blob: 3633202e18f4f19c3bd9074c8e968fdbb8f20b32 [file] [log] [blame]
/*
* Intel MIC Platform Software Stack (MPSS)
*
* Copyright(c) 2016 Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* The full GNU General Public License is included in this distribution in
* the file called "COPYING".
*
* Adapted from:
*
* virtio for kvm on s390
*
* Copyright IBM Corp. 2008
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License (version 2 only)
* as published by the Free Software Foundation.
*
* Author(s): Christian Borntraeger <borntraeger@de.ibm.com>
*
* Intel Virtio Over PCIe (VOP) driver.
*
*/
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/dma-mapping.h>
#include "vop_main.h"
#define VOP_MAX_VRINGS 4
/*
* _vop_vdev - Allocated per virtio device instance injected by the peer.
*
* @vdev: Virtio device
* @desc: Virtio device page descriptor
* @dc: Virtio device control
* @vpdev: VOP device which is the parent for this virtio device
* @vr: Buffer for accessing the VRING
* @used: Buffer for used
* @used_size: Size of the used buffer
* @reset_done: Track whether VOP reset is complete
* @virtio_cookie: Cookie returned upon requesting a interrupt
* @c2h_vdev_db: The doorbell used by the guest to interrupt the host
* @h2c_vdev_db: The doorbell used by the host to interrupt the guest
* @dnode: The destination node
*/
struct _vop_vdev {
struct virtio_device vdev;
struct mic_device_desc __iomem *desc;
struct mic_device_ctrl __iomem *dc;
struct vop_device *vpdev;
void __iomem *vr[VOP_MAX_VRINGS];
dma_addr_t used[VOP_MAX_VRINGS];
int used_size[VOP_MAX_VRINGS];
struct completion reset_done;
struct mic_irq *virtio_cookie;
int c2h_vdev_db;
int h2c_vdev_db;
int dnode;
};
#define to_vopvdev(vd) container_of(vd, struct _vop_vdev, vdev)
#define _vop_aligned_desc_size(d) __mic_align(_vop_desc_size(d), 8)
/* Helper API to obtain the parent of the virtio device */
static inline struct device *_vop_dev(struct _vop_vdev *vdev)
{
return vdev->vdev.dev.parent;
}
static inline unsigned _vop_desc_size(struct mic_device_desc __iomem *desc)
{
return sizeof(*desc)
+ ioread8(&desc->num_vq) * sizeof(struct mic_vqconfig)
+ ioread8(&desc->feature_len) * 2
+ ioread8(&desc->config_len);
}
static inline struct mic_vqconfig __iomem *
_vop_vq_config(struct mic_device_desc __iomem *desc)
{
return (struct mic_vqconfig __iomem *)(desc + 1);
}
static inline u8 __iomem *
_vop_vq_features(struct mic_device_desc __iomem *desc)
{
return (u8 __iomem *)(_vop_vq_config(desc) + ioread8(&desc->num_vq));
}
static inline u8 __iomem *
_vop_vq_configspace(struct mic_device_desc __iomem *desc)
{
return _vop_vq_features(desc) + ioread8(&desc->feature_len) * 2;
}
static inline unsigned
_vop_total_desc_size(struct mic_device_desc __iomem *desc)
{
return _vop_aligned_desc_size(desc) + sizeof(struct mic_device_ctrl);
}
/* This gets the device's feature bits. */
static u64 vop_get_features(struct virtio_device *vdev)
{
unsigned int i, bits;
u32 features = 0;
struct mic_device_desc __iomem *desc = to_vopvdev(vdev)->desc;
u8 __iomem *in_features = _vop_vq_features(desc);
int feature_len = ioread8(&desc->feature_len);
bits = min_t(unsigned, feature_len, sizeof(vdev->features)) * 8;
for (i = 0; i < bits; i++)
if (ioread8(&in_features[i / 8]) & (BIT(i % 8)))
features |= BIT(i);
return features;
}
static int vop_finalize_features(struct virtio_device *vdev)
{
unsigned int i, bits;
struct mic_device_desc __iomem *desc = to_vopvdev(vdev)->desc;
u8 feature_len = ioread8(&desc->feature_len);
/* Second half of bitmap is features we accept. */
u8 __iomem *out_features =
