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Message-ID: <1bb3af07-0ec2-109c-d6d1-83d4d1f410c3@redhat.com>
Date: Tue, 26 Jan 2021 16:08:52 +0800
From: Jason Wang <jasowang@...hat.com>
To: Xie Yongji <xieyongji@...edance.com>, mst@...hat.com,
stefanha@...hat.com, sgarzare@...hat.com, parav@...dia.com,
bob.liu@...cle.com, hch@...radead.org, rdunlap@...radead.org,
willy@...radead.org, viro@...iv.linux.org.uk, axboe@...nel.dk,
bcrl@...ck.org, corbet@....net
Cc: virtualization@...ts.linux-foundation.org, netdev@...r.kernel.org,
kvm@...r.kernel.org, linux-aio@...ck.org,
linux-fsdevel@...r.kernel.org
Subject: Re: [RFC v3 08/11] vduse: Introduce VDUSE - vDPA Device in Userspace
On 2021/1/19 下午1:07, Xie Yongji wrote:
> 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, VDUSE_IOTLB_GET_FD ioctl will be used to get
> the file descriptors referring to vDPA device's iova regions. Then
> userspace can use mmap() to access those iova regions. Besides,
> the eventfd mechanism is used to trigger interrupt callbacks and
> receive virtqueue kicks in userspace.
>
> Signed-off-by: Xie Yongji <xieyongji@...edance.com>
> ---
> Documentation/driver-api/vduse.rst | 85 ++
> Documentation/userspace-api/ioctl/ioctl-number.rst | 1 +
> drivers/vdpa/Kconfig | 7 +
> drivers/vdpa/Makefile | 1 +
> drivers/vdpa/vdpa_user/Makefile | 5 +
> drivers/vdpa/vdpa_user/eventfd.c | 221 ++++
> drivers/vdpa/vdpa_user/eventfd.h | 48 +
> drivers/vdpa/vdpa_user/iova_domain.c | 426 +++++++
> drivers/vdpa/vdpa_user/iova_domain.h | 68 ++
> drivers/vdpa/vdpa_user/vduse.h | 62 +
> drivers/vdpa/vdpa_user/vduse_dev.c | 1217 ++++++++++++++++++++
> include/uapi/linux/vdpa.h | 1 +
> include/uapi/linux/vduse.h | 125 ++
> 13 files changed, 2267 insertions(+)
> create mode 100644 Documentation/driver-api/vduse.rst
> create mode 100644 drivers/vdpa/vdpa_user/Makefile
> create mode 100644 drivers/vdpa/vdpa_user/eventfd.c
> create mode 100644 drivers/vdpa/vdpa_user/eventfd.h
> create mode 100644 drivers/vdpa/vdpa_user/iova_domain.c
> create mode 100644 drivers/vdpa/vdpa_user/iova_domain.h
> create mode 100644 drivers/vdpa/vdpa_user/vduse.h
> create mode 100644 drivers/vdpa/vdpa_user/vduse_dev.c
> create mode 100644 include/uapi/linux/vduse.h
>
> diff --git a/Documentation/driver-api/vduse.rst b/Documentation/driver-api/vduse.rst
> new file mode 100644
> index 000000000000..9418a7f6646b
> --- /dev/null
> +++ b/Documentation/driver-api/vduse.rst
> @@ -0,0 +1,85 @@
> +==================================
> +VDUSE - "vDPA Device in Userspace"
> +==================================
> +
> +vDPA (virtio data path acceleration) device is a device that uses a
> +datapath which complies with the virtio specifications with vendor
> +specific control path. vDPA devices can be both physically located on
> +the hardware or emulated by software. VDUSE is a framework that makes it
> +possible to implement software-emulated vDPA devices in userspace.
> +
> +How VDUSE works
> +------------
> +Each userspace vDPA device is created by the VDUSE_CREATE_DEV ioctl on
> +the VDUSE character device (/dev/vduse). Then a file descriptor pointing
> +to the new resources will be returned, which can be used to implement the
> +userspace vDPA device's control path and data path.
> +
> +To implement control path, the read/write operations to the file descriptor
> +will be used to receive/reply the control messages from/to VDUSE driver.
It's better to document the protocol here. E.g the identifier stuffs.
> +Those control messages are mostly based on the vdpa_config_ops which defines
> +a unified interface to control different types of vDPA device.
> +
> +The following types of messages are provided by the VDUSE framework now:
> +
> +- VDUSE_SET_VQ_ADDR: Set the addresses of the different aspects of virtqueue.
"Set the vring address of a virtqueue" might be better here.
> +
> +- VDUSE_SET_VQ_NUM: Set the size of virtqueue
> +
> +- VDUSE_SET_VQ_READY: Set ready status of virtqueue
> +
> +- VDUSE_GET_VQ_READY: Get ready status of virtqueue
> +
> +- VDUSE_SET_VQ_STATE: Set the state (last_avail_idx) for virtqueue
> +
> +- VDUSE_GET_VQ_STATE: Get the state (last_avail_idx) for virtqueue
It's better not to mention layout specific stuffs here (last_avail_idx).
Consider we should support packed virtqueue in the future.
> +
> +- VDUSE_SET_FEATURES: Set virtio features supported by the driver
> +
> +- VDUSE_GET_FEATURES: Get virtio features supported by the device
> +
> +- VDUSE_SET_STATUS: Set the device status
> +
> +- VDUSE_GET_STATUS: Get the device status
> +
> +- VDUSE_SET_CONFIG: Write to device specific configuration space
> +
> +- VDUSE_GET_CONFIG: Read from device specific configuration space
> +
> +- VDUSE_UPDATE_IOTLB: Notify userspace to update the memory mapping in device IOTLB
> +
> +Please see include/linux/vdpa.h for details.
> +
> +In the data path, vDPA device's iova regions will be mapped into userspace with
> +the help of VDUSE_IOTLB_GET_FD ioctl on the userspace vDPA device fd:
> +
> +- VDUSE_IOTLB_GET_FD: get the file descriptor to iova region. Userspace can
> + access this iova region by passing the fd to mmap(2).
> +
> +Besides, the eventfd mechanism is used to trigger interrupt callbacks and
> +receive virtqueue kicks in userspace. The following ioctls on the userspace
> +vDPA device fd are provided to support that:
> +
> +- VDUSE_VQ_SETUP_KICKFD: set the kickfd for virtqueue, this eventfd is used
> + by VDUSE driver to notify userspace to consume the vring.
> +
> +- VDUSE_VQ_SETUP_IRQFD: set the irqfd for virtqueue, this eventfd is used
> + by userspace to notify VDUSE driver to trigger interrupt callbacks.
> +
> +MMU-based IOMMU Driver
> +----------------------
> +In virtio-vdpa case, VDUSE framework implements a MMU-based on-chip IOMMU
> +driver to support mapping the kernel dma buffer into the userspace iova
> +region dynamically.
> +
> +The basic idea behind this driver is treating MMU (VA->PA) as IOMMU (IOVA->PA).
> +The driver will set up MMU mapping instead of IOMMU mapping for the DMA transfer
> +so that the userspace process is able to use its virtual address to access
> +the dma buffer in kernel.
> +
> +And to avoid security issue, a bounce-buffering mechanism is introduced to
> +prevent userspace accessing the original buffer directly which may contain other
> +kernel data. During the mapping, unmapping, the driver will copy the data from
> +the original buffer to the bounce buffer and back, depending on the direction of
> +the transfer. And the bounce-buffer addresses will be mapped into the user address
> +space instead of the original one.
> 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 4be7be39be26..667354309bf4 100644
> --- a/drivers/vdpa/Kconfig
> +++ b/drivers/vdpa/Kconfig
> @@ -21,6 +21,13 @@ config VDPA_SIM
> to RX. This device is used for testing, prototyping and
> development of vDPA.
>
> +config VDPA_USER
> + tristate "VDUSE (vDPA Device in Userspace) support"
> + depends on EVENTFD && MMU && HAS_DMA
Need select VHOST_IOTLB.
