/*
* Virtio PCI driver
*
* 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
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*/
#include <linux/module.h>
#include <linux/list.h>
#include <linux/pci.h>
#include <linux/interrupt.h>
#include <linux/virtio.h>
#include <linux/virtio_config.h>
#include <linux/virtio_ring.h>
#include <linux/virtio_pci.h>
#include <linux/highmem.h>
#include <linux/spinlock.h>
MODULE_AUTHOR("Anthony Liguori <aliguori@us.ibm.com>");
MODULE_DESCRIPTION("virtio-pci");
MODULE_LICENSE("GPL");
MODULE_VERSION("1");
/* Our device structure */
struct virtio_pci_device
{
struct virtio_device vdev;
struct pci_dev *pci_dev;
/* the IO mapping for the PCI config space */
void *ioaddr;
/* a list of queues so we can dispatch IRQs */
spinlock_t lock;
struct list_head virtqueues;
};
struct virtio_pci_vq_info
{
/* the actual virtqueue */
struct virtqueue *vq;
/* the number of entries in the queue */
int num;
/* the index of the queue */
int queue_index;
/* the virtual address of the ring queue */
void *queue;
/* the list node for the virtqueues list */
struct list_head node;
};
/* Qumranet donated their vendor ID for devices 0x1000 thru 0x10FF. */
static struct pci_device_id virtio_pci_id_table[] = {
{ 0x1af4, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0 },
{ 0 },
};
MODULE_DEVICE_TABLE(pci, virtio_pci_id_table);
/* A PCI device has it's own struct device and so does a virtio device so
* we create a place for the virtio devices to show up in sysfs. I think it
* would make more sense for virtio to not insist on having it's own device. */
static struct device virtio_pci_root = {
.parent = NULL,
.bus_id = "virtio-pci",
};
/* Unique numbering for devices under the kvm root */
static unsigned int dev_index;
/* Convert a generic virtio device to our structure */
static struct virtio_pci_device *to_vp_device(struct virtio_device *vdev)
{
return container_of(vdev, struct virtio_pci_device, vdev);
}
/* virtio config->feature() implementation */
static bool vp_feature(struct virtio_device *vdev, unsigned bit)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
u32 mask;
/* Since this function is supposed to have the side effect of
* enabling a queried feature, we simulate that by doing a read
* from the host feature bitmask and then writing to the guest
* feature bitmask */
mask = ioread32(vp_dev->ioaddr + VIRTIO_PCI_HOST_FEATURES);
if (mask & (1 << bit)) {
mask |= (1 << bit);
iowrite32(mask, vp_dev->ioaddr + VIRTIO_PCI_GUEST_FEATURES);
}
return !!(mask & (1 << bit));
}
/* virtio config->get() implementation */
static void vp_get(struct virtio_device *vdev, unsigned offset,
void *buf, unsigned len)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
void *ioaddr = vp_dev->ioaddr + VIRTIO_PCI_CONFIG + 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 offset,
const void *buf, unsigned len)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
void *ioaddr = vp_dev->ioaddr + VIRTIO_PCI_CONFIG + 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 ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS);
}
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);
return iowrite8(status, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
}
static void vp_reset(struct virtio_device *vdev)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
/* 0 status means a reset. */
return iowrite8(0, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
}
/* the notify function used when creating a virt queue */
static void vp_notify(struct virtqueue *vq)
{
struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
struct virtio_pci_vq_info *info = vq->priv;
/* we write the queue's selector into the notification register to
* signal the other end */
iowrite16(info->queue_index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY);
}
/* A small wrapper to also acknowledge the interrupt when it's handled.
* I really need an EIO hook for the vring so I can ack the interrupt once we
* know that we'll be handling the IRQ but before we invoke the callback since
* the callback may notify the host which results in the host attempting to
* raise an interrupt that we would then mask once we acknowledged the
* interrupt. */
static irqreturn_t vp_interrupt(int irq, void *opaque)
{
struct virtio_pci_device *vp_dev = opaque;
struct virtio_pci_vq_info *info;
irqreturn_t ret = IRQ_NONE;
u8 isr;
/* reading the ISR has the effect of also clearing it so it's very
* important to save off the value. */
isr = ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR);
/* It's definitely not us if the ISR was not high */
if (!isr)
return IRQ_NONE;
/* Configuration change? Tell driver if it wants to know. */
if (isr & VIRTIO_PCI_ISR_CONFIG) {
struct virtio_driver *drv;
drv = container_of(vp_dev->vdev.dev.driver,
struct virtio_driver, driver);
if (drv->config_changed)
drv->config_changed(&vp_dev->vdev);
}
spin_lock(&vp_dev->lock);
list_for_each_entry(info, &vp_dev->virtqueues, node) {
if (vring_interrupt(irq, info->vq) == IRQ_HANDLED)
ret = IRQ_HANDLED;
}
spin_unlock(&vp_dev->lock);
return ret;
}
/* the config->find_vq() implementation */
static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index,
void (*callback)(struct virtqueue *vq))
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
struct virtio_pci_vq_info *info;
struct virtqueue *vq;
u16 num;
int err;
