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Message-ID: <CACycT3uh+wUeDM1H7JiCJTMeCVCBngURGKeXD-h+meekNNwiQw@mail.gmail.com>
Date: Wed, 14 Jul 2021 14:49:21 +0800
From: Yongji Xie <xieyongji@...edance.com>
To: Jason Wang <jasowang@...hat.com>
Cc: "Michael S. Tsirkin" <mst@...hat.com>,
Stefan Hajnoczi <stefanha@...hat.com>,
Stefano Garzarella <sgarzare@...hat.com>,
Parav Pandit <parav@...dia.com>,
Christoph Hellwig <hch@...radead.org>,
Christian Brauner <christian.brauner@...onical.com>,
Randy Dunlap <rdunlap@...radead.org>,
Matthew Wilcox <willy@...radead.org>,
Al Viro <viro@...iv.linux.org.uk>,
Jens Axboe <axboe@...nel.dk>, bcrl@...ck.org,
Jonathan Corbet <corbet@....net>,
Mika Penttilä <mika.penttila@...tfour.com>,
Dan Carpenter <dan.carpenter@...cle.com>, joro@...tes.org,
Greg KH <gregkh@...uxfoundation.org>,
He Zhe <zhe.he@...driver.com>,
Liu Xiaodong <xiaodong.liu@...el.com>,
songmuchun@...edance.com,
virtualization <virtualization@...ts.linux-foundation.org>,
netdev@...r.kernel.org, kvm <kvm@...r.kernel.org>,
linux-fsdevel@...r.kernel.org, iommu@...ts.linux-foundation.org,
linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v9 16/17] vduse: Introduce VDUSE - vDPA Device in Userspace
On Wed, Jul 14, 2021 at 1:45 PM Jason Wang <jasowang@...hat.com> wrote:
>
>
> 在 2021/7/13 下午4:46, Xie Yongji 写道:
> > This VDUSE driver enables implementing software-emulated vDPA
> > devices in userspace. The vDPA device is created by
> > ioctl(VDUSE_CREATE_DEV) on /dev/vduse/control. Then a char device
> > interface (/dev/vduse/$NAME) is exported to userspace for device
> > emulation.
> >
> > In order to make the device emulation more secure, the device's
> > control path is handled in kernel. A message mechnism is introduced
> > to forward some dataplane related control messages to userspace.
> >
> > And in the data path, the DMA buffer will be mapped into userspace
> > address space through different ways depending on the vDPA bus to
> > which the vDPA device is attached. In virtio-vdpa case, the MMU-based
> > IOMMU driver is used to achieve that. And in vhost-vdpa case, the
> > DMA buffer is reside in a userspace memory region which can be shared
> > to the VDUSE userspace processs via transferring the shmfd.
> >
> > For more details on VDUSE design and usage, please see the follow-on
> > Documentation commit.
> >
> > Signed-off-by: Xie Yongji <xieyongji@...edance.com>
> > ---
> > Documentation/userspace-api/ioctl/ioctl-number.rst | 1 +
> > drivers/vdpa/Kconfig | 10 +
> > drivers/vdpa/Makefile | 1 +
> > drivers/vdpa/vdpa_user/Makefile | 5 +
> > drivers/vdpa/vdpa_user/vduse_dev.c | 1502 ++++++++++++++++++++
> > include/uapi/linux/vduse.h | 221 +++
> > 6 files changed, 1740 insertions(+)
> > create mode 100644 drivers/vdpa/vdpa_user/Makefile
> > create mode 100644 drivers/vdpa/vdpa_user/vduse_dev.c
> > create mode 100644 include/uapi/linux/vduse.h
> >
> > diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
> > index 1409e40e6345..293ca3aef358 100644
> > --- a/Documentation/userspace-api/ioctl/ioctl-number.rst
> > +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
> > @@ -300,6 +300,7 @@ Code Seq# Include File Comments
> > 'z' 10-4F drivers/s390/crypto/zcrypt_api.h conflict!
> > '|' 00-7F linux/media.h
> > 0x80 00-1F linux/fb.h
> > +0x81 00-1F linux/vduse.h
> > 0x89 00-06 arch/x86/include/asm/sockios.h
> > 0x89 0B-DF linux/sockios.h
> > 0x89 E0-EF linux/sockios.h SIOCPROTOPRIVATE range
> > diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig
> > index a503c1b2bfd9..6e23bce6433a 100644
> > --- a/drivers/vdpa/Kconfig
> > +++ b/drivers/vdpa/Kconfig
> > @@ -33,6 +33,16 @@ config VDPA_SIM_BLOCK
> > vDPA block device simulator which terminates IO request in a
> > memory buffer.
> >
> > +config VDPA_USER
> > + tristate "VDUSE (vDPA Device in Userspace) support"
> > + depends on EVENTFD && MMU && HAS_DMA
> > + select DMA_OPS
> > + select VHOST_IOTLB
> > + select IOMMU_IOVA
> > + help
> > + With VDUSE it is possible to emulate a vDPA Device
> > + in a userspace program.
