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authorAnthony Liguori <aliguori@us.ibm.com>2007-11-12 22:30:26 -0500
committerRusty Russell <rusty@rustcorp.com.au>2008-02-04 07:50:11 -0500
commit3343660d8c62c6b00b2f15324ef3fcb6be207bfa (patch)
tree06d86446da65fc1814edad944e43aeb62f092422 /drivers/virtio/virtio_pci.c
parentd50ed907dc3db5bf2dd0a05b4e199a65793a3788 (diff)
virtio: PCI device
This is a PCI device that implements a transport for virtio. It allows virtio devices to be used by QEMU based VMMs like KVM or Xen. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'drivers/virtio/virtio_pci.c')
-rw-r--r--drivers/virtio/virtio_pci.c440
1 files changed, 440 insertions, 0 deletions
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
new file mode 100644
index 000000000000..192687e3a56a
--- /dev/null
+++ b/drivers/virtio/virtio_pci.c
@@ -0,0 +1,440 @@
1/*
2 * Virtio PCI driver
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 *
9 * Authors:
10 * Anthony Liguori <aliguori@us.ibm.com>
11 *
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.
14 *
15 */
16
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>
27
28MODULE_AUTHOR("Anthony Liguori <aliguori@us.ibm.com>");
29MODULE_DESCRIPTION("virtio-pci");
30MODULE_LICENSE("GPL");
31MODULE_VERSION("1");
32
33/* Our device structure */
34struct virtio_pci_device
35{
36 struct virtio_device vdev;
37 struct pci_dev *pci_dev;
38
39 /* the IO mapping for the PCI config space */
40 void *ioaddr;
41
42 /* a list of queues so we can dispatch IRQs */
43 spinlock_t lock;
44 struct list_head virtqueues;
45};
46
47struct virtio_pci_vq_info
48{
49 /* the actual virtqueue */
50 struct virtqueue *vq;
51
52 /* the number of entries in the queue */
53 int num;
54
55 /* the index of the queue */
56 int queue_index;
57
58 /* the virtual address of the ring queue */
59 void *queue;
60
61 /* the list node for the virtqueues list */
62 struct list_head node;
63};
64
65/* Qumranet donated their vendor ID for devices 0x1000 thru 0x10FF. */
66static struct pci_device_id virtio_pci_id_table[] = {
67 { 0x1af4, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0 },
68 { 0 },
69};
70
71MODULE_DEVICE_TABLE(pci, virtio_pci_id_table);
72
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. */
76static struct device virtio_pci_root = {
77 .parent = NULL,
78 .bus_id = "virtio-pci",
79};
80
81/* Unique numbering for devices under the kvm root */
82static unsigned int dev_index;
83
84/* Convert a generic virtio device to our structure */
85static struct virtio_pci_device *to_vp_device(struct virtio_device *vdev)
86{
87 return container_of(vdev, struct virtio_pci_device, vdev);
88}
89
90/* virtio config->feature() implementation */
91static bool vp_feature(struct virtio_device *vdev, unsigned bit)
92{
93 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
94 u32 mask;
95
96 /* Since this function is supposed to have the side effect of
97 * enabling a queried feature, we simulate that by doing a read
98 * from the host feature bitmask and then writing to the guest
99 * feature bitmask */
100 mask = ioread32(vp_dev->ioaddr + VIRTIO_PCI_HOST_FEATURES);
101 if (mask & (1 << bit)) {
102 mask |= (1 << bit);
103 iowrite32(mask, vp_dev->ioaddr + VIRTIO_PCI_GUEST_FEATURES);
104 }
105
106 return !!(mask & (1 << bit));
107}
108
109/* virtio config->get() implementation */
110static void vp_get(struct virtio_device *vdev, unsigned offset,
111 void *buf, unsigned len)
112{
113 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
114 void *ioaddr = vp_dev->ioaddr + VIRTIO_PCI_CONFIG + offset;
115 u8 *ptr = buf;
116 int i;
117
118 for (i = 0; i < len; i++)
119 ptr[i] = ioread8(ioaddr + i);
120}
121
122/* the config->set() implementation. it's symmetric to the config->get()
123 * implementation */
124static void vp_set(struct virtio_device *vdev, unsigned offset,
125 const void *buf, unsigned len)
126{
127 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
128 void *ioaddr = vp_dev->ioaddr + VIRTIO_PCI_CONFIG + offset;
129 const u8 *ptr = buf;
130 int i;
131
132 for (i = 0; i < len; i++)
133 iowrite8(ptr[i], ioaddr + i);
134}
135
136/* config->{get,set}_status() implementations */
137static u8 vp_get_status(struct virtio_device *vdev)
138{
139 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
140 return ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS);
141}
142
143static void vp_set_status(struct virtio_device *vdev, u8 status)
144{
145 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
146 /* We should never be setting status to 0. */
147 BUG_ON(status == 0);
148 return iowrite8(status, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
149}
150
151static void vp_reset(struct virtio_device *vdev)
152{
153 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
154 /* 0 status means a reset. */
155 return iowrite8(0, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
156}
157
158/* the notify function used when creating a virt queue */
159static void vp_notify(struct virtqueue *vq)
160{
161 struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
162 struct virtio_pci_vq_info *info = vq->priv;
163
164 /* we write the queue's selector into the notification register to
165 * signal the other end */
166 iowrite16(info->queue_index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY);
167}
168
169/* A small wrapper to also acknowledge the interrupt when it's handled.
