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a0be1db430
Legacy virtio defines the virtqueue base using a 32-bit PFN field, with a read-only register indicating a fixed page size of 4k. This can cause problems for DMA allocators that allocate top down from the DMA mask, which is set to 64 bits. In this case, the addresses are silently truncated to 44-bit, leading to IOMMU faults, failure to read from the queue or data corruption. This patch restricts the coherent DMA mask for legacy PCI virtio devices to 44 bits, which matches the specification. Cc: stable@vger.kernel.org Cc: Andy Lutomirski <luto@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Benjamin Serebrin <serebrin@google.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
268 lines
7.6 KiB
C
268 lines
7.6 KiB
C
/*
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* Virtio PCI driver - legacy device support
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*
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* This module allows virtio devices to be used over a virtual PCI device.
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* This can be used with QEMU based VMMs like KVM or Xen.
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*
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* Copyright IBM Corp. 2007
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* Copyright Red Hat, Inc. 2014
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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* Rusty Russell <rusty@rustcorp.com.au>
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* Michael S. Tsirkin <mst@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*
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*/
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#include "virtio_pci_common.h"
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/* virtio config->get_features() implementation */
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static u64 vp_get_features(struct virtio_device *vdev)
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{
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struct virtio_pci_device *vp_dev = to_vp_device(vdev);
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/* When someone needs more than 32 feature bits, we'll need to
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* steal a bit to indicate that the rest are somewhere else. */
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return ioread32(vp_dev->ioaddr + VIRTIO_PCI_HOST_FEATURES);
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}
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/* virtio config->finalize_features() implementation */
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static int vp_finalize_features(struct virtio_device *vdev)
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{
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struct virtio_pci_device *vp_dev = to_vp_device(vdev);
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/* Give virtio_ring a chance to accept features. */
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vring_transport_features(vdev);
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/* Make sure we don't have any features > 32 bits! */
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BUG_ON((u32)vdev->features != vdev->features);
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/* We only support 32 feature bits. */
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iowrite32(vdev->features, vp_dev->ioaddr + VIRTIO_PCI_GUEST_FEATURES);
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return 0;
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}
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/* virtio config->get() implementation */
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static void vp_get(struct virtio_device *vdev, unsigned offset,
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void *buf, unsigned len)
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{
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struct virtio_pci_device *vp_dev = to_vp_device(vdev);
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void __iomem *ioaddr = vp_dev->ioaddr +
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VIRTIO_PCI_CONFIG(vp_dev) + offset;
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u8 *ptr = buf;
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int i;
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for (i = 0; i < len; i++)
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ptr[i] = ioread8(ioaddr + i);
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}
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/* the config->set() implementation. it's symmetric to the config->get()
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* implementation */
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static void vp_set(struct virtio_device *vdev, unsigned offset,
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const void *buf, unsigned len)
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{
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struct virtio_pci_device *vp_dev = to_vp_device(vdev);
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void __iomem *ioaddr = vp_dev->ioaddr +
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VIRTIO_PCI_CONFIG(vp_dev) + offset;
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const u8 *ptr = buf;
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int i;
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for (i = 0; i < len; i++)
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iowrite8(ptr[i], ioaddr + i);
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}
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/* config->{get,set}_status() implementations */
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static u8 vp_get_status(struct virtio_device *vdev)
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{
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struct virtio_pci_device *vp_dev = to_vp_device(vdev);
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return ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS);
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}
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static void vp_set_status(struct virtio_device *vdev, u8 status)
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{
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struct virtio_pci_device *vp_dev = to_vp_device(vdev);
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/* We should never be setting status to 0. */
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BUG_ON(status == 0);
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iowrite8(status, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
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}
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static void vp_reset(struct virtio_device *vdev)
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{
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struct virtio_pci_device *vp_dev = to_vp_device(vdev);
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/* 0 status means a reset. */
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iowrite8(0, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
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/* Flush out the status write, and flush in device writes,
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* including MSi-X interrupts, if any. */
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ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS);
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/* Flush pending VQ/configuration callbacks. */
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vp_synchronize_vectors(vdev);
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}
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static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
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{
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/* Setup the vector used for configuration events */
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iowrite16(vector, vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR);
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/* Verify we had enough resources to assign the vector */
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/* Will also flush the write out to device */
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return ioread16(vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR);
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}
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static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
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struct virtio_pci_vq_info *info,
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unsigned index,
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void (*callback)(struct virtqueue *vq),
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const char *name,
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u16 msix_vec)
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{
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struct virtqueue *vq;
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u16 num;
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int err;
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/* Select the queue we're interested in */
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iowrite16(index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
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/* Check if queue is either not available or already active. */
