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Message-ID: <ec3e2729-3490-851f-ed4b-6dee9c04831c@redhat.com>
Date: Wed, 14 Jul 2021 17:12:21 +0800
From: Jason Wang <jasowang@...hat.com>
To: Yongji Xie <xieyongji@...edance.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
在 2021/7/14 下午2:49, Yongji Xie 写道:
> 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.
That's fine since for virtio-vdpa, we use bounce buffer, for vhost, it
works like the device can be reset.
> 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.
I think at least we should figure out fatal failures and forbid any
future userspace operations.
> Even userspace can do something like NEEDS_RESET to do
> recovery.
Yes, but that's not someting we can depend.
>
>>> + 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.
Which ioctl can be used for this?
>
>> 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.
Yes, so you need an ioctl for userspace to update the device status
(NEEDS_RESET) probably.
>
>>> + 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
The point is the behavior of "mirroring" is one of the choice:
"
The device MUST present any valid feature bits the driver has written
indriver_feature, starting at bitdriver_feature_select∗32 for
anydriver_feature_selectwritten by the driver. Valid feature bits are
those which are subset of the correspondingdevice_featurebits. The
device MAY present invalid bits written by the driver.Note:This means
that a device can ignore writes for feature bits it never offers, and
simply present 0 on reads. Or it can just mirror what the driver wrote
(but it will still have to check them when the driver sets
FEATURES_OK).Note:A driver shouldn’t write invalid bits anyway, as
per3.1.1
<https://docs.oasis-open.org/virtio/virtio/v1.1/csprd01/virtio-v1.1-csprd01.html#x1-930001>,
but this attempts to handle it.
"
It would be helpful to add a comment here or people may check whether it
follows the spec.
>
>>> + 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?
Should be sufficient for now.
Thanks
>
> Thanks,
> Yongji
>
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