virtio: introduce a vDPA based transport
This patch introduces a vDPA transport for virtio. This is used to use kernel virtio driver to drive the vDPA device that is capable of populating virtqueue directly. A new virtio-vdpa driver will be registered to the vDPA bus, when a new virtio-vdpa device is probed, it will register the device with vdpa based config ops. This means it is a software transport between vDPA driver and vDPA device. The transport was implemented through bus_ops of vDPA parent. Signed-off-by: Jason Wang <jasowang@redhat.com> Link: https://lore.kernel.org/r/20200326140125.19794-7-jasowang@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Jason Wang
Michael S. Tsirkin
parent
961e9c8407
commit
c043b4a8cf
@ -43,6 +43,19 @@ config VIRTIO_PCI_LEGACY
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If unsure, say Y.
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config VIRTIO_VDPA
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tristate "vDPA driver for virtio devices"
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select VDPA
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select VIRTIO
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help
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This driver provides support for virtio based paravirtual
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device driver over vDPA bus. For this to be useful, you need
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an appropriate vDPA device implementation that operates on a
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physical device to allow the datapath of virtio to be
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offloaded to hardware.
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If unsure, say M.
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config VIRTIO_PMEM
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tristate "Support for virtio pmem driver"
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depends on VIRTIO
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@ -6,4 +6,5 @@ virtio_pci-y := virtio_pci_modern.o virtio_pci_common.o
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virtio_pci-$(CONFIG_VIRTIO_PCI_LEGACY) += virtio_pci_legacy.o
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obj-$(CONFIG_VIRTIO_BALLOON) += virtio_balloon.o
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obj-$(CONFIG_VIRTIO_INPUT) += virtio_input.o
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obj-$(CONFIG_VIRTIO_VDPA) += virtio_vdpa.o
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obj-$(CONFIG_VDPA) += vdpa/
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396
drivers/virtio/virtio_vdpa.c
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396
drivers/virtio/virtio_vdpa.c
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@ -0,0 +1,396 @@
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* VIRTIO based driver for vDPA device
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*
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* Copyright (c) 2020, Red Hat. All rights reserved.
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* Author: Jason Wang <jasowang@redhat.com>
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*
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/uuid.h>
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#include <linux/virtio.h>
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#include <linux/vdpa.h>
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#include <linux/virtio_config.h>
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#include <linux/virtio_ring.h>
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#define MOD_VERSION "0.1"
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#define MOD_AUTHOR "Jason Wang <jasowang@redhat.com>"
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#define MOD_DESC "vDPA bus driver for virtio devices"
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#define MOD_LICENSE "GPL v2"
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struct virtio_vdpa_device {
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struct virtio_device vdev;
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struct vdpa_device *vdpa;
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u64 features;
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/* The lock to protect virtqueue list */
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spinlock_t lock;
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/* List of virtio_vdpa_vq_info */
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struct list_head virtqueues;
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};
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struct virtio_vdpa_vq_info {
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/* the actual virtqueue */
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struct virtqueue *vq;
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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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static inline struct virtio_vdpa_device *
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to_virtio_vdpa_device(struct virtio_device *dev)
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{
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return container_of(dev, struct virtio_vdpa_device, vdev);
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}
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static struct vdpa_device *vd_get_vdpa(struct virtio_device *vdev)
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{
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return to_virtio_vdpa_device(vdev)->vdpa;
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}
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static void virtio_vdpa_get(struct virtio_device *vdev, unsigned offset,
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void *buf, unsigned len)
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{
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struct vdpa_device *vdpa = vd_get_vdpa(vdev);
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const struct vdpa_config_ops *ops = vdpa->config;
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ops->get_config(vdpa, offset, buf, len);
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}
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static void virtio_vdpa_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 vdpa_device *vdpa = vd_get_vdpa(vdev);
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const struct vdpa_config_ops *ops = vdpa->config;
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ops->set_config(vdpa, offset, buf, len);
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}
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static u32 virtio_vdpa_generation(struct virtio_device *vdev)
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{
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struct vdpa_device *vdpa = vd_get_vdpa(vdev);
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const struct vdpa_config_ops *ops = vdpa->config;
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if (ops->get_generation)
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return ops->get_generation(vdpa);
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return 0;
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}
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static u8 virtio_vdpa_get_status(struct virtio_device *vdev)
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{
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struct vdpa_device *vdpa = vd_get_vdpa(vdev);
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const struct vdpa_config_ops *ops = vdpa->config;
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return ops->get_status(vdpa);
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}
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static void virtio_vdpa_set_status(struct virtio_device *vdev, u8 status)
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{
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struct vdpa_device *vdpa = vd_get_vdpa(vdev);
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const struct vdpa_config_ops *ops = vdpa->config;
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return ops->set_status(vdpa, status);
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}
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static void virtio_vdpa_reset(struct virtio_device *vdev)
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{
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struct vdpa_device *vdpa = vd_get_vdpa(vdev);
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const struct vdpa_config_ops *ops = vdpa->config;
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return ops->set_status(vdpa, 0);
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}
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static bool virtio_vdpa_notify(struct virtqueue *vq)
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{
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struct vdpa_device *vdpa = vd_get_vdpa(vq->vdev);
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const struct vdpa_config_ops *ops = vdpa->config;
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ops->kick_vq(vdpa, vq->index);
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return true;
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}
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static irqreturn_t virtio_vdpa_config_cb(void *private)
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{
