drivers/virtio/virtio_pci.c

   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
  28 MODULE_AUTHOR("Anthony Liguori <aliguori@us.ibm.com>");
  29 MODULE_DESCRIPTION("virtio-pci");
  30 MODULE_LICENSE("GPL");
  31 MODULE_VERSION("1");
  32
  33 /* Our device structure */
  34 struct 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 __iomem *ioaddr;
  41
  42         /* a list of queues so we can dispatch IRQs */
  43         spinlock_t lock;
  44         struct list_head virtqueues;
  45 };
  46
  47 struct 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. */
  66 static 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
  71 MODULE_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. */
  76 static struct device virtio_pci_root = {
  77         .parent         = NULL,
  78         .init_name      = "virtio-pci",
  79 };
  80
  81 /* Convert a generic virtio device to our structure */
  82 static struct virtio_pci_device *to_vp_device(struct virtio_device *vdev)
  83 {
  84         return container_of(vdev, struct virtio_pci_device, vdev);
  85 }
  86
  87 /* virtio config->get_features() implementation */
  88 static u32 vp_get_features(struct virtio_device *vdev)
  89 {
  90         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
  91
  92         /* When someone needs more than 32 feature bits, we'll need to
  93          * steal a bit to indicate that the rest are somewhere else. */
  94         return ioread32(vp_dev->ioaddr + VIRTIO_PCI_HOST_FEATURES);
  95 }
  96
  97 /* virtio config->finalize_features() implementation */
  98 static void vp_finalize_features(struct virtio_device *vdev)
  99 {
 100         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 101
 102         /* Give virtio_ring a chance to accept features. */
 103         vring_transport_features(vdev);
 104
 105         /* We only support 32 feature bits. */
 106         BUILD_BUG_ON(ARRAY_SIZE(vdev->features) != 1);
 107         iowrite32(vdev->features[0], vp_dev->ioaddr+VIRTIO_PCI_GUEST_FEATURES);
 108 }
 109
 110 /* virtio config->get() implementation */
 111 static void vp_get(struct virtio_device *vdev, unsigned offset,
 112                    void *buf, unsigned len)
 113 {
 114         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 115         void __iomem *ioaddr = vp_dev->ioaddr + VIRTIO_PCI_CONFIG + offset;
 116         u8 *ptr = buf;
 117         int i;
 118
 119         for (i = 0; i < len; i++)
 120                 ptr[i] = ioread8(ioaddr + i);
 121 }
 122
 123 /* the config->set() implementation.  it's symmetric to the config->get()
 124  * implementation */
 125 static void vp_set(struct virtio_device *vdev, unsigned offset,
 126                    const void *buf, unsigned len)
 127 {
 128         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 129         void __iomem *ioaddr = vp_dev->ioaddr + VIRTIO_PCI_CONFIG + offset;
 130         const u8 *ptr = buf;
 131         int i;
 132
 133         for (i = 0; i < len; i++)
 134                 iowrite8(ptr[i], ioaddr + i);
 135 }
 136
 137 /* config->{get,set}_status() implementations */
 138 static u8 vp_get_status(struct virtio_device *vdev)
 139 {
 140         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 141         return ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS);
 142 }
 143
 144 static void vp_set_status(struct virtio_device *vdev, u8 status)
 145 {
 146         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 147         /* We should never be setting status to 0. */
 148         BUG_ON(status == 0);
 149         iowrite8(status, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
 150 }
 151
 152 static void vp_reset(struct virtio_device *vdev)
 153 {
 154         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 155         /* 0 status means a reset. */
 156         iowrite8(0, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
 157 }
 158
 159 /* the notify function used when creating a virt queue */
 160 static void vp_notify(struct virtqueue *vq)
 161 {
 162         struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
 163         struct virtio_pci_vq_info *info = vq->priv;
 164
 165         /* we write the queue's selector into the notification register to
 166          * signal the other end */
 167         iowrite16(info->queue_index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY);
 168 }
 169
 170 /* A small wrapper to also acknowledge the interrupt when it's handled.