> > +
> > config IFCVF
> > tristate "Intel IFC VF vDPA driver"
> > depends on PCI_MSI
> > diff --git a/drivers/vdpa/Makefile b/drivers/vdpa/Makefile
> > index 67fe7f3d6943..f02ebed33f19 100644
> > --- a/drivers/vdpa/Makefile
> > +++ b/drivers/vdpa/Makefile
> > @@ -1,6 +1,7 @@
> > # SPDX-License-Identifier: GPL-2.0
> > obj-$(CONFIG_VDPA) += vdpa.o
> > obj-$(CONFIG_VDPA_SIM) += vdpa_sim/
> > +obj-$(CONFIG_VDPA_USER) += vdpa_user/
> > obj-$(CONFIG_IFCVF) += ifcvf/
> > obj-$(CONFIG_MLX5_VDPA) += mlx5/
> > obj-$(CONFIG_VP_VDPA) += virtio_pci/
> > diff --git a/drivers/vdpa/vdpa_user/Makefile b/drivers/vdpa/vdpa_user/Makefile
> > new file mode 100644
> > index 000000000000..260e0b26af99
> > --- /dev/null
> > +++ b/drivers/vdpa/vdpa_user/Makefile
> > @@ -0,0 +1,5 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +
> > +vduse-y := vduse_dev.o iova_domain.o
> > +
> > +obj-$(CONFIG_VDPA_USER) += vduse.o
> > diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> > new file mode 100644
> > index 000000000000..c994a4a4660c
> > --- /dev/null
> > +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> > @@ -0,0 +1,1502 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * VDUSE: vDPA Device in Userspace
> > + *
> > + * Copyright (C) 2020-2021 Bytedance Inc. and/or its affiliates. All rights reserved.
> > + *
> > + * Author: Xie Yongji <xieyongji@...edance.com>
> > + *
> > + */
> > +
> > +#include <linux/init.h>
> > +#include <linux/module.h>
> > +#include <linux/cdev.h>
> > +#include <linux/device.h>
> > +#include <linux/eventfd.h>
> > +#include <linux/slab.h>
> > +#include <linux/wait.h>
> > +#include <linux/dma-map-ops.h>
> > +#include <linux/poll.h>
> > +#include <linux/file.h>
> > +#include <linux/uio.h>
> > +#include <linux/vdpa.h>
> > +#include <linux/nospec.h>
> > +#include <uapi/linux/vduse.h>
> > +#include <uapi/linux/vdpa.h>
> > +#include <uapi/linux/virtio_config.h>
> > +#include <uapi/linux/virtio_ids.h>
> > +#include <uapi/linux/virtio_blk.h>
> > +#include <linux/mod_devicetable.h>
> > +
> > +#include "iova_domain.h"
> > +
> > +#define DRV_AUTHOR "Yongji Xie <xieyongji@...edance.com>"
> > +#define DRV_DESC "vDPA Device in Userspace"
> > +#define DRV_LICENSE "GPL v2"
> > +
> > +#define VDUSE_DEV_MAX (1U << MINORBITS)
> > +#define VDUSE_MAX_BOUNCE_SIZE (64 * 1024 * 1024)
> > +#define VDUSE_IOVA_SIZE (128 * 1024 * 1024)
> > +#define VDUSE_REQUEST_TIMEOUT 30
> > +
> > +struct vduse_virtqueue {
> > + u16 index;
> > + u16 num_max;
> > + u32 num;
> > + u64 desc_addr;
> > + u64 driver_addr;
> > + u64 device_addr;
> > + struct vdpa_vq_state state;
> > + bool ready;
> > + bool kicked;
> > + spinlock_t kick_lock;
> > + spinlock_t irq_lock;
> > + struct eventfd_ctx *kickfd;
> > + struct vdpa_callback cb;
> > + struct work_struct inject;
> > +};
> > +
> > +struct vduse_dev;
> > +
> > +struct vduse_vdpa {
> > + struct vdpa_device vdpa;
> > + struct vduse_dev *dev;
> > +};
> > +
> > +struct vduse_dev {
> > + struct vduse_vdpa *vdev;
> > + struct device *dev;
> > + struct vduse_virtqueue *vqs;
> > + struct vduse_iova_domain *domain;
> > + char *name;
> > + struct mutex lock;
> > + spinlock_t msg_lock;
> > + u64 msg_unique;
> > + wait_queue_head_t waitq;
> > + struct list_head send_list;
> > + struct list_head recv_list;
> > + struct vdpa_callback config_cb;
> > + struct work_struct inject;
> > + spinlock_t irq_lock;
> > + int minor;
> > + bool connected;
> > + u64 api_version;
> > + u64 device_features;
> > + u64 driver_features;
> > + u32 device_id;
> > + u32 vendor_id;
> > + u32 generation;
> > + u32 config_size;
> > + void *config;
> > + u8 status;
> > + u32 vq_num;
> > + u32 vq_align;
> > +};
> > +
> > +struct vduse_dev_msg {
> > + struct vduse_dev_request req;
> > + struct vduse_dev_response resp;
> > + struct list_head list;
> > + wait_queue_head_t waitq;
> > + bool completed;
> > +};
> > +
> > +struct vduse_control {
> > + u64 api_version;
> > +};
> > +
> > +static DEFINE_MUTEX(vduse_lock);
> > +static DEFINE_IDR(vduse_idr);
> > +
> > +static dev_t vduse_major;
> > +static struct class *vduse_class;
> > +static struct cdev vduse_ctrl_cdev;
> > +static struct cdev vduse_cdev;
> > +static struct workqueue_struct *vduse_irq_wq;
> > +
> > +static u32 allowed_device_id[] = {
> > + VIRTIO_ID_BLOCK,
> > +};
> > +
> > +static inline struct vduse_dev *vdpa_to_vduse(struct vdpa_device *vdpa)
> > +{
> > + struct vduse_vdpa *vdev = container_of(vdpa, struct vduse_vdpa, vdpa);
> > +
> > + return vdev->dev;
> > +}
> > +
> > +static inline struct vduse_dev *dev_to_vduse(struct device *dev)
> > +{
> > + struct vdpa_device *vdpa = dev_to_vdpa(dev);
> > +
> > + return vdpa_to_vduse(vdpa);
> > +}
> > +
