| Message ID | 20191029100734.9861-1-tiwei.bie@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3] vhost: introduce mdev based hardware backend | expand |
On 2019/10/29 下午6:07, Tiwei Bie wrote: > This patch introduces a mdev based hardware vhost backend. > This backend is built on top of the same abstraction used > in virtio-mdev and provides a generic vhost interface for > userspace to accelerate the virtio devices in guest. > > This backend is implemented as a mdev device driver on top > of the same mdev device ops used in virtio-mdev but using > a different mdev class id, and it will register the device > as a VFIO device for userspace to use. Userspace can setup > the IOMMU with the existing VFIO container/group APIs and > then get the device fd with the device name. After getting > the device fd of this device, userspace can use vhost ioctls > to setup the backend. Hi Tiwei: The patch looks good overall, just few comments & nits. > > Signed-off-by: Tiwei Bie <tiwei.bie@intel.com> > --- > This patch depends on below series: > https://lkml.org/lkml/2019/10/23/614 > > v2 -> v3: > - Fix the return value (Jason); > - Don't cache unnecessary information in vhost-mdev (Jason); > - Get rid of the memset in open (Jason); > - Add comments for VHOST_SET_MEM_TABLE, ... (Jason); > - Filter out unsupported features in vhost-mdev (Jason); > - Add _GET_DEVICE_ID ioctl (Jason); > - Add _GET_CONFIG/_SET_CONFIG ioctls (Jason); > - Drop _GET_QUEUE_NUM ioctl (Jason); > - Fix the copy-paste errors in _IOW/_IOR usage; > - Some minor fixes and improvements; > > v1 -> v2: > - Replace _SET_STATE with _SET_STATUS (MST); > - Check status bits at each step (MST); > - Report the max ring size and max number of queues (MST); > - Add missing MODULE_DEVICE_TABLE (Jason); > - Only support the network backend w/o multiqueue for now; > - Some minor fixes and improvements; > - Rebase on top of virtio-mdev series v4; > > RFC v4 -> v1: > - Implement vhost-mdev as a mdev device driver directly and > connect it to VFIO container/group. (Jason); > - Pass ring addresses as GPAs/IOVAs in vhost-mdev to avoid > meaningless HVA->GPA translations (Jason); > > RFC v3 -> RFC v4: > - Build vhost-mdev on top of the same abstraction used by > virtio-mdev (Jason); > - Introduce vhost fd and pass VFIO fd via SET_BACKEND ioctl (MST); > > RFC v2 -> RFC v3: > - Reuse vhost's ioctls instead of inventing a VFIO regions/irqs > based vhost protocol on top of vfio-mdev (Jason); > > RFC v1 -> RFC v2: > - Introduce a new VFIO device type to build a vhost protocol > on top of vfio-mdev; > > drivers/vfio/mdev/mdev_core.c | 20 ++ > drivers/vfio/mdev/mdev_private.h | 1 + > drivers/vhost/Kconfig | 12 + > drivers/vhost/Makefile | 3 + > drivers/vhost/mdev.c | 554 +++++++++++++++++++++++++++++++ > include/linux/mdev.h | 5 + > include/uapi/linux/vhost.h | 18 + > include/uapi/linux/vhost_types.h | 8 + > 8 files changed, 621 insertions(+) > create mode 100644 drivers/vhost/mdev.c > > diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c > index 9b00c3513120..3cfd787d605c 100644 > --- a/drivers/vfio/mdev/mdev_core.c > +++ b/drivers/vfio/mdev/mdev_core.c > @@ -96,6 +96,26 @@ mdev_get_virtio_ops(struct mdev_device *mdev) > } > EXPORT_SYMBOL(mdev_get_virtio_ops); > > +/* Specify the vhost device ops for the mdev device, this > + * must be called during create() callback for vhost mdev device. > + */ > +void mdev_set_vhost_ops(struct mdev_device *mdev, > + const struct virtio_mdev_device_ops *vhost_ops) > +{ > + mdev_set_class(mdev, MDEV_CLASS_ID_VHOST); > + mdev->vhost_ops = vhost_ops; > +} > +EXPORT_SYMBOL(mdev_set_vhost_ops); > + > +/* Get the vhost device ops for the mdev device. */ > +const struct virtio_mdev_device_ops * > +mdev_get_vhost_ops(struct mdev_device *mdev) > +{ > + WARN_ON(mdev->class_id != MDEV_CLASS_ID_VHOST); > + return mdev->vhost_ops; > +} > +EXPORT_SYMBOL(mdev_get_vhost_ops); > + > struct device *mdev_dev(struct mdev_device *mdev) > { > return &mdev->dev; > diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h > index 7b47890c34e7..5597c846e52f 100644 > --- a/drivers/vfio/mdev/mdev_private.h > +++ b/drivers/vfio/mdev/mdev_private.h > @@ -40,6 +40,7 @@ struct mdev_device { > union { > const struct vfio_mdev_device_ops *vfio_ops; > const struct virtio_mdev_device_ops *virtio_ops; > + const struct virtio_mdev_device_ops *vhost_ops; > }; > }; > > diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig > index 3d03ccbd1adc..062cada28f89 100644 > --- a/drivers/vhost/Kconfig > +++ b/drivers/vhost/Kconfig > @@ -34,6 +34,18 @@ config VHOST_VSOCK > To compile this driver as a module, choose M here: the module will be called > vhost_vsock. > > +config VHOST_MDEV > + tristate "Vhost driver for Mediated devices" > + depends on EVENTFD && VFIO && VFIO_MDEV > + select VHOST > + default n > + ---help--- > + This kernel module can be loaded in host kernel to accelerate > + guest virtio devices with the mediated device based backends. > + > + To compile this driver as a module, choose M here: the module will > + be called vhost_mdev. > + > config VHOST > tristate > ---help--- > diff --git a/drivers/vhost/Makefile b/drivers/vhost/Makefile > index 6c6df24f770c..ad9c0f8c6d8c 100644 > --- a/drivers/vhost/Makefile > +++ b/drivers/vhost/Makefile > @@ -10,4 +10,7 @@ vhost_vsock-y := vsock.o > > obj-$(CONFIG_VHOST_RING) += vringh.o > > +obj-$(CONFIG_VHOST_MDEV) += vhost_mdev.o > +vhost_mdev-y := mdev.o > + > obj-$(CONFIG_VHOST) += vhost.o > diff --git a/drivers/vhost/mdev.c b/drivers/vhost/mdev.c > new file mode 100644 > index 000000000000..35b2fb33e686 > --- /dev/null > +++ b/drivers/vhost/mdev.c > @@ -0,0 +1,554 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Vhost driver for mediated device based backends. > + * > + * Copyright (C) 2018-2019 Intel Corporation. > + * > + * Author: Tiwei Bie <tiwei.bie@intel.com> > + * > + * Thanks to Jason Wang and Michael S. Tsirkin for the valuable > + * comments and suggestions. And thanks to Cunming Liang and > + * Zhihong Wang for all their supports. > + */ > + > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/mdev.h> > +#include <linux/vfio.h> > +#include <linux/vhost.h> > +#include <linux/virtio_net.h> > +#include <linux/virtio_mdev_ops.h> > + > +#include "vhost.h" > + > +enum { > + VHOST_MDEV_FEATURES = > + (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) | > + (1ULL << VIRTIO_F_ANY_LAYOUT) | > + (1ULL << VIRTIO_F_VERSION_1) | > + (1ULL << VIRTIO_F_IOMMU_PLATFORM) | > + (1ULL << VIRTIO_F_RING_PACKED) | > + (1ULL << VIRTIO_F_ORDER_PLATFORM) | > + (1ULL << VIRTIO_RING_F_INDIRECT_DESC) | > + (1ULL << VIRTIO_RING_F_EVENT_IDX), > + > + VHOST_MDEV_NET_FEATURES = VHOST_MDEV_FEATURES | > + (1ULL << VIRTIO_NET_F_CSUM) | > + (1ULL << VIRTIO_NET_F_GUEST_CSUM) | > + (1ULL << VIRTIO_NET_F_MTU) | > + (1ULL << VIRTIO_NET_F_MAC) | > + (1ULL << VIRTIO_NET_F_GUEST_TSO4) | > + (1ULL << VIRTIO_NET_F_GUEST_TSO6) | > + (1ULL << VIRTIO_NET_F_GUEST_ECN) | > + (1ULL << VIRTIO_NET_F_GUEST_UFO) | > + (1ULL << VIRTIO_NET_F_HOST_TSO4) | > + (1ULL << VIRTIO_NET_F_HOST_TSO6) | > + (1ULL << VIRTIO_NET_F_HOST_ECN) | > + (1ULL << VIRTIO_NET_F_HOST_UFO) | > + (1ULL << VIRTIO_NET_F_MRG_RXBUF) | > + (1ULL << VIRTIO_NET_F_STATUS) | > + (1ULL << VIRTIO_NET_F_SPEED_DUPLEX), > +}; > + > +/* Currently, only network backend w/o multiqueue is supported. */ > +#define VHOST_MDEV_VQ_MAX 2 > + > +struct vhost_mdev { > + /* The lock is to protect this structure. */ > + struct mutex mutex; > + struct vhost_dev dev; > + struct vhost_virtqueue *vqs; > + int nvqs; > + int virtio_id; > + bool opened; > + struct mdev_device *mdev; > +}; > + > +static const u64 vhost_mdev_features[] = { > + [VIRTIO_ID_NET] = VHOST_MDEV_NET_FEATURES, > +}; > + > +static void handle_vq_kick(struct vhost_work *work) > +{ > + struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, > + poll.work); > + struct vhost_mdev *m = container_of(vq->dev, struct vhost_mdev, dev); > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(m->mdev); > + > + ops->kick_vq(m->mdev, vq - m->vqs); > +} > + > +static irqreturn_t vhost_mdev_virtqueue_cb(void *private) > +{ > + struct vhost_virtqueue *vq = private; > + struct eventfd_ctx *call_ctx = vq->call_ctx; > + > + if (call_ctx) > + eventfd_signal(call_ctx, 1); > + > + return IRQ_HANDLED; > +} > + > +static void vhost_mdev_reset(struct vhost_mdev *m) > +{ > + struct mdev_device *mdev = m->mdev; > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > + > + ops->set_status(mdev, 0); > +} > + > +static long vhost_mdev_get_device_id(struct vhost_mdev *m, u8 __user *argp) > +{ > + struct mdev_device *mdev = m->mdev; > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > + u32 device_id; > + > + device_id = ops->get_device_id(mdev); > + > + if (copy_to_user(argp, &device_id, sizeof(device_id))) > + return -EFAULT; > + > + return 0; > +} I believe we need get_vendor_id() as well? > + > +static long vhost_mdev_get_status(struct vhost_mdev *m, u8 __user *statusp) > +{ > + struct mdev_device *mdev = m->mdev; > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > + u8 status; > + > + status = ops->get_status(mdev); > + > + if (copy_to_user(statusp, &status, sizeof(status))) > + return -EFAULT; > + > + return 0; > +} > + > +static long vhost_mdev_set_status(struct vhost_mdev *m, u8 __user *statusp) > +{ > + struct mdev_device *mdev = m->mdev; > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > + u8 status; > + > + if (copy_from_user(&status, statusp, sizeof(status))) > + return -EFAULT; > + > + /* > + * Userspace shouldn't remove status bits unless reset the > + * status to 0. > + */ > + if (status != 0 && (ops->get_status(mdev) & ~status) != 0) > + return -EINVAL; > + > + ops->set_status(mdev, status); > + > + return 0; > +} > + > +static int vhost_mdev_config_validate(struct vhost_mdev *m, > + struct vhost_mdev_config *c) > +{ > + long size = 0; > + > + switch (m->virtio_id) { > + case VIRTIO_ID_NET: > + size = sizeof(struct virtio_net_config); > + break; > + } > + > + if (c->len == 0) > + return -EINVAL; > + > + if (c->off >= size || c->len > size || c->off + c->len > size) > + return -E2BIG; > + > + return 0; > +} > + > +static long vhost_mdev_get_config(struct vhost_mdev *m, > + struct vhost_mdev_config __user *c) > +{ > + struct mdev_device *mdev = m->mdev; > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > + struct vhost_mdev_config config; > + unsigned long size = offsetof(struct vhost_mdev_config, buf); > + u8 *buf; > + > + if (copy_from_user(&config, c, size)) > + return -EFAULT; > + if (vhost_mdev_config_validate(m, &config)) > + return -EINVAL; I think it's better to let the parent to do such validation. Especially consider that the size of config may depend on feature (e.g MQ). > + buf = kvzalloc(config.len, GFP_KERNEL); > + if (!buf) > + return -ENOMEM; > + > + ops->get_config(mdev, config.off, buf, config.len); > + > + if (copy_to_user(c->buf, buf, config.len)) { > + kvfree(buf); > + return -EFAULT; > + } > + > + kvfree(buf); > + return 0; > +} > + > +static long vhost_mdev_set_config(struct vhost_mdev *m, > + struct vhost_mdev_config __user *c) > +{ > + struct mdev_device *mdev = m->mdev; > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > + struct vhost_mdev_config config; > + unsigned long size = offsetof(struct vhost_mdev_config, buf); > + u8 *buf; > + > + if (copy_from_user(&config, c, size)) > + return -EFAULT; > + if (vhost_mdev_config_validate(m, &config)) > + return -EINVAL; > + buf = kvzalloc(config.len, GFP_KERNEL); > + if (!buf) > + return -ENOMEM; > + > + if (copy_from_user(buf, c->buf, config.len)) { > + kvfree(buf); > + return -EFAULT; > + } > + > + ops->set_config(mdev, config.off, buf, config.len); > + > + kvfree(buf); > + return 0; > +} > + > +static long vhost_mdev_get_features(struct vhost_mdev *m, u64 __user *featurep) > +{ > + struct mdev_device *mdev = m->mdev; > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > + u64 features; > + > + features = ops->get_features(mdev); > + features &= vhost_mdev_features[m->virtio_id]; > + > + if (copy_to_user(featurep, &features, sizeof(features))) > + return -EFAULT; > + > + return 0; > +} > + > +static long vhost_mdev_set_features(struct vhost_mdev *m, u64 __user *featurep) > +{ > + struct mdev_device *mdev = m->mdev; > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > + u64 features; > + > + /* > + * It's not allowed to change the features after they have > + * been negotiated. > + */ > + if (ops->get_status(mdev) & VIRTIO_CONFIG_S_FEATURES_OK) > + return -EBUSY; > + > + if (copy_from_user(&features, featurep, sizeof(features))) > + return -EFAULT; > + > + if (features & ~vhost_mdev_features[m->virtio_id]) > + return -EINVAL; > + > + if (ops->set_features(mdev, features)) > + return -EINVAL; > + > + return 0; > +} > + > +static long vhost_mdev_get_vring_num(struct vhost_mdev *m, u16 __user *argp) > +{ > + struct mdev_device *mdev = m->mdev; > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > + u16 num; > + > + num = ops->get_vq_num_max(mdev); > + > + if (copy_to_user(argp, &num, sizeof(num))) > + return -EFAULT; > + > + return 0; > +} > + > +static long vhost_mdev_vring_ioctl(struct vhost_mdev *m, unsigned int cmd, > + void __user *argp) > +{ > + struct mdev_device *mdev = m->mdev; > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > + struct virtio_mdev_callback cb; > + struct vhost_virtqueue *vq; > + struct vhost_vring_state s; > + u8 status; > + u32 idx; > + long r; > + > + r = get_user(idx, (u32 __user *)argp); > + if (r < 0) > + return r; > + if (idx >= m->nvqs) > + return -ENOBUFS; > + > + status = ops->get_status(mdev); > + > + /* > + * It's not allowed to detect and program vqs before > + * features negotiation or after enabling driver. > + */ > + if (!(status & VIRTIO_CONFIG_S_FEATURES_OK) || > + (status & VIRTIO_CONFIG_S_DRIVER_OK)) > + return -EBUSY; > + > + vq = &m->vqs[idx]; > + > + if (cmd == VHOST_MDEV_SET_VRING_ENABLE) { > + if (copy_from_user(&s, argp, sizeof(s))) > + return -EFAULT; > + ops->set_vq_ready(mdev, idx, s.num); > + return 0; > + } > + > + /* > + * It's not allowed to detect and program vqs with > + * vqs enabled. > + */ > + if (ops->get_vq_ready(mdev, idx)) > + return -EBUSY; > + > + if (cmd == VHOST_GET_VRING_BASE) > + vq->last_avail_idx = ops->get_vq_state(m->mdev, idx); > + > + r = vhost_vring_ioctl(&m->dev, cmd, argp); > + if (r) > + return r; > + > + switch (cmd) { > + case VHOST_SET_VRING_ADDR: > + /* > + * In vhost-mdev, the ring addresses set by userspace should > + * be the DMA addresses within the VFIO container/group. > + */ > + if (ops->set_vq_address(mdev, idx, (u64)vq->desc, > + (u64)vq->avail, (u64)vq->used)) > + r = -ENODEV; Nit: It looks to me that we need expose alignment of vq to userspace (get_vq_align()). Thanks > + break; > + > + case VHOST_SET_VRING_BASE: > + if (ops->set_vq_state(mdev, idx, vq->last_avail_idx)) > + r = -ENODEV; > + break; > + > + case VHOST_SET_VRING_CALL: > + if (vq->call_ctx) { > + cb.callback = vhost_mdev_virtqueue_cb; > + cb.private = vq; > + } else { > + cb.callback = NULL; > + cb.private = NULL; > + } > + ops->set_vq_cb(mdev, idx, &cb); > + break; > + > + case VHOST_SET_VRING_NUM: > + ops->set_vq_num(mdev, idx, vq->num); > + break; > + } > + > + return r; > +} > + > +static int vhost_mdev_open(void *device_data) > +{ > + struct vhost_mdev *m = device_data; > + struct vhost_dev *dev; > + struct vhost_virtqueue **vqs; > + int nvqs, i, r; > + > + if (!try_module_get(THIS_MODULE)) > + return -ENODEV; > + > + mutex_lock(&m->mutex); > + > + if (m->opened) { > + r = -EBUSY; > + goto err; > + } > + > + nvqs = m->nvqs; > + vhost_mdev_reset(m); > + > + vqs = kmalloc_array(nvqs, sizeof(*vqs), GFP_KERNEL); > + if (!vqs) { > + r = -ENOMEM; > + goto err; > + } > + > + dev = &m->dev; > + for (i = 0; i < nvqs; i++) { > + vqs[i] = &m->vqs[i]; > + vqs[i]->handle_kick = handle_vq_kick; > + } > + vhost_dev_init(dev, vqs, nvqs, 0, 0, 0); > + m->opened = true; > + mutex_unlock(&m->mutex); > + > + return 0; > + > +err: > + mutex_unlock(&m->mutex); > + module_put(THIS_MODULE); > + return r; > +} > + > +static void vhost_mdev_release(void *device_data) > +{ > + struct vhost_mdev *m = device_data; > + > + mutex_lock(&m->mutex); > + vhost_mdev_reset(m); > + vhost_dev_stop(&m->dev); > + vhost_dev_cleanup(&m->dev); > + > + kfree(m->dev.vqs); > + m->opened = false; > + mutex_unlock(&m->mutex); > + module_put(THIS_MODULE); > +} > + > +static long vhost_mdev_unlocked_ioctl(void *device_data, > + unsigned int cmd, unsigned long arg) > +{ > + struct vhost_mdev *m = device_data; > + void __user *argp = (void __user *)arg; > + long r; > + > + mutex_lock(&m->mutex); > + > + switch (cmd) { > + case VHOST_MDEV_GET_DEVICE_ID: > + r = vhost_mdev_get_device_id(m, argp); > + break; > + case VHOST_MDEV_GET_STATUS: > + r = vhost_mdev_get_status(m, argp); > + break; > + case VHOST_MDEV_SET_STATUS: > + r = vhost_mdev_set_status(m, argp); > + break; > + case VHOST_MDEV_GET_CONFIG: > + r = vhost_mdev_get_config(m, argp); > + break; > + case VHOST_MDEV_SET_CONFIG: > + r = vhost_mdev_set_config(m, argp); > + break; > + case VHOST_GET_FEATURES: > + r = vhost_mdev_get_features(m, argp); > + break; > + case VHOST_SET_FEATURES: > + r = vhost_mdev_set_features(m, argp); > + break; > + case VHOST_MDEV_GET_VRING_NUM: > + r = vhost_mdev_get_vring_num(m, argp); > + break; > + default: > + /* > + * VHOST_SET_MEM_TABLE, VHOST_SET_LOG_BASE, and > + * VHOST_SET_LOG_FD are not used yet. > + */ > + r = vhost_dev_ioctl(&m->dev, cmd, argp); > + if (r == -ENOIOCTLCMD) > + r = vhost_mdev_vring_ioctl(m, cmd, argp); > + } > + > + mutex_unlock(&m->mutex); > + return r; > +} > + > +static const struct vfio_device_ops vfio_vhost_mdev_dev_ops = { > + .name = "vfio-vhost-mdev", > + .open = vhost_mdev_open, > + .release = vhost_mdev_release, > + .ioctl = vhost_mdev_unlocked_ioctl, > +}; > + > +static int vhost_mdev_probe(struct device *dev) > +{ > + struct mdev_device *mdev = mdev_from_dev(dev); > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > + struct vhost_mdev *m; > + int nvqs, r; > + > + /* Currently, we only accept the network devices. */ > + if (ops->get_device_id(mdev) != VIRTIO_ID_NET) > + return -ENOTSUPP; > + > + if (ops->get_mdev_features(mdev) != VIRTIO_MDEV_F_VERSION_1) > + return -ENOTSUPP; > + > + m = devm_kzalloc(dev, sizeof(*m), GFP_KERNEL | __GFP_RETRY_MAYFAIL); > + if (!m) > + return -ENOMEM; > + > + nvqs = VHOST_MDEV_VQ_MAX; > + > + m->vqs = devm_kmalloc_array(dev, nvqs, sizeof(struct vhost_virtqueue), > + GFP_KERNEL); > + if (!m->vqs) > + return -ENOMEM; > + > + mutex_init(&m->mutex); > + > + m->mdev = mdev; > + m->nvqs = nvqs; > + m->virtio_id = ops->get_device_id(mdev); > + > + r = vfio_add_group_dev(dev, &vfio_vhost_mdev_dev_ops, m); > + if (r) { > + mutex_destroy(&m->mutex); > + return r; > + } > + > + return 0; > +} > + > +static void vhost_mdev_remove(struct device *dev) > +{ > + struct vhost_mdev *m; > + > + m = vfio_del_group_dev(dev); > + mutex_destroy(&m->mutex); > +} > + > +static const struct mdev_class_id vhost_mdev_match[] = { > + { MDEV_CLASS_ID_VHOST }, > + { 0 }, > +}; > +MODULE_DEVICE_TABLE(mdev, vhost_mdev_match); > + > +static struct mdev_driver vhost_mdev_driver = { > + .name = "vhost_mdev", > + .probe = vhost_mdev_probe, > + .remove = vhost_mdev_remove, > + .id_table = vhost_mdev_match, > +}; > + > +static int __init vhost_mdev_init(void) > +{ > + return mdev_register_driver(&vhost_mdev_driver, THIS_MODULE); > +} > +module_init(vhost_mdev_init); > + > +static void __exit vhost_mdev_exit(void) > +{ > + mdev_unregister_driver(&vhost_mdev_driver); > +} > +module_exit(vhost_mdev_exit); > + > +MODULE_VERSION("0.0.1"); > +MODULE_LICENSE("GPL v2"); > +MODULE_AUTHOR("Intel Corporation"); > +MODULE_DESCRIPTION("Mediated device based accelerator for virtio"); > diff --git a/include/linux/mdev.h b/include/linux/mdev.h > index 9b69b0bbebfd..3e1e03926355 100644 > --- a/include/linux/mdev.h > +++ b/include/linux/mdev.h > @@ -117,6 +117,10 @@ void mdev_set_virtio_ops(struct mdev_device *mdev, > const struct virtio_mdev_device_ops *virtio_ops); > const struct virtio_mdev_device_ops * > mdev_get_virtio_ops(struct mdev_device *mdev); > +void mdev_set_vhost_ops(struct mdev_device *mdev, > + const struct virtio_mdev_device_ops *vhost_ops); > +const struct virtio_mdev_device_ops * > +mdev_get_vhost_ops(struct mdev_device *mdev); > > extern struct bus_type mdev_bus_type; > > @@ -133,6 +137,7 @@ struct mdev_device *mdev_from_dev(struct device *dev); > enum { > MDEV_CLASS_ID_VFIO = 1, > MDEV_CLASS_ID_VIRTIO = 2, > + MDEV_CLASS_ID_VHOST = 3, > /* New entries must be added here */ > }; > > diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h > index 40d028eed645..061a2824a1b3 100644 > --- a/include/uapi/linux/vhost.h > +++ b/include/uapi/linux/vhost.h > @@ -116,4 +116,22 @@ > #define VHOST_VSOCK_SET_GUEST_CID _IOW(VHOST_VIRTIO, 0x60, __u64) > #define VHOST_VSOCK_SET_RUNNING _IOW(VHOST_VIRTIO, 0x61, int) > > +/* VHOST_MDEV specific defines */ > + > +/* Get the device id. The device ids follow the same definition of > + * the device id defined in virtio-spec. */ > +#define VHOST_MDEV_GET_DEVICE_ID _IOR(VHOST_VIRTIO, 0x70, __u32) > +/* Get and set the status. The status bits follow the same definition > + * of the device status defined in virtio-spec. */ > +#define VHOST_MDEV_GET_STATUS _IOR(VHOST_VIRTIO, 0x71, __u8) > +#define VHOST_MDEV_SET_STATUS _IOW(VHOST_VIRTIO, 0x72, __u8) > +/* Get and set the device config. The device config follows the same > + * definition of the device config defined in virtio-spec. */ > +#define VHOST_MDEV_GET_CONFIG _IOR(VHOST_VIRTIO, 0x73, struct vhost_mdev_config) > +#define VHOST_MDEV_SET_CONFIG _IOW(VHOST_VIRTIO, 0x74, struct vhost_mdev_config) > +/* Enable/disable the ring. */ > +#define VHOST_MDEV_SET_VRING_ENABLE _IOW(VHOST_VIRTIO, 0x75, struct vhost_vring_state) > +/* Get the max ring size. */ > +#define VHOST_MDEV_GET_VRING_NUM _IOR(VHOST_VIRTIO, 0x76, __u16) > + > #endif > diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h > index c907290ff065..7b105d0b2fb9 100644 > --- a/include/uapi/linux/vhost_types.h > +++ b/include/uapi/linux/vhost_types.h > @@ -119,6 +119,14 @@ struct vhost_scsi_target { > unsigned short reserved; > }; > > +/* VHOST_MDEV specific definitions */ > + > +struct vhost_mdev_config { > + __u32 off; > + __u32 len; > + __u8 buf[0]; > +}; > + > /* Feature bits */ > /* Log all write descriptors. Can be changed while device is active. */ > #define VHOST_F_LOG_ALL 26