> + 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 d160e9b63a66..66e97778ad03 100644
> --- a/drivers/vdpa/Makefile
> +++ b/drivers/vdpa/Makefile
> @@ -1,5 +1,6 @@
> # 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-$(CONFIG_MLX5_VDPA) += mlx5/
> diff --git a/drivers/vdpa/vdpa_user/Makefile b/drivers/vdpa/vdpa_user/Makefile
> new file mode 100644
> index 000000000000..b7645e36992b
> --- /dev/null
> +++ b/drivers/vdpa/vdpa_user/Makefile
> @@ -0,0 +1,5 @@
> +# SPDX-License-Identifier: GPL-2.0
> +
> +vduse-y := vduse_dev.o iova_domain.o eventfd.o
> +
> +obj-$(CONFIG_VDPA_USER) += vduse.o
> diff --git a/drivers/vdpa/vdpa_user/eventfd.c b/drivers/vdpa/vdpa_user/eventfd.c
> new file mode 100644
> index 000000000000..dbffddb08908
> --- /dev/null
> +++ b/drivers/vdpa/vdpa_user/eventfd.c
> @@ -0,0 +1,221 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Eventfd support for VDUSE
> + *
> + * Copyright (C) 2020 Bytedance Inc. and/or its affiliates. All rights reserved.
> + *
> + * Author: Xie Yongji <xieyongji@...edance.com>
> + *
> + */
> +
> +#include <linux/eventfd.h>
> +#include <linux/poll.h>
> +#include <linux/wait.h>
> +#include <linux/slab.h>
> +#include <linux/file.h>
> +#include <uapi/linux/vduse.h>
> +
> +#include "eventfd.h"
> +
> +static struct workqueue_struct *vduse_irqfd_cleanup_wq;
> +
> +static void vduse_virqfd_shutdown(struct work_struct *work)
> +{
> + u64 cnt;
> + struct vduse_virqfd *virqfd = container_of(work,
> + struct vduse_virqfd, shutdown);
> +
> + eventfd_ctx_remove_wait_queue(virqfd->ctx, &virqfd->wait, &cnt);
> + flush_work(&virqfd->inject);
> + eventfd_ctx_put(virqfd->ctx);
> + kfree(virqfd);
> +}
> +
> +static void vduse_virqfd_inject(struct work_struct *work)
> +{
> + struct vduse_virqfd *virqfd = container_of(work,
> + struct vduse_virqfd, inject);
> + struct vduse_virtqueue *vq = virqfd->vq;
> +
> + spin_lock_irq(&vq->irq_lock);
> + if (vq->ready && vq->cb)
> + vq->cb(vq->private);
> + spin_unlock_irq(&vq->irq_lock);
> +}
> +
> +static void virqfd_deactivate(struct vduse_virqfd *virqfd)
> +{
> + queue_work(vduse_irqfd_cleanup_wq, &virqfd->shutdown);
> +}
> +
> +static int vduse_virqfd_wakeup(wait_queue_entry_t *wait, unsigned int mode,
> + int sync, void *key)
> +{
> + struct vduse_virqfd *virqfd = container_of(wait, struct vduse_virqfd, wait);
> + struct vduse_virtqueue *vq = virqfd->vq;
> +
> + __poll_t flags = key_to_poll(key);
> +
> + if (flags & EPOLLIN)
> + schedule_work(&virqfd->inject);
> +
> + if (flags & EPOLLHUP) {
> + spin_lock(&vq->irq_lock);
> + if (vq->virqfd == virqfd) {
> + vq->virqfd = NULL;
> + virqfd_deactivate(virqfd);
> + }
> + spin_unlock(&vq->irq_lock);
> + }
> +
> + return 0;
> +}
> +
> +static void vduse_virqfd_ptable_queue_proc(struct file *file,
> + wait_queue_head_t *wqh, poll_table *pt)
> +{
> + struct vduse_virqfd *virqfd = container_of(pt, struct vduse_virqfd, pt);
> +
> + add_wait_queue(wqh, &virqfd->wait);
> +}
> +
> +int vduse_virqfd_setup(struct vduse_dev *dev,
> + struct vduse_vq_eventfd *eventfd)
> +{
> + struct vduse_virqfd *virqfd;
> + struct fd irqfd;
> + struct eventfd_ctx *ctx;
> + struct vduse_virtqueue *vq;
> + __poll_t events;
> + int ret;
> +
> + if (eventfd->index >= dev->vq_num)
> + return -EINVAL;
> +
> + vq = &dev->vqs[eventfd->index];
> + virqfd = kzalloc(sizeof(*virqfd), GFP_KERNEL);
> + if (!virqfd)
> + return -ENOMEM;
> +
> + INIT_WORK(&virqfd->shutdown, vduse_virqfd_shutdown);
> + INIT_WORK(&virqfd->inject, vduse_virqfd_inject);
> +
> + ret = -EBADF;
> + irqfd = fdget(eventfd->fd);
> + if (!irqfd.file)
> + goto err_fd;
> +
> + ctx = eventfd_ctx_fileget(irqfd.file);
> + if (IS_ERR(ctx)) {
> + ret = PTR_ERR(ctx);
> + goto err_ctx;
> + }
> +
> + virqfd->vq = vq;
> + virqfd->ctx = ctx;
> + spin_lock(&vq->irq_lock);
> + if (vq->virqfd)
> + virqfd_deactivate(virqfd);
> + vq->virqfd = virqfd;
> + spin_unlock(&vq->irq_lock);
> +
> + init_waitqueue_func_entry(&virqfd->wait, vduse_virqfd_wakeup);
> + init_poll_funcptr(&virqfd->pt, vduse_virqfd_ptable_queue_proc);
> +
> + events = vfs_poll(irqfd.file, &virqfd->pt);
> +
> + /*
> + * Check if there was an event already pending on the eventfd
> + * before we registered and trigger it as if we didn't miss it.
> + */
> + if (events & EPOLLIN)
> + schedule_work(&virqfd->inject);
> +
> + fdput(irqfd);
> +
> + return 0;
> +err_ctx:
> + fdput(irqfd);
> +err_fd:
> + kfree(virqfd);
> + return ret;
> +}
> +
> +void vduse_virqfd_release(struct vduse_dev *dev)
> +{
> + int i;
> +
> + for (i = 0; i < dev->vq_num; i++) {
> + struct vduse_virtqueue *vq = &dev->vqs[i];
> +
> + spin_lock(&vq->irq_lock);
> + if (vq->virqfd) {
> + virqfd_deactivate(vq->virqfd);
> + vq->virqfd = NULL;
> + }
> + spin_unlock(&vq->irq_lock);
> + }
> + flush_workqueue(vduse_irqfd_cleanup_wq);
> +}
> +
> +int vduse_virqfd_init(void)
> +{
> + vduse_irqfd_cleanup_wq = alloc_workqueue("vduse-irqfd-cleanup",
> + WQ_UNBOUND, 0);
> + if (!vduse_irqfd_cleanup_wq)
> + return -ENOMEM;
> +
> + return 0;
> +}
> +
> +void vduse_virqfd_exit(void)
> +{
> + destroy_workqueue(vduse_irqfd_cleanup_wq);
> +}
> +
> +void vduse_vq_kick(struct vduse_virtqueue *vq)
> +{
> + spin_lock(&vq->kick_lock);
> + if (vq->ready && vq->kickfd)
> + eventfd_signal(vq->kickfd, 1);
> + spin_unlock(&vq->kick_lock);
> +}
> +
> +int vduse_kickfd_setup(struct vduse_dev *dev,
> + struct vduse_vq_eventfd *eventfd)
> +{
> + struct eventfd_ctx *ctx;
> + struct vduse_virtqueue *vq;
> +
> + if (eventfd->index >= dev->vq_num)
> + return -EINVAL;
> +
> + vq = &dev->vqs[eventfd->index];
> + ctx = eventfd_ctx_fdget(eventfd->fd);
> + if (IS_ERR(ctx))
> + return PTR_ERR(ctx);
> +
> + spin_lock(&vq->kick_lock);
> + if (vq->kickfd)
> + eventfd_ctx_put(vq->kickfd);
> + vq->kickfd = ctx;
> + spin_unlock(&vq->kick_lock);
> +
> + return 0;
> +}
> +
> +void vduse_kickfd_release(struct vduse_dev *dev)
> +{
> + 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);
> + }
> +}
> diff --git a/drivers/vdpa/vdpa_user/eventfd.h b/drivers/vdpa/vdpa_user/eventfd.h
> new file mode 100644
> index 000000000000..14269ff27f47
> --- /dev/null
> +++ b/drivers/vdpa/vdpa_user/eventfd.h
> @@ -0,0 +1,48 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Eventfd support for VDUSE
> + *
> + * Copyright (C) 2020 Bytedance Inc. and/or its affiliates. All rights reserved.