> > +static struct vduse_dev_msg *vduse_find_msg(struct list_head *head,
> > + uint32_t request_id)
> > +{
> > + struct vduse_dev_msg *msg;
> > +
> > + list_for_each_entry(msg, head, list) {
> > + if (msg->req.request_id == request_id) {
> > + list_del(&msg->list);
> > + return msg;
> > + }
> > + }
> > +
> > + return NULL;
> > +}
> > +
> > +static struct vduse_dev_msg *vduse_dequeue_msg(struct list_head *head)
> > +{
> > + struct vduse_dev_msg *msg = NULL;
> > +
> > + if (!list_empty(head)) {
> > + msg = list_first_entry(head, struct vduse_dev_msg, list);
> > + list_del(&msg->list);
> > + }
> > +
> > + return msg;
> > +}
> > +
> > +static void vduse_enqueue_msg(struct list_head *head,
> > + struct vduse_dev_msg *msg)
> > +{
> > + list_add_tail(&msg->list, head);
> > +}
> > +
> > +static int vduse_dev_msg_sync(struct vduse_dev *dev,
> > + struct vduse_dev_msg *msg)
> > +{
> > + int ret;
> > +
> > + init_waitqueue_head(&msg->waitq);
> > + spin_lock(&dev->msg_lock);
> > + msg->req.request_id = dev->msg_unique++;
> > + vduse_enqueue_msg(&dev->send_list, msg);
> > + wake_up(&dev->waitq);
> > + spin_unlock(&dev->msg_lock);
> > +
> > + wait_event_killable_timeout(msg->waitq, msg->completed,
> > + VDUSE_REQUEST_TIMEOUT * HZ);
> > + spin_lock(&dev->msg_lock);
> > + if (!msg->completed) {
> > + list_del(&msg->list);
> > + msg->resp.result = VDUSE_REQ_RESULT_FAILED;
> > + }
> > + ret = (msg->resp.result == VDUSE_REQ_RESULT_OK) ? 0 : -EIO;
>
>
> I think we should mark the device as malfunction when there is a timeout
> and forbid any userspace operations except for the destroy aftwards for
> safety.
>
Is it necessary? Actually we can't stop the dataplane processing in
userspace. It doesn’t seem to help much if we only forbid ioctl and
read/write. And there might be some messages that can tolerate
failure. Even userspace can do something like NEEDS_RESET to do
recovery.
>
> > + spin_unlock(&dev->msg_lock);
> > +
> > + return ret;
> > +}
> > +
> > +static int vduse_dev_get_vq_state_packed(struct vduse_dev *dev,
> > + struct vduse_virtqueue *vq,
> > + struct vdpa_vq_state_packed *packed)
> > +{
> > + struct vduse_dev_msg msg = { 0 };
> > + int ret;
> > +
> > + msg.req.type = VDUSE_GET_VQ_STATE;
> > + msg.req.vq_state.index = vq->index;
> > +
> > + ret = vduse_dev_msg_sync(dev, &msg);
> > + if (ret)
> > + return ret;
> > +
> > + packed->last_avail_counter =
> > + msg.resp.vq_state.packed.last_avail_counter;
> > + packed->last_avail_idx = msg.resp.vq_state.packed.last_avail_idx;
> > + packed->last_used_counter = msg.resp.vq_state.packed.last_used_counter;
> > + packed->last_used_idx = msg.resp.vq_state.packed.last_used_idx;
> > +
> > + return 0;
> > +}
> > +
> > +static int vduse_dev_get_vq_state_split(struct vduse_dev *dev,
> > + struct vduse_virtqueue *vq,
> > + struct vdpa_vq_state_split *split)
> > +{
> > + struct vduse_dev_msg msg = { 0 };
> > + int ret;
> > +
> > + msg.req.type = VDUSE_GET_VQ_STATE;
> > + msg.req.vq_state.index = vq->index;
> > +
> > + ret = vduse_dev_msg_sync(dev, &msg);
> > + if (ret)
> > + return ret;
> > +
> > + split->avail_index = msg.resp.vq_state.split.avail_index;
> > +
> > + return 0;
> > +}
> > +
> > +static int vduse_dev_set_status(struct vduse_dev *dev, u8 status)
> > +{
> > + struct vduse_dev_msg msg = { 0 };
> > +
> > + msg.req.type = VDUSE_SET_STATUS;
> > + msg.req.s.status = status;
> > +
> > + return vduse_dev_msg_sync(dev, &msg);
> > +}
> > +
> > +static int vduse_dev_update_iotlb(struct vduse_dev *dev,
> > + u64 start, u64 last)
> > +{
> > + struct vduse_dev_msg msg = { 0 };
> > +
> > + if (last < start)
> > + return -EINVAL;
> > +
> > + msg.req.type = VDUSE_UPDATE_IOTLB;
> > + msg.req.iova.start = start;
> > + msg.req.iova.last = last;
> > +
> > + return vduse_dev_msg_sync(dev, &msg);
> > +}
> > +
> > +static ssize_t vduse_dev_read_iter(struct kiocb *iocb, struct iov_iter *to)
> > +{
> > + struct file *file = iocb->ki_filp;
> > + struct vduse_dev *dev = file->private_data;
> > + struct vduse_dev_msg *msg;
> > + int size = sizeof(struct vduse_dev_request);
> > + ssize_t ret;
> > +
> > + if (iov_iter_count(to) < size)
> > + return -EINVAL;
> > +
> > + spin_lock(&dev->msg_lock);
> > + while (1) {
> > + msg = vduse_dequeue_msg(&dev->send_list);
> > + if (msg)
> > + break;
> > +
> > + ret = -EAGAIN;
> > + if (file->f_flags & O_NONBLOCK)
> > + goto unlock;
> > +
> > + spin_unlock(&dev->msg_lock);
> > + ret = wait_event_interruptible_exclusive(dev->waitq,
> > + !list_empty(&dev->send_list));
> > + if (ret)
> > + return ret;
> > +
> > + spin_lock(&dev->msg_lock);
> > + }
> > + spin_unlock(&dev->msg_lock);
> > + ret = copy_to_iter(&msg->req, size, to);
> > + spin_lock(&dev->msg_lock);
