LXR linux/drivers/virtio/virtio_pci

   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 */
  23static 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 */
  33static 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 */
  50static 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 */
  65static 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 */
  79static 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
  85static 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
  93static 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
 105static 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
 114static 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        u16 num;
 123        int err;
 124
 125        /* Select the queue we're interested in */
 126        iowrite16(index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
 127
 128        /* Check if queue is either not available or already active. */
 129        num = ioread16(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NUM);
 130        if (!num || ioread32(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN))
 131                return ERR_PTR(-ENOENT);
 132
 133        info->msix_vector = msix_vec;
 134
 135        /* create the vring */
 136        vq = vring_create_virtqueue(index, num,
 137                                    VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev,
 138                                    true, false, vp_notify, callback, name);
 139        if (!vq)
 140                return ERR_PTR(-ENOMEM);
 141
 142        /* activate the queue */
 143        iowrite32(virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT,
 144                  vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
 145
 146        vq->priv = (void __force *)vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY;
 147
 148        if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
 149                iowrite16(msix_vec, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
 150                msix_vec = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
 151                if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
 152                        err = -EBUSY;
 153                        goto out_deactivate;
 154                }
 155        }
 156
 157        return vq;
 158
 159out_deactivate:
 160        iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
 161        vring_del_virtqueue(vq);
 162        return ERR_PTR(err);
 163}
 164
 165static void del_vq(struct virtio_pci_vq_info *info)
 166{
 167        struct virtqueue *vq = info->vq;
 168        struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
 169
 170        iowrite16(vq->index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
 171
 172        if (vp_dev->msix_enabled) {
 173                iowrite16(VIRTIO_MSI_NO_VECTOR,
 174                          vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
 175                /* Flush the write out to device */
 176                ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR);
 177        }
 178
 179        /* Select and deactivate the queue */
 180        iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
 181
 182        vring_del_virtqueue(vq);
 183}
 184
 185static const struct virtio_config_ops virtio_pci_config_ops = {
 186        .get            = vp_get,
 187        .set            = vp_set,
 188        .get_status     = vp_get_status,
 189        .set_status     = vp_set_status,
 190        .reset          = vp_reset,
 191        .find_vqs       = vp_find_vqs,
 192        .del_vqs        = vp_del_vqs,
 193        .get_features   = vp_get_features,
 194        .finalize_features = vp_finalize_features,
 195        .bus_name       = vp_bus_name,
 196        .set_vq_affinity = vp_set_vq_affinity,
 197};
 198
 199/* the PCI probing function */
 200int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev)
 201{
 202        struct pci_dev *pci_dev = vp_dev->pci_dev;
 203        int rc;
 204
 205        /* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */
 206        if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f)
 207                return -ENODEV;
 208
 209        if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) {
 210                printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n",
 211                       VIRTIO_PCI_ABI_VERSION, pci_dev->revision);
 212                return -ENODEV;
 213        }
 214
 215        rc = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64));
 216        if (rc) {
 217                rc = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(32));
 218        } else {
 219                /*
 220                 * The virtio ring base address is expressed as a 32-bit PFN,
 221                 * with a page size of 1 << VIRTIO_PCI_QUEUE_ADDR_SHIFT.
 222                 */
 223                dma_set_coherent_mask(&pci_dev->dev,
 224                                DMA_BIT_MASK(32 + VIRTIO_PCI_QUEUE_ADDR_SHIFT));
 225        }
 226
 227        if (rc)
 228                dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");
 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
 256err_iomap:
 257        pci_release_region(pci_dev, 0);
 258        return rc;
 259}
 260
 261void 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}
 268