On Wed, Oct 30, 2019 at 09:55:57AM +0800, Jason Wang wrote: > On 2019/10/29 下午6:07, Tiwei Bie wrote: > > This patch introduces a mdev based hardware vhost backend. > > This backend is built on top of the same abstraction used > > in virtio-mdev and provides a generic vhost interface for > > userspace to accelerate the virtio devices in guest. > > > > This backend is implemented as a mdev device driver on top > > of the same mdev device ops used in virtio-mdev but using > > a different mdev class id, and it will register the device > > as a VFIO device for userspace to use. Userspace can setup > > the IOMMU with the existing VFIO container/group APIs and > > then get the device fd with the device name. After getting > > the device fd of this device, userspace can use vhost ioctls > > to setup the backend. > > > Hi Tiwei: > > The patch looks good overall, just few comments & nits. Thanks for the review! I do appreciate it. > > > > > > Signed-off-by: Tiwei Bie <tiwei.bie@intel.com> > > --- > > This patch depends on below series: > > https://lkml.org/lkml/2019/10/23/614 > > > > v2 -> v3: > > - Fix the return value (Jason); > > - Don't cache unnecessary information in vhost-mdev (Jason); > > - Get rid of the memset in open (Jason); > > - Add comments for VHOST_SET_MEM_TABLE, ... (Jason); > > - Filter out unsupported features in vhost-mdev (Jason); > > - Add _GET_DEVICE_ID ioctl (Jason); > > - Add _GET_CONFIG/_SET_CONFIG ioctls (Jason); > > - Drop _GET_QUEUE_NUM ioctl (Jason); > > - Fix the copy-paste errors in _IOW/_IOR usage; > > - Some minor fixes and improvements; > > > > v1 -> v2: > > - Replace _SET_STATE with _SET_STATUS (MST); > > - Check status bits at each step (MST); > > - Report the max ring size and max number of queues (MST); > > - Add missing MODULE_DEVICE_TABLE (Jason); > > - Only support the network backend w/o multiqueue for now; > > - Some minor fixes and improvements; > > - Rebase on top of virtio-mdev series v4; > > > > RFC v4 -> v1: > > - Implement vhost-mdev as a mdev device driver directly and > > connect it to VFIO container/group. (Jason); > > - Pass ring addresses as GPAs/IOVAs in vhost-mdev to avoid > > meaningless HVA->GPA translations (Jason); > > > > RFC v3 -> RFC v4: > > - Build vhost-mdev on top of the same abstraction used by > > virtio-mdev (Jason); > > - Introduce vhost fd and pass VFIO fd via SET_BACKEND ioctl (MST); > > > > RFC v2 -> RFC v3: > > - Reuse vhost's ioctls instead of inventing a VFIO regions/irqs > > based vhost protocol on top of vfio-mdev (Jason); > > > > RFC v1 -> RFC v2: > > - Introduce a new VFIO device type to build a vhost protocol > > on top of vfio-mdev; > > > > drivers/vfio/mdev/mdev_core.c | 20 ++ > > drivers/vfio/mdev/mdev_private.h | 1 + > > drivers/vhost/Kconfig | 12 + > > drivers/vhost/Makefile | 3 + > > drivers/vhost/mdev.c | 554 +++++++++++++++++++++++++++++++ > > include/linux/mdev.h | 5 + > > include/uapi/linux/vhost.h | 18 + > > include/uapi/linux/vhost_types.h | 8 + > > 8 files changed, 621 insertions(+) > > create mode 100644 drivers/vhost/mdev.c > > > > diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c > > index 9b00c3513120..3cfd787d605c 100644 > > --- a/drivers/vfio/mdev/mdev_core.c > > +++ b/drivers/vfio/mdev/mdev_core.c > > @@ -96,6 +96,26 @@ mdev_get_virtio_ops(struct mdev_device *mdev) > > } > > EXPORT_SYMBOL(mdev_get_virtio_ops); > > > > +/* Specify the vhost device ops for the mdev device, this > > + * must be called during create() callback for vhost mdev device. > > + */ > > +void mdev_set_vhost_ops(struct mdev_device *mdev, > > + const struct virtio_mdev_device_ops *vhost_ops) > > +{ > > + mdev_set_class(mdev, MDEV_CLASS_ID_VHOST); > > + mdev->vhost_ops = vhost_ops; > > +} > > +EXPORT_SYMBOL(mdev_set_vhost_ops); > > + > > +/* Get the vhost device ops for the mdev device. */ > > +const struct virtio_mdev_device_ops * > > +mdev_get_vhost_ops(struct mdev_device *mdev) > > +{ > > + WARN_ON(mdev->class_id != MDEV_CLASS_ID_VHOST); > > + return mdev->vhost_ops; > > +} > > +EXPORT_SYMBOL(mdev_get_vhost_ops); > > + > > struct device *mdev_dev(struct mdev_device *mdev) > > { > > return &mdev->dev; > > diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h > > index 7b47890c34e7..5597c846e52f 100644 > > --- a/drivers/vfio/mdev/mdev_private.h > > +++ b/drivers/vfio/mdev/mdev_private.h > > @@ -40,6 +40,7 @@ struct mdev_device { > > union { > > const struct vfio_mdev_device_ops *vfio_ops; > > const struct virtio_mdev_device_ops *virtio_ops; > > + const struct virtio_mdev_device_ops *vhost_ops; > > }; > > }; > > > > diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig > > index 3d03ccbd1adc..062cada28f89 100644 > > --- a/drivers/vhost/Kconfig > > +++ b/drivers/vhost/Kconfig > > @@ -34,6 +34,18 @@ config VHOST_VSOCK > > To compile this driver as a module, choose M here: the module will be called > > vhost_vsock. > > > > +config VHOST_MDEV > > + tristate "Vhost driver for Mediated devices" > > + depends on EVENTFD && VFIO && VFIO_MDEV > > + select VHOST > > + default n > > + ---help--- > > + This kernel module can be loaded in host kernel to accelerate > > + guest virtio devices with the mediated device based backends. > > + > > + To compile this driver as a module, choose M here: the module will > > + be called vhost_mdev. > > + > > config VHOST > > tristate > > ---help--- > > diff --git a/drivers/vhost/Makefile b/drivers/vhost/Makefile > > index 6c6df24f770c..ad9c0f8c6d8c 100644 > > --- a/drivers/vhost/Makefile > > +++ b/drivers/vhost/Makefile > > @@ -10,4 +10,7 @@ vhost_vsock-y := vsock.o > > > > obj-$(CONFIG_VHOST_RING) += vringh.o > > > > +obj-$(CONFIG_VHOST_MDEV) += vhost_mdev.o > > +vhost_mdev-y := mdev.o > > + > > obj-$(CONFIG_VHOST) += vhost.o > > diff --git a/drivers/vhost/mdev.c b/drivers/vhost/mdev.c > > new file mode 100644 > > index 000000000000..35b2fb33e686 > > --- /dev/null > > +++ b/drivers/vhost/mdev.c > > @@ -0,0 +1,554 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +/* > > + * Vhost driver for mediated device based backends. > > + * > > + * Copyright (C) 2018-2019 Intel Corporation. > > + * > > + * Author: Tiwei Bie <tiwei.bie@intel.com> > > + * > > + * Thanks to Jason Wang and Michael S. Tsirkin for the valuable > > + * comments and suggestions. And thanks to Cunming Liang and > > + * Zhihong Wang for all their supports. > > + */ > > + > > +#include <linux/kernel.h> > > +#include <linux/module.h> > > +#include <linux/mdev.h> > > +#include <linux/vfio.h> > > +#include <linux/vhost.h> > > +#include <linux/virtio_net.h> > > +#include <linux/virtio_mdev_ops.h> > > + > > +#include "vhost.h" > > + > > +enum { > > + VHOST_MDEV_FEATURES = > > + (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) | > > + (1ULL << VIRTIO_F_ANY_LAYOUT) | > > + (1ULL << VIRTIO_F_VERSION_1) | > > + (1ULL << VIRTIO_F_IOMMU_PLATFORM) | > > + (1ULL << VIRTIO_F_RING_PACKED) | > > + (1ULL << VIRTIO_F_ORDER_PLATFORM) | > > + (1ULL << VIRTIO_RING_F_INDIRECT_DESC) | > > + (1ULL << VIRTIO_RING_F_EVENT_IDX), > > + > > + VHOST_MDEV_NET_FEATURES = VHOST_MDEV_FEATURES | > > + (1ULL << VIRTIO_NET_F_CSUM) | > > + (1ULL << VIRTIO_NET_F_GUEST_CSUM) | > > + (1ULL << VIRTIO_NET_F_MTU) | > > + (1ULL << VIRTIO_NET_F_MAC) | > > + (1ULL << VIRTIO_NET_F_GUEST_TSO4) | > > + (1ULL << VIRTIO_NET_F_GUEST_TSO6) | > > + (1ULL << VIRTIO_NET_F_GUEST_ECN) | > > + (1ULL << VIRTIO_NET_F_GUEST_UFO) | > > + (1ULL << VIRTIO_NET_F_HOST_TSO4) | > > + (1ULL << VIRTIO_NET_F_HOST_TSO6) | > > + (1ULL << VIRTIO_NET_F_HOST_ECN) | > > + (1ULL << VIRTIO_NET_F_HOST_UFO) | > > + (1ULL << VIRTIO_NET_F_MRG_RXBUF) | > > + (1ULL << VIRTIO_NET_F_STATUS) | > > + (1ULL << VIRTIO_NET_F_SPEED_DUPLEX), > > +}; > > + > > +/* Currently, only network backend w/o multiqueue is supported. */ > > +#define VHOST_MDEV_VQ_MAX 2 > > + > > +struct vhost_mdev { > > + /* The lock is to protect this structure. */ > > + struct mutex mutex; > > + struct vhost_dev dev; > > + struct vhost_virtqueue *vqs; > > + int nvqs; > > + int virtio_id; > > + bool opened; > > + struct mdev_device *mdev; > > +}; > > + > > +static const u64 vhost_mdev_features[] = { > > + [VIRTIO_ID_NET] = VHOST_MDEV_NET_FEATURES, > > +}; > > + > > +static void handle_vq_kick(struct vhost_work *work) > > +{ > > + struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, > > + poll.work); > > + struct vhost_mdev *m = container_of(vq->dev, struct vhost_mdev, dev); > > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(m->mdev); > > + > > + ops->kick_vq(m->mdev, vq - m->vqs); > > +} > > + > > +static irqreturn_t vhost_mdev_virtqueue_cb(void *private) > > +{ > > + struct vhost_virtqueue *vq = private; > > + struct eventfd_ctx *call_ctx = vq->call_ctx; > > + > > + if (call_ctx) > > + eventfd_signal(call_ctx, 1); > > + > > + return IRQ_HANDLED; > > +} > > + > > +static void vhost_mdev_reset(struct vhost_mdev *m) > > +{ > > + struct mdev_device *mdev = m->mdev; > > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > > + > > + ops->set_status(mdev, 0); > > +} > > + > > +static long vhost_mdev_get_device_id(struct vhost_mdev *m, u8 __user *argp) > > +{ > > + struct mdev_device *mdev = m->mdev; > > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > > + u32 device_id; > > + > > + device_id = ops->get_device_id(mdev); > > + > > + if (copy_to_user(argp, &device_id, sizeof(device_id))) > > + return -EFAULT; > > + > > + return 0; > > +} > > > I believe we need get_vendor_id() as well? Currently, there is no official way for vendors to do vendor specific extensions in vhost-mdev yet. It might be better to add this ioctl when we support this. > > > > + > > +static long vhost_mdev_get_status(struct vhost_mdev *m, u8 __user *statusp) > > +{ > > + struct mdev_device *mdev = m->mdev; > > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > > + u8 status; > > + > > + status = ops->get_status(mdev); > > + > > + if (copy_to_user(statusp, &status, sizeof(status))) > > + return -EFAULT; > > + > > + return 0; > > +} > > + > > +static long vhost_mdev_set_status(struct vhost_mdev *m, u8 __user *statusp) > > +{ > > + struct mdev_device *mdev = m->mdev; > > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > > + u8 status; > > + > > + if (copy_from_user(&status, statusp, sizeof(status))) > > + return -EFAULT; > > + > > + /* > > + * Userspace shouldn't remove status bits unless reset the > > + * status to 0. > > + */ > > + if (status != 0 && (ops->get_status(mdev) & ~status) != 0) > > + return -EINVAL; > > + > > + ops->set_status(mdev, status); > > + > > + return 0; > > +} > > + > > +static int vhost_mdev_config_validate(struct vhost_mdev *m, > > + struct vhost_mdev_config *c) > > +{ > > + long size = 0; > > + > > + switch (m->virtio_id) { > > + case VIRTIO_ID_NET: > > + size = sizeof(struct virtio_net_config); > > + break; > > + } > > + > > + if (c->len == 0) > > + return -EINVAL; > > + > > + if (c->off >= size || c->len > size || c->off + c->len > size) > > + return -E2BIG; > > + > > + return 0; > > +} > > + > > +static long vhost_mdev_get_config(struct vhost_mdev *m, > > + struct vhost_mdev_config __user *c) > > +{ > > + struct mdev_device *mdev = m->mdev; > > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > > + struct vhost_mdev_config config; > > + unsigned long size = offsetof(struct vhost_mdev_config, buf); > > + u8 *buf; > > + > > + if (copy_from_user(&config, c, size)) > > + return -EFAULT; > > + if (vhost_mdev_config_validate(m, &config)) > > + return -EINVAL; > > > I think it's better to let the parent to do such validation. Especially > consider that the size of config may depend on feature (e.g MQ). Above check is just a basic sanity check to make sure that e.g. we won't alloc a huge amount of memory. > > > > + buf = kvzalloc(config.len, GFP_KERNEL); > > + if (!buf) > > + return -ENOMEM; > > + > > + ops->get_config(mdev, config.off, buf, config.len); > > + > > + if (copy_to_user(c->buf, buf, config.len)) { > > + kvfree(buf); > > + return -EFAULT; > > + } > > + > > + kvfree(buf); > > + return 0; > > +} > > + > > +static long vhost_mdev_set_config(struct vhost_mdev *m, > > + struct vhost_mdev_config __user *c) > > +{ > > + struct mdev_device *mdev = m->mdev; > > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > > + struct vhost_mdev_config config; > > + unsigned long size = offsetof(struct vhost_mdev_config, buf); > > + u8 *buf; > > + > > + if (copy_from_user(&config, c, size)) > > + return -EFAULT; > > + if (vhost_mdev_config_validate(m, &config)) > > + return -EINVAL; > > + buf = kvzalloc(config.len, GFP_KERNEL); > > + if (!buf) > > + return -ENOMEM; > > + > > + if (copy_from_user(buf, c->buf, config.len)) { > > + kvfree(buf); > > + return -EFAULT; > > + } > > + > > + ops->set_config(mdev, config.off, buf, config.len); > > + > > + kvfree(buf); > > + return 0; > > +} > > + > > +static long vhost_mdev_get_features(struct vhost_mdev *m, u64 __user *featurep) > > +{ > > + struct mdev_device *mdev = m->mdev; > > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > > + u64 features; > > + > > + features = ops->get_features(mdev); > > + features &= vhost_mdev_features[m->virtio_id]; > > + > > + if (copy_to_user(featurep, &features, sizeof(features))) > > + return -EFAULT; > > + > > + return 0; > > +} > > + > > +static long vhost_mdev_set_features(struct vhost_mdev *m, u64 __user *featurep) > > +{ > > + struct mdev_device *mdev = m->mdev; > > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > > + u64 features; > > + > > + /* > > + * It's not allowed to change the features after they have > > + * been negotiated. > > + */ > > + if (ops->get_status(mdev) & VIRTIO_CONFIG_S_FEATURES_OK) > > + return -EBUSY; > > + > > + if (copy_from_user(&features, featurep, sizeof(features))) > > + return -EFAULT; > > + > > + if (features & ~vhost_mdev_features[m->virtio_id]) > > + return -EINVAL; > > + > > + if (ops->set_features(mdev, features)) > > + return -EINVAL; > > + > > + return 0; > > +} > > + > > +static long vhost_mdev_get_vring_num(struct vhost_mdev *m, u16 __user *argp) > > +{ > > + struct mdev_device *mdev = m->mdev; > > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > > + u16 num; > > + > > + num = ops->get_vq_num_max(mdev); > > + > > + if (copy_to_user(argp, &num, sizeof(num))) > > + return -EFAULT; > > + > > + return 0; > > +} > > + > > +static long vhost_mdev_vring_ioctl(struct vhost_mdev *m, unsigned int cmd, > > + void __user *argp) > > +{ > > + struct mdev_device *mdev = m->mdev; > > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > > + struct virtio_mdev_callback cb; > > + struct vhost_virtqueue *vq; > > + struct vhost_vring_state s; > > + u8 status; > > + u32 idx; > > + long r; > > + > > + r = get_user(idx, (u32 __user *)argp); > > + if (r < 0) > > + return r; > > + if (idx >= m->nvqs) > > + return -ENOBUFS; > > + > > + status = ops->get_status(mdev); > > + > > + /* > > + * It's not allowed to detect and program vqs before > > + * features negotiation or after enabling driver. > > + */ > > + if (!(status & VIRTIO_CONFIG_S_FEATURES_OK) || > > + (status & VIRTIO_CONFIG_S_DRIVER_OK)) > > + return -EBUSY; > > + > > + vq = &m->vqs[idx]; > > + > > + if (cmd == VHOST_MDEV_SET_VRING_ENABLE) { > > + if (copy_from_user(&s, argp, sizeof(s))) > > + return -EFAULT; > > + ops->set_vq_ready(mdev, idx, s.num); > > + return 0; > > + } > > + > > + /* > > + * It's not allowed to detect and program vqs with > > + * vqs enabled. > > + */ > > + if (ops->get_vq_ready(mdev, idx)) > > + return -EBUSY; > > + > > + if (cmd == VHOST_GET_VRING_BASE) > > + vq->last_avail_idx = ops->get_vq_state(m->mdev, idx); > > + > > + r = vhost_vring_ioctl(&m->dev, cmd, argp); > > + if (r) > > + return r; > > + > > + switch (cmd) { > > + case VHOST_SET_VRING_ADDR: > > + /* > > + * In vhost-mdev, the ring addresses set by userspace should > > + * be the DMA addresses within the VFIO container/group. > > + */ > > + if (ops->set_vq_address(mdev, idx, (u64)vq->desc, > > + (u64)vq->avail, (u64)vq->used)) > > + r = -ENODEV; > > > Nit: It looks to me that we need expose alignment of vq to userspace > (get_vq_align()). Guest drivers are using (maybe hardcoded) alignments based on the alignment requirements defined in the spec. It might be better to let backends follow the same standard for the compatibility. > > Thanks > > > > + break; > > + > > + case VHOST_SET_VRING_BASE: > > + if (ops->set_vq_state(mdev, idx, vq->last_avail_idx)) > > + r = -ENODEV; > > + break; > > + > > + case VHOST_SET_VRING_CALL: > > + if (vq->call_ctx) { > > + cb.callback = vhost_mdev_virtqueue_cb; > > + cb.private = vq; > > + } else { > > + cb.callback = NULL; > > + cb.private = NULL; > > + } > > + ops->set_vq_cb(mdev, idx, &cb); > > + break; > > + > > + case VHOST_SET_VRING_NUM: > > + ops->set_vq_num(mdev, idx, vq->num); > > + break; > > + } > > + > > + return r; > > +} > > + > > +static int vhost_mdev_open(void *device_data) > > +{ > > + struct vhost_mdev *m = device_data; > > + struct vhost_dev *dev; > > + struct vhost_virtqueue **vqs; > > + int nvqs, i, r; > > + > > + if (!try_module_get(THIS_MODULE)) > > + return -ENODEV; > > + > > + mutex_lock(&m->mutex); > > + > > + if (m->opened) { > > + r = -EBUSY; > > + goto err; > > + } > > + > > + nvqs = m->nvqs; > > + vhost_mdev_reset(m); > > + > > + vqs = kmalloc_array(nvqs, sizeof(*vqs), GFP_KERNEL); > > + if (!vqs) { > > + r = -ENOMEM; > > + goto err; > > + } > > + > > + dev = &m->dev; > > + for (i = 0; i < nvqs; i++) { > > + vqs[i] = &m->vqs[i]; > > + vqs[i]->handle_kick = handle_vq_kick; > > + } > > + vhost_dev_init(dev, vqs, nvqs, 0, 0, 0); > > + m->opened = true; > > + mutex_unlock(&m->mutex); > > + > > + return 0; > > + > > +err: > > + mutex_unlock(&m->mutex); > > + module_put(THIS_MODULE); > > + return r; > > +} > > + > > +static void vhost_mdev_release(void *device_data) > > +{ > > + struct vhost_mdev *m = device_data; > > + > > + mutex_lock(&m->mutex); > > + vhost_mdev_reset(m); > > + vhost_dev_stop(&m->dev); > > + vhost_dev_cleanup(&m->dev); > > + > > + kfree(m->dev.vqs); > > + m->opened = false; > > + mutex_unlock(&m->mutex); > > + module_put(THIS_MODULE); > > +} > > + > > +static long vhost_mdev_unlocked_ioctl(void *device_data, > > + unsigned int cmd, unsigned long arg) > > +{ > > + struct vhost_mdev *m = device_data; > > + void __user *argp = (void __user *)arg; > > + long r; > > + > > + mutex_lock(&m->mutex); > > + > > + switch (cmd) { > > + case VHOST_MDEV_GET_DEVICE_ID: > > + r = vhost_mdev_get_device_id(m, argp); > > + break; > > + case VHOST_MDEV_GET_STATUS: > > + r = vhost_mdev_get_status(m, argp); > > + break; > > + case VHOST_MDEV_SET_STATUS: > > + r = vhost_mdev_set_status(m, argp); > > + break; > > + case VHOST_MDEV_GET_CONFIG: > > + r = vhost_mdev_get_config(m, argp); > > + break; > > + case VHOST_MDEV_SET_CONFIG: > > + r = vhost_mdev_set_config(m, argp); > > + break; > > + case VHOST_GET_FEATURES: > > + r = vhost_mdev_get_features(m, argp); > > + break; > > + case VHOST_SET_FEATURES: > > + r = vhost_mdev_set_features(m, argp); > > + break; > > + case VHOST_MDEV_GET_VRING_NUM: > > + r = vhost_mdev_get_vring_num(m, argp); > > + break; > > + default: > > + /* > > + * VHOST_SET_MEM_TABLE, VHOST_SET_LOG_BASE, and > > + * VHOST_SET_LOG_FD are not used yet. > > + */ > > + r = vhost_dev_ioctl(&m->dev, cmd, argp); > > + if (r == -ENOIOCTLCMD) > > + r = vhost_mdev_vring_ioctl(m, cmd, argp); > > + } > > + > > + mutex_unlock(&m->mutex); > > + return r; > > +} > > + > > +static const struct vfio_device_ops vfio_vhost_mdev_dev_ops = { > > + .name = "vfio-vhost-mdev", > > + .open = vhost_mdev_open, > > + .release = vhost_mdev_release, > > + .ioctl = vhost_mdev_unlocked_ioctl, > > +}; > > + > > +static int vhost_mdev_probe(struct device *dev) > > +{ > > + struct mdev_device *mdev = mdev_from_dev(dev); > > + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); > > + struct vhost_mdev *m; > > + int nvqs, r; > > + > > + /* Currently, we only accept the network devices. */ > > + if (ops->get_device_id(mdev) != VIRTIO_ID_NET) > > + return -ENOTSUPP; > > + > > + if (ops->get_mdev_features(mdev) != VIRTIO_MDEV_F_VERSION_1) > > + return -ENOTSUPP; > > + > > + m = devm_kzalloc(dev, sizeof(*m), GFP_KERNEL | __GFP_RETRY_MAYFAIL); > > + if (!m) > > + return -ENOMEM; > > + > > + nvqs = VHOST_MDEV_VQ_MAX; > > + > > + m->vqs = devm_kmalloc_array(dev, nvqs, sizeof(struct vhost_virtqueue), > > + GFP_KERNEL); > > + if (!m->vqs) > > + return -ENOMEM; > > + > > + mutex_init(&m->mutex); > > + > > + m->mdev = mdev; > > + m->nvqs = nvqs; > > + m->virtio_id = ops->get_device_id(mdev); > > + > > + r = vfio_add_group_dev(dev, &vfio_vhost_mdev_dev_ops, m); > > + if (r) { > > + mutex_destroy(&m->mutex); > > + return r; > > + } > > + > > + return 0; > > +} > > + > > +static void vhost_mdev_remove(struct device *dev) > > +{ > > + struct vhost_mdev *m; > > + > > + m = vfio_del_group_dev(dev); > > + mutex_destroy(&m->mutex); > > +} > > + > > +static const struct mdev_class_id vhost_mdev_match[] = { > > + { MDEV_CLASS_ID_VHOST }, > > + { 0 }, > > +}; > > +MODULE_DEVICE_TABLE(mdev, vhost_mdev_match); > > + > > +static struct mdev_driver vhost_mdev_driver = { > > + .name = "vhost_mdev", > > + .probe = vhost_mdev_probe, > > + .remove = vhost_mdev_remove, > > + .id_table = vhost_mdev_match, > > +}; > > + > > +static int __init vhost_mdev_init(void) > > +{ > > + return mdev_register_driver(&vhost_mdev_driver, THIS_MODULE); > > +} > > +module_init(vhost_mdev_init); > > + > > +static void __exit vhost_mdev_exit(void) > > +{ > > + mdev_unregister_driver(&vhost_mdev_driver); > > +} > > +module_exit(vhost_mdev_exit); > > + > > +MODULE_VERSION("0.0.1"); > > +MODULE_LICENSE("GPL v2"); > > +MODULE_AUTHOR("Intel Corporation"); > > +MODULE_DESCRIPTION("Mediated device based accelerator for virtio"); > > diff --git a/include/linux/mdev.h b/include/linux/mdev.h > > index 9b69b0bbebfd..3e1e03926355 100644 > > --- a/include/linux/mdev.h > > +++ b/include/linux/mdev.h > > @@ -117,6 +117,10 @@ void mdev_set_virtio_ops(struct mdev_device *mdev, > > const struct virtio_mdev_device_ops *virtio_ops); > > const struct virtio_mdev_device_ops * > > mdev_get_virtio_ops(struct mdev_device *mdev); > > +void mdev_set_vhost_ops(struct mdev_device *mdev, > > + const struct virtio_mdev_device_ops *vhost_ops); > > +const struct virtio_mdev_device_ops * > > +mdev_get_vhost_ops(struct mdev_device *mdev); > > > > extern struct bus_type mdev_bus_type; > > > > @@ -133,6 +137,7 @@ struct mdev_device *mdev_from_dev(struct device *dev); > > enum { > > MDEV_CLASS_ID_VFIO = 1, > > MDEV_CLASS_ID_VIRTIO = 2, > > + MDEV_CLASS_ID_VHOST = 3, > > /* New entries must be added here */ > > }; > > > > diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h > > index 40d028eed645..061a2824a1b3 100644 > > --- a/include/uapi/linux/vhost.h > > +++ b/include/uapi/linux/vhost.h > > @@ -116,4 +116,22 @@ > > #define VHOST_VSOCK_SET_GUEST_CID _IOW(VHOST_VIRTIO, 0x60, __u64) > > #define VHOST_VSOCK_SET_RUNNING _IOW(VHOST_VIRTIO, 0x61, int) > > > > +/* VHOST_MDEV specific defines */ > > + > > +/* Get the device id. The device ids follow the same definition of > > + * the device id defined in virtio-spec. */ > > +#define VHOST_MDEV_GET_DEVICE_ID _IOR(VHOST_VIRTIO, 0x70, __u32) > > +/* Get and set the status. The status bits follow the same definition > > + * of the device status defined in virtio-spec. */ > > +#define VHOST_MDEV_GET_STATUS _IOR(VHOST_VIRTIO, 0x71, __u8) > > +#define VHOST_MDEV_SET_STATUS _IOW(VHOST_VIRTIO, 0x72, __u8) > > +/* Get and set the device config. The device config follows the same > > + * definition of the device config defined in virtio-spec. */ > > +#define VHOST_MDEV_GET_CONFIG _IOR(VHOST_VIRTIO, 0x73, struct vhost_mdev_config) > > +#define VHOST_MDEV_SET_CONFIG _IOW(VHOST_VIRTIO, 0x74, struct vhost_mdev_config) > > +/* Enable/disable the ring. */ > > +#define VHOST_MDEV_SET_VRING_ENABLE _IOW(VHOST_VIRTIO, 0x75, struct vhost_vring_state) > > +/* Get the max ring size. */ > > +#define VHOST_MDEV_GET_VRING_NUM _IOR(VHOST_VIRTIO, 0x76, __u16) > > + > > #endif > > diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h > > index c907290ff065..7b105d0b2fb9 100644 > > --- a/include/uapi/linux/vhost_types.h > > +++ b/include/uapi/linux/vhost_types.h > > @@ -119,6 +119,14 @@ struct vhost_scsi_target { > > unsigned short reserved; > > }; > > > > +/* VHOST_MDEV specific definitions */ > > + > > +struct vhost_mdev_config { > > + __u32 off; > > + __u32 len; > > + __u8 buf[0]; > > +}; > > + > > /* Feature bits */ > > /* Log all write descriptors. Can be changed while device is active. */ > > #define VHOST_F_LOG_ALL 26 >