> > + if (ret != size) {
> > + ret = -EFAULT;
> > + vduse_enqueue_msg(&dev->send_list, msg);
> > + goto unlock;
> > + }
> > + vduse_enqueue_msg(&dev->recv_list, msg);
> > +unlock:
> > + spin_unlock(&dev->msg_lock);
> > +
> > + return ret;
> > +}
> > +
> > +static ssize_t vduse_dev_write_iter(struct kiocb *iocb, struct iov_iter *from)
> > +{
> > + struct file *file = iocb->ki_filp;
> > + struct vduse_dev *dev = file->private_data;
> > + struct vduse_dev_response resp;
> > + struct vduse_dev_msg *msg;
> > + size_t ret;
> > +
> > + ret = copy_from_iter(&resp, sizeof(resp), from);
> > + if (ret != sizeof(resp))
> > + return -EINVAL;
> > +
> > + spin_lock(&dev->msg_lock);
> > + msg = vduse_find_msg(&dev->recv_list, resp.request_id);
> > + if (!msg) {
> > + ret = -ENOENT;
> > + goto unlock;
> > + }
> > +
> > + memcpy(&msg->resp, &resp, sizeof(resp));
> > + msg->completed = 1;
> > + wake_up(&msg->waitq);
> > +unlock:
> > + spin_unlock(&dev->msg_lock);
> > +
> > + return ret;
> > +}
> > +
> > +static __poll_t vduse_dev_poll(struct file *file, poll_table *wait)
> > +{
> > + struct vduse_dev *dev = file->private_data;
> > + __poll_t mask = 0;
> > +
> > + poll_wait(file, &dev->waitq, wait);
> > +
> > + if (!list_empty(&dev->send_list))
> > + mask |= EPOLLIN | EPOLLRDNORM;
> > + if (!list_empty(&dev->recv_list))
> > + mask |= EPOLLOUT | EPOLLWRNORM;
> > +
> > + return mask;
> > +}
> > +
> > +static void vduse_dev_reset(struct vduse_dev *dev)
> > +{
> > + int i;
> > + struct vduse_iova_domain *domain = dev->domain;
> > +
> > + /* The coherent mappings are handled in vduse_dev_free_coherent() */
> > + if (domain->bounce_map)
> > + vduse_domain_reset_bounce_map(domain);
> > +
> > + dev->driver_features = 0;
> > + dev->generation++;
> > + spin_lock(&dev->irq_lock);
> > + dev->config_cb.callback = NULL;
> > + dev->config_cb.private = NULL;
> > + spin_unlock(&dev->irq_lock);
> > + flush_work(&dev->inject);
> > +
> > + for (i = 0; i < dev->vq_num; i++) {
> > + struct vduse_virtqueue *vq = &dev->vqs[i];
> > +
> > + vq->ready = false;
> > + vq->desc_addr = 0;
> > + vq->driver_addr = 0;
> > + vq->device_addr = 0;
> > + vq->num = 0;
> > + memset(&vq->state, 0, sizeof(vq->state));
> > +
> > + spin_lock(&vq->kick_lock);
> > + vq->kicked = false;
> > + if (vq->kickfd)
> > + eventfd_ctx_put(vq->kickfd);
> > + vq->kickfd = NULL;
> > + spin_unlock(&vq->kick_lock);
> > +
> > + spin_lock(&vq->irq_lock);
> > + vq->cb.callback = NULL;
> > + vq->cb.private = NULL;
> > + spin_unlock(&vq->irq_lock);
> > + flush_work(&vq->inject);
> > + }
> > +}
> > +
> > +static int vduse_vdpa_set_vq_address(struct vdpa_device *vdpa, u16 idx,
> > + u64 desc_area, u64 driver_area,
> > + u64 device_area)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > + struct vduse_virtqueue *vq = &dev->vqs[idx];
> > +
> > + vq->desc_addr = desc_area;
> > + vq->driver_addr = driver_area;
> > + vq->device_addr = device_area;
> > +
> > + return 0;
> > +}
> > +
> > +static void vduse_vdpa_kick_vq(struct vdpa_device *vdpa, u16 idx)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > + struct vduse_virtqueue *vq = &dev->vqs[idx];
> > +
> > + spin_lock(&vq->kick_lock);
> > + if (!vq->ready)
> > + goto unlock;
> > +
> > + if (vq->kickfd)
> > + eventfd_signal(vq->kickfd, 1);
> > + else
> > + vq->kicked = true;
> > +unlock:
> > + spin_unlock(&vq->kick_lock);
> > +}
> > +
> > +static void vduse_vdpa_set_vq_cb(struct vdpa_device *vdpa, u16 idx,
> > + struct vdpa_callback *cb)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > + struct vduse_virtqueue *vq = &dev->vqs[idx];
> > +
> > + spin_lock(&vq->irq_lock);
> > + vq->cb.callback = cb->callback;
> > + vq->cb.private = cb->private;
> > + spin_unlock(&vq->irq_lock);
> > +}
> > +
> > +static void vduse_vdpa_set_vq_num(struct vdpa_device *vdpa, u16 idx, u32 num)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > + struct vduse_virtqueue *vq = &dev->vqs[idx];
> > +
> > + vq->num = num;
> > +}
> > +
> > +static void vduse_vdpa_set_vq_ready(struct vdpa_device *vdpa,
> > + u16 idx, bool ready)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > + struct vduse_virtqueue *vq = &dev->vqs[idx];
> > +
> > + vq->ready = ready;
> > +}
> > +
> > +static bool vduse_vdpa_get_vq_ready(struct vdpa_device *vdpa, u16 idx)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > + struct vduse_virtqueue *vq = &dev->vqs[idx];
> > +
> > + return vq->ready;
> > +}
> > +
> > +static int vduse_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 idx,
> > + const struct vdpa_vq_state *state)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > + struct vduse_virtqueue *vq = &dev->vqs[idx];
> > +
> > + if (dev->driver_features & BIT_ULL(VIRTIO_F_RING_PACKED)) {
