This patch introduces a new mdev transport for virtio. This is used to use kernel virtio driver to drive the mediated device that is capable of populating virtqueue directly.
A new virtio-mdev driver will be registered to the mdev bus, when a new virtio-mdev device is probed, it will register the device with mdev based config ops. This means it is a software transport between mdev driver and mdev device. The transport was implemented through device specific opswhich is a part of mdev_parent_ops now.
Signed-off-by: Jason Wang jasowang@redhat.com --- drivers/virtio/Kconfig | 7 + drivers/virtio/Makefile | 1 + drivers/virtio/virtio_mdev.c | 416 +++++++++++++++++++++++++++++++++++ 3 files changed, 424 insertions(+) create mode 100644 drivers/virtio/virtio_mdev.c
diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig index 078615cf2afc..8d18722ab572 100644 --- a/drivers/virtio/Kconfig +++ b/drivers/virtio/Kconfig @@ -43,6 +43,13 @@ config VIRTIO_PCI_LEGACY
If unsure, say Y.
+config VIRTIO_MDEV_DEVICE + tristate "VIRTIO driver for Mediated devices" + depends on VFIO_MDEV && VIRTIO + default n + help + VIRTIO based driver for Mediated devices. + config VIRTIO_PMEM tristate "Support for virtio pmem driver" depends on VIRTIO diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile index 3a2b5c5dcf46..ebc7fa15ae82 100644 --- a/drivers/virtio/Makefile +++ b/drivers/virtio/Makefile @@ -6,3 +6,4 @@ virtio_pci-y := virtio_pci_modern.o virtio_pci_common.o virtio_pci-$(CONFIG_VIRTIO_PCI_LEGACY) += virtio_pci_legacy.o obj-$(CONFIG_VIRTIO_BALLOON) += virtio_balloon.o obj-$(CONFIG_VIRTIO_INPUT) += virtio_input.o +obj-$(CONFIG_VIRTIO_MDEV_DEVICE) += virtio_mdev.o diff --git a/drivers/virtio/virtio_mdev.c b/drivers/virtio/virtio_mdev.c new file mode 100644 index 000000000000..8516f3f0f658 --- /dev/null +++ b/drivers/virtio/virtio_mdev.c @@ -0,0 +1,416 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * VIRTIO based driver for Mediated device + * + * Copyright (c) 2019, Red Hat. All rights reserved. + * Author: Jason Wang jasowang@redhat.com + * + */ + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/device.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/uuid.h> +#include <linux/mdev.h> +#include <linux/virtio_mdev.h> +#include <linux/virtio.h> +#include <linux/virtio_config.h> +#include <linux/virtio_ring.h> + +#define DRIVER_VERSION "0.1" +#define DRIVER_AUTHOR "Red Hat Corporation" +#define DRIVER_DESC "VIRTIO based driver for Mediated device" + +#define to_virtio_mdev_device(dev) \ + container_of(dev, struct virtio_mdev_device, vdev) + +struct virtio_mdev_device { + struct virtio_device vdev; + struct mdev_device *mdev; + unsigned long version; + + struct virtqueue **vqs; + /* The lock to protect virtqueue list */ + spinlock_t lock; + struct list_head virtqueues; +}; + +struct virtio_mdev_vq_info { + /* the actual virtqueue */ + struct virtqueue *vq; + + /* the list node for the virtqueues list */ + struct list_head node; +}; + +static struct mdev_device *vm_get_mdev(struct virtio_device *vdev) +{ + struct virtio_mdev_device *vm_dev = to_virtio_mdev_device(vdev); + struct mdev_device *mdev = vm_dev->mdev; + + return mdev; +} + +static void virtio_mdev_get(struct virtio_device *vdev, unsigned offset, + void *buf, unsigned len) +{ + struct mdev_device *mdev = vm_get_mdev(vdev); + const struct virtio_mdev_device_ops *ops = mdev_get_dev_ops(mdev); + + ops->get_config(mdev, offset, buf, len); +} + +static void virtio_mdev_set(struct virtio_device *vdev, unsigned offset, + const void *buf, unsigned len) +{ + struct mdev_device *mdev = vm_get_mdev(vdev); + const struct virtio_mdev_device_ops *ops = mdev_get_dev_ops(mdev); + + ops->set_config(mdev, offset, buf, len); +} + +static u32 virtio_mdev_generation(struct virtio_device *vdev) +{ + struct mdev_device *mdev = vm_get_mdev(vdev); + const struct virtio_mdev_device_ops *ops = mdev_get_dev_ops(mdev); + + return ops->get_generation(mdev); +} + +static u8 virtio_mdev_get_status(struct virtio_device *vdev) +{ + struct mdev_device *mdev = vm_get_mdev(vdev); + const struct virtio_mdev_device_ops *ops = mdev_get_dev_ops(mdev); + + return ops->get_status(mdev); +} + +static void virtio_mdev_set_status(struct virtio_device *vdev, u8 status) +{ + struct mdev_device *mdev = vm_get_mdev(vdev); + const struct virtio_mdev_device_ops *ops = mdev_get_dev_ops(mdev); + + return ops->set_status(mdev, status); +} + +static void virtio_mdev_reset(struct virtio_device *vdev) +{ + struct mdev_device *mdev = vm_get_mdev(vdev); + const struct virtio_mdev_device_ops *ops = mdev_get_dev_ops(mdev); + + return ops->set_status(mdev, 0); +} + +static bool virtio_mdev_notify(struct virtqueue *vq) +{ + struct mdev_device *mdev = vm_get_mdev(vq->vdev); + const struct virtio_mdev_device_ops *ops = mdev_get_dev_ops(mdev); + + ops->kick_vq(mdev, vq->index); + + return true; +} + +static irqreturn_t virtio_mdev_config_cb(void *private) +{ + struct virtio_mdev_device *vm_dev = private; + + virtio_config_changed(&vm_dev->vdev); + + return IRQ_HANDLED; +} + +static irqreturn_t virtio_mdev_virtqueue_cb(void *private) +{ + struct virtio_mdev_vq_info *info = private; + + return vring_interrupt(0, info->vq); +} + +static struct virtqueue * +virtio_mdev_setup_vq(struct virtio_device *vdev, unsigned index, + void (*callback)(struct virtqueue *vq), + const char *name, bool ctx) +{ + struct virtio_mdev_device *vm_dev = to_virtio_mdev_device(vdev); + struct mdev_device *mdev = vm_get_mdev(vdev); + const struct virtio_mdev_device_ops *ops = mdev_get_dev_ops(mdev); + struct virtio_mdev_vq_info *info; + struct virtio_mdev_callback cb; + struct virtqueue *vq; + u64 desc_addr, driver_addr, device_addr; + unsigned long flags; + u32 align, num; + int err; + + if (!name) + return NULL; + + /* Queue shouldn't already be set up. */ + if (ops->get_vq_ready(mdev, index)) + return ERR_PTR(-ENOENT); + + /* Allocate and fill out our active queue description */ + info = kmalloc(sizeof(*info), GFP_KERNEL); + if (!info) + return ERR_PTR(-ENOMEM); + + num = ops->get_vq_num_max(mdev); + if (num == 0) { + err = -ENOENT; + goto error_new_virtqueue; + } + + /* Create the vring */ + align = ops->get_vq_align(mdev); + vq = vring_create_virtqueue(index, num, align, vdev, + true, true, ctx, + virtio_mdev_notify, callback, name); + if (!vq) { + err = -ENOMEM; + goto error_new_virtqueue; + } + + /* Setup virtqueue callback */ + cb.callback = virtio_mdev_virtqueue_cb; + cb.private = info; + ops->set_vq_cb(mdev, index, &cb); + ops->set_vq_num(mdev, index, virtqueue_get_vring_size(vq)); + + desc_addr = virtqueue_get_desc_addr(vq); + driver_addr = virtqueue_get_avail_addr(vq); + device_addr = virtqueue_get_used_addr(vq); + + if (ops->set_vq_address(mdev, index, + desc_addr, driver_addr, + device_addr)) { + err = -EINVAL; + goto err_vq; + } + + ops->set_vq_ready(mdev, index, 1); + + vq->priv = info; + info->vq = vq; + + spin_lock_irqsave(&vm_dev->lock, flags); + list_add(&info->node, &vm_dev->virtqueues); + spin_unlock_irqrestore(&vm_dev->lock, flags); + + return vq; + +err_vq: + vring_del_virtqueue(vq); +error_new_virtqueue: + ops->set_vq_ready(mdev, index, 0); + WARN_ON(ops->get_vq_ready(mdev, index)); + kfree(info); + return ERR_PTR(err); + +} + +static void virtio_mdev_del_vq(struct virtqueue *vq) +{ + struct virtio_mdev_device *vm_dev = to_virtio_mdev_device(vq->vdev); + struct mdev_device *mdev = vm_dev->mdev; + const struct virtio_mdev_device_ops *ops = mdev_get_dev_ops(mdev); + struct virtio_mdev_vq_info *info = vq->priv; + unsigned int index = vq->index; + unsigned long flags; + + spin_lock_irqsave(&vm_dev->lock, flags); + list_del(&info->node); + spin_unlock_irqrestore(&vm_dev->lock, flags); + + /* Select and deactivate the queue */ + ops->set_vq_ready(mdev, index, 0); + WARN_ON(ops->get_vq_ready(mdev, index)); + + vring_del_virtqueue(vq); + + kfree(info); +} + +static void virtio_mdev_del_vqs(struct virtio_device *vdev) +{ + struct virtqueue *vq, *n; + + list_for_each_entry_safe(vq, n, &vdev->vqs, list) + virtio_mdev_del_vq(vq); +} + +static int virtio_mdev_find_vqs(struct virtio_device *vdev, unsigned nvqs, + struct virtqueue *vqs[], + vq_callback_t *callbacks[], + const char * const names[], + const bool *ctx, + struct irq_affinity *desc) +{ + struct virtio_mdev_device *vm_dev = to_virtio_mdev_device(vdev); + struct mdev_device *mdev = vm_get_mdev(vdev); + const struct virtio_mdev_device_ops *ops = mdev_get_dev_ops(mdev); + struct virtio_mdev_callback cb; + int i, err, queue_idx = 0; + + vm_dev->vqs = kmalloc_array(queue_idx, sizeof(*vm_dev->vqs), + GFP_KERNEL); + if (!vm_dev->vqs) + return -ENOMEM; + + for (i = 0; i < nvqs; ++i) { + if (!names[i]) { + vqs[i] = NULL; + continue; + } + + vqs[i] = virtio_mdev_setup_vq(vdev, queue_idx++, + callbacks[i], names[i], ctx ? + ctx[i] : false); + if (IS_ERR(vqs[i])) { + err = PTR_ERR(vqs[i]); + goto err_setup_vq; + } + } + + cb.callback = virtio_mdev_config_cb; + cb.private = vm_dev; + ops->set_config_cb(mdev, &cb); + + return 0; + +err_setup_vq: + kfree(vm_dev->vqs); + virtio_mdev_del_vqs(vdev); + return err; +} + +static u64 virtio_mdev_get_features(struct virtio_device *vdev) +{ + struct mdev_device *mdev = vm_get_mdev(vdev); + const struct virtio_mdev_device_ops *ops = mdev_get_dev_ops(mdev); + + return ops->get_features(mdev); +} + +static int virtio_mdev_finalize_features(struct virtio_device *vdev) +{ + struct