_vop_vq_features(desc) + feature_len;
/* Give virtio_ring a chance to accept features. */
vring_transport_features(vdev);
memset_io(out_features, 0, feature_len);
bits = min_t(unsigned, feature_len,
sizeof(vdev->features)) * 8;
for (i = 0; i < bits; i++) {
if (__virtio_test_bit(vdev, i))
iowrite8(ioread8(&out_features[i / 8]) | (1 << (i % 8)),
&out_features[i / 8]);
}
return 0;
}
/*
* Reading and writing elements in config space
*/
static void vop_get(struct virtio_device *vdev, unsigned int offset,
void *buf, unsigned len)
{
struct mic_device_desc __iomem *desc = to_vopvdev(vdev)->desc;
if (offset + len > ioread8(&desc->config_len))
return;
memcpy_fromio(buf, _vop_vq_configspace(desc) + offset, len);
}
static void vop_set(struct virtio_device *vdev, unsigned int offset,
const void *buf, unsigned len)
{
struct mic_device_desc __iomem *desc = to_vopvdev(vdev)->desc;
if (offset + len > ioread8(&desc->config_len))
return;
memcpy_toio(_vop_vq_configspace(desc) + offset, buf, len);
}
/*
* The operations to get and set the status word just access the status
* field of the device descriptor. set_status also interrupts the host
* to tell about status changes.
*/
static u8 vop_get_status(struct virtio_device *vdev)
{
return ioread8(&to_vopvdev(vdev)->desc->status);
}
static void vop_set_status(struct virtio_device *dev, u8 status)
{
struct _vop_vdev *vdev = to_vopvdev(dev);
struct vop_device *vpdev = vdev->vpdev;
if (!status)
return;
iowrite8(status, &vdev->desc->status);
vpdev->hw_ops->send_intr(vpdev, vdev->c2h_vdev_db);
}
/* Inform host on a virtio device reset and wait for ack from host */
static void vop_reset_inform_host(struct virtio_device *dev)
{
struct _vop_vdev *vdev = to_vopvdev(dev);
struct mic_device_ctrl __iomem *dc = vdev->dc;
struct vop_device *vpdev = vdev->vpdev;
int retry;
iowrite8(0, &dc->host_ack);
iowrite8(1, &dc->vdev_reset);
vpdev->hw_ops->send_intr(vpdev, vdev->c2h_vdev_db);
/* Wait till host completes all card accesses and acks the reset */
for (retry = 100; retry--;) {
if (ioread8(&dc->host_ack))
break;
msleep(100);
};
dev_dbg(_vop_dev(vdev), "%s: retry: %d\n", __func__, retry);
/* Reset status to 0 in case we timed out */
iowrite8(0, &vdev->desc->status);
}
static void vop_reset(struct virtio_device *dev)
{
struct _vop_vdev *vdev = to_vopvdev(dev);
dev_dbg(_vop_dev(vdev), "%s: virtio id %d\n",
__func__, dev->id.device);
vop_reset_inform_host(dev);
complete_all(&vdev->reset_done);
}
/*
* The virtio_ring code calls this API when it wants to notify the Host.
*/
static bool vop_notify(struct virtqueue *vq)
{
struct _vop_vdev *vdev = vq->priv;
struct vop_device *vpdev = vdev->vpdev;
vpdev->hw_ops->send_intr(vpdev, vdev->c2h_vdev_db);
return true;
}
static void vop_del_vq(struct virtqueue *vq, int n)
{
struct _vop_vdev *vdev = to_vopvdev(vq->vdev);
struct vring *vr = (struct vring *)(vq + 1);
struct vop_device *vpdev = vdev->vpdev;
dma_unmap_single(&vpdev->dev, vdev->used[n],
vdev->used_size[n], DMA_BIDIRECTIONAL);
free_pages((unsigned long)vr->used, get_order(vdev->used_size[n]));
vring_del_virtqueue(vq);
vpdev->hw_ops->iounmap(vpdev, vdev->vr[n]);
vdev->vr[n] = NULL;
}
static void vop_del_vqs(struct virtio_device *dev)
{
struct _vop_vdev *vdev = to_vopvdev(dev);
struct virtqueue *vq, *n;
int idx = 0;
dev_dbg(_vop_dev(vdev), "%s\n", __func__);
list_for_each_entry_safe(vq, n, &dev->vqs, list)
vop_del_vq(vq, idx++);
}
/*
* This routine will assign vring's allocated in host/io memory. Code in
* virtio_ring.c however continues to access this io memory as if it were local
* memory without io accessors.