/* Select the queue we're interested in */
iowrite16(index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
/* Check if queue is either not available or already active. */
num = ioread16(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NUM);
if (!num || ioread32(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN))
return ERR_PTR(-ENOENT);
/* allocate and fill out our structure the represents an active
* queue */
info = kmalloc(sizeof(struct virtio_pci_vq_info), GFP_KERNEL);
if (!info)
return ERR_PTR(-ENOMEM);
info->queue_index = index;
info->num = num;
info->queue = kzalloc(PAGE_ALIGN(vring_size(num,PAGE_SIZE)), GFP_KERNEL);
if (info->queue == NULL) {
err = -ENOMEM;
goto out_info;
}
/* activate the queue */
iowrite32(virt_to_phys(info->queue) >> PAGE_SHIFT,
vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
/* create the vring */
vq = vring_new_virtqueue(info->num, vdev, info->queue,
vp_notify, callback);
if (!vq) {
err = -ENOMEM;
goto out_activate_queue;
}
vq->priv = info;
info->vq = vq;
spin_lock(&vp_dev->lock);
list_add(&info->node, &vp_dev->virtqueues);
spin_unlock(&vp_dev->lock);
return vq;
out_activate_queue:
iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
kfree(info->queue);
out_info:
kfree(info);
return ERR_PTR(err);
}
/* the config->del_vq() implementation */
static void vp_del_vq(struct virtqueue *vq)
{
struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
struct virtio_pci_vq_info *info = vq->priv;
spin_lock(&vp_dev->lock);
list_del(&info->node);
spin_unlock(&vp_dev->lock);
vring_del_virtqueue(vq);
/* Select and deactivate the queue */
iowrite16(info->queue_index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
kfree(info->queue);
kfree(info);
}
static struct virtio_config_ops virtio_pci_config_ops = {
.feature = vp_feature,
.get = vp_get,
.set = vp_set,
.get_status = vp_get_status,
.set_status = vp_set_status,
.reset = vp_reset,
.find_vq = vp_find_vq,
.del_vq = vp_del_vq,
};
/* the PCI probing function */
static int __devinit virtio_pci_probe(struct pci_dev *pci_dev,
const struct pci_device_id *id)
{
struct virtio_pci_device *vp_dev;
int err;
/* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */
if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f)
return -ENODEV;
if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) {
printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n",
VIRTIO_PCI_ABI_VERSION, pci_dev->revision);
return -ENODEV;
}
/* allocate our structure and fill it out */
vp_dev = kzalloc(sizeof(struct virtio_pci_device), GFP_KERNEL);
if (vp_dev == NULL)
return -ENOMEM;
snprintf(vp_dev->vdev.dev.bus_id, BUS_ID_SIZE, "virtio%d", dev_index);
vp_dev->vdev.index = dev_index;
dev_index++;
vp_dev->vdev.dev.parent = &virtio_pci_root;
vp_dev->vdev.config = &virtio_pci_config_ops;
vp_dev->pci_dev = pci_dev;
INIT_LIST_HEAD(&vp_dev->virtqueues);
spin_lock_init(&vp_dev->lock);
/* enable the device */
err = pci_enable_device(pci_dev);
if (err)
goto out;
err = pci_request_regions(pci_dev, "virtio-pci");
if (err)
goto out_enable_device;
vp_dev->ioaddr = pci_iomap(pci_dev, 0, 0);
if (vp_dev->ioaddr == NULL)
goto out_req_regions;
pci_set_drvdata(pci_dev, vp_dev);
/* we use the subsystem vendor/device id as the virtio vendor/device
* id. this allows us to use the same PCI vendor/device id for all
* virtio devices and to identify the particular virtio driver by
* the subsytem ids */
vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
vp_dev->vdev.id.device = pci_dev->subsystem_device;
/* register a handler for the queue with the PCI device's interrupt */
err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, IRQF_SHARED,
vp_dev->vdev.dev.bus_id, vp_dev);
if (err)
goto out_set_drvdata;
/* finally register the virtio device */
err = register_virtio_device(&vp_dev->vdev);
if (err)
goto out_req_irq;
return 0;
out_req_irq:
free_irq(pci_dev->irq, vp_dev);
out_set_drvdata:
pci_set_drvdata(pci_dev, NULL);
pci_iounmap(pci_dev, vp_dev->ioaddr);
out_req_regions:
pci_release_regions(pci_dev);
out_enable_device:
pci_disable_device(pci_dev);
out:
kfree(vp_dev);
return err;
}
static void __devexit virtio_pci_remove(struct pci_dev *pci_dev)
{
struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
free_irq(pci_dev->irq, vp_dev);
pci_set_drvdata(pci_dev, NULL);
pci_iounmap(pci_dev, vp_dev->ioaddr);
pci_release_regions(pci_dev);
pci_disable_device(pci_dev);
kfree(vp_dev);
}
#ifdef CONFIG_PM
static int virtio_pci_suspend(struct pci_dev *pci_dev, pm_message_t state)
{
pci_save_state(pci_dev);
pci_set_power_state(pci_dev, PCI_D3hot);
return 0;
}
static int virtio_pci_resume(struct pci_dev *pci_dev)
{
pci_restore_state(pci_dev);
pci_set_power_state(pci_dev, PCI_D0);
return 0;
}
#endif
static struct pci_driver virtio_pci_driver = {
.name = "virtio-pci",
.id_table = virtio_pci_id_table,
.probe = virtio_pci_probe,
.remove = virtio_pci_remove,
#ifdef CONFIG_PM
.suspend = virtio_pci_suspend,
.resume = virtio_pci_resume,
#endif
};
static int __init virtio_pci_init(void)
{
int err;
err = device_register(&virtio_pci_root);
if (err)
return err;
err = pci_register_driver(&virtio_pci_driver);
if (err)
device_unregister(&virtio_pci_root);
return err;
}
module_init(virtio_pci_init);
static void __exit virtio_pci_exit(void)
{
device_unregister(&virtio_pci_root);
pci_unregister_driver(&virtio_pci_driver);
}
module_exit(virtio_pci_exit);
