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Date: Thu, 25 Mar 2021 14:30:46 +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>, Bob Liu <bob.liu@...cle.com>,
Christoph Hellwig <hch@...radead.org>,
Randy Dunlap <rdunlap@...radead.org>,
Matthew Wilcox <willy@...radead.org>, 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>,
virtualization@...ts.linux-foundation.org, netdev@...r.kernel.org,
kvm@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH v5 09/11] vduse: Introduce VDUSE - vDPA Device in
Userspace
在 2021/3/24 下午4:55, Yongji Xie 写道:
> On Wed, Mar 24, 2021 at 12:43 PM Jason Wang <jasowang@...hat.com> wrote:
>>
>> 在 2021/3/15 下午1:37, Xie Yongji 写道:
>>> This VDUSE driver enables implementing vDPA devices in userspace.
>>> Both control path and data path of vDPA devices will be able to
>>> be handled in userspace.
>>>
>>> In the control path, the VDUSE driver will make use of message
>>> mechnism to forward the config operation from vdpa bus driver
>>> to userspace. Userspace can use read()/write() to receive/reply
>>> those control messages.
>>>
>>> In the data path, userspace can use mmap() to access vDPA device's
>>> iova regions obtained through VDUSE_IOTLB_GET_ENTRY ioctl. Besides,
>>> userspace can use ioctl() to inject interrupt and use the eventfd
>>> mechanism to receive virtqueue kicks.
>>>
>>> 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 | 1281 ++++++++++++++++++++
>>> include/uapi/linux/vduse.h | 153 +++
>>> 6 files changed, 1451 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 a4c75a28c839..71722e6f8f23 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 a245809c99d0..77a1da522c21 100644
>>> --- a/drivers/vdpa/Kconfig
>>> +++ b/drivers/vdpa/Kconfig
>>> @@ -25,6 +25,16 @@ config VDPA_SIM_NET
>>> help
>>> vDPA networking device simulator which loops TX traffic back to RX.
>>>
>>> +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..07d0ae92d470
>>> --- /dev/null
>>> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
>>> @@ -0,0 +1,1281 @@
>>> +// SPDX-License-Identifier: GPL-2.0-only
>>> +/*
>>> + * VDUSE: vDPA Device in Userspace
>>> + *
>>> + * Copyright (C) 2020 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/miscdevice.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 <uapi/linux/vduse.h>
>>> +#include <uapi/linux/vdpa.h>
>>> +#include <uapi/linux/virtio_config.h>
>>> +#include <linux/mod_devicetable.h>
>>> +
>>> +#include "iova_domain.h"
>>> +
>>> +#define DRV_VERSION "1.0"
>>> +#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)
>>> +
>>> +struct vduse_virtqueue {
>>> + u16 index;
>>> + bool ready;
>>> + 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 cdev cdev;
>>> + struct vduse_virtqueue *vqs;
>>> + struct vduse_iova_domain *domain;
>>> + spinlock_t msg_lock;
>>> + atomic64_t msg_unique;
>>> + wait_queue_head_t waitq;
>>> + struct list_head send_list;
>>> + struct list_head recv_list;
>>> + struct list_head list;
>>> + bool connected;
>>> + int minor;
>>> + u16 vq_size_max;
>>> + u16 vq_num;
>>> + u32 vq_align;
>>> + u32 device_id;
>>> + u32 vendor_id;
>>> +};
>>> +
>>> +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;
>>> +};
>>> +
>>> +static unsigned long max_bounce_size = (64 * 1024 * 1024);
>>> +module_param(max_bounce_size, ulong, 0444);
>>> +MODULE_PARM_DESC(max_bounce_size, "Maximum bounce buffer size. (default: 64M)");
>>> +
>>> +static unsigned long max_iova_size = (128 * 1024 * 1024);
>>> +module_param(max_iova_size, ulong, 0444);
>>> +MODULE_PARM_DESC(max_iova_size, "Maximum iova space size (default: 128M)");
>>> +
>>> +static DEFINE_MUTEX(vduse_lock);
>>> +static LIST_HEAD(vduse_devs);
>>> +static DEFINE_IDA(vduse_ida);
>>> +
>>> +static dev_t vduse_major;
>>> +static struct class *vduse_class;
>>> +static struct workqueue_struct *vduse_irq_wq;
>>> +
>>> +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 *tmp, *msg = NULL;
>>> +
>>> + list_for_each_entry(tmp, head, list) {
>>> + if (tmp->req.request_id == request_id) {
>>> + msg = tmp;
>>> + list_del(&tmp->list);
>>> + break;
>>> + }
>>> + }
>>> +
>>> + return msg;
>>> +}
>>> +
>>> +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)
>>> +{
>>> + init_waitqueue_head(&msg->waitq);
>>> + spin_lock(&dev->msg_lock);
>>> + vduse_enqueue_msg(&dev->send_list, msg);
>>> + wake_up(&dev->waitq);
>>> + spin_unlock(&dev->msg_lock);
>>> + wait_event_interruptible(msg->waitq, msg->completed);
>>> + spin_lock(&dev->msg_lock);
>>> + if (!msg->completed)
>>> + list_del(&msg->list);
>>> + spin_unlock(&dev->msg_lock);
>>> +
>>> + return (msg->resp.result == VDUSE_REQUEST_OK) ? 0 : -1;
>>> +}
>>> +
>>> +static u64 vduse_dev_get_features(struct vduse_dev *dev)
>>> +{
>>> + struct vduse_dev_msg msg = { 0 };
>>> +
>>> + msg.req.type = VDUSE_GET_FEATURES;
>>> + msg.req.request_id = atomic64_fetch_inc(&dev->msg_unique);
>>
>> Let's introduce a helper for the atomic64_fetch_inc() here.
