Messages in this thread | | | Subject | Re: [PATCH v9 16/17] vduse: Introduce VDUSE - vDPA Device in Userspace | From | Jason Wang <> | Date | Wed, 14 Jul 2021 17:12:21 +0800 |
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在 2021/7/14 下午2:49, Yongji Xie 写道: > On Wed, Jul 14, 2021 at 1:45 PM Jason Wang <jasowang@redhat.com> wrote: >> >> 在 2021/7/13 下午4:46, Xie Yongji 写道: >>> This VDUSE driver enables implementing software-emulated vDPA >>> devices in userspace. The vDPA device is created by >>> ioctl(VDUSE_CREATE_DEV) on /dev/vduse/control. Then a char device >>> interface (/dev/vduse/$NAME) is exported to userspace for device >>> emulation. >>> >>> In order to make the device emulation more secure, the device's >>> control path is handled in kernel. A message mechnism is introduced >>> to forward some dataplane related control messages to userspace. >>> >>> And in the data path, the DMA buffer will be mapped into userspace >>> address space through different ways depending on the vDPA bus to >>> which the vDPA device is attached. In virtio-vdpa case, the MMU-based >>> IOMMU driver is used to achieve that. And in vhost-vdpa case, the >>> DMA buffer is reside in a userspace memory region which can be shared >>> to the VDUSE userspace processs via transferring the shmfd. >>> >>> For more details on VDUSE design and usage, please see the follow-on >>> Documentation commit. >>> >>> Signed-off-by: Xie Yongji <xieyongji@bytedance.com> >>> --- >>> Documentation/userspace-api/ioctl/ioctl-number.rst | 1 + >>> drivers/vdpa/Kconfig | 10 + >>> drivers/vdpa/Makefile | 1 + >>> drivers/vdpa/vdpa_user/Makefile | 5 + >>> drivers/vdpa/vdpa_user/vduse_dev.c | 1502 ++++++++++++++++++++ >>> include/uapi/linux/vduse.h | 221 +++ >>> 6 files changed, 1740 insertions(+) >>> create mode 100644 drivers/vdpa/vdpa_user/Makefile >>> create mode 100644 drivers/vdpa/vdpa_user/vduse_dev.c >>> create mode 100644 include/uapi/linux/vduse.h >>> >>> diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst >>> index 1409e40e6345..293ca3aef358 100644 >>> --- a/Documentation/userspace-api/ioctl/ioctl-number.rst >>> +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst >>> @@ -300,6 +300,7 @@ Code Seq# Include File Comments >>> 'z' 10-4F drivers/s390/crypto/zcrypt_api.h conflict! >>> '|' 00-7F linux/media.h >>> 0x80 00-1F linux/fb.h >>> +0x81 00-1F linux/vduse.h >>> 0x89 00-06 arch/x86/include/asm/sockios.h >>> 0x89 0B-DF linux/sockios.h >>> 0x89 E0-EF linux/sockios.h SIOCPROTOPRIVATE range >>> diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig >>> index a503c1b2bfd9..6e23bce6433a 100644 >>> --- a/drivers/vdpa/Kconfig >>> +++ b/drivers/vdpa/Kconfig >>> @@ -33,6 +33,16 @@ config VDPA_SIM_BLOCK >>> vDPA block device simulator which terminates IO request in a >>> memory buffer. >>> >>> +config VDPA_USER >>> + tristate "VDUSE (vDPA Device in Userspace) support" >>> + depends on EVENTFD && MMU && HAS_DMA >>> + select DMA_OPS >>> + select VHOST_IOTLB >>> + select IOMMU_IOVA >>> + help >>> + With VDUSE it is possible to emulate a vDPA Device >>> + in a userspace program. >>> + >>> config IFCVF >>> tristate "Intel IFC VF vDPA driver" >>> depends on PCI_MSI >>> diff --git a/drivers/vdpa/Makefile b/drivers/vdpa/Makefile >>> index 67fe7f3d6943..f02ebed33f19 100644 >>> --- a/drivers/vdpa/Makefile >>> +++ b/drivers/vdpa/Makefile >>> @@ -1,6 +1,7 @@ >>> # SPDX-License-Identifier: GPL-2.0 >>> obj-$(CONFIG_VDPA) += vdpa.o >>> obj-$(CONFIG_VDPA_SIM) += vdpa_sim/ >>> +obj-$(CONFIG_VDPA_USER) += vdpa_user/ >>> obj-$(CONFIG_IFCVF) += ifcvf/ >>> obj-$(CONFIG_MLX5_VDPA) += mlx5/ >>> obj-$(CONFIG_VP_VDPA) += virtio_pci/ >>> diff --git a/drivers/vdpa/vdpa_user/Makefile b/drivers/vdpa/vdpa_user/Makefile >>> new file mode 100644 >>> index 000000000000..260e0b26af99 >>> --- /dev/null >>> +++ b/drivers/vdpa/vdpa_user/Makefile >>> @@ -0,0 +1,5 @@ >>> +# SPDX-License-Identifier: GPL-2.0 >>> + >>> +vduse-y := vduse_dev.o iova_domain.o >>> + >>> +obj-$(CONFIG_VDPA_USER) += vduse.o >>> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c >>> new file mode 100644 >>> index 000000000000..c994a4a4660c >>> --- /dev/null >>> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c >>> @@ -0,0 +1,1502 @@ >>> +// SPDX-License-Identifier: GPL-2.0-only >>> +/* >>> + * VDUSE: vDPA Device in Userspace >>> + * >>> + * Copyright (C) 2020-2021 Bytedance Inc. and/or its affiliates. All rights reserved. >>> + * >>> + * Author: Xie Yongji <xieyongji@bytedance.com> >>> + * >>> + */ >>> + >>> +#include <linux/init.h> >>> +#include <linux/module.h> >>> +#include <linux/cdev.h> >>> +#include <linux/device.h> >>> +#include <linux/eventfd.h> >>> +#include <linux/slab.h> >>> +#include <linux/wait.h> >>> +#include <linux/dma-map-ops.h> >>> +#include <linux/poll.h> >>> +#include <linux/file.h> >>> +#include <linux/uio.h> >>> +#include <linux/vdpa.h> >>> +#include <linux/nospec.h> >>> +#include <uapi/linux/vduse.h> >>> +#include <uapi/linux/vdpa.h> >>> +#include <uapi/linux/virtio_config.h> >>> +#include <uapi/linux/virtio_ids.h> >>> +#include <uapi/linux/virtio_blk.h> >>> +#include <linux/mod_devicetable.h> >>> + >>> +#include "iova_domain.h" >>> + >>> +#define DRV_AUTHOR "Yongji Xie <xieyongji@bytedance.com>" >>> +#define DRV_DESC "vDPA Device in Userspace" >>> +#define DRV_LICENSE "GPL v2" >>> + >>> +#define VDUSE_DEV_MAX (1U << MINORBITS) >>> +#define VDUSE_MAX_BOUNCE_SIZE (64 * 1024 * 1024) >>> +#define VDUSE_IOVA_SIZE (128 * 1024 * 1024) >>> +#define VDUSE_REQUEST_TIMEOUT 30 >>> + >>> +struct vduse_virtqueue { >>> + u16 index; >>> + u16 num_max; >>> + u32 num; >>> + u64 desc_addr; >>> + u64 driver_addr; >>> + u64 device_addr; >>> + struct vdpa_vq_state state; >>> + bool ready; >>> + bool kicked; >>> + spinlock_t kick_lock; >>> + spinlock_t irq_lock; >>> + struct eventfd_ctx *kickfd; >>> + struct vdpa_callback cb; >>> + struct work_struct inject; >>> +}; >>> + >>> +struct vduse_dev; >>> + >>> +struct vduse_vdpa { >>> + struct vdpa_device vdpa; >>> + struct vduse_dev *dev; >>> +}; >>> + >>> +struct vduse_dev { >>> + struct vduse_vdpa *vdev; >>> + struct device *dev; >>> + struct vduse_virtqueue *vqs; >>> + struct vduse_iova_domain *domain; >>> + char *name; >>> + struct mutex lock; >>> + spinlock_t msg_lock; >>> + u64 msg_unique; >>> + wait_queue_head_t waitq; >>> + struct list_head send_list; >>> + struct list_head recv_list; >>> + struct vdpa_callback config_cb; >>> + struct work_struct inject; >>> + spinlock_t irq_lock; >>> + int minor; >>> + bool connected; >>> + u64 api_version; >>> + u64 device_features; >>> + u64 driver_features; >>> + u32 device_id; >>> + u32 