*/
static struct virtqueue *vop_find_vq(struct virtio_device *dev,
unsigned index,
void (*callback)(struct virtqueue *vq),
const char *name, bool ctx)
{
struct _vop_vdev *vdev = to_vopvdev(dev);
struct vop_device *vpdev = vdev->vpdev;
struct mic_vqconfig __iomem *vqconfig;
struct mic_vqconfig config;
struct virtqueue *vq;
void __iomem *va;
struct _mic_vring_info __iomem *info;
void *used;
int vr_size, _vr_size, err, magic;
struct vring *vr;
u8 type = ioread8(&vdev->desc->type);
if (index >= ioread8(&vdev->desc->num_vq))
return ERR_PTR(-ENOENT);
if (!name)
return ERR_PTR(-ENOENT);
/* First assign the vring's allocated in host memory */
vqconfig = _vop_vq_config(vdev->desc) + index;
memcpy_fromio(&config, vqconfig, sizeof(config));
_vr_size = vring_size(le16_to_cpu(config.num), MIC_VIRTIO_RING_ALIGN);
vr_size = PAGE_ALIGN(_vr_size + sizeof(struct _mic_vring_info));
va = vpdev->hw_ops->ioremap(vpdev, le64_to_cpu(config.address),
vr_size);
if (!va)
return ERR_PTR(-ENOMEM);
vdev->vr[index] = va;
memset_io(va, 0x0, _vr_size);
vq = vring_new_virtqueue(
index,
le16_to_cpu(config.num), MIC_VIRTIO_RING_ALIGN,
dev,
false,
ctx,
(void __force *)va, vop_notify, callback, name);
if (!vq) {
err = -ENOMEM;
goto unmap;
}
info = va + _vr_size;
magic = ioread32(&info->magic);
if (WARN(magic != MIC_MAGIC + type + index, "magic mismatch")) {
err = -EIO;
goto unmap;
}
/* Allocate and reassign used ring now */
vdev->used_size[index] = PAGE_ALIGN(sizeof(__u16) * 3 +
sizeof(struct vring_used_elem) *
le16_to_cpu(config.num));
used = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
get_order(vdev->used_size[index]));
if (!used) {
err = -ENOMEM;
dev_err(_vop_dev(vdev), "%s %d err %d\n",
__func__, __LINE__, err);
goto del_vq;
}
vdev->used[index] = dma_map_single(&vpdev->dev, used,
vdev->used_size[index],
DMA_BIDIRECTIONAL);
if (dma_mapping_error(&vpdev->dev, vdev->used[index])) {
err = -ENOMEM;
dev_err(_vop_dev(vdev), "%s %d err %d\n",
__func__, __LINE__, err);
goto free_used;
}
writeq(vdev->used[index], &vqconfig->used_address);
/*
* To reassign the used ring here we are directly accessing
* struct vring_virtqueue which is a private data structure
* in virtio_ring.c. At the minimum, a BUILD_BUG_ON() in
* vring_new_virtqueue() would ensure that
* (&vq->vring == (struct vring *) (&vq->vq + 1));
*/
vr = (struct vring *)(vq + 1);
vr->used = used;
vq->priv = vdev;
return vq;
free_used:
free_pages((unsigned long)used,
get_order(vdev->used_size[index]));
del_vq:
vring_del_virtqueue(vq);
unmap:
vpdev->hw_ops->iounmap(vpdev, vdev->vr[index]);
return ERR_PTR(err);
}
static int vop_find_vqs(struct virtio_device *dev, unsigned nvqs,
struct virtqueue *vqs[],
vq_callback_t *callbacks[],
const char * const names[], const bool *ctx,
struct irq_affinity *desc)
{
struct _vop_vdev *vdev = to_vopvdev(dev);
struct vop_device *vpdev = vdev->vpdev;
struct mic_device_ctrl __iomem *dc = vdev->dc;
int i, err, retry;
/* We must have this many virtqueues. */
if (nvqs > ioread8(&vdev->desc->num_vq))
return -ENOENT;
for (i = 0; i < nvqs; ++i) {
dev_dbg(_vop_dev(vdev), "%s: %d: %s\n",
__func__, i, names[i]);
vqs[i] = vop_find_vq(dev, i, callbacks[i], names[i],
ctx ? ctx[i] : false);
if (IS_ERR(vqs[i])) {
err = PTR_ERR(vqs[i]);
goto error;
}
}
iowrite8(1, &dc->used_address_updated);
/*
* Send an interrupt to the host to inform it that used
* rings have been re-assigned.
