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.
7 * Copyright IBM Corp. 2007
10 * Anthony Liguori <aliguori@us.ibm.com>
12 * This work is licensed under the terms of the GNU GPL, version 2 or later.
13 * See the COPYING file in the top-level directory.
17 #include <linux/module.h>
18 #include <linux/list.h>
19 #include <linux/pci.h>
20 #include <linux/interrupt.h>
21 #include <linux/virtio.h>
22 #include <linux/virtio_config.h>
23 #include <linux/virtio_ring.h>
24 #include <linux/virtio_pci.h>
25 #include <linux/highmem.h>
26 #include <linux/spinlock.h>
28 MODULE_AUTHOR("Anthony Liguori <aliguori@us.ibm.com>");
29 MODULE_DESCRIPTION("virtio-pci");
30 MODULE_LICENSE("GPL");
33 /* Our device structure */
34 struct virtio_pci_device
36 struct virtio_device vdev;
37 struct pci_dev *pci_dev;
39 /* the IO mapping for the PCI config space */
42 /* a list of queues so we can dispatch IRQs */
44 struct list_head virtqueues;
47 struct virtio_pci_vq_info
49 /* the actual virtqueue */
52 /* the number of entries in the queue */
55 /* the index of the queue */
58 /* the virtual address of the ring queue */
61 /* the list node for the virtqueues list */
62 struct list_head node;
65 /* Qumranet donated their vendor ID for devices 0x1000 thru 0x10FF. */
66 static struct pci_device_id virtio_pci_id_table[] = {
67 { 0x1af4, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0 },
71 MODULE_DEVICE_TABLE(pci, virtio_pci_id_table);
73 /* A PCI device has it's own struct device and so does a virtio device so
74 * we create a place for the virtio devices to show up in sysfs. I think it
75 * would make more sense for virtio to not insist on having it's own device. */
76 static struct device *virtio_pci_root;
78 /* Convert a generic virtio device to our structure */
79 static struct virtio_pci_device *to_vp_device(struct virtio_device *vdev)
81 return container_of(vdev, struct virtio_pci_device, vdev);
84 /* virtio config->get_features() implementation */
85 static u32 vp_get_features(struct virtio_device *vdev)
87 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
89 /* When someone needs more than 32 feature bits, we'll need to
90 * steal a bit to indicate that the rest are somewhere else. */
91 return ioread32(vp_dev->ioaddr + VIRTIO_PCI_HOST_FEATURES);
94 /* virtio config->finalize_features() implementation */
95 static void vp_finalize_features(struct virtio_device *vdev)
97 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
99 /* Give virtio_ring a chance to accept features. */
100 vring_transport_features(vdev);
102 /* We only support 32 feature bits. */
103 BUILD_BUG_ON(ARRAY_SIZE(vdev->features) != 1);
104 iowrite32(vdev->features[0], vp_dev->ioaddr+VIRTIO_PCI_GUEST_FEATURES);
107 /* virtio config->get() implementation */
108 static void vp_get(struct virtio_device *vdev, unsigned offset,
109 void *buf, unsigned len)
111 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
112 void __iomem *ioaddr = vp_dev->ioaddr + VIRTIO_PCI_CONFIG + offset;
116 for (i = 0; i < len; i++)
117 ptr[i] = ioread8(ioaddr + i);
120 /* the config->set() implementation. it's symmetric to the config->get()
122 static void vp_set(struct virtio_device *vdev, unsigned offset,
123 const void *buf, unsigned len)
125 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
126 void __iomem *ioaddr = vp_dev->ioaddr + VIRTIO_PCI_CONFIG + offset;
130 for (i = 0; i < len; i++)
131 iowrite8(ptr[i], ioaddr + i);
134 /* config->{get,set}_status() implementations */
135 static u8 vp_get_status(struct virtio_device *vdev)
137 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
138 return ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS);
141 static void vp_set_status(struct virtio_device *vdev, u8 status)
143 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
144 /* We should never be setting status to 0. */
146 iowrite8(status, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
149 static void vp_reset(struct virtio_device *vdev)
151 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
152 /* 0 status means a reset. */
153 iowrite8(0, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
156 /* the notify function used when creating a virt queue */
157 static void vp_notify(struct virtqueue *vq)
159 struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
160 struct virtio_pci_vq_info *info = vq->priv;
162 /* we write the queue's selector into the notification register to
163 * signal the other end */
164 iowrite16(info->queue_index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY);
167 /* A small wrapper to also acknowledge the interrupt when it's handled.
