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                                   unsigned index,
 116                                   void (*callback)(struct virtqueue *vq),
 117                                   const char *name,
 118                                   u16 msix_vec)
 119 {
 120         struct virtqueue *vq;
 121         u16 num;
 122         int err;
 123
 124         /* Select the queue we're interested in */
 125         iowrite16(index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
 126
 127         /* Check if queue is either not available or already active. */
 128         num = ioread16(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NUM);
 129         if (!num || ioread32(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN))
 130                 return ERR_PTR(-ENOENT);
 131
 132         /* create the vring */
 133         vq = vring_create_virtqueue(index, num,
 134                                     VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev,
 135                                     true, false, vp_notify, callback, name);
 136         if (!vq)
 137                 return ERR_PTR(-ENOMEM);
 138
 139         /* activate the queue */
 140         iowrite32(virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT,
 141                   vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
 142
 143         vq->priv = (void __force *)vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY;
 144
 145         if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
 146                 iowrite16(msix_vec, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
 147                 msix_vec = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
 148                 if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
 149                         err = -EBUSY;
 150                         goto out_deactivate;
 151                 }
 152         }
 153
 154         return vq;
 155
 156 out_deactivate:
 157         iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
 158         vring_del_virtqueue(vq);
 159         return ERR_PTR(err);
 160 }
 161
 162 static void del_vq(struct virtqueue *vq)
 163 {
 164         struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
 165
 166         iowrite16(vq->index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
 167
 168         if (vp_dev->pci_dev->msix_enabled) {
 169                 iowrite16(VIRTIO_MSI_NO_VECTOR,
 170                           vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
 171                 /* Flush the write out to device */
 172                 ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR);
 173         }
 174
 175         /* Select and deactivate the queue */
 176         iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
 177
 178         vring_del_virtqueue(vq);
 179 }
 180
 181 static const struct virtio_config_ops virtio_pci_config_ops = {
 182         .get            = vp_get,
 183         .set            = vp_set,
 184         .get_status     = vp_get_status,
 185         .set_status     = vp_set_status,
 186         .reset          = vp_reset,
 187         .find_vqs       = vp_find_vqs,
 188         .del_vqs        = vp_del_vqs,
 189         .get_features   = vp_get_features,
 190         .finalize_features = vp_finalize_features,
 191         .bus_name       = vp_bus_name,
 192         .set_vq_affinity = vp_set_vq_affinity,
 193         .get_vq_affinity = vp_get_vq_affinity,
 194 };
 195
 196 /* the PCI probing function */
 197 int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev)
 198 {
 199         struct pci_dev *pci_dev = vp_dev->pci_dev;
 200         int rc;
 201
 202         /* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */
 203         if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f)
 204                 return -ENODEV;
 205
 206         if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) {
 207                 printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n",
 208                        VIRTIO_PCI_ABI_VERSION, pci_dev->revision);
 209                 return -ENODEV;
 210         }
 211
 212         rc = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64));
 213         if (rc) {
 214                 rc = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(32));
 215         } else {
 216                 /*
 217                  * The virtio ring base address is expressed as a 32-bit PFN,
 218                  * with a page size of 1 << VIRTIO_PCI_QUEUE_ADDR_SHIFT.
 219                  */
 220                 dma_set_coherent_mask(&pci_dev->dev,
 221                                 DMA_BIT_MASK(32 + VIRTIO_PCI_QUEUE_ADDR_SHIFT));
 222         }
 223
 224         if (rc)
 225                 dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");
 226
 227         rc = pci_request_region(pci_dev, 0, "virtio-pci-legacy");
 228         if (rc)
 229                 return rc;
 230
 231         rc = -ENOMEM;
 232         vp_dev->ioaddr = pci_iomap(pci_dev, 0, 0);
 233         if (!vp_dev->ioaddr)
 234                 goto err_iomap;
 235
 236         vp_dev->isr = vp_dev->ioaddr + VIRTIO_PCI_ISR;
 237
 238         /* we use the subsystem vendor/device id as the virtio vendor/device
 239          * id.  this allows us to use the same PCI vendor/device id for all
 240          * virtio devices and to identify the particular virtio driver by
 241          * the subsystem ids */
 242         vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
 243         vp_dev->vdev.id.device = pci_dev->subsystem_device;
 244
 245         vp_dev->vdev.config = &virtio_pci_config_ops;
 246
 247         vp_dev->config_vector = vp_config_vector;
 248         vp_dev->setup_vq = setup_vq;
 249         vp_dev->del_vq = del_vq;
 250
 251         return 0;
 252
 253 err_iomap:
 254         pci_release_region(pci_dev, 0);
 255         return rc;
 256 }
 257
 258 void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev)
 259 {
 260         struct pci_dev *pci_dev = vp_dev->pci_dev;
 261
 262         pci_iounmap(pci_dev, vp_dev->ioaddr);
 263         pci_release_region(pci_dev, 0);
 264 }