170 * I really need an EIO hook for the vring so I can ack the interrupt once we
171 * know that we'll be handling the IRQ but before we invoke the callback since
172 * the callback may notify the host which results in the host attempting to
173 * raise an interrupt that we would then mask once we acknowledged the
174 * interrupt. */
175static irqreturn_t vp_interrupt(int irq, void *opaque)
176{
177 struct virtio_pci_device *vp_dev = opaque;
178 struct virtio_pci_vq_info *info;
179 irqreturn_t ret = IRQ_NONE;
180 u8 isr;
181
182 /* reading the ISR has the effect of also clearing it so it's very
183 * important to save off the value. */
184 isr = ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR);
185
186 /* It's definitely not us if the ISR was not high */
187 if (!isr)
188 return IRQ_NONE;
189
190 /* Configuration change? Tell driver if it wants to know. */
191 if (isr & VIRTIO_PCI_ISR_CONFIG) {
192 struct virtio_driver *drv;
193 drv = container_of(vp_dev->vdev.dev.driver,
194 struct virtio_driver, driver);
195
196 if (drv->config_changed)
197 drv->config_changed(&vp_dev->vdev);
198 }
199
200 spin_lock(&vp_dev->lock);
201 list_for_each_entry(info, &vp_dev->virtqueues, node) {
202 if (vring_interrupt(irq, info->vq) == IRQ_HANDLED)
203 ret = IRQ_HANDLED;
204 }
205 spin_unlock(&vp_dev->lock);
206
207 return ret;
208}
209
210/* the config->find_vq() implementation */
211static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index,
212 void (*callback)(struct virtqueue *vq))
213{
214 struct virtio_pci_device *vp_dev = to_vp_device(vdev);
215 struct virtio_pci_vq_info *info;
216 struct virtqueue *vq;
217 u16 num;
218 int err;
219
220 /* Select the queue we're interested in */
221 iowrite16(index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
222
223 /* Check if queue is either not available or already active. */
224 num = ioread16(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NUM);
225 if (!num || ioread32(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN))
226 return ERR_PTR(-ENOENT);
227
228 /* allocate and fill out our structure the represents an active
229 * queue */
230 info = kmalloc(sizeof(struct virtio_pci_vq_info), GFP_KERNEL);
231 if (!info)
232 return ERR_PTR(-ENOMEM);
233
234 info->queue_index = index;
235 info->num = num;
236
237 info->queue = kzalloc(PAGE_ALIGN(vring_size(num,PAGE_SIZE)), GFP_KERNEL);
238 if (info->queue == NULL) {
239 err = -ENOMEM;
240 goto out_info;
241 }
242
243 /* activate the queue */
244 iowrite32(virt_to_phys(info->queue) >> PAGE_SHIFT,
245 vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
246
247 /* create the vring */
248 vq = vring_new_virtqueue(info->num, vdev, info->queue,
249 vp_notify, callback);
250 if (!vq) {
251 err = -ENOMEM;
252 goto out_activate_queue;
253 }
254
255 vq->priv = info;
256 info->vq = vq;
257
258 spin_lock(&vp_dev->lock);
259 list_add(&info->node, &vp_dev->virtqueues);
260 spin_unlock(&vp_dev->lock);
261
262 return vq;
263
264out_activate_queue:
265 iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
266 kfree(info->queue);
267out_info:
268 kfree(info);
269 return ERR_PTR(err);
270}
271
272/* the config->del_vq() implementation */
273static void vp_del_vq(struct virtqueue *vq)
274{
275 struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
276 struct virtio_pci_vq_info *info = vq->priv;
277
278 spin_lock(&vp_dev->lock);
279 list_del(&info->node);
280 spin_unlock(&vp_dev->lock);
281
282 vring_del_virtqueue(vq);
283
284 /* Select and deactivate the queue */
285 iowrite16(info->queue_index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
286 iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
287
288 kfree(info->queue);
289 kfree(info);
290}
291
292static struct virtio_config_ops virtio_pci_config_ops = {
293 .feature = vp_feature,
294 .get = vp_get,
295 .set = vp_set,
296 .get_status = vp_get_status,