mdev_device *mdev = vm_get_mdev(vdev); + const struct virtio_mdev_device_ops *ops = mdev_get_dev_ops(mdev); + + /* Give virtio_ring a chance to accept features. */ + vring_transport_features(vdev); + + return ops->set_features(mdev, vdev->features); +} + +static const char *virtio_mdev_bus_name(struct virtio_device *vdev) +{ + struct virtio_mdev_device *vm_dev = to_virtio_mdev_device(vdev); + struct mdev_device *mdev = vm_dev->mdev; + + return dev_name(mdev_dev(mdev)); +} + +static const struct virtio_config_ops virtio_mdev_config_ops = { + .get = virtio_mdev_get, + .set = virtio_mdev_set, + .generation = virtio_mdev_generation, + .get_status = virtio_mdev_get_status, + .set_status = virtio_mdev_set_status, + .reset = virtio_mdev_reset, + .find_vqs = virtio_mdev_find_vqs, + .del_vqs = virtio_mdev_del_vqs, + .get_features = virtio_mdev_get_features, + .finalize_features = virtio_mdev_finalize_features, + .bus_name = virtio_mdev_bus_name, +}; + +static void virtio_mdev_release_dev(struct device *_d) +{ + struct virtio_device *vdev = + container_of(_d, struct virtio_device, dev); + struct virtio_mdev_device *vm_dev = + container_of(vdev, struct virtio_mdev_device, vdev); + + devm_kfree(_d, vm_dev); +} + +static int virtio_mdev_probe(struct device *dev) +{ + struct mdev_device *mdev = mdev_from_dev(dev); + const struct virtio_mdev_device_ops *ops = mdev_get_dev_ops(mdev); + struct virtio_mdev_device *vm_dev; + int rc; + + vm_dev = devm_kzalloc(dev, sizeof(*vm_dev), GFP_KERNEL); + if (!vm_dev) + return -ENOMEM; + + vm_dev->vdev.dev.parent = dev; + vm_dev->vdev.dev.release = virtio_mdev_release_dev; + vm_dev->vdev.config = &virtio_mdev_config_ops; + vm_dev->mdev = mdev; + vm_dev->vqs = NULL; + INIT_LIST_HEAD(&vm_dev->virtqueues); + spin_lock_init(&vm_dev->lock); + + vm_dev->version = ops->get_mdev_features(mdev); + if (vm_dev->version != VIRTIO_MDEV_F_VERSION_1) { + dev_err(dev, "VIRTIO_MDEV_F_VERSION_1 is mandatory\n"); + return -ENXIO; + } + + vm_dev->vdev.id.device = ops->get_device_id(mdev); + if (vm_dev->vdev.id.device == 0) + return -ENODEV; + + vm_dev->vdev.id.vendor = ops->get_vendor_id(mdev); + rc = register_virtio_device(&vm_dev->vdev); + if (rc) + put_device(dev); + else + dev_set_drvdata(dev, vm_dev); + + return rc; +} + +static void virtio_mdev_remove(struct device *dev) +{ + struct virtio_mdev_device *vm_dev = dev_get_drvdata(dev); + + unregister_virtio_device(&vm_dev->vdev); +} + +static struct mdev_class_id id_table[] = { + { MDEV_ID_VIRTIO }, + { 0 }, +}; + +MODULE_DEVICE_TABLE(mdev, id_table); + +static struct mdev_driver virtio_mdev_driver = { + .name = "virtio_mdev", + .probe = virtio_mdev_probe, + .remove = virtio_mdev_remove, + .id_table = id_table, +}; + +static int __init virtio_mdev_init(void) +{ + return mdev_register_driver(&virtio_mdev_driver, THIS_MODULE); +} + +static void __exit virtio_mdev_exit(void) +{ + mdev_unregister_driver(&virtio_mdev_driver); +} + +module_init(virtio_mdev_init) +module_exit(virtio_mdev_exit) + +MODULE_VERSION(DRIVER_VERSION); +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR(DRIVER_AUTHOR); +MODULE_DESCRIPTION(DRIVER_DESC);