> > + vq->state.packed.last_avail_counter =
> > + state->packed.last_avail_counter;
> > + vq->state.packed.last_avail_idx = state->packed.last_avail_idx;
> > + vq->state.packed.last_used_counter =
> > + state->packed.last_used_counter;
> > + vq->state.packed.last_used_idx = state->packed.last_used_idx;
> > + } else
> > + vq->state.split.avail_index = state->split.avail_index;
> > +
> > + return 0;
> > +}
> > +
> > +static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx,
> > + struct vdpa_vq_state *state)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > + struct vduse_virtqueue *vq = &dev->vqs[idx];
> > +
> > + if (dev->driver_features & BIT_ULL(VIRTIO_F_RING_PACKED))
> > + return vduse_dev_get_vq_state_packed(dev, vq, &state->packed);
> > +
> > + return vduse_dev_get_vq_state_split(dev, vq, &state->split);
> > +}
> > +
> > +static u32 vduse_vdpa_get_vq_align(struct vdpa_device *vdpa)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > + return dev->vq_align;
> > +}
> > +
> > +static u64 vduse_vdpa_get_features(struct vdpa_device *vdpa)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > + return dev->device_features;
> > +}
> > +
> > +static int vduse_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > + dev->driver_features = features;
> > + return 0;
> > +}
> > +
> > +static void vduse_vdpa_set_config_cb(struct vdpa_device *vdpa,
> > + struct vdpa_callback *cb)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > + spin_lock(&dev->irq_lock);
> > + dev->config_cb.callback = cb->callback;
> > + dev->config_cb.private = cb->private;
> > + spin_unlock(&dev->irq_lock);
> > +}
> > +
> > +static u16 vduse_vdpa_get_vq_num_max(struct vdpa_device *vdpa, u16 idx)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > + return dev->vqs[idx].num_max;
> > +}
> > +
> > +static u32 vduse_vdpa_get_device_id(struct vdpa_device *vdpa)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > + return dev->device_id;
> > +}
> > +
> > +static u32 vduse_vdpa_get_vendor_id(struct vdpa_device *vdpa)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > + return dev->vendor_id;
> > +}
> > +
> > +static u8 vduse_vdpa_get_status(struct vdpa_device *vdpa)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > + return dev->status;
> > +}
> > +
> > +static void vduse_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > + if (vduse_dev_set_status(dev, status))
> > + return;
> > +
> > + dev->status = status;
>
>
> It looks to me such design exclude the possibility of letting userspace
> device to set bit like (NEEDS_RESET) in the future.
>
Looks like we can achieve that via the ioctl.
> I wonder if it's better to do something similar to ccw:
>
> 1) requires the userspace to update the status bit in the response
> 2) update the dev->status to the status in the response if no timeout
>
> Then userspace could then set NEEDS_RESET if necessary.
>
But NEEDS_RESET does not only happen in this case.
>
> > + if (status == 0)
> > + vduse_dev_reset(dev);
> > +}
> > +
> > +static size_t vduse_vdpa_get_config_size(struct vdpa_device *vdpa)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > + return dev->config_size;
> > +}
> > +
> > +static void vduse_vdpa_get_config(struct vdpa_device *vdpa, unsigned int offset,
> > + void *buf, unsigned int len)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > + if (len > dev->config_size - offset)
> > + return;
> > +
> > + memcpy(buf, dev->config + offset, len);
> > +}
> > +
> > +static void vduse_vdpa_set_config(struct vdpa_device *vdpa, unsigned int offset,
> > + const void *buf, unsigned int len)
> > +{
> > + /* Now we only support read-only configuration space */
> > +}
> > +
> > +static u32 vduse_vdpa_get_generation(struct vdpa_device *vdpa)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > + return dev->generation;
> > +}
> > +
> > +static int vduse_vdpa_set_map(struct vdpa_device *vdpa,
> > + struct vhost_iotlb *iotlb)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > + int ret;
> > +
> > + ret = vduse_domain_set_map(dev->domain, iotlb);
> > + if (ret)
> > + return ret;
> > +
> > + ret = vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);
> > + if (ret) {
> > + vduse_domain_clear_map(dev->domain, iotlb);
> > + return ret;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static void vduse_vdpa_free(struct vdpa_device *vdpa)
> > +{
> > + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > + dev->vdev = NULL;
> > +}
> > +
> > +static const struct vdpa_config_ops vduse_vdpa_config_ops = {
> > + .set_vq_address = vduse_vdpa_set_vq_address,
> > + .kick_vq = vduse_vdpa_kick_vq,
> > + .set_vq_cb = vduse_vdpa_set_vq_cb,
> > + .set_vq_num = vduse_vdpa_set_vq_num,
