On Wed, Nov 06, 2019 at 03:54:45PM +0800, Jason Wang wrote: > On 2019/11/5 下午7:53, 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, userspace can use vhost ioctls on top of it > > to setup the backend. > > > > Signed-off-by: Tiwei Bie <tiwei.bie@xxxxxxxxx> > > > Looks good to me. Only minor nits which could be addressed on top. > > Reviewed-by: Jason Wang <jasowang@xxxxxxxxxx> Thanks! > > > > --- > > This patch depends on below series: > > https://lkml.org/lkml/2019/11/5/217 > > > > v4 -> v5: > > - Rebase on top of virtio-mdev series v8; > > - Use the virtio_ops of mdev_device in vhost-mdev (Jason); > > - Some minor improvements on commit log; > > > > v3 -> v4: > > - Rebase on top of virtio-mdev series v6; > > - Some minor tweaks and improvements; > > > > 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 | 21 ++ > > drivers/vhost/Kconfig | 12 + > > drivers/vhost/Makefile | 3 + > > drivers/vhost/mdev.c | 553 +++++++++++++++++++++++++++++++ > > include/linux/mdev.h | 5 + > > include/uapi/linux/vhost.h | 18 + > > include/uapi/linux/vhost_types.h | 8 + > > 7 files changed, 620 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 c58253404ed5..d855be5afbae 100644 > > --- a/drivers/vfio/mdev/mdev_core.c > > +++ b/drivers/vfio/mdev/mdev_core.c > > @@ -99,6 +99,27 @@ 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 mdev_virtio_device_ops *vhost_ops) > > +{ > > + mdev_set_class(mdev, MDEV_CLASS_ID_VHOST); > > + mdev->virtio_ops = vhost_ops; > > +} > > +EXPORT_SYMBOL(mdev_set_vhost_ops); > > + > > +/* Get the vhost device ops for the mdev device. */ > > +const struct mdev_virtio_device_ops * > > +mdev_get_vhost_ops(struct mdev_device *mdev) > > +{ > > + WARN_ON(mdev->class_id != MDEV_CLASS_ID_VHOST); > > + return mdev->virtio_ops; > > +} > > +EXPORT_SYMBOL(mdev_get_vhost_ops); > > + > > struct device *mdev_dev(struct mdev_device *mdev) > > { > > return &mdev->dev; > > 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..0bcde0f3a9cd > > --- /dev/null > > +++ b/drivers/vhost/mdev.c > > @@ -0,0 +1,553 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +/* > > + * Vhost driver for mediated device based backends. > > + * > > + * Copyright (C) 2018-2019 Intel Corporation. > > + * > > + * Author: Tiwei Bie <tiwei.bie@xxxxxxxxx> > > + * > > + * 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/mdev_virtio_ops.h> > > +#include <linux/nospec.h> > > +#include <linux/vfio.h> > > +#include <linux/vhost.h> > > +#include <linux/virtio_net.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 mdev_virtio_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 mdev_virtio_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 mdev_virtio_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 mdev_virtio_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 mdev_virtio_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; > > > Nit: It should be the same as check with c->off + c->len > size only. I did a quick test with below program: #include <stdio.h> int main(void) { unsigned int a, b; long c; scanf("%u%u%ld", &a, &b, &c); printf("%d\n", a + b > c); printf("%d\n", (long)a + b > c); return 0; } And I got this: $ echo 4294967295 1 1 | ./a.out 0 1 As c->off and c->len are __u32, we would need to cast one of them to long if we want to just check c->off + c->len > size, e.g. (long)c->off + c->len > size Off the topic, one thing I'm not quite sure about and want to confirm is that, will it be better to define c->off and c->len as __u64 (they are parts of UAPI)? > > > > + > > + 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 mdev_virtio_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 mdev_virtio_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 mdev_virtio_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 mdev_virtio_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 mdev_virtio_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 mdev_virtio_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; > > + > > + idx = array_index_nospec(idx, m->nvqs); > > + vq = &m->vqs[idx]; > > + > > + 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; > > + > > + 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 = -EINVAL; > > + break; > > + > > + case VHOST_SET_VRING_BASE: > > + if (ops->set_vq_state(mdev, idx, vq->last_avail_idx)) > > + r = -EINVAL; > > + 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. > > + */ > > > If we don't even use them, there's probably no need to call > vhost_dev_ioctl(). This may help to avoid confusion when we want to develop > new API for e.g dirty page tracking. Good point. It's better to reject these ioctls for now. PS. One thing I may need to clarify is that, we need the VHOST_SET_OWNER ioctl to get the vq->handle_kick to work. So if we don't call vhost_dev_ioctl(), we will need to call vhost_dev_set_owner() directly. > > > > + 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 mdev_virtio_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; > > + > > + m = devm_kzalloc(dev, sizeof(*m), GFP_KERNEL | __GFP_RETRY_MAYFAIL); > > + if (!m) > > + return -ENOMEM; > > + > > + nvqs = VHOST_MDEV_VQ_MAX; > > > On top. I think we probably need a better way other than hard-coded value > here. > > E.g we can read config and detect the max virtqueue supported based on > device id. Totally agree. We do need a better way than the hardcoded value in the future. For now, it might be better to keep it as is for simplicity before we have the MQ support. > > Thanks > > > > + > > + 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 f3d75a60c2b5..8af7fb9e0149 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 mdev_virtio_device_ops *virtio_ops); > > const struct mdev_virtio_device_ops * > > mdev_get_virtio_ops(struct mdev_device *mdev); > > +void mdev_set_vhost_ops(struct mdev_device *mdev, > > + const struct mdev_virtio_device_ops *vhost_ops); > > +const struct mdev_virtio_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 >