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num = ioread16(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NUM);
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if (!num || ioread32(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN))
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return ERR_PTR(-ENOENT);
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info->msix_vector = msix_vec;
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/* create the vring */
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vq = vring_create_virtqueue(index, num,
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VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev,
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true, false, vp_notify, callback, name);
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if (!vq)
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return ERR_PTR(-ENOMEM);
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/* activate the queue */
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iowrite32(virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT,
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vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
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vq->priv = (void __force *)vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY;
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if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
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iowrite16(msix_vec, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
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msix_vec = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
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if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
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err = -EBUSY;
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goto out_deactivate;
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}
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}
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return vq;
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out_deactivate:
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iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
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vring_del_virtqueue(vq);
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return ERR_PTR(err);
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}
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static void del_vq(struct virtio_pci_vq_info *info)
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{
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struct virtqueue *vq = info->vq;
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struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
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iowrite16(vq->index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
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if (vp_dev->msix_enabled) {
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iowrite16(VIRTIO_MSI_NO_VECTOR,
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vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
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/* Flush the write out to device */
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ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR);
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}
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/* Select and deactivate the queue */
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iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
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vring_del_virtqueue(vq);
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}
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static const struct virtio_config_ops virtio_pci_config_ops = {
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.get = vp_get,
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.set = vp_set,
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.get_status = vp_get_status,
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.set_status = vp_set_status,
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.reset = vp_reset,
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.find_vqs = vp_find_vqs,
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.del_vqs = vp_del_vqs,
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.get_features = vp_get_features,
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.finalize_features = vp_finalize_features,
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.bus_name = vp_bus_name,
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.set_vq_affinity = vp_set_vq_affinity,
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};
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/* the PCI probing function */
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int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev)
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{
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struct pci_dev *pci_dev = vp_dev->pci_dev;
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int rc;
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/* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */
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if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f)
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return -ENODEV;
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if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) {
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printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n",
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VIRTIO_PCI_ABI_VERSION, pci_dev->revision);
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return -ENODEV;
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}
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rc = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64));
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if (rc) {
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rc = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(32));
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} else {
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/*
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* The virtio ring base address is expressed as a 32-bit PFN,
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* with a page size of 1 << VIRTIO_PCI_QUEUE_ADDR_SHIFT.
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*/
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dma_set_coherent_mask(&pci_dev->dev,
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DMA_BIT_MASK(32 + VIRTIO_PCI_QUEUE_ADDR_SHIFT));
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}
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if (rc)
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dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA. Trying to continue, but this might not work.\n");
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rc = pci_request_region(pci_dev, 0, "virtio-pci-legacy");
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if (rc)
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return rc;
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rc = -ENOMEM;
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vp_dev->ioaddr = pci_iomap(pci_dev, 0, 0);
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if (!vp_dev->ioaddr)
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goto err_iomap;
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vp_dev->isr = vp_dev->ioaddr + VIRTIO_PCI_ISR;
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/* we use the subsystem vendor/device id as the virtio vendor/device
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* id. this allows us to use the same PCI vendor/device id for all
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* virtio devices and to identify the particular virtio driver by
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* the subsystem ids */
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vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
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vp_dev->vdev.id.device = pci_dev->subsystem_device;
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vp_dev->vdev.config = &virtio_pci_config_ops;
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vp_dev->config_vector = vp_config_vector;
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vp_dev->setup_vq = setup_vq;
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vp_dev->del_vq = del_vq;
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return 0;
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err_iomap:
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pci_release_region(pci_dev, 0);
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return rc;
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}
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void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev)
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{
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struct pci_dev *pci_dev = vp_dev->pci_dev;
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pci_iounmap(pci_dev, vp_dev->ioaddr);
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pci_release_region(pci_dev, 0);
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}
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