On 2019/10/30 下午1:52, Tiwei Bie wrote: > On Wed, Oct 30, 2019 at 09:55:57AM +0800, Jason Wang wrote: >> On 2019/10/29 下午6:07, Tiwei Bie wrote: >>> This patch introduces a mdev based hardware vhost backend. >>> This backend is built on top of the same abstraction used >>> in virtio-mdev and provides a generic vhost interface for >>> userspace to accelerate the virtio devices in guest. >>> >>> This backend is implemented as a mdev device driver on top >>> of the same mdev device ops used in virtio-mdev but using >>> a different mdev class id, and it will register the device >>> as a VFIO device for userspace to use. Userspace can setup >>> the IOMMU with the existing VFIO container/group APIs and >>> then get the device fd with the device name. After getting >>> the device fd of this device, userspace can use vhost ioctls >>> to setup the backend. >> >> Hi Tiwei: >> >> The patch looks good overall, just few comments & nits. > Thanks for the review! I do appreciate it. You're welcome :) > >> >>> Signed-off-by: Tiwei Bie <tiwei.bie@intel.com> >>> --- >>> This patch depends on below series: >>> https://lkml.org/lkml/2019/10/23/614 >>> >>> v2 -> v3: >>> - Fix the return value (Jason); >>> - Don't cache unnecessary information in vhost-mdev (Jason); >>> - Get rid of the memset in open (Jason); >>> - Add comments for VHOST_SET_MEM_TABLE, ... (Jason); >>> - Filter out unsupported features in vhost-mdev (Jason); >>> - Add _GET_DEVICE_ID ioctl (Jason); >>> - Add _GET_CONFIG/_SET_CONFIG ioctls (Jason); >>> - Drop _GET_QUEUE_NUM ioctl (Jason); >>> - Fix the copy-paste errors in _IOW/_IOR usage; >>> - Some minor fixes and improvements; >>> >>> v1 -> v2: >>> - Replace _SET_STATE with _SET_STATUS (MST); >>> - Check status bits at each step (MST); >>> - Report the max ring size and max number of queues (MST); >>> - Add missing MODULE_DEVICE_TABLE (Jason); >>> - Only support the network backend w/o multiqueue for now; >>> - Some minor fixes and improvements; >>> - Rebase on top of virtio-mdev series v4; >>> >>> RFC v4 -> v1: >>> - Implement vhost-mdev as a mdev device driver directly and >>> connect it to VFIO container/group. (Jason); >>> - Pass ring addresses as GPAs/IOVAs in vhost-mdev to avoid >>> meaningless HVA->GPA translations (Jason); >>> >>> RFC v3 -> RFC v4: >>> - Build vhost-mdev on top of the same abstraction used by >>> virtio-mdev (Jason); >>> - Introduce vhost fd and pass VFIO fd via SET_BACKEND ioctl (MST); >>> >>> RFC v2 -> RFC v3: >>> - Reuse vhost's ioctls instead of inventing a VFIO regions/irqs >>> based vhost protocol on top of vfio-mdev (Jason); >>> >>> RFC v1 -> RFC v2: >>> - Introduce a new VFIO device type to build a vhost protocol >>> on top of vfio-mdev; >>> >>> drivers/vfio/mdev/mdev_core.c | 20 ++ >>> drivers/vfio/mdev/mdev_private.h | 1 + >>> drivers/vhost/Kconfig | 12 + >>> drivers/vhost/Makefile | 3 + >>> drivers/vhost/mdev.c | 554 +++++++++++++++++++++++++++++++ >>> include/linux/mdev.h | 5 + >>> include/uapi/linux/vhost.h | 18 + >>> include/uapi/linux/vhost_types.h | 8 + >>> 8 files changed, 621 insertions(+) >>> create mode 100644 drivers/vhost/mdev.c >>> >>> diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c >>> index 9b00c3513120..3cfd787d605c 100644 >>> --- a/drivers/vfio/mdev/mdev_core.c >>> +++ b/drivers/vfio/mdev/mdev_core.c >>> @@ -96,6 +96,26 @@ mdev_get_virtio_ops(struct mdev_device *mdev) >>> } >>> EXPORT_SYMBOL(mdev_get_virtio_ops); >>> >>> +/* Specify the vhost device ops for the mdev device, this >>> + * must be called during create() callback for vhost mdev device. >>> + */ >>> +void mdev_set_vhost_ops(struct mdev_device *mdev, >>> + const struct virtio_mdev_device_ops *vhost_ops) >>> +{ >>> + mdev_set_class(mdev, MDEV_CLASS_ID_VHOST); >>> + mdev->vhost_ops = vhost_ops; >>> +} >>> +EXPORT_SYMBOL(mdev_set_vhost_ops); >>> + >>> +/* Get the vhost device ops for the mdev device. */ >>> +const struct virtio_mdev_device_ops * >>> +mdev_get_vhost_ops(struct mdev_device *mdev) >>> +{ >>> + WARN_ON(mdev->class_id != MDEV_CLASS_ID_VHOST); >>> + return mdev->vhost_ops; >>> +} >>> +EXPORT_SYMBOL(mdev_get_vhost_ops); >>> + >>> struct device *mdev_dev(struct mdev_device *mdev) >>> { >>> return &mdev->dev; >>> diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h >>> index 7b47890c34e7..5597c846e52f 100644 >>> --- a/drivers/vfio/mdev/mdev_private.h >>> +++ b/drivers/vfio/mdev/mdev_private.h >>> @@ -40,6 +40,7 @@ struct mdev_device { >>> union { >>> const struct vfio_mdev_device_ops *vfio_ops; >>> const struct virtio_mdev_device_ops *virtio_ops; >>> + const struct virtio_mdev_device_ops *vhost_ops; >>> }; >>> }; >>> >>> diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig >>> index 3d03ccbd1adc..062cada28f89 100644 >>> --- a/drivers/vhost/Kconfig >>> +++ b/drivers/vhost/Kconfig >>> @@ -34,6 +34,18 @@ config VHOST_VSOCK >>> To compile this driver as a module, choose M here: the module will be called >>> vhost_vsock. >>> >>> +config VHOST_MDEV >>> + tristate "Vhost driver for Mediated devices" >>> + depends on EVENTFD && VFIO && VFIO_MDEV >>> + select VHOST >>> + default n >>> + ---help--- >>> + This kernel module can be loaded in host kernel to accelerate >>> + guest virtio devices with the mediated device based backends. >>> + >>> + To compile this driver as a module, choose M here: the module will >>> + be called vhost_mdev. >>> + >>> config VHOST >>> tristate >>> ---help--- >>> diff --git a/drivers/vhost/Makefile b/drivers/vhost/Makefile >>> index 6c6df24f770c..ad9c0f8c6d8c 100644 >>> --- a/drivers/vhost/Makefile >>> +++ b/drivers/vhost/Makefile >>> @@ -10,4 +10,7 @@ vhost_vsock-y := vsock.o >>> >>> obj-$(CONFIG_VHOST_RING) += vringh.o >>> >>> +obj-$(CONFIG_VHOST_MDEV) += vhost_mdev.o >>> +vhost_mdev-y := mdev.o >>> + >>> obj-$(CONFIG_VHOST) += vhost.o >>> diff --git a/drivers/vhost/mdev.c b/drivers/vhost/mdev.c >>> new file mode 100644 >>> index 000000000000..35b2fb33e686 >>> --- /dev/null >>> +++ b/drivers/vhost/mdev.c >>> @@ -0,0 +1,554 @@ >>> +// SPDX-License-Identifier: GPL-2.0 >>> +/* >>> + * Vhost driver for mediated device based backends. >>> + * >>> + * Copyright (C) 2018-2019 Intel Corporation. >>> + * >>> + * Author: Tiwei Bie <tiwei.bie@intel.com> >>> + * >>> + * Thanks to Jason Wang and Michael S. Tsirkin for the valuable >>> + * comments and suggestions. And thanks to Cunming Liang and >>> + * Zhihong Wang for all their supports. >>> + */ >>> + >>> +#include <linux/kernel.h> >>> +#include <linux/module.h> >>> +#include <linux/mdev.h> >>> +#include <linux/vfio.h> >>> +#include <linux/vhost.h> >>> +#include <linux/virtio_net.h> >>> +#include <linux/virtio_mdev_ops.h> >>> + >>> +#include "vhost.h" >>> + >>> +enum { >>> + VHOST_MDEV_FEATURES = >>> + (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) | >>> + (1ULL << VIRTIO_F_ANY_LAYOUT) | >>> + (1ULL << VIRTIO_F_VERSION_1) | >>> + (1ULL << VIRTIO_F_IOMMU_PLATFORM) | >>> + (1ULL << VIRTIO_F_RING_PACKED) | >>> + (1ULL << VIRTIO_F_ORDER_PLATFORM) | >>> + (1ULL << VIRTIO_RING_F_INDIRECT_DESC) | >>> + (1ULL << VIRTIO_RING_F_EVENT_IDX), >>> + >>> + VHOST_MDEV_NET_FEATURES = VHOST_MDEV_FEATURES | >>> + (1ULL << VIRTIO_NET_F_CSUM) | >>> + (1ULL << VIRTIO_NET_F_GUEST_CSUM) | >>> + (1ULL << VIRTIO_NET_F_MTU) | >>> + (1ULL << VIRTIO_NET_F_MAC) | >>> + (1ULL << VIRTIO_NET_F_GUEST_TSO4) | >>> + (1ULL << VIRTIO_NET_F_GUEST_TSO6) | >>> + (1ULL << VIRTIO_NET_F_GUEST_ECN) | >>> + (1ULL << VIRTIO_NET_F_GUEST_UFO) | >>> + (1ULL << VIRTIO_NET_F_HOST_TSO4) | >>> + (1ULL << VIRTIO_NET_F_HOST_TSO6) | >>> + (1ULL << VIRTIO_NET_F_HOST_ECN) | >>> + (1ULL << VIRTIO_NET_F_HOST_UFO) | >>> + (1ULL << VIRTIO_NET_F_MRG_RXBUF) | >>> + (1ULL << VIRTIO_NET_F_STATUS) | >>> + (1ULL << VIRTIO_NET_F_SPEED_DUPLEX), >>> +}; >>> + >>> +/* Currently, only network backend w/o multiqueue is supported. */ >>> +#define VHOST_MDEV_VQ_MAX 2 >>> + >>> +struct vhost_mdev { >>> + /* The lock is to protect this structure. */ >>> + struct mutex mutex; >>> + struct vhost_dev dev; >>> + struct vhost_virtqueue *vqs; >>> + int nvqs; >>> + int virtio_id; >>> + bool opened; >>> + struct mdev_device *mdev; >>> +}; >>> + >>> +static const u64 vhost_mdev_features[] = { >>> + [VIRTIO_ID_NET] = VHOST_MDEV_NET_FEATURES, >>> +}; >>> + >>> +static void handle_vq_kick(struct vhost_work *work) >>> +{ >>> + struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, >>> + poll.work); >>> + struct vhost_mdev *m = container_of(vq->dev, struct vhost_mdev, dev); >>> + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(m->mdev); >>> + >>> + ops->kick_vq(m->mdev, vq - m->vqs); >>> +} >>> + >>> +static irqreturn_t vhost_mdev_virtqueue_cb(void *private) >>> +{ >>> + struct vhost_virtqueue *vq = private; >>> + struct eventfd_ctx *call_ctx = vq->call_ctx; >>> + >>> + if (call_ctx) >>> + eventfd_signal(call_ctx, 1); >>> + >>> + return IRQ_HANDLED; >>> +} >>> + >>> +static void vhost_mdev_reset(struct vhost_mdev *m) >>> +{ >>> + struct mdev_device *mdev = m->mdev; >>> + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); >>> + >>> + ops->set_status(mdev, 0); >>> +} >>> + >>> +static long vhost_mdev_get_device_id(struct vhost_mdev *m, u8 __user *argp) >>> +{ >>> + struct mdev_device *mdev = m->mdev; >>> + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); >>> + u32 device_id; >>> + >>> + device_id = ops->get_device_id(mdev); >>> + >>> + if (copy_to_user(argp, &device_id, sizeof(device_id))) >>> + return -EFAULT; >>> + >>> + return 0; >>> +} >> >> I believe we need get_vendor_id() as well? > Currently, there is no official way for vendors to do vendor > specific extensions in vhost-mdev yet. It might be better to > add this ioctl when we support this. Good point. > >> >>> + >>> +static long vhost_mdev_get_status(struct vhost_mdev *m, u8 __user *statusp) >>> +{ >>> + struct mdev_device *mdev = m->mdev; >>> + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); >>> + u8 status; >>> + >>> + status = ops->get_status(mdev); >>> + >>> + if (copy_to_user(statusp, &status, sizeof(status))) >>> + return -EFAULT; >>> + >>> + return 0; >>> +} >>> + >>> +static long vhost_mdev_set_status(struct vhost_mdev *m, u8 __user *statusp) >>> +{ >>> + struct mdev_device *mdev = m->mdev; >>> + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); >>> + u8 status; >>> + >>> + if (copy_from_user(&status, statusp, sizeof(status))) >>> + return -EFAULT; >>> + >>> + /* >>> + * Userspace shouldn't remove status bits unless reset the >>> + * status to 0. >>> + */ >>> + if (status != 0 && (ops->get_status(mdev) & ~status) != 0) >>> + return -EINVAL; >>> + >>> + ops->set_status(mdev, status); >>> + >>> + return 0; >>> +} >>> + >>> +static