>>
> Fine.
>
>>> +
>>> + return vduse_dev_msg_sync(dev, &msg) ? 0 : msg.resp.f.features;
>>> +}
>>> +
>>> +static int vduse_dev_set_features(struct vduse_dev *dev, u64 features)
>>> +{
>>> + struct vduse_dev_msg msg = { 0 };
>>> +
>>> + msg.req.type = VDUSE_SET_FEATURES;
>>> + msg.req.request_id = atomic64_fetch_inc(&dev->msg_unique);
>>> + msg.req.f.features = features;
>>> +
>>> + return vduse_dev_msg_sync(dev, &msg);
>>> +}
>>> +
>>> +static u8 vduse_dev_get_status(struct vduse_dev *dev)
>>> +{
>>> + struct vduse_dev_msg msg = { 0 };
>>> +
>>> + msg.req.type = VDUSE_GET_STATUS;
>>> + msg.req.request_id = atomic64_fetch_inc(&dev->msg_unique);
>>> +
>>> + return vduse_dev_msg_sync(dev, &msg) ? 0 : msg.resp.s.status;
>>> +}
>>> +
>>> +static void vduse_dev_set_status(struct vduse_dev *dev, u8 status)
>>> +{
>>> + struct vduse_dev_msg msg = { 0 };
>>> +
>>> + msg.req.type = VDUSE_SET_STATUS;
>>> + msg.req.request_id = atomic64_fetch_inc(&dev->msg_unique);
>>> + msg.req.s.status = status;
>>> +
>>> + vduse_dev_msg_sync(dev, &msg);
>>> +}
>>> +
>>> +static void vduse_dev_get_config(struct vduse_dev *dev, unsigned int offset,
>>> + void *buf, unsigned int len)
>>> +{
>>> + struct vduse_dev_msg msg = { 0 };
>>> + unsigned int sz;
>>> +
>>> + while (len) {
>>> + sz = min_t(unsigned int, len, sizeof(msg.req.config.data));
>>> + msg.req.type = VDUSE_GET_CONFIG;
>>> + msg.req.request_id = atomic64_fetch_inc(&dev->msg_unique);
>>> + msg.req.config.offset = offset;
>>> + msg.req.config.len = sz;
>>> + vduse_dev_msg_sync(dev, &msg);
>>> + memcpy(buf, msg.resp.config.data, sz);
>>> + buf += sz;
>>> + offset += sz;
>>> + len -= sz;
>>> + }
>>> +}
>>> +
>>> +static void vduse_dev_set_config(struct vduse_dev *dev, unsigned int offset,
>>> + const void *buf, unsigned int len)
>>> +{
>>> + struct vduse_dev_msg msg = { 0 };
>>> + unsigned int sz;
>>> +
>>> + while (len) {
>>> + sz = min_t(unsigned int, len, sizeof(msg.req.config.data));
>>> + msg.req.type = VDUSE_SET_CONFIG;
>>> + msg.req.request_id = atomic64_fetch_inc(&dev->msg_unique);
>>> + msg.req.config.offset = offset;
>>> + msg.req.config.len = sz;
>>> + memcpy(msg.req.config.data, buf, sz);
>>> + vduse_dev_msg_sync(dev, &msg);
>>> + buf += sz;
>>> + offset += sz;
>>> + len -= sz;
>>> + }
>>> +}
>>> +
>>> +static void vduse_dev_set_vq_num(struct vduse_dev *dev,
>>> + struct vduse_virtqueue *vq, u32 num)
>>> +{
>>> + struct vduse_dev_msg msg = { 0 };
>>> +
>>> + msg.req.type = VDUSE_SET_VQ_NUM;
>>> + msg.req.request_id = atomic64_fetch_inc(&dev->msg_unique);
>>> + msg.req.vq_num.index = vq->index;
>>> + msg.req.vq_num.num = num;
>>> +
>>> + vduse_dev_msg_sync(dev, &msg);
>>> +}
>>> +
>>> +static int vduse_dev_set_vq_addr(struct vduse_dev *dev,
>>> + struct vduse_virtqueue *vq, u64 desc_addr,
>>> + u64 driver_addr, u64 device_addr)
>>> +{
>>> + struct vduse_dev_msg msg = { 0 };
>>> +
>>> + msg.req.type = VDUSE_SET_VQ_ADDR;
>>> + msg.req.request_id = atomic64_fetch_inc(&dev->msg_unique);
>>> + msg.req.vq_addr.index = vq->index;
>>> + msg.req.vq_addr.desc_addr = desc_addr;
>>> + msg.req.vq_addr.driver_addr = driver_addr;
>>> + msg.req.vq_addr.device_addr = device_addr;
>>> +
>>> + return vduse_dev_msg_sync(dev, &msg);
>>> +}
>>> +
>>> +static void vduse_dev_set_vq_ready(struct vduse_dev *dev,
>>> + struct vduse_virtqueue *vq, bool ready)
>>> +{
>>> + struct vduse_dev_msg msg = { 0 };
>>> +
>>> + msg.req.type = VDUSE_SET_VQ_READY;