*/
vpdev->hw_ops->send_intr(vpdev, vdev->c2h_vdev_db);
for (retry = 100; --retry;) {
if (!ioread8(&dc->used_address_updated))
break;
msleep(100);
};
dev_dbg(_vop_dev(vdev), "%s: retry: %d\n", __func__, retry);
if (!retry) {
err = -ENODEV;
goto error;
}
return 0;
error:
vop_del_vqs(dev);
return err;
}
/*
* The config ops structure as defined by virtio config
*/
static struct virtio_config_ops vop_vq_config_ops = {
.get_features = vop_get_features,
.finalize_features = vop_finalize_features,
.get = vop_get,
.set = vop_set,
.get_status = vop_get_status,
.set_status = vop_set_status,
.reset = vop_reset,
.find_vqs = vop_find_vqs,
.del_vqs = vop_del_vqs,
};
static irqreturn_t vop_virtio_intr_handler(int irq, void *data)
{
struct _vop_vdev *vdev = data;
struct vop_device *vpdev = vdev->vpdev;
struct virtqueue *vq;
vpdev->hw_ops->ack_interrupt(vpdev, vdev->h2c_vdev_db);
list_for_each_entry(vq, &vdev->vdev.vqs, list)
vring_interrupt(0, vq);
return IRQ_HANDLED;
}
static void vop_virtio_release_dev(struct device *_d)
{
struct virtio_device *vdev =
container_of(_d, struct virtio_device, dev);
struct _vop_vdev *vop_vdev =
container_of(vdev, struct _vop_vdev, vdev);
kfree(vop_vdev);
}
/*
* adds a new device and register it with virtio
* appropriate drivers are loaded by the device model
*/
static int _vop_add_device(struct mic_device_desc __iomem *d,
unsigned int offset, struct vop_device *vpdev,
int dnode)
{
struct _vop_vdev *vdev, *reg_dev = NULL;
int ret;
u8 type = ioread8(&d->type);
vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
if (!vdev)
return -ENOMEM;
vdev->vpdev = vpdev;
vdev->vdev.dev.parent = &vpdev->dev;
vdev->vdev.dev.release = vop_virtio_release_dev;
vdev->vdev.id.device = type;
vdev->vdev.config = &vop_vq_config_ops;
vdev->desc = d;
vdev->dc = (void __iomem *)d + _vop_aligned_desc_size(d);
vdev->dnode = dnode;
vdev->vdev.priv = (void *)(u64)dnode;
init_completion(&vdev->reset_done);
vdev->h2c_vdev_db = vpdev->hw_ops->next_db(vpdev);
vdev->virtio_cookie = vpdev->hw_ops->request_irq(vpdev,
vop_virtio_intr_handler, "virtio intr",
vdev, vdev->h2c_vdev_db);
if (IS_ERR(vdev->virtio_cookie)) {
ret = PTR_ERR(vdev->virtio_cookie);
goto kfree;
}
iowrite8((u8)vdev->h2c_vdev_db, &vdev->dc->h2c_vdev_db);
vdev->c2h_vdev_db = ioread8(&vdev->dc->c2h_vdev_db);
ret = register_virtio_device(&vdev->vdev);
reg_dev = vdev;
if (ret) {
dev_err(_vop_dev(vdev),
"Failed to register vop device %u type %u\n",
offset, type);
goto free_irq;
}
writeq((u64)vdev, &vdev->dc->vdev);
dev_dbg(_vop_dev(vdev), "%s: registered vop device %u type %u vdev %p\n",
__func__, offset, type, vdev);
return 0;
free_irq:
vpdev->hw_ops->free_irq(vpdev, vdev->virtio_cookie, vdev);
kfree:
if (reg_dev)
put_device(&vdev->vdev.dev);
else
kfree(vdev);
return ret;
}
/*
* match for a vop device with a specific desc pointer
*/
static int vop_match_desc(struct device *dev, void *data)
{
struct virtio_device *_dev = dev_to_virtio(dev);
struct _vop_vdev *vdev = to_vopvdev(_dev);
return vdev->desc == (void __iomem *)data;
}