int vhost_mdev_config_validate(struct vhost_mdev *m, >>> + struct vhost_mdev_config *c) >>> +{ >>> + long size = 0; >>> + >>> + switch (m->virtio_id) { >>> + case VIRTIO_ID_NET: >>> + size = sizeof(struct virtio_net_config); >>> + break; >>> + } >>> + >>> + if (c->len == 0) >>> + return -EINVAL; >>> + >>> + if (c->off >= size || c->len > size || c->off + c->len > size) >>> + return -E2BIG; >>> + >>> + return 0; >>> +} >>> + >>> +static long vhost_mdev_get_config(struct vhost_mdev *m, >>> + struct vhost_mdev_config __user *c) >>> +{ >>> + struct mdev_device *mdev = m->mdev; >>> + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); >>> + struct vhost_mdev_config config; >>> + unsigned long size = offsetof(struct vhost_mdev_config, buf); >>> + u8 *buf; >>> + >>> + if (copy_from_user(&config, c, size)) >>> + return -EFAULT; >>> + if (vhost_mdev_config_validate(m, &config)) >>> + return -EINVAL; >> >> I think it's better to let the parent to do such validation. Especially >> consider that the size of config may depend on feature (e.g MQ). > Above check is just a basic sanity check to make sure > that e.g. we won't alloc a huge amount of memory. I see. > >> >>> + buf = kvzalloc(config.len, GFP_KERNEL); >>> + if (!buf) >>> + return -ENOMEM; >>> + >>> + ops->get_config(mdev, config.off, buf, config.len); >>> + >>> + if (copy_to_user(c->buf, buf, config.len)) { >>> + kvfree(buf); >>> + return -EFAULT; >>> + } >>> + >>> + kvfree(buf); >>> + return 0; >>> +} >>> + >>> +static long vhost_mdev_set_config(struct vhost_mdev *m, >>> + struct vhost_mdev_config __user *c) >>> +{ >>> + struct mdev_device *mdev = m->mdev; >>> + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); >>> + struct vhost_mdev_config config; >>> + unsigned long size = offsetof(struct vhost_mdev_config, buf); >>> + u8 *buf; >>> + >>> + if (copy_from_user(&config, c, size)) >>> + return -EFAULT; >>> + if (vhost_mdev_config_validate(m, &config)) >>> + return -EINVAL; >>> + buf = kvzalloc(config.len, GFP_KERNEL); >>> + if (!buf) >>> + return -ENOMEM; >>> + >>> + if (copy_from_user(buf, c->buf, config.len)) { >>> + kvfree(buf); >>> + return -EFAULT; >>> + } >>> + >>> + ops->set_config(mdev, config.off, buf, config.len); >>> + >>> + kvfree(buf); >>> + return 0; >>> +} >>> + >>> +static long vhost_mdev_get_features(struct vhost_mdev *m, u64 __user *featurep) >>> +{ >>> + struct mdev_device *mdev = m->mdev; >>> + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); >>> + u64 features; >>> + >>> + features = ops->get_features(mdev); >>> + features &= vhost_mdev_features[m->virtio_id]; >>> + >>> + if (copy_to_user(featurep, &features, sizeof(features))) >>> + return -EFAULT; >>> + >>> + return 0; >>> +} >>> + >>> +static long vhost_mdev_set_features(struct vhost_mdev *m, u64 __user *featurep) >>> +{ >>> + struct mdev_device *mdev = m->mdev; >>> + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); >>> + u64 features; >>> + >>> + /* >>> + * It's not allowed to change the features after they have >>> + * been negotiated. >>> + */ >>> + if (ops->get_status(mdev) & VIRTIO_CONFIG_S_FEATURES_OK) >>> + return -EBUSY; >>> + >>> + if (copy_from_user(&features, featurep, sizeof(features))) >>> + return -EFAULT; >>> + >>> + if (features & ~vhost_mdev_features[m->virtio_id]) >>> + return -EINVAL; >>> + >>> + if (ops->set_features(mdev, features)) >>> + return -EINVAL; >>> + >>> + return 0; >>> +} >>> + >>> +static long vhost_mdev_get_vring_num(struct vhost_mdev *m, u16 __user *argp) >>> +{ >>> + struct mdev_device *mdev = m->mdev; >>> + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); >>> + u16 num; >>> + >>> + num = ops->get_vq_num_max(mdev); >>> + >>> + if (copy_to_user(argp, &num, sizeof(num))) >>> + return -EFAULT; >>> + >>> + return 0; >>> +} >>> + >>> +static long vhost_mdev_vring_ioctl(struct vhost_mdev *m, unsigned int cmd, >>> + void __user *argp) >>> +{ >>> + struct mdev_device *mdev = m->mdev; >>> + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); >>> + struct virtio_mdev_callback cb; >>> + struct vhost_virtqueue *vq; >>> + struct vhost_vring_state s; >>> + u8 status; >>> + u32 idx; >>> + long r; >>> + >>> + r = get_user(idx, (u32 __user *)argp); >>> + if (r < 0) >>> + return r; >>> + if (idx >= m->nvqs) >>> + return -ENOBUFS; >>> + >>> + status = ops->get_status(mdev); >>> + >>> + /* >>> + * It's not allowed to detect and program vqs before >>> + * features negotiation or after enabling driver. >>> + */ >>> + if (!(status & VIRTIO_CONFIG_S_FEATURES_OK) || >>> + (status & VIRTIO_CONFIG_S_DRIVER_OK)) >>> + return -EBUSY; >>> + >>> + vq = &m->vqs[idx]; >>> + >>> + if (cmd == VHOST_MDEV_SET_VRING_ENABLE) { >>> + if (copy_from_user(&s, argp, sizeof(s))) >>> + return -EFAULT; >>> + ops->set_vq_ready(mdev, idx, s.num); >>> + return 0; >>> + } >>> + >>> + /* >>> + * It's not allowed to detect and program vqs with >>> + * vqs enabled. >>> + */ >>> + if (ops->get_vq_ready(mdev, idx)) >>> + return -EBUSY; >>> + >>> + if (cmd == VHOST_GET_VRING_BASE) >>> + vq->last_avail_idx = ops->get_vq_state(m->mdev, idx); >>> + >>> + r = vhost_vring_ioctl(&m->dev, cmd, argp); >>> + if (r) >>> + return r; >>> + >>> + switch (cmd) { >>> + case VHOST_SET_VRING_ADDR: >>> + /* >>> + * In vhost-mdev, the ring addresses set by userspace should >>> + * be the DMA addresses within the VFIO container/group. >>> + */ >>> + if (ops->set_vq_address(mdev, idx, (u64)vq->desc, >>> + (u64)vq->avail, (u64)vq->used)) >>> + r = -ENODEV; >> >> Nit: It looks to me that we need expose alignment of vq to userspace >> (get_vq_align()). > Guest drivers are using (maybe hardcoded) alignments based > on the alignment requirements defined in the spec. It might > be better to let backends follow the same standard for the > compatibility. Ok. Thanks > >> Thanks >> >> >>> + break; >>> + >>> + case VHOST_SET_VRING_BASE: >>> + if (ops->set_vq_state(mdev, idx, vq->last_avail_idx)) >>> + r = -ENODEV; >>> + break; >>> + >>> + case VHOST_SET_VRING_CALL: >>> + if (vq->call_ctx) { >>> + cb.callback = vhost_mdev_virtqueue_cb; >>> + cb.private = vq; >>> + } else { >>> + cb.callback = NULL; >>> + cb.private = NULL; >>> + } >>> + ops->set_vq_cb(mdev, idx, &cb); >>> + break; >>> + >>> + case VHOST_SET_VRING_NUM: >>> + ops->set_vq_num(mdev, idx, vq->num); >>> + break; >>> + } >>> + >>> + return r; >>> +} >>> + >>> +static int vhost_mdev_open(void *device_data) >>> +{ >>> + struct vhost_mdev *m = device_data; >>> + struct vhost_dev *dev; >>> + struct vhost_virtqueue **vqs; >>> + int nvqs, i, r; >>> + >>> + if (!try_module_get(THIS_MODULE)) >>> + return -ENODEV; >>> + >>> + mutex_lock(&m->mutex); >>> + >>> + if (m->opened) { >>> + r = -EBUSY; >>> + goto err; >>> + } >>> + >>> + nvqs = m->nvqs; >>> + vhost_mdev_reset(m); >>> + >>> + vqs = kmalloc_array(nvqs, sizeof(*vqs), GFP_KERNEL); >>> + if (!vqs) { >>> + r = -ENOMEM; >>> + goto err; >>> + } >>> + >>> + dev = &m->dev; >>> + for (i = 0; i < nvqs; i++) { >>> + vqs[i] = &m->vqs[i]; >>> + vqs[i]->handle_kick = handle_vq_kick; >>> + } >>> + vhost_dev_init(dev, vqs, nvqs, 0, 0, 0); >>> + m->opened = true; >>> + mutex_unlock(&m->mutex); >>> + >>> + return 0; >>> + >>> +err: >>> + mutex_unlock(&m->mutex); >>> + module_put(THIS_MODULE); >>> + return r; >>> +} >>> + >>> +static void vhost_mdev_release(void *device_data) >>> +{ >>> + struct vhost_mdev *m = device_data; >>> + >>> + mutex_lock(&m->mutex); >>> + vhost_mdev_reset(m); >>> + vhost_dev_stop(&m->dev); >>> + vhost_dev_cleanup(&m->dev); >>> + >>> + kfree(m->dev.vqs); >>> + m->opened = false; >>> + mutex_unlock(&m->mutex); >>> + module_put(THIS_MODULE); >>> +} >>> + >>> +static long vhost_mdev_unlocked_ioctl(void *device_data, >>> + unsigned int cmd, unsigned long arg) >>> +{ >>> + struct vhost_mdev *m = device_data; >>> + void __user *argp = (void __user *)arg; >>> + long r; >>> + >>> + mutex_lock(&m->mutex); >>> + >>> + switch (cmd) { >>> + case VHOST_MDEV_GET_DEVICE_ID: >>> + r = vhost_mdev_get_device_id(m, argp); >>> + break; >>> + case VHOST_MDEV_GET_STATUS: >>> + r = vhost_mdev_get_status(m, argp); >>> + break; >>> + case VHOST_MDEV_SET_STATUS: >>> + r = vhost_mdev_set_status(m, argp); >>> + break; >>> + case VHOST_MDEV_GET_CONFIG: >>> + r = vhost_mdev_get_config(m, argp); >>> + break; >>> + case VHOST_MDEV_SET_CONFIG: >>> + r = vhost_mdev_set_config(m, argp); >>> + break; >>> + case VHOST_GET_FEATURES: >>> + r = vhost_mdev_get_features(m, argp); >>> + break; >>> + case VHOST_SET_FEATURES: >>> + r = vhost_mdev_set_features(m, argp); >>> + break; >>> + case VHOST_MDEV_GET_VRING_NUM: >>> + r = vhost_mdev_get_vring_num(m, argp); >>> + break; >>> + default: >>> + /* >>> + * VHOST_SET_MEM_TABLE, VHOST_SET_LOG_BASE, and >>> + * VHOST_SET_LOG_FD are not used yet. >>> + */ >>> + r = vhost_dev_ioctl(&m->dev, cmd, argp); >>> + if (r == -ENOIOCTLCMD) >>> + r = vhost_mdev_vring_ioctl(m, cmd, argp); >>> + } >>> + >>> + mutex_unlock(&m->mutex); >>> + return r; >>> +} >>> + >>> +static const struct vfio_device_ops vfio_vhost_mdev_dev_ops = { >>> + .name = "vfio-vhost-mdev", >>> + .open = vhost_mdev_open, >>> + .release = vhost_mdev_release, >>> + .ioctl = vhost_mdev_unlocked_ioctl, >>> +}; >>> + >>> +static int vhost_mdev_probe(struct device *dev) >>> +{ >>> + struct mdev_device *mdev = mdev_from_dev(dev); >>> + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); >>> + struct vhost_mdev *m; >>> + int nvqs, r; >>> + >>> + /* Currently, we only accept the network devices. */ >>> + if (ops->get_device_id(mdev) != VIRTIO_ID_NET) >>> + return -ENOTSUPP; >>> + >>> + if (ops->get_mdev_features(mdev) != VIRTIO_MDEV_F_VERSION_1) >>> + return -ENOTSUPP; >>> + >>> + m = devm_kzalloc(dev, sizeof(*m), GFP_KERNEL | __GFP_RETRY_MAYFAIL); >>> + if (!m) >>> + return -ENOMEM; >>> + >>> + nvqs = VHOST_MDEV_VQ_MAX; >>> + >>> + m->vqs = devm_kmalloc_array(dev, nvqs, sizeof(struct vhost_virtqueue), >>> + GFP_KERNEL); >>> + if (!m->vqs) >>> + return -ENOMEM; >>> + >>> + mutex_init(&m->mutex); >>> + >>> + m->mdev = mdev; >>> + m->nvqs = nvqs; >>> + m->virtio_id = ops->get_device_id(mdev); >>> + >>> + r = vfio_add_group_dev(dev, &vfio_vhost_mdev_dev_ops, m); >>> + if (r) { >>> + mutex_destroy(&m->mutex); >>> + return r; >>> + } >>> + >>> + return 0; >>> +} >>> + >>> +static void vhost_mdev_remove(struct device *dev) >>> +{ >>> + struct vhost_mdev *m; >>> + >>> + m = vfio_del_group_dev(dev); >>> + mutex_destroy(&m->mutex); >>> +} >>> + >>> +static const struct mdev_class_id vhost_mdev_match[] = { >>> + { MDEV_CLASS_ID_VHOST }, >>> + { 0 }, >>> +}; >>> +MODULE_DEVICE_TABLE(mdev, vhost_mdev_match); >>> + >>> +static struct mdev_driver vhost_mdev_driver = { >>> + .name = "vhost_mdev", >>> + .probe = vhost_mdev_probe, >>> + .remove = vhost_mdev_remove, >>> + .id_table = vhost_mdev_match, >>> +}; >>> + >>> +static int __init vhost_mdev_init(void) >>> +{ >>> + return mdev_register_driver(&vhost_mdev_driver, THIS_MODULE); >>> +} >>> +module_init(vhost_mdev_init); >>> + >>> +static void __exit vhost_mdev_exit(void) >>> +{ >>> + mdev_unregister_driver(&vhost_mdev_driver); >>> +} >>> +module_exit(vhost_mdev_exit); >>> + >>> +MODULE_VERSION("0.0.1"); >>> +MODULE_LICENSE("GPL v2"); >>> +MODULE_AUTHOR("Intel Corporation"); >>> +MODULE_DESCRIPTION("Mediated device based accelerator for virtio"); >>> diff --git a/include/linux/mdev.h b/include/linux/mdev.h >>> index 9b69b0bbebfd..3e1e03926355 100644 >>> --- a/include/linux/mdev.h >>> +++ b/include/linux/mdev.h >>> @@ -117,6 +117,10 @@ void mdev_set_virtio_ops(struct mdev_device *mdev, >>> const struct virtio_mdev_device_ops *virtio_ops); >>> const struct virtio_mdev_device_ops * >>> mdev_get_virtio_ops(struct mdev_device *mdev); >>> +void mdev_set_vhost_ops(struct mdev_device *mdev, >>> + const struct virtio_mdev_device_ops *vhost_ops); >>> +const struct virtio_mdev_device_ops * >>> +mdev_get_vhost_ops(struct mdev_device *mdev); >>> >>> extern struct bus_type mdev_bus_type; >>> >>> @@ -133,6 +137,7 @@ struct mdev_device *mdev_from_dev(struct device *dev); >>> enum { >>> MDEV_CLASS_ID_VFIO = 1, >>> MDEV_CLASS_ID_VIRTIO = 2, >>> + MDEV_CLASS_ID_VHOST = 3, >>> /* New entries must be added here */ >>> }; >>> >>> diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h >>> index 40d028eed645..061a2824a1b3 100644 >>> --- a/include/uapi/linux/vhost.h >>> +++ b/include/uapi/linux/vhost.h >>> @@ -116,4 +116,22 @@ >>> #define VHOST_VSOCK_SET_GUEST_CID _IOW(VHOST_VIRTIO, 0x60, __u64) >>> #define VHOST_VSOCK_SET_RUNNING _IOW(VHOST_VIRTIO, 0x61, int) >>> >>> +/* VHOST_MDEV specific defines */ >>> + >>> +/* Get the device id. The device ids follow the same definition of >>> + * the device id defined in virtio-spec. */ >>> +#define VHOST_MDEV_GET_DEVICE_ID _IOR(VHOST_VIRTIO, 0x70, __u32) >>> +/* Get and set the status. The status bits follow the same definition >>> + * of the device status defined in virtio-spec. */ >>> +#define VHOST_MDEV_GET_STATUS _IOR(VHOST_VIRTIO, 0x71, __u8) >>> +#define VHOST_MDEV_SET_STATUS _IOW(VHOST_VIRTIO, 0x72, __u8) >>> +/* Get and set the device config. The device config follows the same >>> + * definition of the device config defined in virtio-spec. */ >>> +#define VHOST_MDEV_GET_CONFIG _IOR(VHOST_VIRTIO, 0x73, struct vhost_mdev_config) >>> +#define VHOST_MDEV_SET_CONFIG _IOW(VHOST_VIRTIO, 0x74, struct vhost_mdev_config) >>> +/* Enable/disable the ring. */ >>> +#define VHOST_MDEV_SET_VRING_ENABLE _IOW(VHOST_VIRTIO, 0x75, struct vhost_vring_state) >>> +/* Get the max ring size. */ >>> +#define VHOST_MDEV_GET_VRING_NUM _IOR(VHOST_VIRTIO, 0x76, __u16) >>> + >>> #endif >>> diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h >>> index c907290ff065..7b105d0b2fb9 100644 >>> --- a/include/uapi/linux/vhost_types.h >>> +++ b/include/uapi/linux/vhost_types.h >>> @@ -119,6 +119,14 @@ struct vhost_scsi_target { >>> unsigned short reserved; >>> }; >>> >>> +/* VHOST_MDEV specific definitions */ >>> + >>> +struct vhost_mdev_config { >>> + __u32 off; >>> + __u32 len; >>> + __u8 buf[0]; >>> +}; >>> + >>> /* Feature bits */ >>> /* Log all write descriptors. Can be changed while device is active. */ >>> #define VHOST_F_LOG_ALL 26
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c index 9b00c3513120..3cfd787d605c 100644 --- a/drivers/vfio/mdev/mdev_core.c +++ b/drivers/vfio/mdev/mdev_core.c @@ -96,6 +96,26 @@ mdev_get_virtio_ops(struct mdev_device *mdev) } EXPORT_SYMBOL(mdev_get_virtio_ops); +/* Specify the vhost device ops for the mdev device, this + * must be called during create() callback for vhost mdev device. + */ +void mdev_set_vhost_ops(struct mdev_device *mdev, + const struct virtio_mdev_device_ops *vhost_ops) +{ + mdev_set_class(mdev, MDEV_CLASS_ID_VHOST); + mdev->vhost_ops = vhost_ops; +} +EXPORT_SYMBOL(mdev_set_vhost_ops); + +/* Get the vhost device ops for the mdev device. */ +const struct virtio_mdev_device_ops * +mdev_get_vhost_ops(struct mdev_device *mdev) +{ + WARN_ON(mdev->class_id != MDEV_CLASS_ID_VHOST); + return mdev->vhost_ops; +} +EXPORT_SYMBOL(mdev_get_vhost_ops); + struct device *mdev_dev(struct mdev_device *mdev) { return &mdev->dev; diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h index 7b47890c34e7..5597c846e52f 100644 --- a/drivers/vfio/mdev/mdev_private.h +++ b/drivers/vfio/mdev/mdev_private.h @@ -40,6 +40,7 @@ struct mdev_device { union { const struct vfio_mdev_device_ops *vfio_ops; const struct virtio_mdev_device_ops *virtio_ops; + const struct virtio_mdev_device_ops *vhost_ops; }; }; diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig index 3d03ccbd1adc..062cada28f89 100644 --- a/drivers/vhost/Kconfig +++ b/drivers/vhost/Kconfig @@ -34,6 +34,18 @@ config VHOST_VSOCK To compile this driver as a module, choose M here: the module will be called vhost_vsock. +config VHOST_MDEV + tristate "Vhost driver for Mediated devices" + depends on EVENTFD && VFIO && VFIO_MDEV + select VHOST + default n + ---help--- + This kernel module can be loaded in host kernel to accelerate + guest virtio devices with the mediated device based backends. + + To compile this driver as a module, choose M here: the module will + be called vhost_mdev. + config VHOST tristate ---help--- diff --git a/drivers/vhost/Makefile b/drivers/vhost/Makefile index 6c6df24f770c..ad9c0f8c6d8c 100644 --- a/drivers/vhost/Makefile +++ b/drivers/vhost/Makefile @@ -10,4 +10,7 @@ vhost_vsock-y := vsock.o obj-$(CONFIG_VHOST_RING) += vringh.o +obj-$(CONFIG_VHOST_MDEV) += vhost_mdev.o +vhost_mdev-y := mdev.o + obj-$(CONFIG_VHOST) += vhost.o diff --git a/drivers/vhost/mdev.c b/drivers/vhost/mdev.c new file mode 100644 index 000000000000..35b2fb33e686 --- /dev/null +++ b/drivers/vhost/mdev.c @@ -0,0 +1,554 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Vhost driver for mediated device based backends. + * + * Copyright (C) 2018-2019 Intel Corporation. + * + * Author: Tiwei Bie <tiwei.bie@intel.com> + * + * Thanks to Jason Wang and Michael S. Tsirkin for the valuable + * comments and suggestions. And thanks to Cunming Liang and + * Zhihong Wang for all their supports. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/mdev.h> +#include <linux/vfio.h> +#include <linux/vhost.h> +#include <linux/virtio_net.h> +#include <linux/virtio_mdev_ops.h> + +#include "vhost.h" + +enum { + VHOST_MDEV_FEATURES = + (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) | + (1ULL << VIRTIO_F_ANY_LAYOUT) | + (1ULL << VIRTIO_F_VERSION_1) | + (1ULL << VIRTIO_F_IOMMU_PLATFORM) | + (1ULL << VIRTIO_F_RING_PACKED) | + (1ULL << VIRTIO_F_ORDER_PLATFORM) | + (1ULL << VIRTIO_RING_F_INDIRECT_DESC) | + (1ULL << VIRTIO_RING_F_EVENT_IDX), + + VHOST_MDEV_NET_FEATURES = VHOST_MDEV_FEATURES | + (1ULL << VIRTIO_NET_F_CSUM) | + (1ULL << VIRTIO_NET_F_GUEST_CSUM) | + (1ULL << VIRTIO_NET_F_MTU) | + (1ULL << VIRTIO_NET_F_MAC) | + (1ULL << VIRTIO_NET_F_GUEST_TSO4) | + (1ULL << VIRTIO_NET_F_GUEST_TSO6) | + (1ULL << VIRTIO_NET_F_GUEST_ECN) | + (1ULL << VIRTIO_NET_F_GUEST_UFO) | + (1ULL << VIRTIO_NET_F_HOST_TSO4) | + (1ULL << VIRTIO_NET_F_HOST_TSO6) | + (1ULL << VIRTIO_NET_F_HOST_ECN) | + (1ULL << VIRTIO_NET_F_HOST_UFO) | + (1ULL << VIRTIO_NET_F_MRG_RXBUF) | + (1ULL << VIRTIO_NET_F_STATUS) | + (1ULL << VIRTIO_NET_F_SPEED_DUPLEX), +}; + +/* Currently, only network backend w/o multiqueue is supported. */ +#define VHOST_MDEV_VQ_MAX 2 + +struct vhost_mdev { + /* The lock is to protect this structure. */ + struct mutex mutex; + struct vhost_dev dev; + struct vhost_virtqueue *vqs; + int nvqs; + int virtio_id; + bool opened; + struct mdev_device *mdev; +}; + +static const u64 vhost_mdev_features[] = { + [VIRTIO_ID_NET] = VHOST_MDEV_NET_FEATURES, +}; + +static void handle_vq_kick(struct vhost_work *work) +{ + struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, + poll.work); + struct vhost_mdev *m = container_of(vq->dev, struct vhost_mdev, dev); + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(m->mdev); + + ops->kick_vq(m->mdev, vq - m->vqs); +} + +static irqreturn_t vhost_mdev_virtqueue_cb(void *private) +{ + struct vhost_virtqueue *vq = private; + struct eventfd_ctx *call_ctx = vq->call_ctx; + + if (call_ctx) + eventfd_signal(call_ctx, 1); + + return IRQ_HANDLED; +} + +static void vhost_mdev_reset(struct vhost_mdev *m) +{ + struct mdev_device *mdev = m->mdev; + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); + + ops->set_status(mdev, 0); +} + +static long vhost_mdev_get_device_id(struct vhost_mdev *m, u8 __user *argp) +{ + struct mdev_device *mdev = m->mdev; + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); + u32 device_id; + + device_id = ops->get_device_id(mdev); + + if (copy_to_user(argp, &device_id, sizeof(device_id))) + return -EFAULT; + + return 0; +} + +static long vhost_mdev_get_status(struct vhost_mdev *m, u8 __user *statusp) +{ + struct mdev_device *mdev = m->mdev; + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); + u8 status; + + status = ops->get_status(mdev); + + if (copy_to_user(statusp, &status, sizeof(status))) + return -EFAULT; + + return 0; +} + +static long vhost_mdev_set_status(struct vhost_mdev *m, u8 __user *statusp) +{ + struct mdev_device *mdev = m->mdev; + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); + u8 status; + + if (copy_from_user(&status, statusp, sizeof(status))) + return -EFAULT; + + /* + * Userspace shouldn't remove status bits unless reset the + * status to 0. + */ + if (status != 0 && (ops->get_status(mdev) & ~status) != 0) + return -EINVAL; + + ops->set_status(mdev, status); + + return 0; +} + +static int vhost_mdev_config_validate(struct vhost_mdev *m, + struct vhost_mdev_config *c) +{ + long size = 0; + + switch (m->virtio_id) { + case VIRTIO_ID_NET: + size = sizeof(struct virtio_net_config); + break; + } + + if (c->len == 0) + return -EINVAL; + + if (c->off >= size || c->len > size || c->off + c->len > size) + return -E2BIG; + + return 0; +} + +static long vhost_mdev_get_config(struct vhost_mdev *m, + struct vhost_mdev_config __user *c) +{ + struct mdev_device *mdev = m->mdev; + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); + struct vhost_mdev_config config; + unsigned long size = offsetof(struct vhost_mdev_config, buf); + u8 *buf; + + if (copy_from_user(&config, c, size)) + return -EFAULT; + if (vhost_mdev_config_validate(m, &config)) + return -EINVAL; + buf = kvzalloc(config.len, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + ops->get_config(mdev, config.off, buf, config.len); + + if (copy_to_user(c->buf, buf, config.len)) { + kvfree(buf); + return -EFAULT; + } + + kvfree(buf); + return 0; +} + +static long vhost_mdev_set_config(struct vhost_mdev *m, + struct vhost_mdev_config __user *c) +{ + struct mdev_device *mdev = m->mdev; + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); + struct vhost_mdev_config config; + unsigned long size = offsetof(struct vhost_mdev_config, buf); + u8 *buf; + + if (copy_from_user(&config, c, size)) + return -EFAULT; + if (vhost_mdev_config_validate(m, &config)) + return -EINVAL; + buf = kvzalloc(config.len, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + if (copy_from_user(buf, c->buf, config.len)) { + kvfree(buf); + return -EFAULT; + } + + ops->set_config(mdev, config.off, buf, config.len); + + kvfree(buf); + return 0; +} + +static long vhost_mdev_get_features(struct vhost_mdev *m, u64 __user *featurep) +{ + struct mdev_device *mdev = m->mdev; + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); + u64 features; + + features = ops->get_features(mdev); + features &= vhost_mdev_features[m->virtio_id]; + + if (copy_to_user(featurep, &features, sizeof(features))) + return -EFAULT; + + return 0; +} + +static long vhost_mdev_set_features(struct vhost_mdev *m, u64 __user *featurep) +{ + struct mdev_device *mdev = m->mdev; + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); + u64 features; + + /* + * It's not allowed to change the features after they have + * been negotiated. + */ + if (ops->get_status(mdev) & VIRTIO_CONFIG_S_FEATURES_OK) + return -EBUSY; + + if (copy_from_user(&features, featurep, sizeof(features))) + return -EFAULT; + + if (features & ~vhost_mdev_features[m->virtio_id]) + return -EINVAL; + + if (ops->set_features(mdev, features)) + return -EINVAL; + + return 0; +} + +static long vhost_mdev_get_vring_num(struct vhost_mdev *m, u16 __user *argp) +{ + struct mdev_device *mdev = m->mdev; + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); + u16 num; + + num = ops->get_vq_num_max(mdev); + + if (copy_to_user(argp, &num, sizeof(num))) + return -EFAULT; + + return 0; +} + +static long vhost_mdev_vring_ioctl(struct vhost_mdev *m, unsigned int cmd, + void __user *argp) +{ + struct mdev_device *mdev = m->mdev; + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); + struct virtio_mdev_callback cb; + struct vhost_virtqueue *vq; + struct vhost_vring_state s; + u8 status; + u32 idx; + long r; + + r = get_user(idx, (u32 __user *)argp); + if (r < 0) + return r; + if (idx >= m->nvqs) + return -ENOBUFS; + + status = ops->get_status(mdev); + + /* + * It's not allowed to detect and program vqs before + * features negotiation or after enabling driver. + */ + if (!