>>> + msg.req.request_id = atomic64_fetch_inc(&dev->msg_unique);
>>> + msg.req.vq_ready.index = vq->index;
>>> + msg.req.vq_ready.ready = ready;
>>> +
>>> + vduse_dev_msg_sync(dev, &msg);
>>> +}
>>> +
>>> +static bool vduse_dev_get_vq_ready(struct vduse_dev *dev,
>>> + struct vduse_virtqueue *vq)
>>> +{
>>> + struct vduse_dev_msg msg = { 0 };
>>> +
>>> + msg.req.type = VDUSE_GET_VQ_READY;
>>> + msg.req.request_id = atomic64_fetch_inc(&dev->msg_unique);
>>> + msg.req.vq_ready.index = vq->index;
>>> +
>>> + return vduse_dev_msg_sync(dev, &msg) ? false : msg.resp.vq_ready.ready;
>>> +}
>>> +
>>> +static int vduse_dev_get_vq_state(struct vduse_dev *dev,
>>> + struct vduse_virtqueue *vq,
>>> + struct vdpa_vq_state *state)
>>> +{
>>> + struct vduse_dev_msg msg = { 0 };
>>> + int ret;
>>> +
>>> + msg.req.type = VDUSE_GET_VQ_STATE;
>>> + msg.req.request_id = atomic64_fetch_inc(&dev->msg_unique);
>>> + msg.req.vq_state.index = vq->index;
>>> +
>>> + ret = vduse_dev_msg_sync(dev, &msg);
>>> + if (!ret)
>>> + state->avail_index = msg.resp.vq_state.avail_idx;
>>> +
>>> + return ret;
>>> +}
>>> +
>>> +static int vduse_dev_set_vq_state(struct vduse_dev *dev,
>>> + struct vduse_virtqueue *vq,
>>> + const struct vdpa_vq_state *state)
>>> +{
>>> + struct vduse_dev_msg msg = { 0 };
>>> +
>>> + msg.req.type = VDUSE_SET_VQ_STATE;
>>> + msg.req.request_id = atomic64_fetch_inc(&dev->msg_unique);
>>> + msg.req.vq_state.index = vq->index;
>>> + msg.req.vq_state.avail_idx = state->avail_index;
>>> +
>>> + 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;
>>> +
>>> + if (last < start)
>>> + return -EINVAL;
>>> +
>>> + msg = kzalloc(sizeof(*msg), GFP_ATOMIC);
>>
>> The return value is not checked.
>>
> Will fix it.
>
>>> + msg->req.type = VDUSE_UPDATE_IOTLB;
>>
>> What would usespace do after receiving VDUSE_UPDATE_IOTLB? If it still
>> needs to issue VDUSE_GET_ENTRY with probably -EINVAL, it's kind of
>> overkill. So it looks to me that the VDUSE_UPDATE_IOTLB is acutally kind
>> of flush or unmap here. If this is true, should we introduce a new type
>> or just rename it as VDUSE_IOTLB_UNMAP?
>>
> VDUSE_UPDATE_IOTLB is used to notify userspace of refreshing (include
> mapping and unmapping) the iotlb mapping. The reason why we can't use
> flush/unmap is explained below.
>
>>> + msg->req.request_id = atomic64_fetch_inc(&dev->msg_unique);
>>> + 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 = 0;
>>> +
>>> + if (iov_iter_count(to) < size)
>>> + return 0;
>>> +
>>> + 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 = -EINVAL;
>>> + 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;
>>
>> EPOLLOUT is missed here?
>>
> Why do we need EPOLLOUT here?
It means the fd is ready to be wrote?
>
>>> +
>>> + return mask;
>>> +}
>>> +
>>> +static void vduse_dev_reset(struct vduse_dev *dev)
>>> +{
>>> + int i;
>>> +
>>> + vduse_domain_reset_bounce_map(dev->domain);
>>> + vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);
>>
>> Simialrly, IOTLB update should be done before the resetting?
>>
> The problem is userspace can still get valid bounce mapping through
> VDUSE_IOTLB_GET_ENTRY between receiving IOTLB_UNMAP and bounce mapping
> reset. Then userspace has no way to know when to invalidate these
> mappings.
Right, I think it might be helpful to add a comment here to explain the
order.
>
>> And it would be helpful to add comment to explain how coherent mappings
>> is handled.
>>
> OK. It would be handled in vduse_dev_free_coherent().