168 * I really need an EIO hook for the vring so I can ack the interrupt once we
169 * know that we'll be handling the IRQ but before we invoke the callback since
170 * the callback may notify the host which results in the host attempting to
171 * raise an interrupt that we would then mask once we acknowledged the
173 static irqreturn_t vp_interrupt(int irq, void *opaque)
175 struct virtio_pci_device *vp_dev = opaque;
176 struct virtio_pci_vq_info *info;
177 irqreturn_t ret = IRQ_NONE;
181 /* reading the ISR has the effect of also clearing it so it's very
182 * important to save off the value. */
183 isr = ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR);
185 /* It's definitely not us if the ISR was not high */
189 /* Configuration change? Tell driver if it wants to know. */
190 if (isr & VIRTIO_PCI_ISR_CONFIG) {
191 struct virtio_driver *drv;
192 drv = container_of(vp_dev->vdev.dev.driver,
193 struct virtio_driver, driver);
195 if (drv && drv->config_changed)
196 drv->config_changed(&vp_dev->vdev);
199 spin_lock_irqsave(&vp_dev->lock, flags);
200 list_for_each_entry(info, &vp_dev->virtqueues, node) {
201 if (vring_interrupt(irq, info->vq) == IRQ_HANDLED)
204 spin_unlock_irqrestore(&vp_dev->lock, flags);
209 /* the config->find_vq() implementation */
210 static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index,
211 void (*callback)(struct virtqueue *vq),
214 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
215 struct virtio_pci_vq_info *info;
216 struct virtqueue *vq;
217 unsigned long flags, size;
221 /* Select the queue we're interested in */
222 iowrite16(index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
224 /* Check if queue is either not available or already active. */
225 num = ioread16(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NUM);
226 if (!num || ioread32(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN))
227 return ERR_PTR(-ENOENT);
229 /* allocate and fill out our structure the represents an active
231 info = kmalloc(sizeof(struct virtio_pci_vq_info), GFP_KERNEL);
233 return ERR_PTR(-ENOMEM);
235 info->queue_index = index;
238 size = PAGE_ALIGN(vring_size(num, VIRTIO_PCI_VRING_ALIGN));
239 info->queue = alloc_pages_exact(size, GFP_KERNEL|__GFP_ZERO);
240 if (info->queue == NULL) {
245 /* activate the queue */
246 iowrite32(virt_to_phys(info->queue) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT,
247 vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
249 /* create the vring */
250 vq = vring_new_virtqueue(info->num, VIRTIO_PCI_VRING_ALIGN,
251 vdev, info->queue, vp_notify, callback, name);
254 goto out_activate_queue;
260 spin_lock_irqsave(&vp_dev->lock, flags);
261 list_add(&info->node, &vp_dev->virtqueues);
262 spin_unlock_irqrestore(&vp_dev->lock, flags);
267 iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
268 free_pages_exact(info->queue, size);
274 /* the config->del_vq() implementation */
275 static void vp_del_vq(struct virtqueue *vq)
277 struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
278 struct virtio_pci_vq_info *info = vq->priv;
279 unsigned long flags, size;
281 spin_lock_irqsave(&vp_dev->lock, flags);
282 list_del(&info->node);
283 spin_unlock_irqrestore(&vp_dev->lock, flags);
285 vring_del_virtqueue(vq);
287 /* Select and deactivate the queue */
288 iowrite16(info->queue_index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
289 iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
291 size = PAGE_ALIGN(vring_size(info->num, VIRTIO_PCI_VRING_ALIGN));
292 free_pages_exact(info->queue, size);
296 static struct virtio_config_ops virtio_pci_config_ops = {
299 .get_status = vp_get_status,
300 .set_status = vp_set_status,