static void _vop_handle_config_change(struct mic_device_desc __iomem *d,
unsigned int offset,
struct vop_device *vpdev)
{
struct mic_device_ctrl __iomem *dc
= (void __iomem *)d + _vop_aligned_desc_size(d);
struct _vop_vdev *vdev = (struct _vop_vdev *)readq(&dc->vdev);
if (ioread8(&dc->config_change) != MIC_VIRTIO_PARAM_CONFIG_CHANGED)
return;
dev_dbg(&vpdev->dev, "%s %d\n", __func__, __LINE__);
virtio_config_changed(&vdev->vdev);
iowrite8(1, &dc->guest_ack);
}
/*
* removes a virtio device if a hot remove event has been
* requested by the host.
*/
static int _vop_remove_device(struct mic_device_desc __iomem *d,
unsigned int offset, struct vop_device *vpdev)
{
struct mic_device_ctrl __iomem *dc
= (void __iomem *)d + _vop_aligned_desc_size(d);
struct _vop_vdev *vdev = (struct _vop_vdev *)readq(&dc->vdev);
u8 status;
int ret = -1;
if (ioread8(&dc->config_change) == MIC_VIRTIO_PARAM_DEV_REMOVE) {
dev_dbg(&vpdev->dev,
"%s %d config_change %d type %d vdev %p\n",
__func__, __LINE__,
ioread8(&dc->config_change), ioread8(&d->type), vdev);
status = ioread8(&d->status);
reinit_completion(&vdev->reset_done);
unregister_virtio_device(&vdev->vdev);
vpdev->hw_ops->free_irq(vpdev, vdev->virtio_cookie, vdev);
iowrite8(-1, &dc->h2c_vdev_db);
if (status & VIRTIO_CONFIG_S_DRIVER_OK)
wait_for_completion(&vdev->reset_done);
put_device(&vdev->vdev.dev);
iowrite8(1, &dc->guest_ack);
dev_dbg(&vpdev->dev, "%s %d guest_ack %d\n",
__func__, __LINE__, ioread8(&dc->guest_ack));
iowrite8(-1, &d->type);
ret = 0;
}
return ret;
}
#define REMOVE_DEVICES true
static void _vop_scan_devices(void __iomem *dp, struct vop_device *vpdev,
bool remove, int dnode)
{
s8 type;
unsigned int i;
struct mic_device_desc __iomem *d;
struct mic_device_ctrl __iomem *dc;
struct device *dev;
int ret;
for (i = sizeof(struct mic_bootparam);
i < MIC_DP_SIZE; i += _vop_total_desc_size(d)) {
d = dp + i;
dc = (void __iomem *)d + _vop_aligned_desc_size(d);
/*
* This read barrier is paired with the corresponding write
* barrier on the host which is inserted before adding or
* removing a virtio device descriptor, by updating the type.
*/
rmb();
type = ioread8(&d->type);
/* end of list */
if (type == 0)
break;
if (type == -1)
continue;
/* device already exists */
dev = device_find_child(&vpdev->dev, (void __force *)d,
vop_match_desc);
if (dev) {
if (remove)
iowrite8(MIC_VIRTIO_PARAM_DEV_REMOVE,
&dc->config_change);
put_device(dev);
_vop_handle_config_change(d, i, vpdev);
ret = _vop_remove_device(d, i, vpdev);
if (remove) {
iowrite8(0, &dc->config_change);
iowrite8(0, &dc->guest_ack);
}
continue;
}
/* new device */
dev_dbg(&vpdev->dev, "%s %d Adding new virtio device %p\n",
__func__, __LINE__, d);
if (!remove)
_vop_add_device(d, i, vpdev, dnode);
}
}
static void vop_scan_devices(struct vop_info *vi,
struct vop_device *vpdev, bool remove)
{
void __iomem *dp = vpdev->hw_ops->get_remote_dp(vpdev);
if (!dp)
return;
mutex_lock(&vi->vop_mutex);
_vop_scan_devices(dp, vpdev, remove, vpdev->dnode);
mutex_unlock(&vi->vop_mutex);
}
/*
* vop_hotplug_device tries to find changes in the device page.