> + *
> + * Author: Xie Yongji <xieyongji@...edance.com>
> + *
> + */
> +
> +#ifndef _VDUSE_EVENTFD_H
> +#define _VDUSE_EVENTFD_H
> +
> +#include <linux/eventfd.h>
> +#include <linux/poll.h>
> +#include <linux/wait.h>
> +#include <uapi/linux/vduse.h>
> +
> +#include "vduse.h"
> +
> +struct vduse_dev;
> +
> +struct vduse_virqfd {
> + struct eventfd_ctx *ctx;
> + struct vduse_virtqueue *vq;
> + struct work_struct inject;
> + struct work_struct shutdown;
> + wait_queue_entry_t wait;
> + poll_table pt;
> +};
> +
> +int vduse_virqfd_setup(struct vduse_dev *dev,
> + struct vduse_vq_eventfd *eventfd);
> +
> +void vduse_virqfd_release(struct vduse_dev *dev);
> +
> +int vduse_virqfd_init(void);
> +
> +void vduse_virqfd_exit(void);
> +
> +void vduse_vq_kick(struct vduse_virtqueue *vq);
> +
> +int vduse_kickfd_setup(struct vduse_dev *dev,
> + struct vduse_vq_eventfd *eventfd);
> +
> +void vduse_kickfd_release(struct vduse_dev *dev);
> +
> +#endif /* _VDUSE_EVENTFD_H */
> diff --git a/drivers/vdpa/vdpa_user/iova_domain.c b/drivers/vdpa/vdpa_user/iova_domain.c
> new file mode 100644
> index 000000000000..cdfef8e9f9d6
> --- /dev/null
> +++ b/drivers/vdpa/vdpa_user/iova_domain.c
> @@ -0,0 +1,426 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * MMU-based IOMMU implementation
> + *
> + * Copyright (C) 2020 Bytedance Inc. and/or its affiliates. All rights reserved.
> + *
> + * Author: Xie Yongji <xieyongji@...edance.com>
> + *
> + */
> +
> +#include <linux/slab.h>
> +#include <linux/file.h>
> +#include <linux/anon_inodes.h>
> +
> +#include "iova_domain.h"
> +
> +#define IOVA_START_PFN 1
> +#define IOVA_ALLOC_ORDER 12
> +#define IOVA_ALLOC_SIZE (1 << IOVA_ALLOC_ORDER)
Can this work for all archs (e.g why not use PAGE_SIZE)?
> +
> +#define CONSISTENT_DMA_SIZE (1024 * 1024 * 1024)
> +
> +static inline struct page *
> +vduse_domain_get_bounce_page(struct vduse_iova_domain *domain,
> + unsigned long iova)
> +{
> + unsigned long index = iova >> PAGE_SHIFT;
> +
> + return domain->bounce_pages[index];
> +}
> +
> +static inline void
> +vduse_domain_set_bounce_page(struct vduse_iova_domain *domain,
> + unsigned long iova, struct page *page)
> +{
> + unsigned long index = iova >> PAGE_SHIFT;
> +
> + domain->bounce_pages[index] = page;
> +}
> +
> +static struct vduse_iova_map *
> +vduse_domain_alloc_iova_map(struct vduse_iova_domain *domain,
> + unsigned long iova, unsigned long orig,
> + size_t size, enum dma_data_direction dir)
> +{
> + struct vduse_iova_map *map;
> +
> + map = kzalloc(sizeof(struct vduse_iova_map), GFP_ATOMIC);
> + if (!map)
> + return NULL;
> +
> + map->iova.start = iova;
> + map->iova.last = iova + size - 1;
> + map->orig = orig;
> + map->size = size;
> + map->dir = dir;
> +
> + return map;
> +}
> +
> +static struct page *
> +vduse_domain_get_mapping_page(struct vduse_iova_domain *domain,
> + unsigned long iova)
> +{
> + unsigned long start = iova & PAGE_MASK;
> + unsigned long last = start + PAGE_SIZE - 1;
> + struct vduse_iova_map *map;
> + struct interval_tree_node *node;
> + struct page *page = NULL;
> +
> + spin_lock(&domain->map_lock);
> + node = interval_tree_iter_first(&domain->mappings, start, last);
> + if (!node)
> + goto out;
> +
> + map = container_of(node, struct vduse_iova_map, iova);
> + page = virt_to_page(map->orig + iova - map->iova.start);
> + get_page(page);
> +out:
> + spin_unlock(&domain->map_lock);
> +
> + return page;
> +}
> +
> +static struct page *
> +vduse_domain_alloc_bounce_page(struct vduse_iova_domain *domain,
> + unsigned long iova)
> +{
> + unsigned long start = iova & PAGE_MASK;
> + unsigned long last = start + PAGE_SIZE - 1;
> + struct vduse_iova_map *map;
> + struct interval_tree_node *node;
> + struct page *page = NULL, *new_page = alloc_page(GFP_KERNEL);
> +
> + if (!new_page)
> + return NULL;
> +
> + spin_lock(&domain->map_lock);
> + node = interval_tree_iter_first(&domain->mappings, start, last);
> + if (!node) {
> + __free_page(new_page);
> + goto out;
> + }
> + page = vduse_domain_get_bounce_page(domain, iova);
> + if (page) {
> + get_page(page);
> + __free_page(new_page);
Let's delay the allocation of new_page until it is really required.
> + goto out;
> + }
> + vduse_domain_set_bounce_page(domain, iova, new_page);
> + get_page(new_page);
> + page = new_page;
> +
> + while (node) {
I may miss something but which case should we do the loop here?
> + unsigned int src_offset = 0, dst_offset = 0;
> + void *src, *dst;
> + size_t copy_len;
> +
> + map = container_of(node, struct vduse_iova_map, iova);
> + node = interval_tree_iter_next(node, start, last);
> + if (map->dir == DMA_FROM_DEVICE)
> + continue;
> +
> + if (start > map->iova.start)
> + src_offset = start - map->iova.start;
> + else
> + dst_offset = map->iova.start - start;
> +
> + src = (void *)(map->orig + src_offset);
> + dst = page_address(page) + dst_offset;
> + copy_len = min_t(size_t, map->size - src_offset,
> + PAGE_SIZE - dst_offset);
> + memcpy(dst, src, copy_len);
> + }
> +out:
> + spin_unlock(&domain->map_lock);
> +
> + return page;
> +}
> +
> +static void
> +vduse_domain_free_bounce_pages(struct vduse_iova_domain *domain,
> + unsigned long iova, size_t size)
> +{
> + struct page *page;
> + struct interval_tree_node *node;
> + unsigned long last = iova + size - 1;
> +
> + spin_lock(&domain->map_lock);
> + node = interval_tree_iter_first(&domain->mappings, iova, last);
> + if (WARN_ON(node))
> + goto out;
> +
> + while (size > 0) {
> + page = vduse_domain_get_bounce_page(domain, iova);
> + if (page) {
> + vduse_domain_set_bounce_page(domain, iova, NULL);
> + __free_page(page);
> + }
> + size -= PAGE_SIZE;
> + iova += PAGE_SIZE;
> + }
> +out:
> + spin_unlock(&domain->map_lock);
> +}
> +
> +static void vduse_domain_bounce(struct vduse_iova_domain *domain,
> + unsigned long iova, unsigned long orig,
> + size_t size, enum dma_data_direction dir)
> +{
> + unsigned int offset = offset_in_page(iova);
> +
> + while (size) {
> + struct page *p = vduse_domain_get_bounce_page(domain, iova);
> + size_t copy_len = min_t(size_t, PAGE_SIZE - offset, size);
> + void *addr;
> +
> + WARN_ON(!p && dir == DMA_FROM_DEVICE);
> +
> + if (p) {
> + addr = page_address(p) + offset;
> + if (dir == DMA_TO_DEVICE)
> + memcpy(addr, (void *)orig, copy_len);
> + else if (dir == DMA_FROM_DEVICE)
> + memcpy((void *)orig, addr, copy_len);
> + }
> +
> + size -= copy_len;
> + orig += copy_len;
> + iova += copy_len;
> + offset = 0;
> + }
> +}
> +
> +static unsigned long vduse_domain_alloc_iova(struct iova_domain *iovad,
> + unsigned long size, unsigned long limit)
> +{
> + unsigned long shift = iova_shift(iovad);
> + unsigned long iova_len = iova_align(iovad, size) >> shift;
> + unsigned long iova_pfn;
> +
> + if (iova_len < (1 << (IOVA_RANGE_CACHE_MAX_SIZE - 1)))
> + iova_len = roundup_pow_of_two(iova_len);
> + iova_pfn = alloc_iova_fast(iovad, iova_len, limit >> shift, true);
> +
> + return iova_pfn << shift;
> +}
> +