> > + .set_vq_ready = vduse_vdpa_set_vq_ready,
> > + .get_vq_ready = vduse_vdpa_get_vq_ready,
> > + .set_vq_state = vduse_vdpa_set_vq_state,
> > + .get_vq_state = vduse_vdpa_get_vq_state,
> > + .get_vq_align = vduse_vdpa_get_vq_align,
> > + .get_features = vduse_vdpa_get_features,
> > + .set_features = vduse_vdpa_set_features,
> > + .set_config_cb = vduse_vdpa_set_config_cb,
> > + .get_vq_num_max = vduse_vdpa_get_vq_num_max,
> > + .get_device_id = vduse_vdpa_get_device_id,
> > + .get_vendor_id = vduse_vdpa_get_vendor_id,
> > + .get_status = vduse_vdpa_get_status,
> > + .set_status = vduse_vdpa_set_status,
> > + .get_config_size = vduse_vdpa_get_config_size,
> > + .get_config = vduse_vdpa_get_config,
> > + .set_config = vduse_vdpa_set_config,
> > + .get_generation = vduse_vdpa_get_generation,
> > + .set_map = vduse_vdpa_set_map,
> > + .free = vduse_vdpa_free,
> > +};
> > +
> > +static dma_addr_t vduse_dev_map_page(struct device *dev, struct page *page,
> > + unsigned long offset, size_t size,
> > + enum dma_data_direction dir,
> > + unsigned long attrs)
> > +{
> > + struct vduse_dev *vdev = dev_to_vduse(dev);
> > + struct vduse_iova_domain *domain = vdev->domain;
> > +
> > + return vduse_domain_map_page(domain, page, offset, size, dir, attrs);
> > +}
> > +
> > +static void vduse_dev_unmap_page(struct device *dev, dma_addr_t dma_addr,
> > + size_t size, enum dma_data_direction dir,
> > + unsigned long attrs)
> > +{
> > + struct vduse_dev *vdev = dev_to_vduse(dev);
> > + struct vduse_iova_domain *domain = vdev->domain;
> > +
> > + return vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs);
> > +}
> > +
> > +static void *vduse_dev_alloc_coherent(struct device *dev, size_t size,
> > + dma_addr_t *dma_addr, gfp_t flag,
> > + unsigned long attrs)
> > +{
> > + struct vduse_dev *vdev = dev_to_vduse(dev);
> > + struct vduse_iova_domain *domain = vdev->domain;
> > + unsigned long iova;
> > + void *addr;
> > +
> > + *dma_addr = DMA_MAPPING_ERROR;
> > + addr = vduse_domain_alloc_coherent(domain, size,
> > + (dma_addr_t *)&iova, flag, attrs);
> > + if (!addr)
> > + return NULL;
> > +
> > + *dma_addr = (dma_addr_t)iova;
> > +
> > + return addr;
> > +}
> > +
> > +static void vduse_dev_free_coherent(struct device *dev, size_t size,
> > + void *vaddr, dma_addr_t dma_addr,
> > + unsigned long attrs)
> > +{
> > + struct vduse_dev *vdev = dev_to_vduse(dev);
> > + struct vduse_iova_domain *domain = vdev->domain;
> > +
> > + vduse_domain_free_coherent(domain, size, vaddr, dma_addr, attrs);
> > +}
> > +
> > +static size_t vduse_dev_max_mapping_size(struct device *dev)
> > +{
> > + struct vduse_dev *vdev = dev_to_vduse(dev);
> > + struct vduse_iova_domain *domain = vdev->domain;
> > +
> > + return domain->bounce_size;
> > +}
> > +
> > +static const struct dma_map_ops vduse_dev_dma_ops = {
> > + .map_page = vduse_dev_map_page,
> > + .unmap_page = vduse_dev_unmap_page,
> > + .alloc = vduse_dev_alloc_coherent,
> > + .free = vduse_dev_free_coherent,
> > + .max_mapping_size = vduse_dev_max_mapping_size,
> > +};
> > +
> > +static unsigned int perm_to_file_flags(u8 perm)
> > +{
> > + unsigned int flags = 0;
> > +
> > + switch (perm) {
> > + case VDUSE_ACCESS_WO:
> > + flags |= O_WRONLY;
> > + break;
> > + case VDUSE_ACCESS_RO:
> > + flags |= O_RDONLY;
> > + break;
> > + case VDUSE_ACCESS_RW:
> > + flags |= O_RDWR;
> > + break;
> > + default:
> > + WARN(1, "invalidate vhost IOTLB permission\n");
> > + break;
> > + }
> > +
> > + return flags;
> > +}
> > +
> > +static int vduse_kickfd_setup(struct vduse_dev *dev,
> > + struct vduse_vq_eventfd *eventfd)
> > +{
> > + struct eventfd_ctx *ctx = NULL;
> > + struct vduse_virtqueue *vq;
> > + u32 index;
> > +
> > + if (eventfd->index >= dev->vq_num)
> > + return -EINVAL;
> > +
> > + index = array_index_nospec(eventfd->index, dev->vq_num);
> > + vq = &dev->vqs[index];
> > + if (eventfd->fd >= 0) {
> > + ctx = eventfd_ctx_fdget(eventfd->fd);
> > + if (IS_ERR(ctx))
> > + return PTR_ERR(ctx);
> > + } else if (eventfd->fd != VDUSE_EVENTFD_DEASSIGN)
> > + return 0;
> > +
> > + spin_lock(&vq->kick_lock);
> > + if (vq->kickfd)
> > + eventfd_ctx_put(vq->kickfd);
> > + vq->kickfd = ctx;
> > + if (vq->ready && vq->kicked && vq->kickfd) {
> > + eventfd_signal(vq->kickfd, 1);
> > + vq->kicked = false;
> > + }
> > + spin_unlock(&vq->kick_lock);
> > +
> > + return 0;
> > +}
> > +
> > +static bool vduse_dev_is_ready(struct vduse_dev *dev)
> > +{
> > + int i;
> > +
> > + for (i = 0; i < dev->vq_num; i++)
> > + if (!dev->vqs[i].num_max)
> > + return false;
> > +
> > + return true;
> > +}
> > +
> > +static void vduse_dev_irq_inject(struct work_struct *work)
> > +{