302 .find_vq = vp_find_vq,
304 .get_features = vp_get_features,
305 .finalize_features = vp_finalize_features,
308 static void virtio_pci_release_dev(struct device *_d)
310 struct virtio_device *dev = container_of(_d, struct virtio_device, dev);
311 struct virtio_pci_device *vp_dev = to_vp_device(dev);
312 struct pci_dev *pci_dev = vp_dev->pci_dev;
314 free_irq(pci_dev->irq, vp_dev);
315 pci_set_drvdata(pci_dev, NULL);
316 pci_iounmap(pci_dev, vp_dev->ioaddr);
317 pci_release_regions(pci_dev);
318 pci_disable_device(pci_dev);
322 /* the PCI probing function */
323 static int __devinit virtio_pci_probe(struct pci_dev *pci_dev,
324 const struct pci_device_id *id)
326 struct virtio_pci_device *vp_dev;
329 /* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */
330 if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f)
333 if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) {
334 printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n",
335 VIRTIO_PCI_ABI_VERSION, pci_dev->revision);
339 /* allocate our structure and fill it out */
340 vp_dev = kzalloc(sizeof(struct virtio_pci_device), GFP_KERNEL);
344 vp_dev->vdev.dev.parent = virtio_pci_root;
345 vp_dev->vdev.dev.release = virtio_pci_release_dev;
346 vp_dev->vdev.config = &virtio_pci_config_ops;
347 vp_dev->pci_dev = pci_dev;
348 INIT_LIST_HEAD(&vp_dev->virtqueues);
349 spin_lock_init(&vp_dev->lock);
351 /* enable the device */
352 err = pci_enable_device(pci_dev);
356 err = pci_request_regions(pci_dev, "virtio-pci");
358 goto out_enable_device;
360 vp_dev->ioaddr = pci_iomap(pci_dev, 0, 0);
361 if (vp_dev->ioaddr == NULL)
362 goto out_req_regions;
364 pci_set_drvdata(pci_dev, vp_dev);
366 /* we use the subsystem vendor/device id as the virtio vendor/device
367 * id. this allows us to use the same PCI vendor/device id for all
368 * virtio devices and to identify the particular virtio driver by
369 * the subsytem ids */
370 vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
371 vp_dev->vdev.id.device = pci_dev->subsystem_device;
373 /* register a handler for the queue with the PCI device's interrupt */
374 err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, IRQF_SHARED,
375 dev_name(&vp_dev->vdev.dev), vp_dev);
377 goto out_set_drvdata;
379 /* finally register the virtio device */
380 err = register_virtio_device(&vp_dev->vdev);
387 free_irq(pci_dev->irq, vp_dev);
389 pci_set_drvdata(pci_dev, NULL);
390 pci_iounmap(pci_dev, vp_dev->ioaddr);
392 pci_release_regions(pci_dev);
394 pci_disable_device(pci_dev);
400 static void __devexit virtio_pci_remove(struct pci_dev *pci_dev)
402 struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
404 unregister_virtio_device(&vp_dev->vdev);
408 static int virtio_pci_suspend(struct pci_dev *pci_dev, pm_message_t state)
410 pci_save_state(pci_dev);
411 pci_set_power_state(pci_dev, PCI_D3hot);
415 static int virtio_pci_resume(struct pci_dev *pci_dev)
417 pci_restore_state(pci_dev);
418 pci_set_power_state(pci_dev, PCI_D0);
423 static struct pci_driver virtio_pci_driver = {
424 .name = "virtio-pci",
425 .id_table = virtio_pci_id_table,
426 .probe = virtio_pci_probe,
427 .remove = virtio_pci_remove,
429 .suspend = virtio_pci_suspend,
430 .resume = virtio_pci_resume,
434 static int __init virtio_pci_init(void)
438 virtio_pci_root = root_device_register("virtio-pci");
439 if (IS_ERR(virtio_pci_root))
440 return PTR_ERR(virtio_pci_root);
442 err = pci_register_driver(&virtio_pci_driver);
444 device_unregister(virtio_pci_root);
449 module_init(virtio_pci_init);
451 static void __exit virtio_pci_exit(void)
453 pci_unregister_driver(&virtio_pci_driver);
454 root_device_unregister(virtio_pci_root);
457 module_exit(virtio_pci_exit);