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struct virtio_vdpa_device *vd_dev = private;
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virtio_config_changed(&vd_dev->vdev);
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return IRQ_HANDLED;
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}
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static irqreturn_t virtio_vdpa_virtqueue_cb(void *private)
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{
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struct virtio_vdpa_vq_info *info = private;
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return vring_interrupt(0, info->vq);
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}
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static struct virtqueue *
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virtio_vdpa_setup_vq(struct virtio_device *vdev, unsigned int index,
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void (*callback)(struct virtqueue *vq),
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const char *name, bool ctx)
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{
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struct virtio_vdpa_device *vd_dev = to_virtio_vdpa_device(vdev);
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struct vdpa_device *vdpa = vd_get_vdpa(vdev);
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const struct vdpa_config_ops *ops = vdpa->config;
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struct virtio_vdpa_vq_info *info;
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struct vdpa_callback cb;
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struct virtqueue *vq;
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u64 desc_addr, driver_addr, device_addr;
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unsigned long flags;
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u32 align, num;
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int err;
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if (!name)
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return NULL;
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/* Queue shouldn't already be set up. */
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if (ops->get_vq_ready(vdpa, index))
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return ERR_PTR(-ENOENT);
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/* Allocate and fill out our active queue description */
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info = kmalloc(sizeof(*info), GFP_KERNEL);
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if (!info)
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return ERR_PTR(-ENOMEM);
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num = ops->get_vq_num_max(vdpa);
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if (num == 0) {
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err = -ENOENT;
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goto error_new_virtqueue;
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}
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/* Create the vring */
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align = ops->get_vq_align(vdpa);
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vq = vring_create_virtqueue(index, num, align, vdev,
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true, true, ctx,
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virtio_vdpa_notify, callback, name);
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if (!vq) {
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err = -ENOMEM;
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goto error_new_virtqueue;
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}
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/* Setup virtqueue callback */
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cb.callback = virtio_vdpa_virtqueue_cb;
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cb.private = info;
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ops->set_vq_cb(vdpa, index, &cb);
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ops->set_vq_num(vdpa, index, virtqueue_get_vring_size(vq));
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desc_addr = virtqueue_get_desc_addr(vq);
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driver_addr = virtqueue_get_avail_addr(vq);
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device_addr = virtqueue_get_used_addr(vq);
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if (ops->set_vq_address(vdpa, index,
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desc_addr, driver_addr,
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device_addr)) {
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err = -EINVAL;
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goto err_vq;
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}
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ops->set_vq_ready(vdpa, index, 1);
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vq->priv = info;
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info->vq = vq;
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spin_lock_irqsave(&vd_dev->lock, flags);
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list_add(&info->node, &vd_dev->virtqueues);
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spin_unlock_irqrestore(&vd_dev->lock, flags);
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return vq;
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err_vq:
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vring_del_virtqueue(vq);
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error_new_virtqueue:
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ops->set_vq_ready(vdpa, index, 0);
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/* VDPA driver should make sure vq is stopeed here */
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WARN_ON(ops->get_vq_ready(vdpa, index));
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kfree(info);
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return ERR_PTR(err);
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}
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static void virtio_vdpa_del_vq(struct virtqueue *vq)
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{
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struct virtio_vdpa_device *vd_dev = to_virtio_vdpa_device(vq->vdev);
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struct vdpa_device *vdpa = vd_dev->vdpa;
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const struct vdpa_config_ops *ops = vdpa->config;
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struct virtio_vdpa_vq_info *info = vq->priv;
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unsigned int index = vq->index;
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unsigned long flags;
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spin_lock_irqsave(&vd_dev->lock, flags);
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list_del(&info->node);
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spin_unlock_irqrestore(&vd_dev->lock, flags);
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/* Select and deactivate the queue */
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ops->set_vq_ready(vdpa, index, 0);
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WARN_ON(ops->get_vq_ready(vdpa, index));
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vring_del_virtqueue(vq);
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kfree(info);
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}
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static void virtio_vdpa_del_vqs(struct virtio_device *vdev)
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{
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struct virtqueue *vq, *n;
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list_for_each_entry_safe(vq, n, &vdev->vqs, list)
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virtio_vdpa_del_vq(vq);
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}
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static int virtio_vdpa_find_vqs(struct virtio_device *vdev, unsigned nvqs,
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struct virtqueue *vqs[],
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vq_callback_t *callbacks[],
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const char * const names[],
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const bool *ctx,
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struct irq_affinity *desc)
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{
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struct virtio_vdpa_device *vd_dev = to_virtio_vdpa_device(vdev);
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struct vdpa_device *vdpa = vd_get_vdpa(vdev);
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const struct vdpa_config_ops *ops = vdpa->config;
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struct vdpa_callback cb;
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int i, err, queue_idx = 0;
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for (i = 0; i < nvqs; ++i) {
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if (!names[i]) {
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vqs[i] = NULL;
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continue;
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}
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vqs[i] = virtio_vdpa_setup_vq(vdev, queue_idx++,
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callbacks[i], names[i], ctx ?