> +static void vduse_domain_free_iova(struct iova_domain *iovad,
> + unsigned long iova, size_t size)
> +{
> + unsigned long shift = iova_shift(iovad);
> + unsigned long iova_len = iova_align(iovad, size) >> shift;
> +
> + free_iova_fast(iovad, iova >> shift, iova_len);
> +}
> +
> +dma_addr_t vduse_domain_map_page(struct vduse_iova_domain *domain,
> + struct page *page, unsigned long offset,
> + size_t size, enum dma_data_direction dir,
> + unsigned long attrs)
> +{
> + struct iova_domain *iovad = &domain->stream_iovad;
> + unsigned long limit = domain->bounce_size - 1;
> + unsigned long iova = vduse_domain_alloc_iova(iovad, size, limit);
> + unsigned long orig = (unsigned long)page_address(page) + offset;
> + struct vduse_iova_map *map;
> +
> + if (!iova)
> + return DMA_MAPPING_ERROR;
> +
> + map = vduse_domain_alloc_iova_map(domain, iova, orig, size, dir);
> + if (!map) {
> + vduse_domain_free_iova(iovad, iova, size);
> + return DMA_MAPPING_ERROR;
> + }
> +
> + spin_lock(&domain->map_lock);
> + interval_tree_insert(&map->iova, &domain->mappings);
> + spin_unlock(&domain->map_lock);
> +
> + if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
> + vduse_domain_bounce(domain, iova, orig, size, DMA_TO_DEVICE);
> +
> + return (dma_addr_t)iova;
> +}
> +
> +void vduse_domain_unmap_page(struct vduse_iova_domain *domain,
> + dma_addr_t dma_addr, size_t size,
> + enum dma_data_direction dir, unsigned long attrs)
> +{
> + struct iova_domain *iovad = &domain->stream_iovad;
> + unsigned long iova = (unsigned long)dma_addr;
> + struct interval_tree_node *node;
> + struct vduse_iova_map *map;
> +
> + spin_lock(&domain->map_lock);
> + node = interval_tree_iter_first(&domain->mappings, iova, iova + 1);
> + if (WARN_ON(!node)) {
> + spin_unlock(&domain->map_lock);
> + return;
> + }
> + interval_tree_remove(node, &domain->mappings);
> + spin_unlock(&domain->map_lock);
> +
> + map = container_of(node, struct vduse_iova_map, iova);
> + if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL)
> + vduse_domain_bounce(domain, iova, map->orig,
> + size, DMA_FROM_DEVICE);
> + vduse_domain_free_iova(iovad, iova, size);
> + kfree(map);
> +}
> +
> +void *vduse_domain_alloc_coherent(struct vduse_iova_domain *domain,
> + size_t size, dma_addr_t *dma_addr,
> + gfp_t flag, unsigned long attrs)
> +{
> + struct iova_domain *iovad = &domain->consistent_iovad;
> + unsigned long limit = domain->bounce_size + CONSISTENT_DMA_SIZE - 1;
> + unsigned long iova = vduse_domain_alloc_iova(iovad, size, limit);
> + void *orig = alloc_pages_exact(size, flag);
> + struct vduse_iova_map *map;
> +
> + if (!iova || !orig)
> + goto err;
> +
> + map = vduse_domain_alloc_iova_map(domain, iova, (unsigned long)orig,
> + size, DMA_BIDIRECTIONAL);
> + if (!map)
> + goto err;
> +
> + spin_lock(&domain->map_lock);
> + interval_tree_insert(&map->iova, &domain->mappings);
> + spin_unlock(&domain->map_lock);
> + *dma_addr = (dma_addr_t)iova;
> +
> + return orig;
> +err:
> + *dma_addr = DMA_MAPPING_ERROR;
> + if (orig)
> + free_pages_exact(orig, size);
> + if (iova)
> + vduse_domain_free_iova(iovad, iova, size);
> +
> + return NULL;
> +}
> +
> +void vduse_domain_free_coherent(struct vduse_iova_domain *domain, size_t size,
> + void *vaddr, dma_addr_t dma_addr,
> + unsigned long attrs)
> +{
> + struct iova_domain *iovad = &domain->consistent_iovad;
> + unsigned long iova = (unsigned long)dma_addr;
> + struct interval_tree_node *node;
> + struct vduse_iova_map *map;
> +
> + spin_lock(&domain->map_lock);
> + node = interval_tree_iter_first(&domain->mappings, iova, iova + 1);
> + if (WARN_ON(!node)) {
> + spin_unlock(&domain->map_lock);
> + return;
> + }
> + interval_tree_remove(node, &domain->mappings);
> + spin_unlock(&domain->map_lock);
> +
> + map = container_of(node, struct vduse_iova_map, iova);
> + vduse_domain_free_iova(iovad, iova, size);
> + free_pages_exact(vaddr, size);
> + kfree(map);
> +}
> +
> +static vm_fault_t vduse_domain_mmap_fault(struct vm_fault *vmf)
> +{
> + struct vduse_iova_domain *domain = vmf->vma->vm_private_data;
> + unsigned long iova = vmf->pgoff << PAGE_SHIFT;
> + struct page *page;
> +
> + if (!domain)
> + return VM_FAULT_SIGBUS;
> +
> + if (iova < domain->bounce_size)
> + page = vduse_domain_alloc_bounce_page(domain, iova);
> + else
> + page = vduse_domain_get_mapping_page(domain, iova);
> +
> + if (!page)
> + return VM_FAULT_SIGBUS;
> +
> + vmf->page = page;
> +
> + return 0;
> +}
> +
> +static const struct vm_operations_struct vduse_domain_mmap_ops = {
> + .fault = vduse_domain_mmap_fault,
> +};
> +
> +static int vduse_domain_mmap(struct file *file, struct vm_area_struct *vma)
> +{
> + struct vduse_iova_domain *domain = file->private_data;
> +
> + vma->vm_flags |= VM_DONTCOPY | VM_DONTDUMP | VM_DONTEXPAND;
> + vma->vm_private_data = domain;
> + vma->vm_ops = &vduse_domain_mmap_ops;
> +
> + return 0;
> +}
> +
> +static int vduse_domain_release(struct inode *inode, struct file *file)
> +{
> + struct vduse_iova_domain *domain = file->private_data;
> +
> + vduse_domain_free_bounce_pages(domain, 0, domain->bounce_size);
> + put_iova_domain(&domain->stream_iovad);
> + put_iova_domain(&domain->consistent_iovad);
> + vfree(domain->bounce_pages);
> + kfree(domain);
> +
> + return 0;
> +}
> +
> +static const struct file_operations vduse_domain_fops = {
> + .mmap = vduse_domain_mmap,
> + .release = vduse_domain_release,
> +};
It's better to explain the reason for introducing a dedicated file for
mmap() here.
> +
> +void vduse_domain_destroy(struct vduse_iova_domain *domain)
> +{
> + fput(domain->file);
> +}
> +
> +struct vduse_iova_domain *vduse_domain_create(size_t bounce_size)
> +{
> + struct vduse_iova_domain *domain;
> + struct file *file;
> + unsigned long bounce_pfns = PAGE_ALIGN(bounce_size) >> PAGE_SHIFT;
> +
> + domain = kzalloc(sizeof(*domain), GFP_KERNEL);
> + if (!domain)
> + return NULL;
> +
> + domain->bounce_size = PAGE_ALIGN(bounce_size);
> + domain->bounce_pages = vzalloc(bounce_pfns * sizeof(struct page *));
> + if (!domain->bounce_pages)
> + goto err_page;
> +
> + file = anon_inode_getfile("[vduse-domain]", &vduse_domain_fops,
> + domain, O_RDWR);
> + if (IS_ERR(file))
> + goto err_file;
> +
> + domain->file = file;
> + spin_lock_init(&domain->map_lock);
> + domain->mappings = RB_ROOT_CACHED;
> + init_iova_domain(&domain->stream_iovad,
> + IOVA_ALLOC_SIZE, IOVA_START_PFN);
> + init_iova_domain(&domain->consistent_iovad,
> + PAGE_SIZE, bounce_pfns);
> +
> + return domain;
> +err_file:
> + vfree(domain->bounce_pages);
> +err_page:
> + kfree(domain);
> + return NULL;
> +}
> diff --git a/drivers/vdpa/vdpa_user/iova_domain.h b/drivers/vdpa/vdpa_user/iova_domain.h
> new file mode 100644
> index 000000000000..cc61866acb56
> --- /dev/null
> +++ b/drivers/vdpa/vdpa_user/iova_domain.h
> @@ -0,0 +1,68 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * MMU-based IOMMU implementation
> + *
> + * Copyright (C) 2020 Bytedance Inc. and/or its affiliates. All rights reserved.