(status & VIRTIO_CONFIG_S_FEATURES_OK) || + (status & VIRTIO_CONFIG_S_DRIVER_OK)) + return -EBUSY; + + vq = &m->vqs[idx]; + + if (cmd == VHOST_MDEV_SET_VRING_ENABLE) { + if (copy_from_user(&s, argp, sizeof(s))) + return -EFAULT; + ops->set_vq_ready(mdev, idx, s.num); + return 0; + } + + /* + * It's not allowed to detect and program vqs with + * vqs enabled. + */ + if (ops->get_vq_ready(mdev, idx)) + return -EBUSY; + + if (cmd == VHOST_GET_VRING_BASE) + vq->last_avail_idx = ops->get_vq_state(m->mdev, idx); + + r = vhost_vring_ioctl(&m->dev, cmd, argp); + if (r) + return r; + + switch (cmd) { + case VHOST_SET_VRING_ADDR: + /* + * In vhost-mdev, the ring addresses set by userspace should + * be the DMA addresses within the VFIO container/group. + */ + if (ops->set_vq_address(mdev, idx, (u64)vq->desc, + (u64)vq->avail, (u64)vq->used)) + r = -ENODEV; + break; + + case VHOST_SET_VRING_BASE: + if (ops->set_vq_state(mdev, idx, vq->last_avail_idx)) + r = -ENODEV; + break; + + case VHOST_SET_VRING_CALL: + if (vq->call_ctx) { + cb.callback = vhost_mdev_virtqueue_cb; + cb.private = vq; + } else { + cb.callback = NULL; + cb.private = NULL; + } + ops->set_vq_cb(mdev, idx, &cb); + break; + + case VHOST_SET_VRING_NUM: + ops->set_vq_num(mdev, idx, vq->num); + break; + } + + return r; +} + +static int vhost_mdev_open(void *device_data) +{ + struct vhost_mdev *m = device_data; + struct vhost_dev *dev; + struct vhost_virtqueue **vqs; + int nvqs, i, r; + + if (!try_module_get(THIS_MODULE)) + return -ENODEV; + + mutex_lock(&m->mutex); + + if (m->opened) { + r = -EBUSY; + goto err; + } + + nvqs = m->nvqs; + vhost_mdev_reset(m); + + vqs = kmalloc_array(nvqs, sizeof(*vqs), GFP_KERNEL); + if (!vqs) { + r = -ENOMEM; + goto err; + } + + dev = &m->dev; + for (i = 0; i < nvqs; i++) { + vqs[i] = &m->vqs[i]; + vqs[i]->handle_kick = handle_vq_kick; + } + vhost_dev_init(dev, vqs, nvqs, 0, 0, 0); + m->opened = true; + mutex_unlock(&m->mutex); + + return 0; + +err: + mutex_unlock(&m->mutex); + module_put(THIS_MODULE); + return r; +} + +static void vhost_mdev_release(void *device_data) +{ + struct vhost_mdev *m = device_data; + + mutex_lock(&m->mutex); + vhost_mdev_reset(m); + vhost_dev_stop(&m->dev); + vhost_dev_cleanup(&m->dev); + + kfree(m->dev.vqs); + m->opened = false; + mutex_unlock(&m->mutex); + module_put(THIS_MODULE); +} + +static long vhost_mdev_unlocked_ioctl(void *device_data, + unsigned int cmd, unsigned long arg) +{ + struct vhost_mdev *m = device_data; + void __user *argp = (void __user *)arg; + long r; + + mutex_lock(&m->mutex); + + switch (cmd) { + case VHOST_MDEV_GET_DEVICE_ID: + r = vhost_mdev_get_device_id(m, argp); + break; + case VHOST_MDEV_GET_STATUS: + r = vhost_mdev_get_status(m, argp); + break; + case VHOST_MDEV_SET_STATUS: + r = vhost_mdev_set_status(m, argp); + break; + case VHOST_MDEV_GET_CONFIG: + r = vhost_mdev_get_config(m, argp); + break; + case VHOST_MDEV_SET_CONFIG: + r = vhost_mdev_set_config(m, argp); + break; + case VHOST_GET_FEATURES: + r = vhost_mdev_get_features(m, argp); + break; + case VHOST_SET_FEATURES: + r = vhost_mdev_set_features(m, argp); + break; + case VHOST_MDEV_GET_VRING_NUM: + r = vhost_mdev_get_vring_num(m, argp); + break; + default: + /* + * VHOST_SET_MEM_TABLE, VHOST_SET_LOG_BASE, and + * VHOST_SET_LOG_FD are not used yet. + */ + r = vhost_dev_ioctl(&m->dev, cmd, argp); + if (r == -ENOIOCTLCMD) + r = vhost_mdev_vring_ioctl(m, cmd, argp); + } + + mutex_unlock(&m->mutex); + return r; +} + +static const struct vfio_device_ops vfio_vhost_mdev_dev_ops = { + .name = "vfio-vhost-mdev", + .open = vhost_mdev_open, + .release = vhost_mdev_release, + .ioctl = vhost_mdev_unlocked_ioctl, +}; + +static int vhost_mdev_probe(struct device *dev) +{ + struct mdev_device *mdev = mdev_from_dev(dev); + const struct virtio_mdev_device_ops *ops = mdev_get_vhost_ops(mdev); + struct vhost_mdev *m; + int nvqs, r; + + /* Currently, we only accept the network devices. */ + if (ops->get_device_id(mdev) != VIRTIO_ID_NET) + return -ENOTSUPP; + + if (ops->get_mdev_features(mdev) != VIRTIO_MDEV_F_VERSION_1) + return -ENOTSUPP; + + m = devm_kzalloc(dev, sizeof(*m), GFP_KERNEL | __GFP_RETRY_MAYFAIL); + if (!m) + return -ENOMEM; + + nvqs = VHOST_MDEV_VQ_MAX; + + m->vqs = devm_kmalloc_array(dev, nvqs, sizeof(struct vhost_virtqueue), + GFP_KERNEL); + if (!m->vqs) + return -ENOMEM; + + mutex_init(&m->mutex); + + m->mdev = mdev; + m->nvqs = nvqs; + m->virtio_id = ops->get_device_id(mdev); + + r = vfio_add_group_dev(dev, &vfio_vhost_mdev_dev_ops, m); + if (r) { + mutex_destroy(&m->mutex); + return r; + } + + return 0; +} + +static void vhost_mdev_remove(struct device *dev) +{ + struct vhost_mdev *m; + + m = vfio_del_group_dev(dev); + mutex_destroy(&m->mutex); +} + +static const struct mdev_class_id vhost_mdev_match[] = { + { MDEV_CLASS_ID_VHOST }, + { 0 }, +}; +MODULE_DEVICE_TABLE(mdev, vhost_mdev_match); + +static struct mdev_driver vhost_mdev_driver = { + .name = "vhost_mdev", + .probe = vhost_mdev_probe, + .remove = vhost_mdev_remove, + .id_table = vhost_mdev_match, +}; + +static int __init vhost_mdev_init(void) +{ + return mdev_register_driver(&vhost_mdev_driver, THIS_MODULE); +} +module_init(vhost_mdev_init); + +static void __exit vhost_mdev_exit(void) +{ + mdev_unregister_driver(&vhost_mdev_driver); +} +module_exit(vhost_mdev_exit); + +MODULE_VERSION("0.0.1"); +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Intel Corporation"); +MODULE_DESCRIPTION("Mediated device based accelerator for virtio"); diff --git a/include/linux/mdev.h b/include/linux/mdev.h index 9b69b0bbebfd..3e1e03926355 100644 --- a/include/linux/mdev.h +++ b/include/linux/mdev.h @@ -117,6 +117,10 @@ void mdev_set_virtio_ops(struct mdev_device *mdev, const struct virtio_mdev_device_ops *virtio_ops); const struct virtio_mdev_device_ops * mdev_get_virtio_ops(struct mdev_device *mdev); +void mdev_set_vhost_ops(struct mdev_device *mdev, + const struct virtio_mdev_device_ops *vhost_ops); +const struct virtio_mdev_device_ops * +mdev_get_vhost_ops(struct mdev_device *mdev); extern struct bus_type mdev_bus_type; @@ -133,6 +137,7 @@ struct mdev_device *mdev_from_dev(struct device *dev); enum { MDEV_CLASS_ID_VFIO = 1, MDEV_CLASS_ID_VIRTIO = 2, + MDEV_CLASS_ID_VHOST = 3, /* New entries must be added here */ }; diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h index 40d028eed645..061a2824a1b3 100644 --- a/include/uapi/linux/vhost.h +++ b/include/uapi/linux/vhost.h @@ -116,4 +116,22 @@ #define VHOST_VSOCK_SET_GUEST_CID _IOW(VHOST_VIRTIO, 0x60, __u64) #define VHOST_VSOCK_SET_RUNNING _IOW(VHOST_VIRTIO, 0x61, int) +/* VHOST_MDEV specific defines */ + +/* Get the device id. The device ids follow the same definition of + * the device id defined in virtio-spec. */ +#define VHOST_MDEV_GET_DEVICE_ID _IOR(VHOST_VIRTIO, 0x70, __u32) +/* Get and set the status. The status bits follow the same definition + * of the device status defined in virtio-spec. */ +#define VHOST_MDEV_GET_STATUS _IOR(VHOST_VIRTIO, 0x71, __u8) +#define VHOST_MDEV_SET_STATUS _IOW(VHOST_VIRTIO, 0x72, __u8) +/* Get and set the device config. The device config follows the same + * definition of the device config defined in virtio-spec. */ +#define VHOST_MDEV_GET_CONFIG _IOR(VHOST_VIRTIO, 0x73, struct vhost_mdev_config) +#define VHOST_MDEV_SET_CONFIG _IOW(VHOST_VIRTIO, 0x74, struct vhost_mdev_config) +/* Enable/disable the ring. */ +#define VHOST_MDEV_SET_VRING_ENABLE _IOW(VHOST_VIRTIO, 0x75, struct vhost_vring_state) +/* Get the max ring size. */ +#define VHOST_MDEV_GET_VRING_NUM _IOR(VHOST_VIRTIO, 0x76, __u16) + #endif diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h index c907290ff065..7b105d0b2fb9 100644 --- a/include/uapi/linux/vhost_types.h +++ b/include/uapi/linux/vhost_types.h @@ -119,6 +119,14 @@ struct vhost_scsi_target { unsigned short reserved; }; +/* VHOST_MDEV specific definitions */ + +struct vhost_mdev_config { + __u32 off; + __u32 len; + __u8 buf[0]; +}; + /* Feature bits */ /* Log all write descriptors. Can be changed while device is active. */ #define VHOST_F_LOG_ALL 26
This patch introduces a mdev based hardware vhost backend. This backend is built on top of the same abstraction used in virtio-mdev and provides a generic vhost interface for userspace to accelerate the virtio devices in guest. This backend is implemented as a mdev device driver on top of the same mdev device ops used in virtio-mdev but using a different mdev class id, and it will register the device as a VFIO device for userspace to use. Userspace can setup the IOMMU with the existing VFIO container/group APIs and then get the device fd with the device name. After getting the device fd of this device, userspace can use vhost ioctls to setup the backend. Signed-off-by: Tiwei Bie <tiwei.bie@intel.com> --- This patch depends on below series: https://lkml.org/lkml/2019/10/23/614 v2 -> v3: - Fix the return value (Jason); - Don't cache unnecessary information in vhost-mdev (Jason); - Get rid of the memset in open (Jason); - Add comments for VHOST_SET_MEM_TABLE, ... (Jason); - Filter out unsupported features in vhost-mdev (Jason); - Add _GET_DEVICE_ID ioctl (Jason); - Add _GET_CONFIG/_SET_CONFIG ioctls (Jason); - Drop _GET_QUEUE_NUM ioctl (Jason); - Fix the copy-paste errors in _IOW/_IOR usage; - Some minor fixes and improvements; v1 -> v2: - Replace _SET_STATE with _SET_STATUS (MST); - Check status bits at each step (MST); - Report the max ring size and max number of queues (MST); - Add missing MODULE_DEVICE_TABLE (Jason); - Only support the network backend w/o multiqueue for now; - Some minor fixes and improvements; - Rebase on top of virtio-mdev series v4; RFC v4 -> v1: - Implement vhost-mdev as a mdev device driver directly and connect it to VFIO container/group. (Jason); - Pass ring addresses as GPAs/IOVAs in vhost-mdev to avoid meaningless HVA->GPA translations (Jason); RFC v3 -> RFC v4: - Build vhost-mdev on top of the same abstraction used by virtio-mdev (Jason); - Introduce vhost fd and pass VFIO fd via SET_BACKEND ioctl (MST); RFC v2 -> RFC v3: - Reuse vhost's ioctls instead of inventing a VFIO regions/irqs based vhost protocol on top of vfio-mdev (Jason); RFC v1 -> RFC v2: - Introduce a new VFIO device type to build a vhost protocol on top of vfio-mdev; drivers/vfio/mdev/mdev_core.c | 20 ++ drivers/vfio/mdev/mdev_private.h | 1 + drivers/vhost/Kconfig | 12 + drivers/vhost/Makefile | 3 + drivers/vhost/mdev.c | 554 +++++++++++++++++++++++++++++++ include/linux/mdev.h | 5 + include/uapi/linux/vhost.h | 18 + include/uapi/linux/vhost_types.h | 8 + 8 files changed, 621 insertions(+) create mode 100644 drivers/vhost/mdev.c