> > + struct vduse_dev *dev = container_of(work, struct vduse_dev, inject);
> > +
> > + spin_lock_irq(&dev->irq_lock);
> > + if (dev->config_cb.callback)
> > + dev->config_cb.callback(dev->config_cb.private);
> > + spin_unlock_irq(&dev->irq_lock);
> > +}
> > +
> > +static void vduse_vq_irq_inject(struct work_struct *work)
> > +{
> > + struct vduse_virtqueue *vq = container_of(work,
> > + struct vduse_virtqueue, inject);
> > +
> > + spin_lock_irq(&vq->irq_lock);
> > + if (vq->ready && vq->cb.callback)
> > + vq->cb.callback(vq->cb.private);
> > + spin_unlock_irq(&vq->irq_lock);
> > +}
> > +
> > +static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
> > + unsigned long arg)
> > +{
> > + struct vduse_dev *dev = file->private_data;
> > + void __user *argp = (void __user *)arg;
> > + int ret;
> > +
> > + switch (cmd) {
> > + case VDUSE_IOTLB_GET_FD: {
> > + struct vduse_iotlb_entry entry;
> > + struct vhost_iotlb_map *map;
> > + struct vdpa_map_file *map_file;
> > + struct vduse_iova_domain *domain = dev->domain;
> > + struct file *f = NULL;
> > +
> > + ret = -EFAULT;
> > + if (copy_from_user(&entry, argp, sizeof(entry)))
> > + break;
> > +
> > + ret = -EINVAL;
> > + if (entry.start > entry.last)
> > + break;
> > +
> > + spin_lock(&domain->iotlb_lock);
> > + map = vhost_iotlb_itree_first(domain->iotlb,
> > + entry.start, entry.last);
> > + if (map) {
> > + map_file = (struct vdpa_map_file *)map->opaque;
> > + f = get_file(map_file->file);
> > + entry.offset = map_file->offset;
> > + entry.start = map->start;
> > + entry.last = map->last;
> > + entry.perm = map->perm;
> > + }
> > + spin_unlock(&domain->iotlb_lock);
> > + ret = -EINVAL;
> > + if (!f)
> > + break;
> > +
> > + ret = -EFAULT;
> > + if (copy_to_user(argp, &entry, sizeof(entry))) {
> > + fput(f);
> > + break;
> > + }
> > + ret = receive_fd(f, perm_to_file_flags(entry.perm));
> > + fput(f);
> > + break;
> > + }
> > + case VDUSE_DEV_GET_FEATURES:
>
>
> Let's add a comment to explain here. E.g we just mirror what driver
> wrote and the drier is expected to check FEATURE_OK.
>
I already document some details in include/uapi/linux/vduse.h and
Documentation/userspace-api/vduse.rst
>
> > + ret = put_user(dev->driver_features, (u64 __user *)argp);
> > + break;
> > + case VDUSE_DEV_SET_CONFIG: {
> > + struct vduse_config_data config;
> > + unsigned long size = offsetof(struct vduse_config_data,
> > + buffer);
> > +
> > + ret = -EFAULT;
> > + if (copy_from_user(&config, argp, size))
> > + break;
> > +
> > + ret = -EINVAL;
> > + if (config.length == 0 ||
> > + config.length > dev->config_size - config.offset)
> > + break;
> > +
> > + ret = -EFAULT;
> > + if (copy_from_user(dev->config + config.offset, argp + size,
> > + config.length))
> > + break;
> > +
> > + ret = 0;
> > + break;
> > + }
> > + case VDUSE_DEV_INJECT_IRQ:
>
>
> It's better to have "config" in the name.
>
OK.
>
> > + ret = 0;
> > + queue_work(vduse_irq_wq, &dev->inject);
> > + break;
> > + case VDUSE_VQ_SETUP: {
> > + struct vduse_vq_config config;
> > + u32 index;
> > +
> > + ret = -EFAULT;
> > + if (copy_from_user(&config, argp, sizeof(config)))
> > + break;
> > +
> > + ret = -EINVAL;
> > + if (config.index >= dev->vq_num)
> > + break;
> > +
> > + index = array_index_nospec(config.index, dev->vq_num);
> > + dev->vqs[index].num_max = config.max_size;
> > + ret = 0;
> > + break;
> > + }
> > + case VDUSE_VQ_GET_INFO: {
> > + struct vduse_vq_info vq_info;
> > + struct vduse_virtqueue *vq;
> > + u32 index;
> > +
> > + ret = -EFAULT;
> > + if (copy_from_user(&vq_info, argp, sizeof(vq_info)))
> > + break;
> > +
> > + ret = -EINVAL;
> > + if (vq_info.index >= dev->vq_num)
> > + break;
> > +
> > + index = array_index_nospec(vq_info.index, dev->vq_num);
> > + vq = &dev->vqs[index];
> > + vq_info.desc_addr = vq->desc_addr;
> > + vq_info.driver_addr = vq->driver_addr;
> > + vq_info.device_addr = vq->device_addr;
> > + vq_info.num = vq->num;
> > +
> > + if (dev->driver_features & BIT_ULL(VIRTIO_F_RING_PACKED)) {
> > + vq_info.packed.last_avail_counter =
> > + vq->state.packed.last_avail_counter;
> > + vq_info.packed.last_avail_idx =
> > + vq->state.packed.last_avail_idx;
> > + vq_info.packed.last_used_counter =
> > + vq->state.packed.last_used_counter;
> > + vq_info.packed.last_used_idx =
> > + vq->state.packed.last_used_idx;
> > + } else
> > + vq_info.split.avail_index =
> > + vq->state.split.avail_index;
> > +
> > + vq_info.ready = vq->ready;
> > +
> > + ret = -EFAULT;
> > + if (copy_to_user(argp, &vq_info, sizeof(vq_info)))
> > + break;
> > +
> > + ret = 0;
> > + break;
> > + }
> > + case VDUSE_VQ_SETUP_KICKFD: {
> > + struct vduse_vq_eventfd eventfd;
> > +
> > + ret = -EFAULT;
> > + if (copy_from_user(&eventfd, argp, sizeof(eventfd)))