> + *
> + * Author: Xie Yongji <xieyongji@...edance.com>
> + *
> + */
> +
> +#ifndef _VDUSE_IOVA_DOMAIN_H
> +#define _VDUSE_IOVA_DOMAIN_H
> +
> +#include <linux/iova.h>
> +#include <linux/interval_tree.h>
> +#include <linux/dma-mapping.h>
> +
> +struct vduse_iova_map {
> + struct interval_tree_node iova;
> + unsigned long orig;
Need a better name, probably "va"?
> + size_t size;
> + enum dma_data_direction dir;
> +};
> +
> +struct vduse_iova_domain {
> + struct iova_domain stream_iovad;
> + struct iova_domain consistent_iovad;
> + struct page **bounce_pages;
> + size_t bounce_size;
> + struct rb_root_cached mappings;
We had IOTLB, any reason for this extra mappings here?
> + spinlock_t map_lock;
> + struct file *file;
> +};
> +
> +static inline struct file *
> +vduse_domain_file(struct vduse_iova_domain *domain)
> +{
> + return domain->file;
> +}
> +
> +static inline unsigned long
> +vduse_domain_get_offset(struct vduse_iova_domain *domain, unsigned long iova)
> +{
> + return iova;
> +}
> +
> +dma_addr_t vduse_domain_map_page(struct vduse_iova_domain *domain,
> + struct page *page, unsigned long offset,
> + size_t size, enum dma_data_direction dir,
> + unsigned long attrs);
> +
> +void vduse_domain_unmap_page(struct vduse_iova_domain *domain,
> + dma_addr_t dma_addr, size_t size,
> + enum dma_data_direction dir, unsigned long attrs);
> +
> +void *vduse_domain_alloc_coherent(struct vduse_iova_domain *domain,
> + size_t size, dma_addr_t *dma_addr,
> + gfp_t flag, unsigned long attrs);
> +
> +void vduse_domain_free_coherent(struct vduse_iova_domain *domain, size_t size,
> + void *vaddr, dma_addr_t dma_addr,
> + unsigned long attrs);
> +
> +void vduse_domain_destroy(struct vduse_iova_domain *domain);
> +
> +struct vduse_iova_domain *vduse_domain_create(size_t bounce_size);
> +
> +#endif /* _VDUSE_IOVA_DOMAIN_H */
> diff --git a/drivers/vdpa/vdpa_user/vduse.h b/drivers/vdpa/vdpa_user/vduse.h
> new file mode 100644
> index 000000000000..3566d229382e
> --- /dev/null
> +++ b/drivers/vdpa/vdpa_user/vduse.h
> @@ -0,0 +1,62 @@
> +/* 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>
> + *
> + */
> +
> +#ifndef _VDUSE_H
> +#define _VDUSE_H
> +
> +#include <linux/eventfd.h>
> +#include <linux/wait.h>
> +#include <linux/vdpa.h>
> +
> +#include "iova_domain.h"
> +#include "eventfd.h"
> +
> +struct vduse_virtqueue {
> + u16 index;
> + bool ready;
> + spinlock_t kick_lock;
> + spinlock_t irq_lock;
> + struct eventfd_ctx *kickfd;
> + struct vduse_virqfd *virqfd;
> + void *private;
> + irqreturn_t (*cb)(void *data);
> +};
> +
> +struct vduse_dev;
> +
> +struct vduse_vdpa {
> + struct vdpa_device vdpa;
> + struct vduse_dev *dev;
> +};
> +
> +struct vduse_dev {
> + struct vduse_vdpa *vdev;
> + struct mutex lock;
> + struct vduse_virtqueue *vqs;
> + struct vduse_iova_domain *domain;
> + struct vhost_iotlb *iommu;
> + spinlock_t iommu_lock;
> + atomic_t bounce_map;
> + 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;
> + u32 id;
> + u16 vq_size_max;
> + u16 vq_num;
> + u32 vq_align;
> + u32 device_id;
> + u32 vendor_id;
> +};
> +
> +#endif /* _VDUSE_H_ */
> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> new file mode 100644
> index 000000000000..1cf759bc5914
> --- /dev/null
> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> @@ -0,0 +1,1217 @@
> +// 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/device.h>
> +#include <linux/eventfd.h>
> +#include <linux/slab.h>
> +#include <linux/wait.h>
> +#include <linux/dma-map-ops.h>
> +#include <linux/anon_inodes.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 "vduse.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"
> +
> +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;
> + refcount_t refcnt;
The reference count here will bring extra complexity. I think we can
sync through msg_lock.
> +};
> +
> +static struct workqueue_struct *vduse_vdpa_wq;
> +static DEFINE_MUTEX(vduse_lock);
> +static LIST_HEAD(vduse_devs);
> +
> +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_dev_new_msg(struct vduse_dev *dev, int type)
> +{
> + struct vduse_dev_msg *msg = kzalloc(sizeof(*msg),
> + GFP_KERNEL | __GFP_NOFAIL);
> +
> + msg->req.type = type;
> + msg->req.unique = atomic64_fetch_inc(&dev->msg_unique);
This looks not safe, let's use idr here.
> + init_waitqueue_head(&msg->waitq);
> + refcount_set(&msg->refcnt, 1);
> +
> + return msg;
> +}
> +
> +static void vduse_dev_msg_get(struct vduse_dev_msg *msg)
> +{
> + refcount_inc(&msg->refcnt);
> +}
> +
> +static void vduse_dev_msg_put(struct vduse_dev_msg *msg)
> +{
> + if (refcount_dec_and_test(&msg->refcnt))
> + kfree(msg);
> +}
> +
> +static struct vduse_dev_msg *vduse_dev_find_msg(struct vduse_dev *dev,
> + struct list_head *head,
> + uint32_t unique)
> +{
> + struct vduse_dev_msg *tmp, *msg = NULL;
> +
> + spin_lock(&dev->msg_lock);
> + list_for_each_entry(tmp, head, list) {
> + if (tmp->req.unique == unique) {
> + msg = tmp;
> + list_del(&tmp->list);
> + break;
> + }
> + }
> + spin_unlock(&dev->msg_lock);
> +
> + return msg;
> +}
> +
> +static struct vduse_dev_msg *vduse_dev_dequeue_msg(struct vduse_dev *dev,
> + struct list_head *head)
> +{
> + struct vduse_dev_msg *msg = NULL;
> +
> + spin_lock(&dev->msg_lock);
> + if (!list_empty(head)) {
> + msg = list_first_entry(head, struct vduse_dev_msg, list);
> + list_del(&msg->list);
> + }
> + spin_unlock(&dev->msg_lock);
> +
> + return msg;
> +}
> +
> +static void vduse_dev_enqueue_msg(struct vduse_dev *dev,
> + struct vduse_dev_msg *msg, struct list_head *head)
> +{
> + spin_lock(&dev->msg_lock);
> + list_add_tail(&msg->list, head);
> + spin_unlock(&dev->msg_lock);
> +}
> +
> +static int vduse_dev_msg_sync(struct vduse_dev *dev, struct vduse_dev_msg *msg)
> +{
> + int ret;
> +
> + vduse_dev_enqueue_msg(dev, msg, &dev->send_list);
> + wake_up(&dev->waitq);
> + wait_event(msg->waitq, msg->completed);
This is uninterruptible wait, it means if the userspace forget to
process the command, we will stuck here forever.
> + /* coupled with smp_wmb() in vduse_dev_msg_complete() */
> + smp_rmb();
Instead of using barriers, I wonder why not simply use msg lock here?