>
>>> +
>>> + for (i = 0; i < dev->vq_num; i++) {
>>> + struct vduse_virtqueue *vq = &dev->vqs[i];
>>> +
>>> + spin_lock(&vq->irq_lock);
>>> + vq->ready = false;
>>> + vq->cb.callback = NULL;
>>> + vq->cb.private = NULL;
>>> + spin_unlock(&vq->irq_lock);
>>> + }
>>> +}
>>> +
>>> +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];
>>> +
>>> + return vduse_dev_set_vq_addr(dev, vq, desc_area,
>>> + driver_area, device_area);
>>> +}
>>> +
>>> +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 && vq->kickfd)
>>> + eventfd_signal(vq->kickfd, 1);
>>> + 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];
>>> +
>>> + vduse_dev_set_vq_num(dev, vq, 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];
>>> +
>>> + vduse_dev_set_vq_ready(dev, vq, ready);
>>> + 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];
>>> +
>>> + vq->ready = vduse_dev_get_vq_ready(dev, vq);
>>> +
>>> + 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];
>>> +
>>> + return vduse_dev_set_vq_state(dev, vq, state);
>>> +}
>>> +
>>> +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];
>>> +
>>> + return vduse_dev_get_vq_state(dev, vq, state);
>>> +}
>>> +
>>> +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 vduse_dev_get_features(dev);
>>> +}
>>> +
>>> +static int vduse_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
>>> +{
>>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +
>>> + if (!(features & (1ULL << VIRTIO_F_ACCESS_PLATFORM)))
>>> + return -EINVAL;
>>> +
>>> + return vduse_dev_set_features(dev, features);
>>> +}
>>> +
>>> +static void vduse_vdpa_set_config_cb(struct vdpa_device *vdpa,
>>> + struct vdpa_callback *cb)
>>> +{
>>> + /* We don't support config interrupt */
>>> +}
>>> +
>>> +static u16 vduse_vdpa_get_vq_num_max(struct vdpa_device *vdpa)
>>> +{
>>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +
>>> + return dev->vq_size_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 vduse_dev_get_status(dev);
>>> +}
>>> +
>>> +static void vduse_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
>>> +{
>>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +
>>> + if (status == 0)
>>> + vduse_dev_reset(dev);
>>> +
>>> + vduse_dev_set_status(dev, status);
>>> +}
>>> +
>>> +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);
>>> +
>>> + vduse_dev_get_config(dev, offset, buf, len);
>>> +}
>>> +
>>> +static void vduse_vdpa_set_config(struct vdpa_device *vdpa, unsigned int offset,
>>> + const void *buf, unsigned int len)
>>> +{
>>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +
>>> + vduse_dev_set_config(dev, offset, buf, len);
>>> +}
>>> +
>>> +static int vduse_vdpa_set_map(struct vdpa_device *vdpa,
>>> + struct vhost_iotlb *iotlb)
>>> +{
>>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> + int ret;
>>> +
>>
>> So I wonder we need to do the vhost_dev_update_iotlb() before
>> vduse_domain_set_map().
>>
>> That is, we need to make sure the userspace's IOTLB is cleared after
>> setting up the new map?
>>
> The same problem I described above. So we use UPDATE_IOTLB messages to
> notify userspace of refreshing the IOTLB after we change the iotlb
> itree.
Yes.
>
>>> + ret = vduse_domain_set_map(dev->domain, iotlb);
>>> + vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);
>>> +
>>> + return ret;
>>> +}
>>> +
>>> +static void vduse_vdpa_free(struct vdpa_device *vdpa)
>>> +{
>>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
>>> +
>>> + WARN_ON(!list_empty(&dev->send_list));
>>> + WARN_ON(!list_empty(&dev->recv_list));
>>> + 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 = vduse_vdpa_get_config,
>>> + .set_config = vduse_vdpa_set_config,
>>> + .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;
>>> + vduse_dev_update_iotlb(vdev, iova, iova + size - 1);
>>> +
>>> + 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;
>>> + unsigned long start = (unsigned long)dma_addr;
>>> + unsigned long last = start + size - 1;
>>> +
>>> + vduse_domain_free_coherent(domain, size, vaddr, dma_addr, attrs);
>>> + vduse_dev_update_iotlb(vdev, start, last);
>>> +}
>>> +
>>> +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,
>>> +};
>>> +
>>> +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;
>>> +
>>> + if (eventfd->index >= dev->vq_num)
>>> + return -EINVAL;
>>> +
>>> + vq = &dev->vqs[eventfd->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;
>>> + spin_unlock(&vq->kick_lock);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +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_ENTRY: {
>>> + 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;
>>> +
>>> + spin_lock(&domain->iotlb_lock);
>>> + map = vhost_iotlb_itree_first(domain->iotlb,
>>> + entry.start, entry.start + 1);
>>> + 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;
>>
>> So we need document this in the uAPI doc. I think when userspace see
>> -EINVAL it means the map doesn't exist.
>>
> Fine with me.
>
>> Or should we make it more explicitly by e.g introduing new flags.
>>
>>
>>> + if (!f)
>>> + break;
>>> +
>>> + ret = -EFAULT;
>>> + if (copy_to_user(argp, &entry, sizeof(entry))) {
>>> + fput(f);
>>> + break;
>>> + }
>>> + ret = receive_fd_user(f, argp, perm_to_file_flags(entry.perm));
>>> + fput(f);
>>> + 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_INJECT_VQ_IRQ:
>>> + ret = -EINVAL;
>>> + if (arg >= dev->vq_num)
>>> + break;
>>> +
>>> + ret = 0;
>>> + queue_work(vduse_irq_wq, &dev->vqs[arg].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;
>>> + struct vduse_dev_msg *msg;
>>> + int i;
>>> +
>>> + for (i = 0; i < dev->vq_num; i++) {
>>> + struct vduse_virtqueue *vq = &dev->vqs[i];
>>> +
>>> + spin_lock(&vq->kick_lock);
>>> + if (vq->kickfd)
>>> + eventfd_ctx_put(vq->kickfd);
>>> + vq->kickfd = NULL;
>>> + spin_unlock(&vq->kick_lock);
>>> + }
>>> +
>>> + spin_lock(&dev->msg_lock);
>>> + while ((msg = vduse_dequeue_msg(&dev->recv_list)))
>>> + vduse_enqueue_msg(&dev->send_list, msg);
>>
>> What's the goal of this?
