diff options
Diffstat (limited to 'drivers/virtio')
| -rw-r--r-- | drivers/virtio/Kconfig | 17 | ||||
| -rw-r--r-- | drivers/virtio/Makefile | 1 | ||||
| -rw-r--r-- | drivers/virtio/virtio_pci.c | 440 |
3 files changed, 458 insertions, 0 deletions
diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig index de0c8c2654e..833db2f36e9 100644 --- a/drivers/virtio/Kconfig +++ b/drivers/virtio/Kconfig @@ -6,3 +6,20 @@ config VIRTIO config VIRTIO_RING tristate 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. + diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile index f70e40971dd..cc84999f305 100644 --- a/drivers/virtio/Makefile +++ b/drivers/virtio/Makefile @@ -1,2 +1,3 @@ obj-$(CONFIG_VIRTIO) += virtio.o obj-$(CONFIG_VIRTIO_RING) += virtio_ring.o +obj-$(CONFIG_VIRTIO_PCI) += virtio_pci.o diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c new file mode 100644 index 00000000000..192687e3a56 --- /dev/null +++ b/drivers/virtio/virtio_pci.c @@ -0,0 +1,440 @@ +/* + * 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; + + /* 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); |