virtio additions
Subsystems (2)
PATCH RESEND 5/13 virtio additions
From c8a8b56ccb6e12954b4752fd8ca46850fe354741 Mon Sep 17 00:00:00 2001
From: Anthony Liguori <aliguori-r/[email protected]>
Date: Mon, 12 Nov 2007 21:30:26 -0600
Subject: [PATCH] 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.
--- drivers/virtio/Kconfig | 17 ++ drivers/virtio/Makefile | 1 + drivers/virtio/virtio_pci.c | 414 +++++++++++++++++++++++++++++++++++++++++++ include/linux/virtio_pci.h | 52 ++++++ 4 files changed, 484 insertions(+), 0 deletions(-) create mode 100644 drivers/virtio/virtio_pci.c create mode 100644 include/linux/virtio_pci.h
drivers/virtio/Kconfig +17 -0
@@ -6,3 +6,20 @@ config VIRTIO config VIRTIO_RING bool depends on VIRTIO + +config VIRTIO_PCI + tristate "PCI driver for virtio devices (EXPERIMENTAL)" + depends on PCI && EXPERIMENTAL + select VIRTIO + select VIRTIO_RING + ---help--- + This drivers provides support for virtio based paravirtual device + drivers over PCI. This requires that your VMM has appropriate PCI + virtio backends. Most QEMU based VMMs should support these devices + (like KVM or Xen). + + Currently, the ABI is not considered stable so there is no guarantee + that this version of the driver will work with your VMM. + + If unsure, say M. +
drivers/virtio/Makefile +1 -0
@@ -1,2 +1,3 @@ obj-$(CONFIG_VIRTIO) += virtio.o obj-$(CONFIG_VIRTIO_RING) += virtio_ring.o +obj-$(CONFIG_VIRTIO_PCI) += virtio_pci.o
drivers/virtio/virtio_pci.c new file +76 -0
76 lines not on this page · raw message
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);
+ return iowrite8(status, 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;
+
+ 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,
+ bool (*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;
+
+ list_add(&info->node, &vp_dev->virtqueues);
+
+ 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;
+
+ list_del(&info->node);
+
+ 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, + .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;
+
+ /* 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);
include/linux/virtio_pci.h new file +43 -0
43 lines not on this page · raw message
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 remaining space is defined by each driver as the per-driver
+ * configuration space */
+#define VIRTIO_PCI_CONFIG 20
+
+#endif
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