vendor_id; >>> + u32 generation; >>> + u32 config_size; >>> + void *config; >>> + u8 status; >>> + u32 vq_num; >>> + u32 vq_align; >>> +}; >>> + >>> +struct vduse_dev_msg { >>> + struct vduse_dev_request req; >>> + struct vduse_dev_response resp; >>> + struct list_head list; >>> + wait_queue_head_t waitq; >>> + bool completed; >>> +}; >>> + >>> +struct vduse_control { >>> + u64 api_version; >>> +}; >>> + >>> +static DEFINE_MUTEX(vduse_lock); >>> +static DEFINE_IDR(vduse_idr); >>> + >>> +static dev_t vduse_major; >>> +static struct class *vduse_class; >>> +static struct cdev vduse_ctrl_cdev; >>> +static struct cdev vduse_cdev; >>> +static struct workqueue_struct *vduse_irq_wq; >>> + >>> +static u32 allowed_device_id[] = { >>> + VIRTIO_ID_BLOCK, >>> +}; >>> + >>> +static inline struct vduse_dev *vdpa_to_vduse(struct vdpa_device *vdpa) >>> +{ >>> + struct vduse_vdpa *vdev = container_of(vdpa, struct vduse_vdpa, vdpa); >>> + >>> + return vdev->dev; >>> +} >>> + >>> +static inline struct vduse_dev *dev_to_vduse(struct device *dev) >>> +{ >>> + struct vdpa_device *vdpa = dev_to_vdpa(dev); >>> + >>> + return vdpa_to_vduse(vdpa); >>> +} >>> + >>> +static struct vduse_dev_msg *vduse_find_msg(struct list_head *head, >>> + uint32_t request_id) >>> +{ >>> + struct vduse_dev_msg *msg; >>> + >>> + list_for_each_entry(msg, head, list) { >>> + if (msg->req.request_id == request_id) { >>> + list_del(&msg->list); >>> + return msg; >>> + } >>> + } >>> + >>> + return NULL; >>> +} >>> + >>> +static struct vduse_dev_msg *vduse_dequeue_msg(struct list_head *head) >>> +{ >>> + struct vduse_dev_msg *msg = NULL; >>> + >>> + if (!list_empty(head)) { >>> + msg = list_first_entry(head, struct vduse_dev_msg, list); >>> + list_del(&msg->list); >>> + } >>> + >>> + return msg; >>> +} >>> + >>> +static void vduse_enqueue_msg(struct list_head *head, >>> + struct vduse_dev_msg *msg) >>> +{ >>> + list_add_tail(&msg->list, head); >>> +} >>> + >>> +static int vduse_dev_msg_sync(struct vduse_dev *dev, >>> + struct vduse_dev_msg *msg) >>> +{ >>> + int ret; >>> + >>> + init_waitqueue_head(&msg->waitq); >>> + spin_lock(&dev->msg_lock); >>> + msg->req.request_id = dev->msg_unique++; >>> + vduse_enqueue_msg(&dev->send_list, msg); >>> + wake_up(&dev->waitq); >>> + spin_unlock(&dev->msg_lock); >>> + >>> + wait_event_killable_timeout(msg->waitq, msg->completed, >>> + VDUSE_REQUEST_TIMEOUT * HZ); >>> + spin_lock(&dev->msg_lock); >>> + if (!msg->completed) { >>> + list_del(&msg->list); >>> + msg->resp.result = VDUSE_REQ_RESULT_FAILED; >>> + } >>> + ret = (msg->resp.result == VDUSE_REQ_RESULT_OK) ? 0 : -EIO; >> >> I think we should mark the device as malfunction when there is a timeout >> and forbid any userspace operations except for the destroy aftwards for >> safety. >> > Is it necessary? Actually we can't stop the dataplane processing in > userspace.
That's fine since for virtio-vdpa, we use bounce buffer, for vhost, it works like the device can be reset.
> It doesn’t seem to help much if we only forbid ioctl and > read/write. And there might be some messages that can tolerate > failure.
I think at least we should figure out fatal failures and forbid any future userspace operations.
> Even userspace can do something like NEEDS_RESET to do > recovery.
Yes, but that's not someting we can depend.
