root/drivers/virtio/virtio_pci_legacy.c

DEFINITIONS

1. vp_get_features
2. vp_finalize_features
3. vp_get
4. vp_set
5. vp_get_status
6. vp_set_status
7. vp_reset
8. vp_config_vector
9. setup_vq
10. del_vq
11. virtio_pci_legacy_probe
12. virtio_pci_legacy_remove

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Virtio PCI driver - legacy device support
   4  *
   5  * This module allows virtio devices to be used over a virtual PCI device.
   6  * This can be used with QEMU based VMMs like KVM or Xen.
   7  *
   8  * Copyright IBM Corp. 2007
   9  * Copyright Red Hat, Inc. 2014
  10  *
  11  * Authors:
  12  *  Anthony Liguori  <aliguori@us.ibm.com>
  13  *  Rusty Russell <rusty@rustcorp.com.au>
  14  *  Michael S. Tsirkin <mst@redhat.com>
  15  */
  16 
  17 #include "virtio_pci_common.h"
  18 
  19 /* virtio config->get_features() implementation */
  20 static u64 vp_get_features(struct virtio_device *vdev)
  21 {
  22         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
  23 
  24         /* When someone needs more than 32 feature bits, we'll need to
  25          * steal a bit to indicate that the rest are somewhere else. */
  26         return ioread32(vp_dev->ioaddr + VIRTIO_PCI_HOST_FEATURES);
  27 }
  28 
  29 /* virtio config->finalize_features() implementation */
  30 static int vp_finalize_features(struct virtio_device *vdev)
  31 {
  32         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
  33 
  34         /* Give virtio_ring a chance to accept features. */
  35         vring_transport_features(vdev);
  36 
  37         /* Make sure we don't have any features > 32 bits! */
  38         BUG_ON((u32)vdev->features != vdev->features);
  39 
  40         /* We only support 32 feature bits. */
  41         iowrite32(vdev->features, vp_dev->ioaddr + VIRTIO_PCI_GUEST_FEATURES);
  42 
  43         return 0;
  44 }
  45 
  46 /* virtio config->get() implementation */
  47 static void vp_get(struct virtio_device *vdev, unsigned offset,
  48                    void *buf, unsigned len)
  49 {
  50         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
  51         void __iomem *ioaddr = vp_dev->ioaddr +
  52                         VIRTIO_PCI_CONFIG_OFF(vp_dev->msix_enabled) +
  53                         offset;
  54         u8 *ptr = buf;
  55         int i;
  56 
  57         for (i = 0; i < len; i++)
  58                 ptr[i] = ioread8(ioaddr + i);
  59 }
  60 
  61 /* the config->set() implementation.  it's symmetric to the config->get()
  62  * implementation */
  63 static void vp_set(struct virtio_device *vdev, unsigned offset,
  64                    const void *buf, unsigned len)
  65 {
  66         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
  67         void __iomem *ioaddr = vp_dev->ioaddr +
  68                         VIRTIO_PCI_CONFIG_OFF(vp_dev->msix_enabled) +
  69                         offset;
  70         const u8 *ptr = buf;
  71         int i;
  72 
  73         for (i = 0; i < len; i++)
  74                 iowrite8(ptr[i], ioaddr + i);
  75 }
  76 
  77 /* config->{get,set}_status() implementations */
  78 static u8 vp_get_status(struct virtio_device *vdev)
  79 {
  80         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
  81         return ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS);
  82 }
  83 
  84 static void vp_set_status(struct virtio_device *vdev, u8 status)
  85 {
  86         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
  87         /* We should never be setting status to 0. */
  88         BUG_ON(status == 0);
  89         iowrite8(status, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
  90 }
  91 
  92 static void vp_reset(struct virtio_device *vdev)
  93 {
  94         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
  95         /* 0 status means a reset. */
  96         iowrite8(0, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
  97         /* Flush out the status write, and flush in device writes,
  98          * including MSi-X interrupts, if any. */
  99         ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS);
 100         /* Flush pending VQ/configuration callbacks. */
 101         vp_synchronize_vectors(vdev);
 102 }
 103 
 104 static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
 105 {
 106         /* Setup the vector used for configuration events */
 107         iowrite16(vector, vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR);
 108         /* Verify we had enough resources to assign the vector */
 109         /* Will also flush the write out to device */
 110         return ioread16(vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR);
 111 }
 112 
 113 static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
 114                                   struct virtio_pci_vq_info *info,
 115                                   unsigned index,
 116                                   void (*callback)(struct virtqueue *vq),
 117                                   const char *name,
 118                                   bool ctx,
 119                                   u16 msix_vec)
 120 {
 121         struct virtqueue *vq;
 122         u16 num;
 123         int err;
 124         u64 q_pfn;
 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->msix_vector = msix_vec;
 135 
 136         /* create the vring */
 137         vq = vring_create_virtqueue(index, num,
 138                                     VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev,
