diff options
Diffstat (limited to 'drivers/virtio/virtio_pci_legacy.c')
| -rw-r--r-- | drivers/virtio/virtio_pci_legacy.c | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/drivers/virtio/virtio_pci_legacy.c b/drivers/virtio/virtio_pci_legacy.c new file mode 100644 index 000000000..2257f1b3d --- /dev/null +++ b/drivers/virtio/virtio_pci_legacy.c @@ -0,0 +1,235 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Virtio PCI driver - legacy device support + * + * This module allows virtio devices to be used over a virtual PCI device. + * This can be used with QEMU based VMMs like KVM or Xen. + * + * Copyright IBM Corp. 2007 + * Copyright Red Hat, Inc. 2014 + * + * Authors: + * Anthony Liguori <aliguori@us.ibm.com> + * Rusty Russell <rusty@rustcorp.com.au> + * Michael S. Tsirkin <mst@redhat.com> + */ + +#include "linux/virtio_pci_legacy.h" +#include "virtio_pci_common.h" + +/* virtio config->get_features() implementation */ +static u64 vp_get_features(struct virtio_device *vdev) +{ + struct virtio_pci_device *vp_dev = to_vp_device(vdev); + + /* When someone needs more than 32 feature bits, we'll need to + * steal a bit to indicate that the rest are somewhere else. */ + return vp_legacy_get_features(&vp_dev->ldev); +} + +/* virtio config->finalize_features() implementation */ +static int vp_finalize_features(struct virtio_device *vdev) +{ + struct virtio_pci_device *vp_dev = to_vp_device(vdev); + + /* Give virtio_ring a chance to accept features. */ + vring_transport_features(vdev); + + /* Make sure we don't have any features > 32 bits! */ + BUG_ON((u32)vdev->features != vdev->features); + + /* We only support 32 feature bits. */ + vp_legacy_set_features(&vp_dev->ldev, vdev->features); + + return 0; +} + +/* virtio config->get() implementation */ +static void vp_get(struct virtio_device *vdev, unsigned int offset, + void *buf, unsigned int len) +{ + struct virtio_pci_device *vp_dev = to_vp_device(vdev); + void __iomem *ioaddr = vp_dev->ldev.ioaddr + + VIRTIO_PCI_CONFIG_OFF(vp_dev->msix_enabled) + + offset; + u8 *ptr = buf; + int i; + + for (i = 0; i < len; i++) + ptr[i] = ioread8(ioaddr + i); +} + +/* the config->set() implementation. it's symmetric to the config->get() + * implementation */ +static void vp_set(struct virtio_device *vdev, unsigned int offset, + const void *buf, unsigned int len) +{ + struct virtio_pci_device *vp_dev = to_vp_device(vdev); + void __iomem *ioaddr = vp_dev->ldev.ioaddr + + VIRTIO_PCI_CONFIG_OFF(vp_dev->msix_enabled) + + offset; + const u8 *ptr = buf; + int i; + + for (i = 0; i < len; i++) + iowrite8(ptr[i], ioaddr + i); +} + +/* config->{get,set}_status() implementations */ +static u8 vp_get_status(struct virtio_device *vdev) +{ + struct virtio_pci_device *vp_dev = to_vp_device(vdev); + return vp_legacy_get_status(&vp_dev->ldev); +} + +static void vp_set_status(struct virtio_device *vdev, u8 status) +{ + struct virtio_pci_device *vp_dev = to_vp_device(vdev); + /* We should never be setting status to 0. */ + BUG_ON(status == 0); + vp_legacy_set_status(&vp_dev->ldev, status); +} + +static void vp_reset(struct virtio_device *vdev) +{ + struct virtio_pci_device *vp_dev = to_vp_device(vdev); + /* 0 status means a reset. */ + vp_legacy_set_status(&vp_dev->ldev, 0); + /* Flush out the status write, and flush in device writes, + * including MSi-X interrupts, if any. */ + vp_legacy_get_status(&vp_dev->ldev); + /* Flush pending