virtio: PCI device
This is a PCI device that implements a transport for virtio. It allows virtio devices to be used by QEMU based VMMs like KVM or Xen. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Anthony Liguori
Rusty Russell
parent
d50ed907dc
commit
3343660d8c
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@ -6,3 +6,20 @@ config VIRTIO
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config VIRTIO_RING
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tristate
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depends on VIRTIO
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config VIRTIO_PCI
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tristate "PCI driver for virtio devices (EXPERIMENTAL)"
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depends on PCI && EXPERIMENTAL
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select VIRTIO
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select VIRTIO_RING
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---help---
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This drivers provides support for virtio based paravirtual device
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drivers over PCI. This requires that your VMM has appropriate PCI
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virtio backends. Most QEMU based VMMs should support these devices
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(like KVM or Xen).
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Currently, the ABI is not considered stable so there is no guarantee
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that this version of the driver will work with your VMM.
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If unsure, say M.
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@ -1,2 +1,3 @@
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obj-$(CONFIG_VIRTIO) += virtio.o
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obj-$(CONFIG_VIRTIO_RING) += virtio_ring.o
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obj-$(CONFIG_VIRTIO_PCI) += virtio_pci.o
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@ -0,0 +1,440 @@
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/*
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* Virtio PCI driver
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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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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.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 <linux/module.h>
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#include <linux/list.h>
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#include <linux/pci.h>
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#include <linux/interrupt.h>
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#include <linux/virtio.h>
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#include <linux/virtio_config.h>
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#include <linux/virtio_ring.h>
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#include <linux/virtio_pci.h>
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#include <linux/highmem.h>
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#include <linux/spinlock.h>
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MODULE_AUTHOR("Anthony Liguori <aliguori@us.ibm.com>");
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MODULE_DESCRIPTION("virtio-pci");
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MODULE_LICENSE("GPL");
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MODULE_VERSION("1");
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/* Our device structure */
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struct virtio_pci_device
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{
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struct virtio_device vdev;
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struct pci_dev *pci_dev;
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/* the IO mapping for the PCI config space */
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void *ioaddr;
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/* a list of queues so we can dispatch IRQs */
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spinlock_t lock;
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struct list_head virtqueues;
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};
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struct virtio_pci_vq_info
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{
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/* the actual virtqueue */
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struct virtqueue *vq;
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/* the number of entries in the queue */
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int num;
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/* the index of the queue */
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int queue_index;
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/* the virtual address of the ring queue */
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void *queue;
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/* the list node for the virtqueues list */
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struct list_head node;
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};
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/* Qumranet donated their vendor ID for devices 0x1000 thru 0x10FF. */
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static struct pci_device_id virtio_pci_id_table[] = {
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{ 0x1af4, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0 },
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{ 0 },
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};
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MODULE_DEVICE_TABLE(pci, virtio_pci_id_table);
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/* A PCI device has it's own struct device and so does a virtio device so
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* we create a place for the virtio devices to show up in sysfs. I think it
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* would make more sense for virtio to not insist on having it's own device. */
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static struct device virtio_pci_root = {
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.parent = NULL,
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.bus_id = "virtio-pci",
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};
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/* Unique numbering for devices under the kvm root */
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static unsigned int dev_index;
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/* Convert a generic virtio device to our structure */
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static struct virtio_pci_device *to_vp_device(struct virtio_device *vdev)
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{
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return container_of(vdev, struct virtio_pci_device, vdev);
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}
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/* virtio config->feature() implementation */
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static bool vp_feature(struct virtio_device *vdev, unsigned bit)
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{
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struct virtio_pci_device *vp_dev = to_vp_device(vdev);
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u32 mask;
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/* Since this function is supposed to have the side effect of
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* enabling a queried feature, we simulate that by doing a read
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* from the host feature bitmask and then writing to the guest
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* feature bitmask */
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mask = ioread32(vp_dev->ioaddr + VIRTIO_PCI_HOST_FEATURES);
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if (mask & (1 << bit)) {
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mask |= (1 << bit);
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iowrite32(mask, vp_dev->ioaddr + VIRTIO_PCI_GUEST_FEATURES);
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}
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return !!(mask & (1 << bit));
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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 *ioaddr = vp_dev->ioaddr + VIRTIO_PCI_CONFIG + 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 *ioaddr = vp_dev->ioaddr + VIRTIO_PCI_CONFIG + 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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return 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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return iowrite8(0, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
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}
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/* the notify function used when creating a virt queue */
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static void vp_notify(struct virtqueue *vq)
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{
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struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
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struct virtio_pci_vq_info *info = vq->priv;
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/* we write the queue's selector into the notification register to
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* signal the other end */
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iowrite16(info->queue_index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY);
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}
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/* A small wrapper to also acknowledge the interrupt when it's handled.