 171  * I really need an EIO hook for the vring so I can ack the interrupt once we
 172  * know that we'll be handling the IRQ but before we invoke the callback since
 173  * the callback may notify the host which results in the host attempting to
 174  * raise an interrupt that we would then mask once we acknowledged the
 175  * interrupt. */
 176 static irqreturn_t vp_interrupt(int irq, void *opaque)
 177 {
 178         struct virtio_pci_device *vp_dev = opaque;
 179         struct virtio_pci_vq_info *info;
 180         irqreturn_t ret = IRQ_NONE;
 181         unsigned long flags;
 182         u8 isr;
 183
 184         /* reading the ISR has the effect of also clearing it so it's very
 185          * important to save off the value. */
 186         isr = ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR);
 187
 188         /* It's definitely not us if the ISR was not high */
 189         if (!isr)
 190                 return IRQ_NONE;
 191
 192         /* Configuration change?  Tell driver if it wants to know. */
 193         if (isr & VIRTIO_PCI_ISR_CONFIG) {
 194                 struct virtio_driver *drv;
 195                 drv = container_of(vp_dev->vdev.dev.driver,
 196                                    struct virtio_driver, driver);
 197
 198                 if (drv->config_changed)
 199                         drv->config_changed(&vp_dev->vdev);
 200         }
 201
 202         spin_lock_irqsave(&vp_dev->lock, flags);
 203         list_for_each_entry(info, &vp_dev->virtqueues, node) {
 204                 if (vring_interrupt(irq, info->vq) == IRQ_HANDLED)
 205                         ret = IRQ_HANDLED;
 206         }
 207         spin_unlock_irqrestore(&vp_dev->lock, flags);
 208
 209         return ret;
 210 }
 211
 212 /* the config->find_vq() implementation */
 213 static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index,
 214                                     void (*callback)(struct virtqueue *vq))
 215 {
 216         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 217         struct virtio_pci_vq_info *info;
 218         struct virtqueue *vq;
 219         unsigned long flags, size;
 220         u16 num;
 221         int err;
 222
 223         /* Select the queue we're interested in */
 224         iowrite16(index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
 225
 226         /* Check if queue is either not available or already active. */
 227         num = ioread16(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NUM);
 228         if (!num || ioread32(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN))
 229                 return ERR_PTR(-ENOENT);
 230
 231         /* allocate and fill out our structure the represents an active
 232          * queue */
 233         info = kmalloc(sizeof(struct virtio_pci_vq_info), GFP_KERNEL);
 234         if (!info)
 235                 return ERR_PTR(-ENOMEM);
 236
 237         info->queue_index = index;
 238         info->num = num;
 239
 240         size = PAGE_ALIGN(vring_size(num, VIRTIO_PCI_VRING_ALIGN));
 241         info->queue = alloc_pages_exact(size, GFP_KERNEL|__GFP_ZERO);
 242         if (info->queue == NULL) {
 243                 err = -ENOMEM;
 244                 goto out_info;
 245         }
 246
 247         /* activate the queue */
 248         iowrite32(virt_to_phys(info->queue) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT,
 249                   vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
 250
 251         /* create the vring */
 252         vq = vring_new_virtqueue(info->num, VIRTIO_PCI_VRING_ALIGN,
 253                                  vdev, info->queue, vp_notify, callback);
 254         if (!vq) {
 255                 err = -ENOMEM;
 256                 goto out_activate_queue;
 257         }
 258
 259         vq->priv = info;
 260         info->vq = vq;
 261
 262         spin_lock_irqsave(&vp_dev->lock, flags);
 263         list_add(&info->node, &vp_dev->virtqueues);
 264         spin_unlock_irqrestore(&vp_dev->lock, flags);
 265
 266         return vq;
 267
 268 out_activate_queue:
 269         iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
 270         free_pages_exact(info->queue, size);
 271 out_info:
 272         kfree(info);
 273         return ERR_PTR(err);
 274 }
 275
 276 /* the config->del_vq() implementation */
 277 static void vp_del_vq(struct virtqueue *vq)
 278 {
 279         struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
 280         struct virtio_pci_vq_info *info = vq->priv;
 281         unsigned long flags, size;
 282
 283         spin_lock_irqsave(&vp_dev->lock, flags);
 284         list_del(&info->node);
 285         spin_unlock_irqrestore(&vp_dev->lock, flags);
 286
 287         vring_del_virtqueue(vq);
 288
 289         /* Select and deactivate the queue */
 290         iowrite16(info->queue_index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
 291         iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
 292
 293         size = PAGE_ALIGN(vring_size(info->num, VIRTIO_PCI_VRING_ALIGN));
 294         free_pages_exact(info->queue, size);
 295         kfree(info);
 296 }
 297
 298 static struct virtio_config_ops virtio_pci_config_ops = {
 299         .get            = vp_get,