 139                                     true, false, ctx,
 140                                     vp_notify, callback, name);
 141         if (!vq)
 142                 return ERR_PTR(-ENOMEM);
 143 
 144         q_pfn = virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT;
 145         if (q_pfn >> 32) {
 146                 dev_err(&vp_dev->pci_dev->dev,
 147                         "platform bug: legacy virtio-mmio must not be used with RAM above 0x%llxGB\n",
 148                         0x1ULL << (32 + PAGE_SHIFT - 30));
 149                 err = -E2BIG;
 150                 goto out_del_vq;
 151         }
 152 
 153         /* activate the queue */
 154         iowrite32(q_pfn, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
 155 
 156         vq->priv = (void __force *)vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY;
 157 
 158         if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
 159                 iowrite16(msix_vec, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
 160                 msix_vec = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
 161                 if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
 162                         err = -EBUSY;
 163                         goto out_deactivate;
 164                 }
 165         }
 166 
 167         return vq;
 168 
 169 out_deactivate:
 170         iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
 171 out_del_vq:
 172         vring_del_virtqueue(vq);
 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 
 181         iowrite16(vq->index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
 182 
 183         if (vp_dev->msix_enabled) {
 184                 iowrite16(VIRTIO_MSI_NO_VECTOR,
 185                           vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
 186                 /* Flush the write out to device */
 187                 ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR);
 188         }
 189 
 190         /* Select and deactivate the queue */
 191         iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
 192 
 193         vring_del_virtqueue(vq);
 194 }
 195 
 196 static const struct virtio_config_ops virtio_pci_config_ops = {
 197         .get            = vp_get,
 198         .set            = vp_set,
 199         .get_status     = vp_get_status,
 200         .set_status     = vp_set_status,
 201         .reset          = vp_reset,
 202         .find_vqs       = vp_find_vqs,
 203         .del_vqs        = vp_del_vqs,
 204         .get_features   = vp_get_features,
 205         .finalize_features = vp_finalize_features,
 206         .bus_name       = vp_bus_name,
 207         .set_vq_affinity = vp_set_vq_affinity,
 208         .get_vq_affinity = vp_get_vq_affinity,
 209 };
 210 
 211 /* the PCI probing function */
 212 int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev)
 213 {
 214         struct pci_dev *pci_dev = vp_dev->pci_dev;
 215         int rc;
 216 
 217         /* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */
 218         if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f)
 219                 return -ENODEV;
 220 
 221         if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) {
 222                 printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n",
 223                        VIRTIO_PCI_ABI_VERSION, pci_dev->revision);
 224                 return -ENODEV;
 225         }
 226 
 227         rc = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64));
 228         if (rc) {
 229                 rc = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(32));
 230         } else {
 231                 /*
 232                  * The virtio ring base address is expressed as a 32-bit PFN,
 233                  * with a page size of 1 << VIRTIO_PCI_QUEUE_ADDR_SHIFT.
 234                  */
 235                 dma_set_coherent_mask(&pci_dev->dev,
 236                                 DMA_BIT_MASK(32 + VIRTIO_PCI_QUEUE_ADDR_SHIFT));
 237         }
 238 
 239         if (rc)
 240                 dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");
 241 
 242         rc = pci_request_region(pci_dev, 0, "virtio-pci-legacy");
 243         if (rc)
 244                 return rc;
 245 
 246         rc = -ENOMEM;
 247         vp_dev->ioaddr = pci_iomap(pci_dev, 0, 0);
 248         if (!vp_dev->ioaddr)
 249                 goto err_iomap;
 250 
 251         vp_dev->isr = vp_dev->ioaddr + VIRTIO_PCI_ISR;
 252 
 253         /* we use the subsystem vendor/device id as the virtio vendor/device
 254          * id.  this allows us to use the same PCI vendor/device id for all
 255          * virtio devices and to identify the particular virtio driver by
 256          * the subsystem ids */
 257         vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
 258         vp_dev->vdev.id.device = pci_dev->subsystem_device;
 259 
 260         vp_dev->vdev.config = &virtio_pci_config_ops;
 261 
 262         vp_dev->config_vector = vp_config_vector;
 263         vp_dev->setup_vq = setup_vq;
 264         vp_dev->del_vq = del_vq;
 265 
 266         return 0;
 267 
 268 err_iomap:
 269         pci_release_region(pci_dev, 0);
 270         return rc;
 271 }
 272 
 273 void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev)
 274 {
 275         struct pci_dev *pci_dev = vp_dev->pci_dev;
 276 
 277         pci_iounmap(pci_dev, vp_dev->ioaddr);
 278         pci_release_region(pci_dev, 0);
 279 }