297 .set_status = vp_set_status,
298 .reset = vp_reset,
299 .find_vq = vp_find_vq,
300 .del_vq = vp_del_vq,
301};
302
303/* the PCI probing function */
304static int __devinit virtio_pci_probe(struct pci_dev *pci_dev,
305 const struct pci_device_id *id)
306{
307 struct virtio_pci_device *vp_dev;
308 int err;
309
310 /* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */
311 if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f)
312 return -ENODEV;
313
314 /* allocate our structure and fill it out */
315 vp_dev = kzalloc(sizeof(struct virtio_pci_device), GFP_KERNEL);
316 if (vp_dev == NULL)
317 return -ENOMEM;
318
319 snprintf(vp_dev->vdev.dev.bus_id, BUS_ID_SIZE, "virtio%d", dev_index);
320 vp_dev->vdev.index = dev_index;
321 dev_index++;
322
323 vp_dev->vdev.dev.parent = &virtio_pci_root;
324 vp_dev->vdev.config = &virtio_pci_config_ops;
325 vp_dev->pci_dev = pci_dev;
326 INIT_LIST_HEAD(&vp_dev->virtqueues);
327 spin_lock_init(&vp_dev->lock);
328
329 /* enable the device */
330 err = pci_enable_device(pci_dev);
331 if (err)
332 goto out;
333
334 err = pci_request_regions(pci_dev, "virtio-pci");
335 if (err)
336 goto out_enable_device;
337
338 vp_dev->ioaddr = pci_iomap(pci_dev, 0, 0);
339 if (vp_dev->ioaddr == NULL)
340 goto out_req_regions;
341
342 pci_set_drvdata(pci_dev, vp_dev);
343
344 /* we use the subsystem vendor/device id as the virtio vendor/device
345 * id. this allows us to use the same PCI vendor/device id for all
346 * virtio devices and to identify the particular virtio driver by
347 * the subsytem ids */
348 vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
349 vp_dev->vdev.id.device = pci_dev->subsystem_device;
350
351 /* register a handler for the queue with the PCI device's interrupt */
352 err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, IRQF_SHARED,
353 vp_dev->vdev.dev.bus_id, vp_dev);
354 if (err)
355 goto out_set_drvdata;
356
357 /* finally register the virtio device */
358 err = register_virtio_device(&vp_dev->vdev);
359 if (err)
360 goto out_req_irq;
361
362 return 0;
363
364out_req_irq:
365 free_irq(pci_dev->irq, vp_dev);
366out_set_drvdata:
367 pci_set_drvdata(pci_dev, NULL);
368 pci_iounmap(pci_dev, vp_dev->ioaddr);
369out_req_regions:
370 pci_release_regions(pci_dev);
371out_enable_device:
372 pci_disable_device(pci_dev);
373out:
374 kfree(vp_dev);
375 return err;
376}
377
378static void __devexit virtio_pci_remove(struct pci_dev *pci_dev)
379{
380 struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
381
382 free_irq(pci_dev->irq, vp_dev);
383 pci_set_drvdata(pci_dev, NULL);
384 pci_iounmap(pci_dev, vp_dev->ioaddr);
385 pci_release_regions(pci_dev);
386 pci_disable_device(pci_dev);
387 kfree(vp_dev);
388}
389
390#ifdef CONFIG_PM
391static int virtio_pci_suspend(struct pci_dev *pci_dev, pm_message_t state)
392{
393 pci_save_state(pci_dev);
394 pci_set_power_state(pci_dev, PCI_D3hot);
395 return 0;
396}
397
398static int virtio_pci_resume(struct pci_dev *pci_dev)
399{
400 pci_restore_state(pci_dev);
401 pci_set_power_state(pci_dev, PCI_D0);
402 return 0;
403}
404#endif
405
406static struct pci_driver virtio_pci_driver = {
407 .name = "virtio-pci",
408 .id_table = virtio_pci_id_table,
409 .probe = virtio_pci_probe,
410 .remove = virtio_pci_remove,
411#ifdef CONFIG_PM
412 .suspend = virtio_pci_suspend,
413 .resume = virtio_pci_resume,
414#endif
415};
416
417static int __init virtio_pci_init(void)
418{
419 int err;
420
421 err = device_register(&virtio_pci_root);
422 if (err)
423 return err;
424
425 err = pci_register_driver(&virtio_pci_driver);
426 if (err)
427 device_unregister(&virtio_pci_root);
428
429 return err;
430}
431
432module_init(virtio_pci_init);
433
434static void __exit virtio_pci_exit(void)
435{
436 device_unregister(&virtio_pci_root);
437 pci_unregister_driver(&virtio_pci_driver);
438}
439
440module_exit(virtio_pci_exit);