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_OFF(vp_dev->msix_enabled) +
  56                        offset;
  57        u8 *ptr = buf;
  58        int i;
  59
  60        for (i = 0; i < len; i++)
  61                ptr[i] = ioread8(ioaddr + i);
  62}
  63
  64/* the config->set() implementation.  it's symmetric to the config->get()
  65 * implementation */
  66static void vp_set(struct virtio_device *vdev, unsigned offset,
  67                   const void *buf, unsigned len)
  68{
  69        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
  70        void __iomem *ioaddr = vp_dev->ioaddr +
  71                        VIRTIO_PCI_CONFIG_OFF(vp_dev->msix_enabled) +
  72                        offset;
  73        const u8 *ptr = buf;
  74        int i;
  75
  76        for (i = 0; i < len; i++)
  77                iowrite8(ptr[i], ioaddr + i);
  78}
  79
  80/* config->{get,set}_status() implementations */
  81static u8 vp_get_status(struct virtio_device *vdev)
  82{
  83        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
  84        return ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS);
  85}
  86
  87static void vp_set_status(struct virtio_device *vdev, u8 status)
  88{
  89        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
  90        /* We should never be setting status to 0. */
  91        BUG_ON(status == 0);
  92        iowrite8(status, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
  93}
  94
  95static void vp_reset(struct virtio_device *vdev)
  96{
  97        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
  98        /* 0 status means a reset. */
  99        iowrite8(0, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
 100        /* Flush out the status write, and flush in device writes,
 101         * including MSi-X interrupts, if any. */
 102        ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS);
 103        /* Flush pending VQ/configuration callbacks. */
 104        vp_synchronize_vectors(vdev);
 105}
 106
 107static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
 108{
 109        /* Setup the vector used for configuration events */
 110        iowrite16(vector, vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR);
 111        /* Verify we had enough resources to assign the vector */
 112        /* Will also flush the write out to device */
 113        return ioread16(vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR);
 114}
 115
 116static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
 117                                  struct virtio_pci_vq_info *info,
 118                                  unsigned index,
 119                                  void (*callback)(struct virtqueue *vq),
 120                                  const char *name,
 121                                  bool ctx,
 122                                  u16 msix_vec)
 123{
 124        struct virtqueue *vq;
 125        u16 num;
 126        int err;
 127        u64 q_pfn;
 128
 129        /* Select the queue we're interested in */
 130        iowrite16(index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
 131
 132        /* Check if queue is either not available or already active. */
 133        num = ioread16(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NUM);
 134        if (!num || ioread32(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN))
 135                return ERR_PTR(-ENOENT);
 136
 137        info->msix_vector = msix_vec;
 138
 139        /* create the vring */
 140        vq = vring_create_virtqueue(index, num,
 141                                    VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev,
 142                                    true, false, ctx,
 143                                    vp_notify, callback, name);
 144        if (!vq)
 145                return ERR_PTR(-ENOMEM);
 146
 147        q_pfn = virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT;
 148        if (q_pfn >> 32) {
 149                dev_err(&vp_dev->pci_dev->dev,
 150                        "platform bug: legacy virtio-mmio must not be used with RAM above 0x%llxGB\n",
 151                        0x1ULL << (32 + PAGE_SHIFT - 30));
 152                err = -E2BIG;
 153                goto out_del_vq;
 154        }
 155
 156        /* activate the queue */
 157        iowrite32(q_pfn, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
 158
 159        vq->priv = (void __force *)vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY;
 160
 161        if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
 162                iowrite16(msix_vec, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
 163                msix_vec = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
 164                if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
 165                        err = -EBUSY;
 166                        goto out_deactivate;
 167                }
 168        }
 169
 170        return vq;
 171
 172out_deactivate:
 173        iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
 174out_del_vq:
 175        vring_del_virtqueue(vq);
 176        return ERR_PTR(err);
 177}
 178
 179static void del_vq(struct virtio_pci_vq_info *info)
 180{
 181        struct virtqueue *vq = info->vq;
 182        struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
 183
 184        iowrite16(vq->index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
 185
 186        if (vp_dev->msix_enabled) {
 187                iowrite16(VIRTIO_MSI_NO_VECTOR,
 188                          vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
 189                /* Flush the write out to device */
 190                ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR);
 191        }
 192
 193        /* Select and deactivate the queue */
 194        iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
 195
 196        vring_del_virtqueue(vq);
 197}
 198
 199static const struct virtio_config_ops virtio_pci_config_ops = {
 200        .get            = vp_get,
 201        .set            = vp_set,
 202        .get_status     = vp_get_status,
 203        .set_status     = vp_set_status,
 204        .reset          = vp_reset,
 205        .find_vqs       = vp_find_vqs,
 206        .del_vqs        = vp_del_vqs,
 207        .get_features   = vp_get_features,
 208        .finalize_features = vp_finalize_features,
 209        .bus_name       = vp_bus_name,
 210        .set_vq_affinity = vp_set_vq_affinity,
 211        .get_vq_affinity = vp_get_vq_affinity,
 212};
 213
 214/* the PCI probing function */
 215int 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 = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64));
 231        if (rc) {
 232                rc = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(32));
 233        } else {
 234                /*
 235                 * The virtio ring base address is expressed as a 32-bit PFN,
 236                 * with a page size of 1 << VIRTIO_PCI_QUEUE_ADDR_SHIFT.
 237                 */
 238                dma_set_coherent_mask(&pci_dev->dev,
 239                                DMA_BIT_MASK(32 + VIRTIO_PCI_QUEUE_ADDR_SHIFT));
 240        }
 241
 242        if (rc)
 243                dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");
 244
 245        rc = pci_request_region(pci_dev, 0, "virtio-pci-legacy");
 246        if (rc)
 247                return rc;
 248
 249        rc = -ENOMEM;
 250        vp_dev->ioaddr = pci_iomap(pci_dev, 0, 0);
 251        if (!vp_dev->ioaddr)
 252                goto err_iomap;
 253
 254        vp_dev->isr = vp_dev->ioaddr + VIRTIO_PCI_ISR;
 255
 256        /* we use the subsystem vendor/device id as the virtio vendor/device
 257         * id.  this allows us to use the same PCI vendor/device id for all
 258         * virtio devices and to identify the particular virtio driver by
 259         * the subsystem ids */
 260        vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
 261        vp_dev->vdev.id.device = pci_dev->subsystem_device;
 262
 263        vp_dev->vdev.config = &virtio_pci_config_ops;
 264
 265        vp_dev->config_vector = vp_config_vector;
 266        vp_dev->setup_vq = setup_vq;
 267        vp_dev->del_vq = del_vq;
 268
 269        return 0;
 270
 271err_iomap:
 272        pci_release_region(pci_dev, 0);
 273        return rc;
 274}
 275
 276void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev)
 277{
 278        struct pci_dev *pci_dev = vp_dev->pci_dev;
 279
 280        pci_iounmap(pci_dev, vp_dev->ioaddr);
 281        pci_release_region(pci_dev, 0);
 282}
 283