>>
> Support reconnecting. Make sure userspace daemon can get the inflight
> messages after reboot.
I see, plase add a comment for this.
>
>> In addition to free the messages, we need wake up the processes that is
>> in the waitq in this case.
>>
>>
>>> + spin_unlock(&dev->msg_lock);
>>> +
>>> + dev->connected = false;
>>
>> Do we need to hold vduse mutex here?
>>
> Looks like I didn't find any situation that requires the mutex.
Ok, I guess the reason is because there will be no external reference
for the device?
>
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int vduse_dev_open(struct inode *inode, struct file *file)
>>> +{
>>> + struct vduse_dev *dev = container_of(inode->i_cdev,
>>> + struct vduse_dev, cdev);
>>> + int ret = -EBUSY;
>>> +
>>> + mutex_lock(&vduse_lock);
>>> + if (dev->connected)
>>> + goto unlock;
>>> +
>>> + ret = 0;
>>> + dev->connected = true;
>>> + file->private_data = dev;
>>> +unlock:
>>> + mutex_unlock(&vduse_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;
>>> +
>>> + spin_lock_init(&dev->msg_lock);
>>> + INIT_LIST_HEAD(&dev->send_list);
>>> + INIT_LIST_HEAD(&dev->recv_list);
>>> + atomic64_set(&dev->msg_unique, 0);
>>> +
>>> + 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 *tmp, *dev = NULL;
>>> +
>>> + list_for_each_entry(tmp, &vduse_devs, list) {
>>> + if (!strcmp(dev_name(&tmp->dev), name)) {
>>> + dev = tmp;
>>> + break;
>>> + }
>>> + }
>>> + return dev;
>>> +}
>>> +
>>> +static int vduse_destroy_dev(char *name)
>>> +{
>>> + struct vduse_dev *dev = vduse_find_dev(name);
>>> +
>>> + if (!dev)
>>> + return -EINVAL;
>>> +
>>> + if (dev->vdev || dev->connected)
>>> + return -EBUSY;
>>> +
>>> + dev->connected = true;
>>
>> Need mutex here?
>>
> vduse_destroy_dev() is protected by the vduse_mutex.
I see.
>
>>> + list_del(&dev->list);
>>> + cdev_device_del(&dev->cdev, &dev->dev);
>>> + put_device(&dev->dev);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static void vduse_release_dev(struct device *device)
>>> +{
>>> + struct vduse_dev *dev =
>>> + container_of(device, struct vduse_dev, dev);
>>> +
>>> + ida_simple_remove(&vduse_ida, dev->minor);
>>> + kfree(dev->vqs);
>>> + vduse_domain_destroy(dev->domain);
>>> + vduse_dev_destroy(dev);
>>> + module_put(THIS_MODULE);
>>> +}
>>> +
>>> +static int vduse_create_dev(struct vduse_dev_config *config)
>>> +{
>>> + int i, ret = -ENOMEM;
>>> + struct vduse_dev *dev;
>>> +
>>> + if (config->bounce_size > max_bounce_size)
>>> + return -EINVAL;
>>> +
>>> + if (config->bounce_size > max_iova_size)
>>> + return -EINVAL;
>>> +
>>> + if (vduse_find_dev(config->name))
>>> + return -EEXIST;
>>> +
>>> + dev = vduse_dev_create();
>>> + if (!dev)
>>> + return -ENOMEM;
>>> +
>>> + dev->device_id = config->device_id;
>>> + dev->vendor_id = config->vendor_id;
>>> + dev->domain = vduse_domain_create(max_iova_size - 1,
>>> + config->bounce_size);
>>> + if (!dev->domain)
>>> + goto err_domain;
>>> +
>>> + dev->vq_align = config->vq_align;
>>> + dev->vq_size_max = config->vq_size_max;
>>> + dev->vq_num = config->vq_num;
>>> + dev->vqs = kcalloc(dev->vq_num, sizeof(*dev->vqs), GFP_KERNEL);
>>> + if (!dev->vqs)
>>> + goto err_vqs;
>>> +
>>> + for (i = 0; i < dev->vq_num; i++) {
>>> + dev->vqs[i].index = i;
>>> + INIT_WORK(&dev->vqs[i].inject, vduse_vq_irq_inject);
>>> + spin_lock_init(&dev->vqs[i].kick_lock);
>>> + spin_lock_init(&dev->vqs[i].irq_lock);
>>> + }
>>> +
>>> + ret = ida_simple_get(&vduse_ida, 0, VDUSE_DEV_MAX, GFP_KERNEL);
>>> + if (ret < 0)
>>> + goto err_ida;
>>> +
>>> + dev->minor = ret;
>>> + device_initialize(&dev->dev);
>>> + dev->dev.release = vduse_release_dev;
>>> + dev->dev.class = vduse_class;
>>> + dev->dev.devt = MKDEV(MAJOR(vduse_major), dev->minor);
>>> + ret = dev_set_name(&dev->dev, "%s", config->name);
>>> + if (ret)
>>> + goto err_name;
>>> +
>>> + cdev_init(&dev->cdev, &vduse_dev_fops);
>>> + dev->cdev.owner = THIS_MODULE;
>>> +
>>> + ret = cdev_device_add(&dev->cdev, &dev->dev);
>>> + if (ret) {
>>> + put_device(&dev->dev);
>>> + return ret;
>>> + }
>>> + list_add(&dev->list, &vduse_devs);
>>> + __module_get(THIS_MODULE);
>>> +
>>> + return 0;
>>> +err_name:
>>> + ida_simple_remove(&vduse_ida, dev->minor);
>>> +err_ida:
>>> + kfree(dev->vqs);
>>> +err_vqs:
>>> + vduse_domain_destroy(dev->domain);
>>> +err_domain:
>>
>> So the rewind after device_initialize() looks wrong, we should use
>> put_device() which will use dev.relase().