> > + break;
> > +
> > + ret = vduse_kickfd_setup(dev, &eventfd);
> > + break;
> > + }
> > + case VDUSE_VQ_INJECT_IRQ: {
> > + u32 index;
> > +
> > + ret = -EFAULT;
> > + if (get_user(index, (u32 __user *)argp))
> > + break;
> > +
> > + ret = -EINVAL;
> > + if (index >= dev->vq_num)
> > + break;
> > +
> > + ret = 0;
> > + index = array_index_nospec(index, dev->vq_num);
> > + queue_work(vduse_irq_wq, &dev->vqs[index].inject);
> > + break;
> > + }
> > + default:
> > + ret = -ENOIOCTLCMD;
> > + break;
> > + }
> > +
> > + return ret;
> > +}
> > +
> > +static int vduse_dev_release(struct inode *inode, struct file *file)
> > +{
> > + struct vduse_dev *dev = file->private_data;
> > +
> > + spin_lock(&dev->msg_lock);
> > + /* Make sure the inflight messages can processed after reconncection */
> > + list_splice_init(&dev->recv_list, &dev->send_list);
> > + spin_unlock(&dev->msg_lock);
> > + dev->connected = false;
> > +
> > + return 0;
> > +}
> > +
> > +static struct vduse_dev *vduse_dev_get_from_minor(int minor)
> > +{
> > + struct vduse_dev *dev;
> > +
> > + mutex_lock(&vduse_lock);
> > + dev = idr_find(&vduse_idr, minor);
> > + mutex_unlock(&vduse_lock);
> > +
> > + return dev;
> > +}
> > +
> > +static int vduse_dev_open(struct inode *inode, struct file *file)
> > +{
> > + int ret;
> > + struct vduse_dev *dev = vduse_dev_get_from_minor(iminor(inode));
> > +
> > + if (!dev)
> > + return -ENODEV;
> > +
> > + ret = -EBUSY;
> > + mutex_lock(&dev->lock);
> > + if (dev->connected)
> > + goto unlock;
> > +
> > + ret = 0;
> > + dev->connected = true;
> > + file->private_data = dev;
> > +unlock:
> > + mutex_unlock(&dev->lock);
> > +
> > + return ret;
> > +}
> > +
> > +static const struct file_operations vduse_dev_fops = {
> > + .owner = THIS_MODULE,
> > + .open = vduse_dev_open,
> > + .release = vduse_dev_release,
> > + .read_iter = vduse_dev_read_iter,
> > + .write_iter = vduse_dev_write_iter,
> > + .poll = vduse_dev_poll,
> > + .unlocked_ioctl = vduse_dev_ioctl,
> > + .compat_ioctl = compat_ptr_ioctl,
> > + .llseek = noop_llseek,
> > +};
> > +
> > +static struct vduse_dev *vduse_dev_create(void)
> > +{
> > + struct vduse_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);
> > +
> > + if (!dev)
> > + return NULL;
> > +
> > + mutex_init(&dev->lock);
> > + spin_lock_init(&dev->msg_lock);
> > + INIT_LIST_HEAD(&dev->send_list);
> > + INIT_LIST_HEAD(&dev->recv_list);
> > + spin_lock_init(&dev->irq_lock);
> > +
> > + INIT_WORK(&dev->inject, vduse_dev_irq_inject);
> > + init_waitqueue_head(&dev->waitq);
> > +
> > + return dev;
> > +}
> > +
> > +static void vduse_dev_destroy(struct vduse_dev *dev)
> > +{
> > + kfree(dev);
> > +}
> > +
> > +static struct vduse_dev *vduse_find_dev(const char *name)
> > +{
> > + struct vduse_dev *dev;
> > + int id;
> > +
> > + idr_for_each_entry(&vduse_idr, dev, id)
> > + if (!strcmp(dev->name, name))
> > + return dev;
> > +
> > + return NULL;
> > +}
> > +
> > +static int vduse_destroy_dev(char *name)
> > +{
> > + struct vduse_dev *dev = vduse_find_dev(name);
> > +
> > + if (!dev)
> > + return -EINVAL;
> > +
> > + mutex_lock(&dev->lock);
> > + if (dev->vdev || dev->connected) {
> > + mutex_unlock(&dev->lock);
> > + return -EBUSY;
> > + }
> > + dev->connected = true;
> > + mutex_unlock(&dev->lock);
> > +
> > + vduse_dev_reset(dev);
> > + device_destroy(vduse_class, MKDEV(MAJOR(vduse_major), dev->minor));
> > + idr_remove(&vduse_idr, dev->minor);
> > + kvfree(dev->config);
> > + kfree(dev->vqs);
> > + vduse_domain_destroy(dev->domain);
> > + kfree(dev->name);
> > + vduse_dev_destroy(dev);
> > + module_put(THIS_MODULE);
> > +
> > + return 0;
> > +}
> > +
> > +static bool device_is_allowed(u32 device_id)
> > +{
> > + int i;
> > +
> > + for (i = 0; i < ARRAY_SIZE(allowed_device_id); i++)
> > + if (allowed_device_id[i] == device_id)
> > + return true;
> > +
> > + return false;
> > +}
> > +
> > +static bool features_is_valid(u64 features)
> > +{
> > + if (!(features & (1ULL << VIRTIO_F_ACCESS_PLATFORM)))
> > + return false;
> > +
> > + /* Now we only support read-only configuration space */
> > + if (features & (1ULL << VIRTIO_BLK_F_CONFIG_WCE))
> > + return false;
> > +
> > + return true;
> > +}
> > +
> > +static bool vduse_validate_config(struct vduse_dev_config *config)
> > +{
> > + if (config->bounce_size > VDUSE_MAX_BOUNCE_SIZE)
> > + return false;
> > +
> > + if (config->vq_align > PAGE_SIZE)
> > + return false;
> > +
> > + if (config->config_size > PAGE_SIZE)
> > + return false;
>
>
> Any reason for this check?
>
To limit the kernel buffer size for configuration space. Is the
PAGE_SIZE enough?
Thanks,
Yongji
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