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 <[email protected]>
---
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 <[email protected]>
+ *
+ * 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
--
2.23.0
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 <[email protected]>
> ---
> 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 <[email protected]>
> + *
> + * 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 <[email protected]>
> > ---
> > 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 <[email protected]>
> > + *
> > + * 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 <[email protected]>
>>> ---
>>> 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 <[email protected]>
>>> + *
>>> + * 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