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* I really need an EIO hook for the vring so I can ack the interrupt once we
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* know that we'll be handling the IRQ but before we invoke the callback since
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* the callback may notify the host which results in the host attempting to
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* raise an interrupt that we would then mask once we acknowledged the
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* interrupt. */
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static irqreturn_t vp_interrupt(int irq, void *opaque)
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{
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struct virtio_pci_device *vp_dev = opaque;
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struct virtio_pci_vq_info *info;
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irqreturn_t ret = IRQ_NONE;
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u8 isr;
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/* reading the ISR has the effect of also clearing it so it's very
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* important to save off the value. */
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isr = ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR);
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/* It's definitely not us if the ISR was not high */
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if (!isr)
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return IRQ_NONE;
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/* Configuration change? Tell driver if it wants to know. */
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if (isr & VIRTIO_PCI_ISR_CONFIG) {
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struct virtio_driver *drv;
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drv = container_of(vp_dev->vdev.dev.driver,
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struct virtio_driver, driver);
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if (drv->config_changed)
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drv->config_changed(&vp_dev->vdev);
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}
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spin_lock(&vp_dev->lock);
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list_for_each_entry(info, &vp_dev->virtqueues, node) {
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if (vring_interrupt(irq, info->vq) == IRQ_HANDLED)
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ret = IRQ_HANDLED;
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}
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spin_unlock(&vp_dev->lock);
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return ret;
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}
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/* the config->find_vq() implementation */
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static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index,
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void (*callback)(struct virtqueue *vq))
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{
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struct virtio_pci_device *vp_dev = to_vp_device(vdev);
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struct virtio_pci_vq_info *info;
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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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/* allocate and fill out our structure the represents an active
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* queue */
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info = kmalloc(sizeof(struct virtio_pci_vq_info), GFP_KERNEL);
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if (!info)
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return ERR_PTR(-ENOMEM);
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info->queue_index = index;
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info->num = num;
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info->queue = kzalloc(PAGE_ALIGN(vring_size(num,PAGE_SIZE)), GFP_KERNEL);
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if (info->queue == NULL) {
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err = -ENOMEM;
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goto out_info;
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}
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/* activate the queue */
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iowrite32(virt_to_phys(info->queue) >> PAGE_SHIFT,
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vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
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/* create the vring */
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vq = vring_new_virtqueue(info->num, vdev, info->queue,
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vp_notify, callback);
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if (!vq) {
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err = -ENOMEM;
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goto out_activate_queue;
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}
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vq->priv = info;
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info->vq = vq;
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spin_lock(&vp_dev->lock);
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list_add(&info->node, &vp_dev->virtqueues);
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spin_unlock(&vp_dev->lock);
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return vq;
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out_activate_queue:
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iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
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kfree(info->queue);
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out_info:
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kfree(info);
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return ERR_PTR(err);
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}
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/* the config->del_vq() implementation */
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static void vp_del_vq(struct virtqueue *vq)
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{
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struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
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struct virtio_pci_vq_info *info = vq->priv;
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spin_lock(&vp_dev->lock);
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list_del(&info->node);
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spin_unlock(&vp_dev->lock);
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vring_del_virtqueue(vq);
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/* Select and deactivate the queue */
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iowrite16(info->queue_index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
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iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
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kfree(info->queue);
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kfree(info);
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}
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static struct virtio_config_ops virtio_pci_config_ops = {
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.feature = vp_feature,
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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_vq = vp_find_vq,
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.del_vq = vp_del_vq,
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};
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/* the PCI probing function */
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static int __devinit virtio_pci_probe(struct pci_dev *pci_dev,
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const struct pci_device_id *id)
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{
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struct virtio_pci_device *vp_dev;
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int err;
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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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/* allocate our structure and fill it out */
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vp_dev = kzalloc(sizeof(struct virtio_pci_device), GFP_KERNEL);
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if (vp_dev == NULL)
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return -ENOMEM;