> + ret = msg->resp.result;
> +
> + return ret;
> +}
> +
> +static void vduse_dev_msg_complete(struct vduse_dev_msg *msg,
> + struct vduse_dev_response *resp)
> +{
> + vduse_dev_msg_get(msg);
> + memcpy(&msg->resp, resp, sizeof(*resp));
> + /* coupled with smp_rmb() in vduse_dev_msg_sync() */
> + smp_wmb();
> + msg->completed = 1;
> + wake_up(&msg->waitq);
> + vduse_dev_msg_put(msg);
> +}
> +
> +static u64 vduse_dev_get_features(struct vduse_dev *dev)
> +{
> + struct vduse_dev_msg *msg = vduse_dev_new_msg(dev, VDUSE_GET_FEATURES);
> + u64 features;
> +
> + vduse_dev_msg_sync(dev, msg);
> + features = msg->resp.features;
> + vduse_dev_msg_put(msg);
> +
> + return features;
> +}
> +
> +static int vduse_dev_set_features(struct vduse_dev *dev, u64 features)
> +{
> + struct vduse_dev_msg *msg = vduse_dev_new_msg(dev, VDUSE_SET_FEATURES);
> + int ret;
> +
> + msg->req.size = sizeof(features);
> + msg->req.features = features;
> +
> + ret = vduse_dev_msg_sync(dev, msg);
> + vduse_dev_msg_put(msg);
> +
> + return ret;
> +}
> +
> +static u8 vduse_dev_get_status(struct vduse_dev *dev)
> +{
> + struct vduse_dev_msg *msg = vduse_dev_new_msg(dev, VDUSE_GET_STATUS);
> + u8 status;
> +
> + vduse_dev_msg_sync(dev, msg);
> + status = msg->resp.status;
> + vduse_dev_msg_put(msg);
> +
> + return status;
> +}
> +
> +static void vduse_dev_set_status(struct vduse_dev *dev, u8 status)
> +{
> + struct vduse_dev_msg *msg = vduse_dev_new_msg(dev, VDUSE_SET_STATUS);
> +
> + msg->req.size = sizeof(status);
> + msg->req.status = status;
> +
> + vduse_dev_msg_sync(dev, msg);
> + vduse_dev_msg_put(msg);
> +}
> +
> +static void vduse_dev_get_config(struct vduse_dev *dev, unsigned int offset,
> + void *buf, unsigned int len)
> +{
> + struct vduse_dev_msg *msg = vduse_dev_new_msg(dev, VDUSE_GET_CONFIG);
> +
> + WARN_ON(len > sizeof(msg->req.config.data));
> +
> + msg->req.size = sizeof(struct vduse_dev_config_data);
> + msg->req.config.offset = offset;
> + msg->req.config.len = len;
> + vduse_dev_msg_sync(dev, msg);
> + memcpy(buf, msg->resp.config.data, len);
> + vduse_dev_msg_put(msg);
> +}
> +
> +static void vduse_dev_set_config(struct vduse_dev *dev, unsigned int offset,
> + const void *buf, unsigned int len)
> +{
> + struct vduse_dev_msg *msg = vduse_dev_new_msg(dev, VDUSE_SET_CONFIG);
> +
> + WARN_ON(len > sizeof(msg->req.config.data));
> +
> + msg->req.size = sizeof(struct vduse_dev_config_data);
> + msg->req.config.offset = offset;
> + msg->req.config.len = len;
> + memcpy(msg->req.config.data, buf, len);
> + vduse_dev_msg_sync(dev, msg);
> + vduse_dev_msg_put(msg);
> +}
> +
> +static void vduse_dev_set_vq_num(struct vduse_dev *dev,
> + struct vduse_virtqueue *vq, u32 num)
> +{
> + struct vduse_dev_msg *msg = vduse_dev_new_msg(dev, VDUSE_SET_VQ_NUM);
> +
> + msg->req.size = sizeof(struct vduse_vq_num);
> + msg->req.vq_num.index = vq->index;
> + msg->req.vq_num.num = num;
> +
> + vduse_dev_msg_sync(dev, msg);
> + vduse_dev_msg_put(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 = vduse_dev_new_msg(dev, VDUSE_SET_VQ_ADDR);
> + int ret;
> +
> + msg->req.size = sizeof(struct vduse_vq_addr);
> + 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;
> +
> + ret = vduse_dev_msg_sync(dev, msg);
> + vduse_dev_msg_put(msg);
> +
> + return ret;
> +}
> +
> +static void vduse_dev_set_vq_ready(struct vduse_dev *dev,
> + struct vduse_virtqueue *vq, bool ready)
> +{
> + struct vduse_dev_msg *msg = vduse_dev_new_msg(dev, VDUSE_SET_VQ_READY);
> +
> + msg->req.size = sizeof(struct vduse_vq_ready);
> + msg->req.vq_ready.index = vq->index;
> + msg->req.vq_ready.ready = ready;
> +
> + vduse_dev_msg_sync(dev, msg);
> + vduse_dev_msg_put(msg);
> +}
> +
> +static bool vduse_dev_get_vq_ready(struct vduse_dev *dev,
> + struct vduse_virtqueue *vq)
> +{
> + struct vduse_dev_msg *msg = vduse_dev_new_msg(dev, VDUSE_GET_VQ_READY);
> + bool ready;
> +
> + msg->req.size = sizeof(struct vduse_vq_ready);
> + msg->req.vq_ready.index = vq->index;
> +
> + vduse_dev_msg_sync(dev, msg);
> + ready = msg->resp.vq_ready.ready;
> + vduse_dev_msg_put(msg);
> +
> + return 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 = vduse_dev_new_msg(dev, VDUSE_GET_VQ_STATE);
> + int ret;
> +
> + msg->req.size = sizeof(struct vduse_vq_state);
> + msg->req.vq_state.index = vq->index;
> +
> + ret = vduse_dev_msg_sync(dev, msg);
> + state->avail_index = msg->resp.vq_state.avail_idx;
> + vduse_dev_msg_put(msg);
> +
> + 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 = vduse_dev_new_msg(dev, VDUSE_SET_VQ_STATE);
> + int ret;
> +
> + msg->req.size = sizeof(struct vduse_vq_state);
> + msg->req.vq_state.index = vq->index;
> + msg->req.vq_state.avail_idx = state->avail_index;
> +
> + ret = vduse_dev_msg_sync(dev, msg);
> + vduse_dev_msg_put(msg);
> +
> + return ret;
> +}
> +
> +static int vduse_dev_update_iotlb(struct vduse_dev *dev,
> + u64 start, u64 last)
> +{
> + struct vduse_dev_msg *msg;
> + int ret;
> +
> + if (last < start)
> + return -EINVAL;
> +
> + msg = vduse_dev_new_msg(dev, VDUSE_UPDATE_IOTLB);
This is actually a IOTLB invalidation. So let's rename the function and
message type.
> + msg->req.size = sizeof(struct vduse_iova_range);
> + msg->req.iova.start = start;
> + msg->req.iova.last = last;
> +
> + ret = vduse_dev_msg_sync(dev, msg);
> + vduse_dev_msg_put(msg);
> +
> + return ret;
> +}
> +
> +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;
> +
> + while (1) {
> + msg = vduse_dev_dequeue_msg(dev, &dev->send_list);
> + if (msg)
> + break;
> +
> + if (file->f_flags & O_NONBLOCK)
> + return -EAGAIN;
> +
> + ret = wait_event_interruptible_exclusive(dev->waitq,
> + !list_empty(&dev->send_list));
> + if (ret)
> + return ret;
> + }
> + ret = copy_to_iter(&msg->req, size, to);
> + if (ret != size) {
> + vduse_dev_enqueue_msg(dev, msg, &dev->send_list);
> + return -EFAULT;
> + }
> + vduse_dev_enqueue_msg(dev, msg, &dev->recv_list);
> +
> + 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;
> +
> + msg = vduse_dev_find_msg(dev, &dev->recv_list, resp.unique);
> + if (!msg)
> + return -EINVAL;
> +
> + vduse_dev_msg_complete(msg, &resp);
So we had multiple types of requests/responses, is this better to
introduce a queue based admin interface other than ioctl?
