq_set_affinity_hint(irq, mask);
428 }
429 }
430 return 0;
431}
432
433#ifdef CONFIG_PM_SLEEP
434static int virtio_pci_freeze(struct device *dev)
435{
436 struct pci_dev *pci_dev = to_pci_dev(dev);
437 struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
438 int ret;
439
440 ret = virtio_device_freeze(&vp_dev->vdev);
441
442 if (!ret)
443 pci_disable_device(pci_dev);
444 return ret;
445}
446
447static int virtio_pci_restore(struct device *dev)
448{
449 struct pci_dev *pci_dev = to_pci_dev(dev);
450 struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
451 int ret;
452
453 ret = pci_enable_device(pci_dev);
454 if (ret)
455 return ret;
456
457 pci_set_master(pci_dev);
458 return virtio_device_restore(&vp_dev->vdev);
459}
460
461static const struct dev_pm_ops virtio_pci_pm_ops = {
462 SET_SYSTEM_SLEEP_PM_OPS(virtio_pci_freeze, virtio_pci_restore)
463};
464#endif
465
466
467/* Qumranet donated their vendor ID for devices 0x1000 thru 0x10FF. */
468static const struct pci_device_id virtio_pci_id_table[] = {
469 { PCI_DEVICE(PCI_VENDOR_ID_REDHAT_QUMRANET, PCI_ANY_ID) },
470 { 0 }
471};
472
473MODULE_DEVICE_TABLE(pci, virtio_pci_id_table);
474
475static void virtio_pci_release_dev(struct device *_d)
476{
477 struct virtio_device *vdev = dev_to_virtio(_d);
478 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
479
480 /* As struct device is a kobject, it's not safe to
481 * free the memory (including the reference counter itself)
482 * until it's release callback. */
483 kfree(vp_dev);
484}
485
486static int virtio_pci_probe(struct pci_dev *pci_dev,
487 const struct pci_device_id *id)
488{
489 struct virtio_pci_device *vp_dev;
490 int rc;
491
492 /* allocate our structure and fill it out */
493 vp_dev = kzalloc(sizeof(struct virtio_pci_device), GFP_KERNEL);
494 if (!vp_dev)
495 return -ENOMEM;
496
497 pci_set_drvdata(pci_dev, vp_dev);
498 vp_dev->vdev.dev.parent = &pci_dev->dev;
499 vp_dev->vdev.dev.release = virtio_pci_release_dev;
500 vp_dev->pci_dev = pci_dev;
501 INIT_LIST_HEAD(&vp_dev->virtqueues);
502 spin_lock_init(&vp_dev->lock);
503
504 /* enable the device */
505 rc = pci_enable_device(pci_dev);
506 if (rc)
507 goto err_enable_device;
508
509 if (force_legacy) {
510 rc = virtio_pci_legacy_probe(vp_dev);
511 /* Also try modern mode if we can't map BAR0 (no IO space). */
512 if (rc == -ENODEV || rc == -ENOMEM)
513 rc = virtio_pci_modern_probe(vp_dev);
514 if (rc)
515 goto err_probe;
516 } else {
517 rc = virtio_pci_modern_probe(vp_dev);
518 if (rc == -ENODEV)
519 rc = virtio_pci_legacy_probe(vp_dev);
520 if (rc)
521 goto err_probe;
522 }
523
524 pci_set_master(pci_dev);
525
526 rc = register_virtio_device(&vp_dev->vdev);
527 if (rc)
528 goto err_register;
529
530 return 0;
531
532err_register:
533 if (vp_dev->ioaddr)
534 virtio_pci_legacy_remove(vp_dev);
535 else
536 virtio_pci_modern_remove(vp_dev);
537err_probe:
538 pci_disable_device(pci_dev);
539err_enable_device:
540 kfree(vp_dev);
541 return rc;
542}
543
544static void virtio_pci_remove(struct pci_dev *pci_dev)
545{
546 struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
547 struct device *dev = get_device(&vp_dev->vdev.dev);
548
549 unregister_virtio_device(&vp_dev->vdev);
550
551 if (vp_dev->ioaddr)
552 virtio_pci_legacy_remove(vp_dev);
553 else
554 virtio_pci_modern_remove(vp_dev);
555
556 pci_disable_device(pci_dev);
557 put_device(dev);
558}
559
560static struct pci_driver virtio_pci_driver = {
561 .name = "virtio-pci",
562 .id_table = virtio_pci_id_table,
563 .probe = virtio_pci_probe,
564 .remove = virtio_pci_remove,
565#ifdef CONFIG_PM_SLEEP
566 .driver.pm = &virtio_pci_pm_ops,
567#endif
568};
569
570module_pci_driver(virtio_pci_driver);
571
572MODULE_AUTHOR("Anthony Liguori <aliguori@us.ibm.com>");
573MODULE_DESCRIPTION("virtio-pci");
574MODULE_LICENSE("GPL");
575MODULE_VERSION("1");