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snprintf(vp_dev->vdev.dev.bus_id, BUS_ID_SIZE, "virtio%d", dev_index);
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vp_dev->vdev.index = dev_index;
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dev_index++;
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vp_dev->vdev.dev.parent = &virtio_pci_root;
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vp_dev->vdev.config = &virtio_pci_config_ops;
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vp_dev->pci_dev = pci_dev;
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INIT_LIST_HEAD(&vp_dev->virtqueues);
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spin_lock_init(&vp_dev->lock);
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/* enable the device */
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err = pci_enable_device(pci_dev);
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if (err)
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goto out;
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err = pci_request_regions(pci_dev, "virtio-pci");
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if (err)
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goto out_enable_device;
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vp_dev->ioaddr = pci_iomap(pci_dev, 0, 0);
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if (vp_dev->ioaddr == NULL)
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goto out_req_regions;
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pci_set_drvdata(pci_dev, vp_dev);
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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 subsytem 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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/* register a handler for the queue with the PCI device's interrupt */
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err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, IRQF_SHARED,
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vp_dev->vdev.dev.bus_id, vp_dev);
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if (err)
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goto out_set_drvdata;
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/* finally register the virtio device */
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err = register_virtio_device(&vp_dev->vdev);
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if (err)
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goto out_req_irq;
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return 0;
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out_req_irq:
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free_irq(pci_dev->irq, vp_dev);
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out_set_drvdata:
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pci_set_drvdata(pci_dev, NULL);
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pci_iounmap(pci_dev, vp_dev->ioaddr);
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out_req_regions:
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pci_release_regions(pci_dev);
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out_enable_device:
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pci_disable_device(pci_dev);
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out:
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kfree(vp_dev);
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return err;
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}
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static void __devexit virtio_pci_remove(struct pci_dev *pci_dev)
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{
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struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
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free_irq(pci_dev->irq, vp_dev);
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pci_set_drvdata(pci_dev, NULL);
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pci_iounmap(pci_dev, vp_dev->ioaddr);
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pci_release_regions(pci_dev);
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pci_disable_device(pci_dev);
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kfree(vp_dev);
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}
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#ifdef CONFIG_PM
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static int virtio_pci_suspend(struct pci_dev *pci_dev, pm_message_t state)
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{
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pci_save_state(pci_dev);
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pci_set_power_state(pci_dev, PCI_D3hot);
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return 0;
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}
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static int virtio_pci_resume(struct pci_dev *pci_dev)
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{
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pci_restore_state(pci_dev);
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pci_set_power_state(pci_dev, PCI_D0);
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return 0;
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}
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#endif
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static struct pci_driver virtio_pci_driver = {
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.name = "virtio-pci",
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.id_table = virtio_pci_id_table,
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.probe = virtio_pci_probe,
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.remove = virtio_pci_remove,
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#ifdef CONFIG_PM
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.suspend = virtio_pci_suspend,
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.resume = virtio_pci_resume,
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#endif
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};
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static int __init virtio_pci_init(void)
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{
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int err;
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err = device_register(&virtio_pci_root);
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if (err)
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return err;
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err = pci_register_driver(&virtio_pci_driver);
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if (err)
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device_unregister(&virtio_pci_root);
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return err;
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}
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module_init(virtio_pci_init);
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static void __exit virtio_pci_exit(void)
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{
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device_unregister(&virtio_pci_root);
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||||
pci_unregister_driver(&virtio_pci_driver);
|
||||
}
|
||||
|
||||
module_exit(virtio_pci_exit);
|
||||
|
|
@ -0,0 +1,55 @@
|
|||
/*
|
||||
* 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.
|
||||
*
|
||||
*/
|
||||
|
||||
#ifndef _LINUX_VIRTIO_PCI_H
|
||||
#define _LINUX_VIRTIO_PCI_H
|
||||
|
||||
#include <linux/virtio_config.h>
|
||||
|
||||
/* A 32-bit r/o bitmask of the features supported by the host */
|
||||
#define VIRTIO_PCI_HOST_FEATURES 0
|
||||
|
||||
/* A 32-bit r/w bitmask of features activated by the guest */
|
||||
#define VIRTIO_PCI_GUEST_FEATURES 4
|
||||
|
||||
/* A 32-bit r/w PFN for the currently selected queue */
|
||||
#define VIRTIO_PCI_QUEUE_PFN 8
|
||||
|
||||
/* A 16-bit r/o queue size for the currently selected queue */
|
||||
#define VIRTIO_PCI_QUEUE_NUM 12
|
||||
|
||||
/* A 16-bit r/w queue selector */
|
||||
#define VIRTIO_PCI_QUEUE_SEL 14
|
||||
|
||||
/* A 16-bit r/w queue notifier */
|
||||
#define VIRTIO_PCI_QUEUE_NOTIFY 16
|
||||
|
||||
/* An 8-bit device status register. */
|
||||
#define VIRTIO_PCI_STATUS 18
|
||||
|
||||
/* An 8-bit r/o interrupt status register. Reading the value will return the
|
||||
* current contents of the ISR and will also clear it. This is effectively
|
||||
* a read-and-acknowledge. */
|
||||
#define VIRTIO_PCI_ISR 19
|
||||
|
||||
/* The bit of the ISR which indicates a device configuration change. */
|
||||
#define VIRTIO_PCI_ISR_CONFIG 0x2
|
||||
|
||||
/* The remaining space is defined by each driver as the per-driver
|
||||
* configuration space */
|
||||
#define VIRTIO_PCI_CONFIG 20
|
||||
|
||||
#endif
|
||||
Reference in New Issue