> >>> + spin_unlock(&dev->msg_lock); >>> + >>> + return ret; >>> +} >>> + >>> +static int vduse_dev_get_vq_state_packed(struct vduse_dev *dev, >>> + struct vduse_virtqueue *vq, >>> + struct vdpa_vq_state_packed *packed) >>> +{ >>> + struct vduse_dev_msg msg = { 0 }; >>> + int ret; >>> + >>> + msg.req.type = VDUSE_GET_VQ_STATE; >>> + msg.req.vq_state.index = vq->index; >>> + >>> + ret = vduse_dev_msg_sync(dev, &msg); >>> + if (ret) >>> + return ret; >>> + >>> + packed->last_avail_counter = >>> + msg.resp.vq_state.packed.last_avail_counter; >>> + packed->last_avail_idx = msg.resp.vq_state.packed.last_avail_idx; >>> + packed->last_used_counter = msg.resp.vq_state.packed.last_used_counter; >>> + packed->last_used_idx = msg.resp.vq_state.packed.last_used_idx; >>> + >>> + return 0; >>> +} >>> + >>> +static int vduse_dev_get_vq_state_split(struct vduse_dev *dev, >>> + struct vduse_virtqueue *vq, >>> + struct vdpa_vq_state_split *split) >>> +{ >>> + struct vduse_dev_msg msg = { 0 }; >>> + int ret; >>> + >>> + msg.req.type = VDUSE_GET_VQ_STATE; >>> + msg.req.vq_state.index = vq->index; >>> + >>> + ret = vduse_dev_msg_sync(dev, &msg); >>> + if (ret) >>> + return ret; >>> + >>> + split->avail_index = msg.resp.vq_state.split.avail_index; >>> + >>> + return 0; >>> +} >>> + >>> +static int vduse_dev_set_status(struct vduse_dev *dev, u8 status) >>> +{ >>> + struct vduse_dev_msg msg = { 0 }; >>> + >>> + msg.req.type = VDUSE_SET_STATUS; >>> + msg.req.s.status = status; >>> + >>> + return vduse_dev_msg_sync(dev, &msg); >>> +} >>> + >>> +static int vduse_dev_update_iotlb(struct vduse_dev *dev, >>> + u64 start, u64 last) >>> +{ >>> + struct vduse_dev_msg msg = { 0 }; >>> + >>> + if (last < start) >>> + return -EINVAL; >>> + >>> + msg.req.type = VDUSE_UPDATE_IOTLB; >>> + msg.req.iova.start = start; >>> + msg.req.iova.last = last; >>> + >>> + return vduse_dev_msg_sync(dev, &msg); >>> +} >>> + >>> +static ssize_t vduse_dev_read_iter(struct kiocb *iocb, struct iov_iter *to) >>> +{ >>> + struct file *file = iocb->ki_filp; >>> + struct vduse_dev *dev = file->private_data; >>> + struct vduse_dev_msg *msg; >>> + int size = sizeof(struct vduse_dev_request); >>> + ssize_t ret; >>> + >>> + if (iov_iter_count(to) < size) >>> + return -EINVAL; >>> + >>> + spin_lock(&dev->msg_lock); >>> + while (1) { >>> + msg = vduse_dequeue_msg(&dev->send_list); >>> + if (msg) >>> + break; >>> + >>> + ret = -EAGAIN; >>> + if (file->f_flags & O_NONBLOCK) >>> + goto unlock; >>> + >>> + spin_unlock(&dev->msg_lock); >>> + ret = wait_event_interruptible_exclusive(dev->waitq, >>> + !list_empty(&dev->send_list)); >>> + if (ret) >>> + return ret; >>> + >>> + spin_lock(&dev->msg_lock); >>> + } >>> + spin_unlock(&dev->msg_lock); >>> + ret = copy_to_iter(&msg->req, size, to); >>> + spin_lock(&dev->msg_lock); >>> + if (ret != size) { >>> + ret = -EFAULT; >>> + vduse_enqueue_msg(&dev->send_list, msg); >>> + goto unlock; >>> + } >>> + vduse_enqueue_msg(&dev->recv_list, msg); >>> +unlock: >>> + spin_unlock(&dev->msg_lock); >>> + >>> + return ret; >>> +} >>> + >>> +static ssize_t vduse_dev_write_iter(struct kiocb *iocb, struct iov_iter *from) >>> +{ >>> + struct file *file = iocb->ki_filp; >>> + struct vduse_dev *dev = file->private_data; >>> + struct vduse_dev_response resp; >>> + struct vduse_dev_msg *msg; >>> + size_t ret; >>> + >>> + ret = copy_from_iter(&resp, sizeof(resp), from); >>> + if (ret != sizeof(resp)) >>> + return -EINVAL; >>> + >>> + spin_lock(&dev->msg_lock); >>> + msg = vduse_find_msg(&dev->recv_list, resp.request_id); >>> + if (!msg) { >>> + ret = -ENOENT; >>> + goto unlock; >>> + } >>> + >>> + memcpy(&msg->resp, &resp, sizeof(resp)); >>> + msg->completed = 1; >>> + wake_up(&msg->waitq); >>> +unlock: >>> + spin_unlock(&dev->msg_lock); >>> + >>> + return ret; >>> +} >>> + >>> +static __poll_t vduse_dev_poll(struct file *file, poll_table *wait) >>> +{ >>> + struct vduse_dev *dev = file->private_data; >>> + __poll_t mask = 0; >>> + >>> + poll_wait(file, &dev->waitq, wait); >>> + >>> + if (!list_empty(&dev->send_list)) >>> + mask |= EPOLLIN | EPOLLRDNORM; >>> + if (!list_empty(&dev->recv_list)) >>> + mask |= EPOLLOUT | EPOLLWRNORM; >>> + >>> + return mask; >>> +} >>> + >>> +static void vduse_dev_reset(struct vduse_dev *dev) >>> +{ >>> + int i; >>> + struct vduse_iova_domain *domain = dev->domain; >>> + >>> + /* The coherent mappings are handled in vduse_dev_free_coherent() */ >>> + if (domain->bounce_map) >>> + vduse_domain_reset_bounce_map(domain); >>> + >>> + dev->driver_features = 0; >>> + dev->generation++; >>> + spin_lock(&dev->irq_lock); >>> + dev->config_cb.callback = NULL; >>> + dev->config_cb.private = NULL; >>> + spin_unlock(&dev->irq_lock); >>> + flush_work(&dev->inject); >>> + >>> + for (i = 0; i < dev->vq_num; i++) { >>> + struct vduse_virtqueue *vq = &dev->vqs[i]; >>> + >>> + vq->ready = false; >>> + vq->desc_addr = 0; >>> + vq->driver_addr = 0; >>> + vq->device_addr = 0; >>> + vq->num = 0; >>> + memset(&vq->state, 0, sizeof(vq->state)); >>> + >>> + spin_lock(&vq->kick_lock); >>> + vq->kicked = false; >>> + if (vq->kickfd) >>> + eventfd_ctx_put(vq->kickfd); >>> + vq->kickfd = NULL; >>> + spin_unlock(&vq->kick_lock); >>> + >>> + spin_lock(&vq->irq_lock); >>> + vq->cb.callback = NULL; >>> + vq->cb.private = NULL; >>> + spin_unlock(&vq->irq_lock); >>> + flush_work(&vq->inject); >>> + } >>> +} >>> + >>> +static int vduse_vdpa_set_vq_address(struct vdpa_device *vdpa, u16 idx, >>> + u64 desc_area, u64 driver_area, >>> + u64 device_area) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + struct vduse_virtqueue *vq = &dev->vqs[idx]; >>> + >>> + vq->desc_addr = desc_area; >>> + vq->driver_addr = driver_area; >>> + vq->device_addr = device_area; >>> + >>> + return 0; >>> +} >>> + >>> +static void vduse_vdpa_kick_vq(struct vdpa_device *vdpa, u16 idx) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + struct vduse_virtqueue *vq = &dev->vqs[idx]; >>> + >>> + spin_lock(&vq->kick_lock); >>> + if (!vq->ready) >>> + goto unlock; >>> + >>> + if (vq->kickfd) >>> + eventfd_signal(vq->kickfd, 1); >>> + else >>> + vq->kicked = true; >>> +unlock: >>> + spin_unlock(&vq->kick_lock); >>> +} >>> + >>> +static void vduse_vdpa_set_vq_cb(struct vdpa_device *vdpa, u16 idx, >>> + struct vdpa_callback *cb) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + struct vduse_virtqueue *vq = &dev->vqs[idx]; >>> + >>> + spin_lock(&vq->irq_lock); >>> + vq->cb.callback = cb->callback; >>> + vq->cb.private = cb->private; >>> + spin_unlock(&vq->irq_lock); >>> +} >>> + >>> +static void vduse_vdpa_set_vq_num(struct vdpa_device *vdpa, u16 idx, u32 num) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + struct vduse_virtqueue *vq = &dev->vqs[idx]; >>> + >>> + vq->num = num; >>> +} >>> + >>> +static void vduse_vdpa_set_vq_ready(struct vdpa_device *vdpa, >>> + u16 idx, bool ready) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + struct vduse_virtqueue *vq = &dev->vqs[idx]; >>> + >>> + vq->ready = ready; >>> +} >>> + >>> +static bool vduse_vdpa_get_vq_ready(struct vdpa_device *vdpa, u16 idx) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + struct vduse_virtqueue *vq = &dev->vqs[idx]; >>> + >>> + return vq->ready; >>> +} >>> + >>> +static int vduse_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 idx, >>> + const struct vdpa_vq_state *state) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + struct vduse_virtqueue *vq = &dev->vqs[idx]; >>> + >>> + if (dev->driver_features & BIT_ULL(VIRTIO_F_RING_PACKED)) { >>> + vq->state.packed.last_avail_counter = >>> + state->packed.last_avail_counter; >>> + vq->state.packed.last_avail_idx = state->packed.last_avail_idx; >>> + vq->state.packed.last_used_counter = >>> + state->packed.last_used_counter; >>> + vq->state.packed.last_used_idx = state->packed.last_used_idx; >>> + } else >>> + vq->state.split.avail_index = state->split.avail_index; >>> + >>> + return 0; >>> +} >>> + >>> +static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx, >>> + struct vdpa_vq_state *state) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + struct vduse_virtqueue *vq = &dev->vqs[idx]; >>> + >>> + if (dev->driver_features & BIT_ULL(VIRTIO_F_RING_PACKED)) >>> + return vduse_dev_get_vq_state_packed(dev, vq, &state->packed); >>> + >>> + return vduse_dev_get_vq_state_split(dev, vq, &state->split); >>> +} >>> + >>> +static u32 vduse_vdpa_get_vq_align(struct vdpa_device *vdpa) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + >>> + return dev->vq_align; >>> +} >>> + >>> +static u64 vduse_vdpa_get_features(struct vdpa_device *vdpa) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + >>> + return dev->device_features; >>> +} >>> + >>> +static int vduse_vdpa_set_features(struct vdpa_device *vdpa, u64 features) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + >>> + dev->driver_features = features; >>> + return 0; >>> +} >>> + >>> +static void vduse_vdpa_set_config_cb(struct vdpa_device *vdpa, >>> + struct vdpa_callback *cb) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + >>> + spin_lock(&dev->irq_lock); >>> + dev->config_cb.callback = cb->callback; >>> + dev->config_cb.private = cb->private; >>> + spin_unlock(&dev->irq_lock); >>> +} >>> + >>> +static u16 vduse_vdpa_get_vq_num_max(struct vdpa_device *vdpa, u16 idx) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + >>> + return dev->vqs[idx].num_max; >>> +} >>> + >>> +static u32 vduse_vdpa_get_device_id(struct vdpa_device *vdpa) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + >>> + return dev->device_id; >>> +} >>> + >>> +static u32 vduse_vdpa_get_vendor_id(struct vdpa_device *vdpa) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + >>> + return dev->vendor_id; >>> +} >>> + >>> +static u8 vduse_vdpa_get_status(struct vdpa_device *vdpa) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + >>> + return dev->status; >>> +} >>> + >>> +static void vduse_vdpa_set_status(struct vdpa_device *vdpa, u8 status) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + >>> + if (vduse_dev_set_status(dev, status)) >>> + return; >>> + >>> + dev->status = status; >> >> It looks to me such design exclude the possibility of letting userspace >> device to set bit like (NEEDS_RESET) in the future. >> > Looks like we can achieve that via the ioctl.
Which ioctl can be used for this?
> >> I wonder if it's better to do something similar to ccw: >> >> 1) requires the userspace to update the status bit in the response >> 2) update the dev->status to the status in the response if no timeout >> >> Then userspace could then set NEEDS_RESET if necessary. >> > But NEEDS_RESET does not only happen in this case.
Yes, so you need an ioctl for userspace to update the device status (NEEDS_RESET) probably.