VQ/configuration callbacks. */ + vp_synchronize_vectors(vdev); +} + +static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector) +{ + return vp_legacy_config_vector(&vp_dev->ldev, vector); +} + +static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev, + struct virtio_pci_vq_info *info, + unsigned int index, + void (*callback)(struct virtqueue *vq), + const char *name, + bool ctx, + u16 msix_vec) +{ + struct virtqueue *vq; + u16 num; + int err; + u64 q_pfn; + + /* Check if queue is either not available or already active. */ + num = vp_legacy_get_queue_size(&vp_dev->ldev, index); + if (!num || vp_legacy_get_queue_enable(&vp_dev->ldev, index)) + return ERR_PTR(-ENOENT); + + info->msix_vector = msix_vec; + + /* create the vring */ + vq = vring_create_virtqueue(index, num, + VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev, + true, false, ctx, + vp_notify, callback, name); + if (!vq) + return ERR_PTR(-ENOMEM); + + vq->num_max = num; + + q_pfn = virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT; + if (q_pfn >> 32) { + dev_err(&vp_dev->pci_dev->dev, + "platform bug: legacy virtio-pci must not be used with RAM above 0x%llxGB\n", + 0x1ULL << (32 + PAGE_SHIFT - 30)); + err = -E2BIG; + goto out_del_vq; + } + + /* activate the queue */ + vp_legacy_set_queue_address(&vp_dev->ldev, index, q_pfn); + + vq->priv = (void __force *)vp_dev->ldev.ioaddr + VIRTIO_PCI_QUEUE_NOTIFY; + + if (msix_vec != VIRTIO_MSI_NO_VECTOR) { + msix_vec = vp_legacy_queue_vector(&vp_dev->ldev, index, msix_vec); + if (msix_vec == VIRTIO_MSI_NO_VECTOR) { + err = -EBUSY; + goto out_deactivate; + } + } + + return vq; + +out_deactivate: + vp_legacy_set_queue_address(&vp_dev->ldev, index, 0); +out_del_vq: + vring_del_virtqueue(vq); + return ERR_PTR(err); +} + +static void del_vq(struct virtio_pci_vq_info *info) +{ + struct virtqueue *vq = info->vq; + struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev); + + if (vp_dev->msix_enabled) { + vp_legacy_queue_vector(&vp_dev->ldev, vq->index, + VIRTIO_MSI_NO_VECTOR); + /* Flush the write out to device */ + ioread8(vp_dev->ldev.ioaddr + VIRTIO_PCI_ISR); + } + + /* Select and deactivate the queue */ + vp_legacy_set_queue_address(&vp_dev->ldev, vq->index, 0); + + vring_del_virtqueue(vq); +} + +static const struct virtio_config_ops virtio_pci_config_ops = { + .get = vp_get, + .set = vp_set, + .get_status = vp_get_status, + .set_status = vp_set_status, + .reset = vp_reset, + .find_vqs = vp_find_vqs, + .del_vqs = vp_del_vqs, + .synchronize_cbs = vp_synchronize_vectors, + .get_features = vp_get_features, + .finalize_features = vp_finalize_features, + .bus_name = vp_bus_name, + .set_vq_affinity = vp_set_vq_affinity, + .get_vq_affinity = vp_get_vq_affinity, +}; + +/* the PCI probing function */ +int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev) +{ + struct virtio_pci_legacy_device *ldev = &vp_dev->ldev; + struct pci_dev *pci_dev = vp_dev->pci_dev; + int rc; + + ldev->pci_dev = pci_dev; + + rc = vp_legacy_probe(ldev); + if (rc) + return rc; + + vp_dev->isr = ldev->isr; + vp_dev->vdev.id = ldev->id; + + vp_dev->vdev.config = &virtio_pci_config_ops; + + vp_dev->config_vector = vp_config_vector; + vp_dev->setup_vq = setup_vq; + vp_dev->del_vq = del_vq; + + return 0; +} + +void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev) +{ + struct virtio_pci_legacy_device *ldev = &vp_dev->ldev; + + vp_legacy_remove(ldev); +} |