>>
> Oh, yes. We should also call put_device() in err_name case.
>
>> See the comment of device_initialize():
>>
>> * NOTE: Use put_device() to give up your reference instead of freeing
>> * @dev directly once you have called this function.
>> */
>>
>>> + vduse_dev_destroy(dev);
>>> + return ret;
>>> +}
>>> +
>>> +static long vduse_ioctl(struct file *file, unsigned int cmd,
>>> + unsigned long arg)
>>> +{
>>> + int ret;
>>> + void __user *argp = (void __user *)arg;
>>> +
>>> + mutex_lock(&vduse_lock);
>>> + switch (cmd) {
>>> + case VDUSE_GET_API_VERSION:
>>> + ret = VDUSE_API_VERSION;
>>
>> To preseve the uAPI compatibility, besides GET_API_VERSION, we need
>> SET_API_VERSION to support older userspace.
>>
> Shouldn't the userspace keep compatibility to support older kernel? If
> so, we only need GET_API_VERSION here.
Actually the reverse. The new kernel need to make sure the old userspace
can work. That is to say the kenrel should support version 0 forever
even if it supports e.g version 1.
In this case, we should let userspace to choose which version it wants
to use.
Thanks
>
>> And we need probably all the ioctls when API version is not set from
>> userspace.
>>
>>
>>> + break;
>>> + case VDUSE_CREATE_DEV: {
>>> + struct vduse_dev_config config;
>>> +
>>> + ret = -EFAULT;
>>> + if (copy_from_user(&config, argp, sizeof(config)))
>>> + break;
>>> +
>>> + ret = vduse_create_dev(&config);
>>> + break;
>>> + }
>>> + case VDUSE_DESTROY_DEV: {
>>> + char name[VDUSE_NAME_MAX];
>>> +
>>> + ret = -EFAULT;
>>> + if (copy_from_user(name, argp, VDUSE_NAME_MAX))
>>> + break;
>>> +
>>> + ret = vduse_destroy_dev(name);
>>> + break;
>>> + }
>>> + default:
>>> + ret = -EINVAL;
>>> + break;
>>> + }
>>> + mutex_unlock(&vduse_lock);
>>> +
>>> + return ret;
>>> +}
>>> +
>>> +static const struct file_operations vduse_fops = {
>>> + .owner = THIS_MODULE,
>>> + .unlocked_ioctl = vduse_ioctl,
>>> + .compat_ioctl = compat_ptr_ioctl,
>>> + .llseek = noop_llseek,
>>> +};
>>> +
>>> +static char *vduse_devnode(struct device *dev, umode_t *mode)
>>> +{
>>> + return kasprintf(GFP_KERNEL, "vduse/%s", dev_name(dev));
>>> +}
>>> +
>>> +static struct miscdevice vduse_misc = {
>>> + .fops = &vduse_fops,
>>> + .minor = MISC_DYNAMIC_MINOR,
>>> + .name = "vduse",
>>> + .nodename = "vduse/control",
>>> +};
>>> +
>>> +static void vduse_mgmtdev_release(struct device *dev)
>>> +{
>>> +}
>>> +
>>> +static struct device vduse_mgmtdev = {
>>> + .init_name = "vduse",
>>> + .release = vduse_mgmtdev_release,
>>> +};
>>> +
>>> +static struct vdpa_mgmt_dev mgmt_dev;
>>> +
>>> +static int vduse_dev_add_vdpa(struct vduse_dev *dev, const char *name)
>>> +{
>>> + struct vduse_vdpa *vdev = dev->vdev;
>>> + int ret;
>>> +
>>> + if (vdev)
>>> + return -EEXIST;
>>> +
>>> + vdev = vdpa_alloc_device(struct vduse_vdpa, vdpa, &dev->dev,
>>> + &vduse_vdpa_config_ops, name, true);
>>> + if (!vdev)
>>> + return -ENOMEM;
>>> +
>>> + vdev->dev = dev;
>>> + vdev->vdpa.dev.dma_mask = &vdev->vdpa.dev.coherent_dma_mask;
>>> + ret = dma_set_mask_and_coherent(&vdev->vdpa.dev, DMA_BIT_MASK(64));
>>> + if (ret)
>>> + goto err;
>>> +
>>> + set_dma_ops(&vdev->vdpa.dev, &vduse_dev_dma_ops);
>>> + vdev->vdpa.dma_dev = &vdev->vdpa.dev;
>>> + vdev->vdpa.mdev = &mgmt_dev;
>>> +
>>> + ret = _vdpa_register_device(&vdev->vdpa, dev->vq_num);
>>> + if (ret)
>>> + goto err;
>>> +
>>> + dev->vdev = vdev;
>>> +
>>> + return 0;
>>> +err:
>>> + put_device(&vdev->vdpa.dev);
>>> + return ret;
>>> +}
>>> +
>>> +static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, const char *name)
>>> +{
>>> + struct vduse_dev *dev;
>>> + int ret = -EINVAL;
>>> +
>>> + mutex_lock(&vduse_lock);
>>> + dev = vduse_find_dev(name);
>>> + if (!dev)
>>> + goto unlock;
>>> +