 300         .set            = vp_set,
 301         .get_status     = vp_get_status,
 302         .set_status     = vp_set_status,
 303         .reset          = vp_reset,
 304         .find_vq        = vp_find_vq,
 305         .del_vq         = vp_del_vq,
 306         .get_features   = vp_get_features,
 307         .finalize_features = vp_finalize_features,
 308 };
 309
 310 /* the PCI probing function */
 311 static int __devinit virtio_pci_probe(struct pci_dev *pci_dev,
 312                                       const struct pci_device_id *id)
 313 {
 314         struct virtio_pci_device *vp_dev;
 315         int err;
 316
 317         /* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */
 318         if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f)
 319                 return -ENODEV;
 320
 321         if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) {
 322                 printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n",
 323                        VIRTIO_PCI_ABI_VERSION, pci_dev->revision);
 324                 return -ENODEV;
 325         }
 326
 327         /* allocate our structure and fill it out */
 328         vp_dev = kzalloc(sizeof(struct virtio_pci_device), GFP_KERNEL);
 329         if (vp_dev == NULL)
 330                 return -ENOMEM;
 331
 332         vp_dev->vdev.dev.parent = &virtio_pci_root;
 333         vp_dev->vdev.config = &virtio_pci_config_ops;
 334         vp_dev->pci_dev = pci_dev;
 335         INIT_LIST_HEAD(&vp_dev->virtqueues);
 336         spin_lock_init(&vp_dev->lock);
 337
 338         /* enable the device */
 339         err = pci_enable_device(pci_dev);
 340         if (err)
 341                 goto out;
 342
 343         err = pci_request_regions(pci_dev, "virtio-pci");
 344         if (err)
 345                 goto out_enable_device;
 346
 347         vp_dev->ioaddr = pci_iomap(pci_dev, 0, 0);
 348         if (vp_dev->ioaddr == NULL)
 349                 goto out_req_regions;
 350
 351         pci_set_drvdata(pci_dev, vp_dev);
 352
 353         /* we use the subsystem vendor/device id as the virtio vendor/device
 354          * id.  this allows us to use the same PCI vendor/device id for all
 355          * virtio devices and to identify the particular virtio driver by
 356          * the subsytem ids */
 357         vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
 358         vp_dev->vdev.id.device = pci_dev->subsystem_device;
 359
 360         /* register a handler for the queue with the PCI device's interrupt */
 361         err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, IRQF_SHARED,
 362                           dev_name(&vp_dev->vdev.dev), vp_dev);
 363         if (err)
 364                 goto out_set_drvdata;
 365
 366         /* finally register the virtio device */
 367         err = register_virtio_device(&vp_dev->vdev);
 368         if (err)
 369                 goto out_req_irq;
 370
 371         return 0;
 372
 373 out_req_irq:
 374         free_irq(pci_dev->irq, vp_dev);
 375 out_set_drvdata:
 376         pci_set_drvdata(pci_dev, NULL);
 377         pci_iounmap(pci_dev, vp_dev->ioaddr);
 378 out_req_regions:
 379         pci_release_regions(pci_dev);
 380 out_enable_device:
 381         pci_disable_device(pci_dev);
 382 out:
 383         kfree(vp_dev);
 384         return err;
 385 }
 386
 387 static void __devexit virtio_pci_remove(struct pci_dev *pci_dev)
 388 {
 389         struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
 390
 391         unregister_virtio_device(&vp_dev->vdev);
 392         free_irq(pci_dev->irq, vp_dev);
 393         pci_set_drvdata(pci_dev, NULL);
 394         pci_iounmap(pci_dev, vp_dev->ioaddr);
 395         pci_release_regions(pci_dev);
 396         pci_disable_device(pci_dev);
 397         kfree(vp_dev);
 398 }
 399
 400 #ifdef CONFIG_PM
 401 static int virtio_pci_suspend(struct pci_dev *pci_dev, pm_message_t state)
 402 {
 403         pci_save_state(pci_dev);
 404         pci_set_power_state(pci_dev, PCI_D3hot);
 405         return 0;
 406 }
 407
 408 static int virtio_pci_resume(struct pci_dev *pci_dev)
 409 {
 410         pci_restore_state(pci_dev);
 411         pci_set_power_state(pci_dev, PCI_D0);
 412         return 0;
 413 }
 414 #endif
 415
 416 static struct pci_driver virtio_pci_driver = {
 417         .name           = "virtio-pci",
 418         .id_table       = virtio_pci_id_table,
 419         .probe          = virtio_pci_probe,
 420         .remove         = virtio_pci_remove,
 421 #ifdef CONFIG_PM
 422         .suspend        = virtio_pci_suspend,
 423         .resume         = virtio_pci_resume,
 424 #endif
 425 };
 426
 427 static int __init virtio_pci_init(void)
 428 {
 429         int err;
 430
 431         err = device_register(&virtio_pci_root);
 432         if (err)
 433                 return err;
 434
 435         err = pci_register_driver(&virtio_pci_driver);
 436         if (err)
 437                 device_unregister(&virtio_pci_root);
 438
 439         return err;
 440 }
 441
 442 module_init(virtio_pci_init);
 443
 444 static void __exit virtio_pci_exit(void)
 445 {
 446         device_unregister(&virtio_pci_root);
 447         pci_unregister_driver(&virtio_pci_driver);
 448 }
 449
 450 module_exit(virtio_pci_exit);