drivers/virtio/virtio_pci_legacy.c

   1 /*
   2  * Virtio PCI driver - legacy device support
   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
  22 /* virtio config->get_features() implementation */
  23 static u64 vp_get_features(struct virtio_device *vdev)
  24 {
  25         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
  26
  27         /* When someone needs more than 32 feature bits, we'll need to
  28          * steal a bit to indicate that the rest are somewhere else. */
  29         return ioread32(vp_dev->ioaddr + VIRTIO_PCI_HOST_FEATURES);
  30 }
  31
  32 /* virtio config->finalize_features() implementation */
  33 static int vp_finalize_features(struct virtio_device *vdev)
  34 {
  35         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
  36
  37         /* Give virtio_ring a chance to accept features. */
  38         vring_transport_features(vdev);
  39
  40         /* Make sure we don't have any features > 32 bits! */
  41         BUG_ON((u32)vdev->features != vdev->features);
  42
  43         /* We only support 32 feature bits. */
  44         iowrite32(vdev->features, vp_dev->ioaddr + VIRTIO_PCI_GUEST_FEATURES);
  45
  46         return 0;
  47 }
  48
  49 /* virtio config->get() implementation */
  50 static void vp_get(struct virtio_device *vdev, unsigned offset,
  51                    void *buf, unsigned len)
  52 {
  53         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
  54         void __iomem *ioaddr = vp_dev->ioaddr +
  55                                 VIRTIO_PCI_CONFIG(vp_dev) + offset;
  56         u8 *ptr = buf;
  57         int i;
  58
  59         for (i = 0; i < len; i++)
  60                 ptr[i] = ioread8(ioaddr + i);
  61 }
  62
  63 /* the config->set() implementation.  it's symmetric to the config->get()
  64  * implementation */
  65 static void vp_set(struct virtio_device *vdev, unsigned offset,
  66                    const void *buf, unsigned len)
  67 {
  68         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
  69         void __iomem *ioaddr = vp_dev->ioaddr +
  70                                 VIRTIO_PCI_CONFIG(vp_dev) + offset;
  71         const u8 *ptr = buf;
  72         int i;
  73
  74         for (i = 0; i < len; i++)
  75                 iowrite8(ptr[i], ioaddr + i);
  76 }
  77
  78 /* config->{get,set}_status() implementations */
  79 static u8 vp_get_status(struct virtio_device *vdev)
  80 {
  81         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
  82         return ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS);
  83 }
  84
  85 static void vp_set_status(struct virtio_device *vdev, u8 status)
  86 {
  87         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
  88         /* We should never be setting status to 0. */
  89         BUG_ON(status == 0);
  90         iowrite8(status, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
  91 }
  92
  93 static void vp_reset(struct virtio_device *vdev)
  94 {
  95         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
  96         /* 0 status means a reset. */
  97         iowrite8(0, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
  98         /* Flush out the status write, and flush in device writes,
  99          * including MSi-X interrupts, if any. */
 100         ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS);
 101         /* Flush pending VQ/configuration callbacks. */
 102         vp_synchronize_vectors(vdev);
 103 }
 104
 105 static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
 106 {
 107         /* Setup the vector used for configuration events */
 108         iowrite16(vector, vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR);
 109         /* Verify we had enough resources to assign the vector */
 110         /* Will also flush the write out to device */
 111         return ioread16(vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR);
 112 }
 113
 114 static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
 115                                   struct virtio_pci_vq_info *info,
 116                                   unsigned index,
 117                                   void (*callback)(struct virtqueue *vq),
 118                                   const char *name,
 119                                   u16 msix_vec)
 120 {
 121         struct virtqueue *vq;
 122         unsigned long size;
 123         u16 num;
 124         int err;
 125
 126         /* Select the queue we're interested in */
 127         iowrite16(index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
 128
 129         /* Check if queue is either not available or already active. */
 130         num = ioread16(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NUM);
 131         if (!num || ioread32(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN))
 132                 return ERR_PTR(-ENOENT);
 133
 134         info->num = num;
 135         info->msix_vector = msix_vec;
 136
 137         size = PAGE_ALIGN(vring_size(num, VIRTIO_PCI_VRING_ALIGN));
 138         info->queue = alloc_pages_exact(size, GFP_KERNEL|__GFP_ZERO);