>>> + ret = vduse_dev_add_vdpa(dev, name);
>>> +unlock:
>>> + mutex_unlock(&vduse_lock);
>>> +
>>> + return ret;
>>> +}
>>> +
>>> +static void vdpa_dev_del(struct vdpa_mgmt_dev *mdev, struct vdpa_device *dev)
>>> +{
>>> + _vdpa_unregister_device(dev);
>>> +}
>>> +
>>> +static const struct vdpa_mgmtdev_ops vdpa_dev_mgmtdev_ops = {
>>> + .dev_add = vdpa_dev_add,
>>> + .dev_del = vdpa_dev_del,
>>> +};
>>> +
>>> +static struct virtio_device_id id_table[] = {
>>> + { VIRTIO_DEV_ANY_ID, VIRTIO_DEV_ANY_ID },
>>> + { 0 },
>>> +};
>>> +
>>> +static struct vdpa_mgmt_dev mgmt_dev = {
>>> + .device = &vduse_mgmtdev,
>>> + .id_table = id_table,
>>> + .ops = &vdpa_dev_mgmtdev_ops,
>>> +};
>>> +
>>> +static int vduse_mgmtdev_init(void)
>>> +{
>>> + int ret;
>>> +
>>> + ret = device_register(&vduse_mgmtdev);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + ret = vdpa_mgmtdev_register(&mgmt_dev);
>>> + if (ret)
>>> + goto err;
>>> +
>>> + return 0;
>>> +err:
>>> + device_unregister(&vduse_mgmtdev);
>>> + return ret;
>>> +}
>>> +
>>> +static void vduse_mgmtdev_exit(void)
>>> +{
>>> + vdpa_mgmtdev_unregister(&mgmt_dev);
>>> + device_unregister(&vduse_mgmtdev);
>>> +}
>>> +
>>> +static int vduse_init(void)
>>> +{
>>> + int ret;
>>> +
>>> + if (max_bounce_size >= max_iova_size)
>>> + return -EINVAL;
>>> +
>>> + ret = misc_register(&vduse_misc);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + vduse_class = class_create(THIS_MODULE, "vduse");
>>> + if (IS_ERR(vduse_class)) {
>>> + ret = PTR_ERR(vduse_class);
>>> + goto err_class;
>>> + }
>>> + vduse_class->devnode = vduse_devnode;
>>> +
>>> + ret = alloc_chrdev_region(&vduse_major, 0, VDUSE_DEV_MAX, "vduse");
>>> + if (ret)
>>> + goto err_chardev;
>>> +
>>> + vduse_irq_wq = alloc_workqueue("vduse-irq",
>>> + WQ_HIGHPRI | WQ_SYSFS | WQ_UNBOUND, 0);
>>> + if (!vduse_irq_wq)
>>> + goto err_wq;
>>> +
>>> + ret = vduse_domain_init();
>>> + if (ret)
>>> + goto err_domain;
>>> +
>>> + ret = vduse_mgmtdev_init();
>>> + if (ret)
>>> + goto err_mgmtdev;
>>> +
>>> + return 0;
>>> +err_mgmtdev:
>>> + vduse_domain_exit();
>>> +err_domain:
>>> + destroy_workqueue(vduse_irq_wq);
>>> +err_wq:
>>> + unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);
>>> +err_chardev:
>>> + class_destroy(vduse_class);
>>> +err_class:
>>> + misc_deregister(&vduse_misc);
>>> + return ret;
>>> +}
>>> +module_init(vduse_init);
>>> +
>>> +static void vduse_exit(void)
>>> +{
>>> + misc_deregister(&vduse_misc);
>>> + class_destroy(vduse_class);
>>> + unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);
>>> + destroy_workqueue(vduse_irq_wq);
>>> + vduse_domain_exit();
>>> + vduse_mgmtdev_exit();
>>> +}
>>> +module_exit(vduse_exit);
>>> +
>>> +MODULE_VERSION(DRV_VERSION);
>>> +MODULE_LICENSE(DRV_LICENSE);
>>> +MODULE_AUTHOR(DRV_AUTHOR);
>>> +MODULE_DESCRIPTION(DRV_DESC);
>>> diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
>>> new file mode 100644
>>> index 000000000000..37f7d7059aa8
>>> --- /dev/null
>>> +++ b/include/uapi/linux/vduse.h
>>> @@ -0,0 +1,153 @@
>>> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
>>> +#ifndef _UAPI_VDUSE_H_
>>> +#define _UAPI_VDUSE_H_
>>> +
>>> +#include <linux/types.h>
>>> +
>>> +#define VDUSE_API_VERSION 0
>>> +
>>> +#define VDUSE_CONFIG_DATA_LEN 256
>>> +#define VDUSE_NAME_MAX 256
>>> +
>>> +/* the control messages definition for read/write */
>>> +
>>> +enum vduse_req_type {
>>> + VDUSE_SET_VQ_NUM,
>>> + VDUSE_SET_VQ_ADDR,
>>> + VDUSE_SET_VQ_READY,
>>> + VDUSE_GET_VQ_READY,
>>> + VDUSE_SET_VQ_STATE,
>>> + VDUSE_GET_VQ_STATE,
>>> + VDUSE_SET_FEATURES,
>>> + VDUSE_GET_FEATURES,
>>> + VDUSE_SET_STATUS,
>>> + VDUSE_GET_STATUS,
>>> + VDUSE_SET_CONFIG,
>>> + VDUSE_GET_CONFIG,
>>> + VDUSE_UPDATE_IOTLB,
>>> +};
>>
>> Need comment to explain each type.