*/
static void vop_hotplug_devices(struct work_struct *work)
{
struct vop_info *vi = container_of(work, struct vop_info,
hotplug_work);
vop_scan_devices(vi, vi->vpdev, !REMOVE_DEVICES);
}
/*
* Interrupt handler for hot plug/config changes etc.
*/
static irqreturn_t vop_extint_handler(int irq, void *data)
{
struct vop_info *vi = data;
struct mic_bootparam __iomem *bp;
struct vop_device *vpdev = vi->vpdev;
bp = vpdev->hw_ops->get_remote_dp(vpdev);
dev_dbg(&vpdev->dev, "%s %d hotplug work\n",
__func__, __LINE__);
vpdev->hw_ops->ack_interrupt(vpdev, ioread8(&bp->h2c_config_db));
schedule_work(&vi->hotplug_work);
return IRQ_HANDLED;
}
static int vop_driver_probe(struct vop_device *vpdev)
{
struct vop_info *vi;
int rc;
vi = kzalloc(sizeof(*vi), GFP_KERNEL);
if (!vi) {
rc = -ENOMEM;
goto exit;
}
dev_set_drvdata(&vpdev->dev, vi);
vi->vpdev = vpdev;
mutex_init(&vi->vop_mutex);
INIT_WORK(&vi->hotplug_work, vop_hotplug_devices);
if (vpdev->dnode) {
rc = vop_host_init(vi);
if (rc < 0)
goto free;
} else {
struct mic_bootparam __iomem *bootparam;
vop_scan_devices(vi, vpdev, !REMOVE_DEVICES);
vi->h2c_config_db = vpdev->hw_ops->next_db(vpdev);
vi->cookie = vpdev->hw_ops->request_irq(vpdev,
vop_extint_handler,
"virtio_config_intr",
vi, vi->h2c_config_db);
if (IS_ERR(vi->cookie)) {
rc = PTR_ERR(vi->cookie);
goto free;
}
bootparam = vpdev->hw_ops->get_remote_dp(vpdev);
iowrite8(vi->h2c_config_db, &bootparam->h2c_config_db);
}
vop_init_debugfs(vi);
return 0;
free:
kfree(vi);
exit:
return rc;
}
static void vop_driver_remove(struct vop_device *vpdev)
{
struct vop_info *vi = dev_get_drvdata(&vpdev->dev);
if (vpdev->dnode) {
vop_host_uninit(vi);
} else {
struct mic_bootparam __iomem *bootparam =
vpdev->hw_ops->get_remote_dp(vpdev);
if (bootparam)
iowrite8(-1, &bootparam->h2c_config_db);
vpdev->hw_ops->free_irq(vpdev, vi->cookie, vi);
flush_work(&vi->hotplug_work);
vop_scan_devices(vi, vpdev, REMOVE_DEVICES);
}
vop_exit_debugfs(vi);
kfree(vi);
}
static struct vop_device_id id_table[] = {
{ VOP_DEV_TRNSP, VOP_DEV_ANY_ID },
{ 0 },
};
static struct vop_driver vop_driver = {
.driver.name = KBUILD_MODNAME,
.driver.owner = THIS_MODULE,
.id_table = id_table,
.probe = vop_driver_probe,
.remove = vop_driver_remove,
};
module_vop_driver(vop_driver);
MODULE_DEVICE_TABLE(mbus, id_table);
MODULE_AUTHOR("Intel Corporation");
MODULE_DESCRIPTION("Intel(R) Virtio Over PCIe (VOP) driver");
MODULE_LICENSE("GPL v2");