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ctx[i] : false);
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if (IS_ERR(vqs[i])) {
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err = PTR_ERR(vqs[i]);
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goto err_setup_vq;
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}
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}
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cb.callback = virtio_vdpa_config_cb;
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cb.private = vd_dev;
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ops->set_config_cb(vdpa, &cb);
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return 0;
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err_setup_vq:
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virtio_vdpa_del_vqs(vdev);
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return err;
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}
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static u64 virtio_vdpa_get_features(struct virtio_device *vdev)
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{
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struct vdpa_device *vdpa = vd_get_vdpa(vdev);
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const struct vdpa_config_ops *ops = vdpa->config;
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return ops->get_features(vdpa);
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}
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static int virtio_vdpa_finalize_features(struct virtio_device *vdev)
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{
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struct vdpa_device *vdpa = vd_get_vdpa(vdev);
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const struct vdpa_config_ops *ops = vdpa->config;
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/* Give virtio_ring a chance to accept features. */
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vring_transport_features(vdev);
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return ops->set_features(vdpa, vdev->features);
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}
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static const char *virtio_vdpa_bus_name(struct virtio_device *vdev)
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{
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struct virtio_vdpa_device *vd_dev = to_virtio_vdpa_device(vdev);
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struct vdpa_device *vdpa = vd_dev->vdpa;
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return dev_name(&vdpa->dev);
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}
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static const struct virtio_config_ops virtio_vdpa_config_ops = {
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.get = virtio_vdpa_get,
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.set = virtio_vdpa_set,
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.generation = virtio_vdpa_generation,
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.get_status = virtio_vdpa_get_status,
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.set_status = virtio_vdpa_set_status,
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.reset = virtio_vdpa_reset,
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.find_vqs = virtio_vdpa_find_vqs,
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.del_vqs = virtio_vdpa_del_vqs,
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.get_features = virtio_vdpa_get_features,
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.finalize_features = virtio_vdpa_finalize_features,
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.bus_name = virtio_vdpa_bus_name,
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};
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static void virtio_vdpa_release_dev(struct device *_d)
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{
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struct virtio_device *vdev =
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container_of(_d, struct virtio_device, dev);
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struct virtio_vdpa_device *vd_dev =
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container_of(vdev, struct virtio_vdpa_device, vdev);
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kfree(vd_dev);
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}
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static int virtio_vdpa_probe(struct vdpa_device *vdpa)
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{
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const struct vdpa_config_ops *ops = vdpa->config;
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struct virtio_vdpa_device *vd_dev, *reg_dev = NULL;
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int ret = -EINVAL;
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vd_dev = kzalloc(sizeof(*vd_dev), GFP_KERNEL);
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if (!vd_dev)
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return -ENOMEM;
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vd_dev->vdev.dev.parent = vdpa_get_dma_dev(vdpa);
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vd_dev->vdev.dev.release = virtio_vdpa_release_dev;
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vd_dev->vdev.config = &virtio_vdpa_config_ops;
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vd_dev->vdpa = vdpa;
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INIT_LIST_HEAD(&vd_dev->virtqueues);
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spin_lock_init(&vd_dev->lock);
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vd_dev->vdev.id.device = ops->get_device_id(vdpa);
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if (vd_dev->vdev.id.device == 0)
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goto err;
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vd_dev->vdev.id.vendor = ops->get_vendor_id(vdpa);
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ret = register_virtio_device(&vd_dev->vdev);
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reg_dev = vd_dev;
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if (ret)
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goto err;
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vdpa_set_drvdata(vdpa, vd_dev);
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return 0;
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err:
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if (reg_dev)
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put_device(&vd_dev->vdev.dev);
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else
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kfree(vd_dev);
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return ret;
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}
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static void virtio_vdpa_remove(struct vdpa_device *vdpa)
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{
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struct virtio_vdpa_device *vd_dev = vdpa_get_drvdata(vdpa);
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unregister_virtio_device(&vd_dev->vdev);
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}
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static struct vdpa_driver virtio_vdpa_driver = {
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.driver = {
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.name = "virtio_vdpa",
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},
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.probe = virtio_vdpa_probe,
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.remove = virtio_vdpa_remove,
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};
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module_vdpa_driver(virtio_vdpa_driver);
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MODULE_VERSION(MOD_VERSION);
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MODULE_LICENSE(MOD_LICENSE);
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MODULE_AUTHOR(MOD_AUTHOR);
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MODULE_DESCRIPTION(MOD_DESC);
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