> +
> + 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;
> +
> + return mask;
> +}
> +
> +static int vduse_iotlb_add_range(struct vduse_dev *dev,
> + u64 start, u64 last,
> + u64 addr, unsigned int perm,
> + struct file *file, u64 offset)
> +{
> + struct vhost_iotlb_file *iotlb_file;
> + int ret;
> +
> + iotlb_file = kmalloc(sizeof(*iotlb_file), GFP_ATOMIC);
> + if (!iotlb_file)
> + return -ENOMEM;
> +
> + iotlb_file->file = get_file(file);
> + iotlb_file->offset = offset;
> +
> + spin_lock(&dev->iommu_lock);
> + ret = vhost_iotlb_add_range(dev->iommu, start, last,
> + addr, perm, iotlb_file);
> + spin_unlock(&dev->iommu_lock);
> + if (ret) {
> + fput(iotlb_file->file);
> + kfree(iotlb_file);
> + return ret;
> + }
> + return 0;
> +}
> +
> +static void vduse_iotlb_del_range(struct vduse_dev *dev, u64 start, u64 last)
> +{
> + struct vhost_iotlb_file *iotlb_file;
> + struct vhost_iotlb_map *map;
> +
> + spin_lock(&dev->iommu_lock);
> + while ((map = vhost_iotlb_itree_first(dev->iommu, start, last))) {
> + iotlb_file = (struct vhost_iotlb_file *)map->opaque;
> + fput(iotlb_file->file);
> + kfree(iotlb_file);
> + vhost_iotlb_map_free(dev->iommu, map);
> + }
> + spin_unlock(&dev->iommu_lock);
> +}
> +
> +static void vduse_dev_reset(struct vduse_dev *dev)
> +{
> + int i;
> +
> + atomic_set(&dev->bounce_map, 0);
> + vduse_iotlb_del_range(dev, 0ULL, 0ULL - 1);
> + vduse_dev_update_iotlb(dev, 0ULL, 0ULL - 1);
ULLONG_MAX please.
> +
> + 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 = NULL;
> + vq->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];
> +
> + vduse_vq_kick(vq);
> +}
> +
> +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];
> +
> + vq->cb = cb->callback;
> + vq->private = cb->private;
> +}
> +
> +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);
> + u64 fixed = (1ULL << VIRTIO_F_ACCESS_PLATFORM);
> +
> + return (vduse_dev_get_features(dev) | fixed);
> +}
> +
> +static int vduse_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
> +{
> + struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +
> + 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 */
If it's not hard, let's add this. Otherwise we need a per device feature
blacklist to filter out all features that depends on 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);
> + else
> + vduse_dev_update_iotlb(dev, 0ULL, 0ULL - 1);
Any reason for such IOTLB invalidation here?
> +
> + 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);
> + struct vhost_iotlb_map *map;
> + struct vhost_iotlb_file *iotlb_file;
> + u64 start = 0ULL, last = 0ULL - 1;
> + int ret = 0;
> +
> + vduse_iotlb_del_range(dev, start, last);
> +
> + for (map = vhost_iotlb_itree_first(iotlb, start, last); map;
> + map = vhost_iotlb_itree_next(map, start, last)) {
> + if (!map->opaque)
> + continue;
What will happen if we simply accept NULL opaque here?
> +
> + iotlb_file = (struct vhost_iotlb_file *)map->opaque;
> + ret = vduse_iotlb_add_range(dev, map->start, map->last,
> + map->addr, map->perm,
> + iotlb_file->file,
> + iotlb_file->offset);
> + if (ret)
> + break;
> + }
> + vduse_dev_update_iotlb(dev, start, last);
> +
> + 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;
> +
> + if (atomic_xchg(&vdev->bounce_map, 1) == 0 &&
> + vduse_iotlb_add_range(vdev, 0, domain->bounce_size - 1,
> + 0, VDUSE_ACCESS_RW,
Is this safe to use VDUSE_ACCESS_RW here, consider we might have device
readonly mappings.
> + vduse_domain_file(domain),
> + vduse_domain_get_offset(domain, 0))) {
> + atomic_set(&vdev->bounce_map, 0);
> + return DMA_MAPPING_ERROR;
> + }
> +
> + 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;
> +
> + if (vduse_iotlb_add_range(vdev, iova, iova + size - 1,
> + iova, VDUSE_ACCESS_RW,
> + vduse_domain_file(domain),
> + vduse_domain_get_offset(domain, iova))) {
> + vduse_domain_free_coherent(domain, size, addr, iova, attrs);
> + 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;
> + unsigned long start = (unsigned long)dma_addr;
> + unsigned long last = start + size - 1;
> +
> + vduse_iotlb_del_range(vdev, start, last);
> + vduse_dev_update_iotlb(vdev, start, last);
> + vduse_domain_free_coherent(domain, size, vaddr, dma_addr, attrs);
> +}
> +
> +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 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;
> +
> + mutex_lock(&dev->lock);
> + switch (cmd) {
> + case VDUSE_IOTLB_GET_FD: {
> + struct vduse_iotlb_entry entry;
> + struct vhost_iotlb_map *map;
> + struct vhost_iotlb_file *iotlb_file;
> + struct file *f = NULL;
> +
> + ret = -EFAULT;
> + if (copy_from_user(&entry, argp, sizeof(entry)))
> + break;
> +
> + spin_lock(&dev->iommu_lock);
> + map = vhost_iotlb_itree_first(dev->iommu, entry.start,
> + entry.last);
> + if (map) {
> + iotlb_file = (struct vhost_iotlb_file *)map->opaque;
> + f = get_file(iotlb_file->file);
> + entry.offset = iotlb_file->offset;
> + entry.start = map->start;
> + entry.last = map->last;
> + entry.perm = map->perm;
> + }
> + spin_unlock(&dev->iommu_lock);
> + if (!f) {
> + ret = -EINVAL;
> + break;
> + }
> + if (copy_to_user(argp, &entry, sizeof(entry))) {
> + fput(f);
> + ret = -EFAULT;
> + break;
> + }
> + ret = get_unused_fd_flags(perm_to_file_flags(entry.perm));
> + if (ret < 0) {
> + fput(f);
> + break;
> + }
> + fd_install(ret, 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_VQ_SETUP_IRQFD: {
> + struct vduse_vq_eventfd eventfd;
> +
> + ret = -EFAULT;
> + if (copy_from_user(&eventfd, argp, sizeof(eventfd)))
> + break;
> +
> + ret = vduse_virqfd_setup(dev, &eventfd);
> + break;
> + }
> + }
> + mutex_unlock(&dev->lock);
> +
> + return ret;
> +}
> +
> +static int vduse_dev_release(struct inode *inode, struct file *file)
> +{
> + struct vduse_dev *dev = file->private_data;
> +
> + vduse_kickfd_release(dev);
> + vduse_virqfd_release(dev);
> + dev->connected = false;
> +
> + return 0;
> +}
> +
> +static const struct file_operations vduse_dev_fops = {
> + .owner = THIS_MODULE,
> + .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;
> +
> + dev->iommu = vhost_iotlb_alloc(2048, 0);
Is 2048 sufficient here?
> + if (!dev->iommu) {
> + kfree(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);
> + atomic64_set(&dev->msg_unique, 0);
> + spin_lock_init(&dev->iommu_lock);
> + atomic_set(&dev->bounce_map, 0);
> +
> + init_waitqueue_head(&dev->waitq);
> +
> + return dev;
> +}
> +
> +static void vduse_dev_destroy(struct vduse_dev *dev)
> +{
> + vhost_iotlb_free(dev->iommu);
> + mutex_destroy(&dev->lock);
> + kfree(dev);
> +}
> +
> +static struct vduse_dev *vduse_find_dev(u32 id)
> +{
> + struct vduse_dev *tmp, *dev = NULL;
> +
> + list_for_each_entry(tmp, &vduse_devs, list) {
> + if (tmp->id == id) {
> + dev = tmp;
> + break;
> + }
> + }
> + return dev;
> +}
> +
> +static int vduse_destroy_dev(u32 id)
> +{
> + struct vduse_dev *dev = vduse_find_dev(id);
> +
> + if (!dev)
> + return -EINVAL;
> +
> + if (dev->vdev || dev->connected)
> + return -EBUSY;
> +
> + list_del(&dev->list);
> + kfree(dev->vqs);
> + vduse_domain_destroy(dev->domain);
> + vduse_dev_destroy(dev);
> +
> + return 0;
> +}
> +
> +static int vduse_create_dev(struct vduse_dev_config *config)
> +{
> + int i, fd;
> + struct vduse_dev *dev;
> + char name[64];
> +
> + if (vduse_find_dev(config->id))
> + return -EEXIST;
> +
> + dev = vduse_dev_create();
> + if (!dev)
> + return -ENOMEM;
> +
> + dev->id = config->id;
> + dev->device_id = config->device_id;
> + dev->vendor_id = config->vendor_id;
> + dev->domain = vduse_domain_create(config->bounce_size);
Do we need a upper limit of 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;
> + spin_lock_init(&dev->vqs[i].kick_lock);
> + spin_lock_init(&dev->vqs[i].irq_lock);
> + }
> +
> + snprintf(name, sizeof(name), "[vduse-dev:%u]", config->id);
> + fd = anon_inode_getfd(name, &vduse_dev_fops, dev, O_RDWR | O_CLOEXEC);
Any reason for closing on exec here?
