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_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 */
  66 static 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 */
  81 static 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
  87 static 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
  95 static 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
 107 static 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
 116 static 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
 172 out_deactivate:
 173         iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
 174 out_del_vq:
 175         vring_del_virtqueue(vq);
 176         return ERR_PTR(err);
 177 }
 178
 179 static 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
 199 static 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 */
 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 = 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
 271 err_iomap:
 272         pci_release_region(pci_dev, 0);
 273         return rc;
 274 }
 275
 276 void 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 }