 139         if (info->queue == NULL)
 140                 return ERR_PTR(-ENOMEM);
 141
 142         /* activate the queue */
 143         iowrite32(virt_to_phys(info->queue) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT,
 144                   vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
 145
 146         /* create the vring */
 147         vq = vring_new_virtqueue(index, info->num,
 148                                  VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev,
 149                                  true, info->queue, vp_notify, callback, name);
 150         if (!vq) {
 151                 err = -ENOMEM;
 152                 goto out_activate_queue;
 153         }
 154
 155         vq->priv = (void __force *)vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY;
 156
 157         if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
 158                 iowrite16(msix_vec, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
 159                 msix_vec = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
 160                 if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
 161                         err = -EBUSY;
 162                         goto out_assign;
 163                 }
 164         }
 165
 166         return vq;
 167
 168 out_assign:
 169         vring_del_virtqueue(vq);
 170 out_activate_queue:
 171         iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
 172         free_pages_exact(info->queue, size);
 173         return ERR_PTR(err);
 174 }
 175
 176 static void del_vq(struct virtio_pci_vq_info *info)
 177 {
 178         struct virtqueue *vq = info->vq;
 179         struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
 180         unsigned long size;
 181
 182         iowrite16(vq->index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
 183
 184         if (vp_dev->msix_enabled) {
 185                 iowrite16(VIRTIO_MSI_NO_VECTOR,
 186                           vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
 187                 /* Flush the write out to device */
 188                 ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR);
 189         }
 190
 191         vring_del_virtqueue(vq);
 192
 193         /* Select and deactivate the queue */
 194         iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
 195
 196         size = PAGE_ALIGN(vring_size(info->num, VIRTIO_PCI_VRING_ALIGN));
 197         free_pages_exact(info->queue, size);
 198 }
 199
 200 static const struct virtio_config_ops virtio_pci_config_ops = {
 201         .get            = vp_get,
 202         .set            = vp_set,
 203         .get_status     = vp_get_status,
 204         .set_status     = vp_set_status,
 205         .reset          = vp_reset,
 206         .find_vqs       = vp_find_vqs,
 207         .del_vqs        = vp_del_vqs,
 208         .get_features   = vp_get_features,
 209         .finalize_features = vp_finalize_features,
 210         .bus_name       = vp_bus_name,
 211         .set_vq_affinity = vp_set_vq_affinity,
 212 };
 213
 214 /* the PCI probing function */
 215 int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev)
 216 {
 217         struct pci_dev *pci_dev = vp_dev->pci_dev;
 218         int rc;
 219
 220         /* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */
 221         if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f)
 222                 return -ENODEV;
 223
 224         if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) {
 225                 printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n",
 226                        VIRTIO_PCI_ABI_VERSION, pci_dev->revision);
 227                 return -ENODEV;
 228         }
 229
 230         rc = pci_request_region(pci_dev, 0, "virtio-pci-legacy");
 231         if (rc)
 232                 return rc;
 233
 234         rc = -ENOMEM;
 235         vp_dev->ioaddr = pci_iomap(pci_dev, 0, 0);
 236         if (!vp_dev->ioaddr)
 237                 goto err_iomap;
 238
 239         vp_dev->isr = vp_dev->ioaddr + VIRTIO_PCI_ISR;
 240
 241         /* we use the subsystem vendor/device id as the virtio vendor/device
 242          * id.  this allows us to use the same PCI vendor/device id for all
 243          * virtio devices and to identify the particular virtio driver by
 244          * the subsystem ids */
 245         vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
 246         vp_dev->vdev.id.device = pci_dev->subsystem_device;
 247
 248         vp_dev->vdev.config = &virtio_pci_config_ops;
 249
 250         vp_dev->config_vector = vp_config_vector;
 251         vp_dev->setup_vq = setup_vq;
 252         vp_dev->del_vq = del_vq;
 253
 254         return 0;
 255
 256 err_iomap:
 257         pci_release_region(pci_dev, 0);
 258         return rc;
 259 }
 260
 261 void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev)
 262 {
 263         struct pci_dev *pci_dev = vp_dev->pci_dev;
 264
 265         pci_iounmap(pci_dev, vp_dev->ioaddr);
 266         pci_release_region(pci_dev, 0);
 267 }