> + if (fd < 0)
> + goto err_fd;
> +
> + dev->connected = true;
> + list_add(&dev->list, &vduse_devs);
> +
> + return fd;
> +err_fd:
> + kfree(dev->vqs);
> +err_vqs:
> + vduse_domain_destroy(dev->domain);
> +err_domain:
> + vduse_dev_destroy(dev);
> + return fd;
> +}
> +
> +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_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:
> + ret = vduse_destroy_dev(arg);
> + 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 struct miscdevice vduse_misc = {
> + .fops = &vduse_fops,
> + .minor = MISC_DYNAMIC_MINOR,
> + .name = "vduse",
> +};
> +
> +static void vduse_parent_release(struct device *dev)
> +{
> +}
> +
> +static struct device vduse_parent = {
> + .init_name = "vduse",
> + .release = vduse_parent_release,
> +};
> +
> +static struct vdpa_parent_dev parent_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, NULL,
> + &vduse_vdpa_config_ops,
> + dev->vq_num, 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.pdev = &parent_dev;
> +
> + ret = _vdpa_register_device(&vdev->vdpa);
> + if (ret)
> + goto err;
> +
> + dev->vdev = vdev;
> +
> + return 0;
> +err:
> + put_device(&vdev->vdpa.dev);
> + return ret;
> +}
> +
> +static struct vdpa_device *vdpa_dev_add(struct vdpa_parent_dev *pdev,
> + const char *name, u32 device_id,
> + struct nlattr **attrs)
> +{
> + u32 vduse_id;
> + struct vduse_dev *dev;
> + int ret = -EINVAL;
> +
> + if (!attrs[VDPA_ATTR_BACKEND_ID])
> + return ERR_PTR(-EINVAL);
> +
> + mutex_lock(&vduse_lock);
> + vduse_id = nla_get_u32(attrs[VDPA_ATTR_BACKEND_ID]);
I wonder why not using name here?
And it looks to me it would be easier if we create a char device per
vduse. This makes the device addressing more robust than passing id
silently among processes.
> + dev = vduse_find_dev(vduse_id);
> + if (!dev)
> + goto unlock;
> +
> + if (dev->device_id != device_id)
> + goto unlock;
> +
> + ret = vduse_dev_add_vdpa(dev, name);
> +unlock:
> + mutex_unlock(&vduse_lock);
> + if (ret)
> + return ERR_PTR(ret);
> +
> + return &dev->vdev->vdpa;
> +}
> +
> +static void vdpa_dev_del(struct vdpa_parent_dev *pdev, struct vdpa_device *dev)
> +{
> + _vdpa_unregister_device(dev);
> +}
> +
> +static const struct vdpa_dev_ops vdpa_dev_parent_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_parent_dev parent_dev = {
> + .device = &vduse_parent,
> + .id_table = id_table,
> + .ops = &vdpa_dev_parent_ops,
> +};
> +
> +static int vduse_parentdev_init(void)
> +{
> + int ret;
> +
> + ret = device_register(&vduse_parent);
> + if (ret)
> + return ret;
> +
> + ret = vdpa_parentdev_register(&parent_dev);
> + if (ret)
> + goto err;
> +
> + return 0;
> +err:
> + device_unregister(&vduse_parent);
> + return ret;
> +}
> +
> +static void vduse_parentdev_exit(void)
> +{
> + vdpa_parentdev_unregister(&parent_dev);
> + device_unregister(&vduse_parent);
> +}
> +
> +static int vduse_init(void)
> +{
> + int ret;
> +
> + ret = misc_register(&vduse_misc);
> + if (ret)
> + return ret;
> +
> + ret = -ENOMEM;
> + vduse_vdpa_wq = alloc_workqueue("vduse-vdpa", WQ_UNBOUND, 1);
> + if (!vduse_vdpa_wq)
> + goto err_vdpa_wq;
> +
> + ret = vduse_virqfd_init();
> + if (ret)
> + goto err_irqfd;
> +
> + ret = vduse_parentdev_init();
> + if (ret)
> + goto err_parentdev;
> +
> + return 0;
> +err_parentdev:
> + vduse_virqfd_exit();
> +err_irqfd:
> + destroy_workqueue(vduse_vdpa_wq);
> +err_vdpa_wq:
> + misc_deregister(&vduse_misc);
> + return ret;
> +}
> +module_init(vduse_init);
> +
> +static void vduse_exit(void)
> +{
> + misc_deregister(&vduse_misc);
> + destroy_workqueue(vduse_vdpa_wq);
> + vduse_virqfd_exit();
> + vduse_parentdev_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/vdpa.h b/include/uapi/linux/vdpa.h
> index bba8b83a94b5..a7a841e5ffc7 100644
> --- a/include/uapi/linux/vdpa.h
> +++ b/include/uapi/linux/vdpa.h
> @@ -33,6 +33,7 @@ enum vdpa_attr {
> VDPA_ATTR_DEV_VENDOR_ID, /* u32 */
> VDPA_ATTR_DEV_MAX_VQS, /* u32 */
> VDPA_ATTR_DEV_MAX_VQ_SIZE, /* u16 */
> + VDPA_ATTR_BACKEND_ID, /* u32 */
As discussed, this needs more thought. But if necessary, we need a
separate patch for this.
>
> /* new attributes must be added above here */
> VDPA_ATTR_MAX,
> diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
> new file mode 100644
> index 000000000000..9fb555ddcfbd
> --- /dev/null
> +++ b/include/uapi/linux/vduse.h
> @@ -0,0 +1,125 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +#ifndef _UAPI_VDUSE_H_
> +#define _UAPI_VDUSE_H_
> +
> +#include <linux/types.h>
> +
> +/* the control messages definition for read/write */
> +
> +#define VDUSE_CONFIG_DATA_LEN 256
> +
> +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,
> +};
> +
> +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];
This no guarantee that 256 is sufficient here.
> +};
> +
> +struct vduse_iova_range {
> + __u64 start;
> + __u64 last;
> +};
> +
> +struct vduse_dev_request {
> + __u32 type; /* request type */
> + __u32 unique; /* request id */
> + __u32 flags; /* request flags */
Seems unused in this series.
> + __u32 size; /* the payload size */
Unused.
> + 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 */
> + __u64 features; /* virtio features */
> + __u8 status; /* device status */
Let's add some padding for future extensions.
> + };
> +};
> +
> +struct vduse_dev_response {
> + __u32 unique; /* corresponding request id */
Let's use request id.
> + __s32 result; /* the result of request */
Let's use macro or enum to define the success and failure value.
> + 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 */
> + __u64 features; /* virtio features */
> + __u8 status; /* device status */
> + };
> +};
> +
> +/* ioctls */
> +
> +struct vduse_dev_config {
> + __u32 id; /* vduse device id */
> + __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 {
> + __u64 offset; /* the mmap offset on fd */
> + __u64 start; /* start of the IOVA range */
> + __u64 last; /* last of the IOVA range */
> +#define VDUSE_ACCESS_RO 0x1
> +#define VDUSE_ACCESS_WO 0x2
> +#define VDUSE_ACCESS_RW 0x3
> + __u8 perm; /* access permission of this range */
> +};
> +
> +struct vduse_vq_eventfd {
> + __u32 index; /* virtqueue index */
> + __u32 fd; /* eventfd */
Any reason for not using int here?
> +};
> +
> +#define VDUSE_BASE 0x81
> +
> +#define VDUSE_CREATE_DEV _IOW(VDUSE_BASE, 0x01, struct vduse_dev_config)
> +#define VDUSE_DESTROY_DEV _IO(VDUSE_BASE, 0x02)
> +
> +#define VDUSE_IOTLB_GET_FD _IOWR(VDUSE_BASE, 0x04, struct vduse_iotlb_entry)
> +#define VDUSE_VQ_SETUP_KICKFD _IOW(VDUSE_BASE, 0x05, struct vduse_vq_eventfd)
> +#define VDUSE_VQ_SETUP_IRQFD _IOW(VDUSE_BASE, 0x06, struct vduse_vq_eventfd)
Better with documentation to explain those ioctls.
Thanks
> +
> +#endif /* _UAPI_VDUSE_H_ */
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