>>
> Fine.
>
>>> +
>>> +struct vduse_vq_num {
>>> + __u32 index;
>>> + __u32 num;
>>> +};
>>> +
>>> +struct vduse_vq_addr {
>>> + __u32 index;
>>> + __u64 desc_addr;
>>> + __u64 driver_addr;
>>> + __u64 device_addr;
>>> +};
>>> +
>>> +struct vduse_vq_ready {
>>> + __u32 index;
>>> + __u8 ready;
>>> +};
>>> +
>>> +struct vduse_vq_state {
>>> + __u32 index;
>>> + __u16 avail_idx;
>>> +};
>>> +
>>> +struct vduse_dev_config_data {
>>> + __u32 offset;
>>> + __u32 len;
>>> + __u8 data[VDUSE_CONFIG_DATA_LEN];
>>> +};
>>> +
>>> +struct vduse_iova_range {
>>> + __u64 start;
>>> + __u64 last;
>>> +};
>>> +
>>> +struct vduse_features {
>>> + __u64 features;
>>> +};
>>> +
>>> +struct vduse_status {
>>> + __u8 status;
>>> +};
>>
>> Need comment for all the above uapi.
>>
> Fine.
>
>>> +
>>> +struct vduse_dev_request {
>>> + __u32 type; /* request type */
>>> + __u32 request_id; /* request id */
>>> + __u32 reserved[2]; /* for feature use */
>>> + union {
>>> + struct vduse_vq_num vq_num; /* virtqueue num */
>>> + struct vduse_vq_addr vq_addr; /* virtqueue address */
>>> + struct vduse_vq_ready vq_ready; /* virtqueue ready status */
>>> + struct vduse_vq_state vq_state; /* virtqueue state */
>>> + struct vduse_dev_config_data config; /* virtio device config space */
>>> + struct vduse_iova_range iova; /* iova range for updating */
>>> + struct vduse_features f; /* virtio features */
>>> + struct vduse_status s; /* device status */
>>> + __u32 padding[16]; /* padding */
>>> + };
>>> +};
>>> +
>>> +struct vduse_dev_response {
>>> + __u32 request_id; /* corresponding request id */
>>> +#define VDUSE_REQUEST_OK 0x00
>>> +#define VDUSE_REQUEST_FAILED 0x01
>>> + __u32 result; /* the result of request */
>>> + __u32 reserved[2]; /* for feature use */
>>> + union {
>>> + struct vduse_vq_ready vq_ready; /* virtqueue ready status */
>>> + struct vduse_vq_state vq_state; /* virtqueue state */
>>> + struct vduse_dev_config_data config; /* virtio device config space */
>>> + struct vduse_features f; /* virtio features */
>>> + struct vduse_status s; /* device status */
>>> + __u32 padding[16]; /* padding */
>>> + };
>>> +};
>>> +
>>> +/* ioctls */
>>> +
>>> +struct vduse_dev_config {
>>> + char name[VDUSE_NAME_MAX]; /* vduse device name */
>>> + __u32 vendor_id; /* virtio vendor id */
>>> + __u32 device_id; /* virtio device id */
>>> + __u64 bounce_size; /* bounce buffer size for iommu */
>>> + __u16 vq_num; /* the number of virtqueues */
>>> + __u16 vq_size_max; /* the max size of virtqueue */
>>> + __u32 vq_align; /* the allocation alignment of virtqueue's metadata */
>>> +};
>>> +
>>> +struct vduse_iotlb_entry {
>>> + int fd;
>>> +#define VDUSE_ACCESS_RO 0x1
>>> +#define VDUSE_ACCESS_WO 0x2
>>> +#define VDUSE_ACCESS_RW 0x3
>>> + __u8 perm; /* access permission of this range */
>>
>> Let's re-order the perm or add explict padding here to avoid hole.
>>
> OK.
>
> Thanks,
> Yongji
>
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