> >>> + if (status == 0) >>> + vduse_dev_reset(dev); >>> +} >>> + >>> +static size_t vduse_vdpa_get_config_size(struct vdpa_device *vdpa) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + >>> + return dev->config_size; >>> +} >>> + >>> +static void vduse_vdpa_get_config(struct vdpa_device *vdpa, unsigned int offset, >>> + void *buf, unsigned int len) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + >>> + if (len > dev->config_size - offset) >>> + return; >>> + >>> + memcpy(buf, dev->config + offset, len); >>> +} >>> + >>> +static void vduse_vdpa_set_config(struct vdpa_device *vdpa, unsigned int offset, >>> + const void *buf, unsigned int len) >>> +{ >>> + /* Now we only support read-only configuration space */ >>> +} >>> + >>> +static u32 vduse_vdpa_get_generation(struct vdpa_device *vdpa) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + >>> + return dev->generation; >>> +} >>> + >>> +static int vduse_vdpa_set_map(struct vdpa_device *vdpa, >>> + struct vhost_iotlb *iotlb) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + int ret; >>> + >>> + ret = vduse_domain_set_map(dev->domain, iotlb); >>> + if (ret) >>> + return ret; >>> + >>> + ret = vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX); >>> + if (ret) { >>> + vduse_domain_clear_map(dev->domain, iotlb); >>> + return ret; >>> + } >>> + >>> + return 0; >>> +} >>> + >>> +static void vduse_vdpa_free(struct vdpa_device *vdpa) >>> +{ >>> + struct vduse_dev *dev = vdpa_to_vduse(vdpa); >>> + >>> + dev->vdev = NULL; >>> +} >>> + >>> +static const struct vdpa_config_ops vduse_vdpa_config_ops = { >>> + .set_vq_address = vduse_vdpa_set_vq_address, >>> + .kick_vq = vduse_vdpa_kick_vq, >>> + .set_vq_cb = vduse_vdpa_set_vq_cb, >>> + .set_vq_num = vduse_vdpa_set_vq_num, >>> + .set_vq_ready = vduse_vdpa_set_vq_ready, >>> + .get_vq_ready = vduse_vdpa_get_vq_ready, >>> + .set_vq_state = vduse_vdpa_set_vq_state, >>> + .get_vq_state = vduse_vdpa_get_vq_state, >>> + .get_vq_align = vduse_vdpa_get_vq_align, >>> + .get_features = vduse_vdpa_get_features, >>> + .set_features = vduse_vdpa_set_features, >>> + .set_config_cb = vduse_vdpa_set_config_cb, >>> + .get_vq_num_max = vduse_vdpa_get_vq_num_max, >>> + .get_device_id = vduse_vdpa_get_device_id, >>> + .get_vendor_id = vduse_vdpa_get_vendor_id, >>> + .get_status = vduse_vdpa_get_status, >>> + .set_status = vduse_vdpa_set_status, >>> + .get_config_size = vduse_vdpa_get_config_size, >>> + .get_config = vduse_vdpa_get_config, >>> + .set_config = vduse_vdpa_set_config, >>> + .get_generation = vduse_vdpa_get_generation, >>> + .set_map = vduse_vdpa_set_map, >>> + .free = vduse_vdpa_free, >>> +}; >>> + >>> +static dma_addr_t vduse_dev_map_page(struct device *dev, struct page *page, >>> + unsigned long offset, size_t size, >>> + enum dma_data_direction dir, >>> + unsigned long attrs) >>> +{ >>> + struct vduse_dev *vdev = dev_to_vduse(dev); >>> + struct vduse_iova_domain *domain = vdev->domain; >>> + >>> + return vduse_domain_map_page(domain, page, offset, size, dir, attrs); >>> +} >>> + >>> +static void vduse_dev_unmap_page(struct device *dev, dma_addr_t dma_addr, >>> + size_t size, enum dma_data_direction dir, >>> + unsigned long attrs) >>> +{ >>> + struct vduse_dev *vdev = dev_to_vduse(dev); >>> + struct vduse_iova_domain *domain = vdev->domain; >>> + >>> + return vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs); >>> +} >>> + >>> +static void *vduse_dev_alloc_coherent(struct device *dev, size_t size, >>> + dma_addr_t *dma_addr, gfp_t flag, >>> + unsigned long attrs) >>> +{ >>> + struct vduse_dev *vdev = dev_to_vduse(dev); >>> + struct vduse_iova_domain *domain = vdev->domain; >>> + unsigned long iova; >>> + void *addr; >>> + >>> + *dma_addr = DMA_MAPPING_ERROR; >>> + addr = vduse_domain_alloc_coherent(domain, size, >>> + (dma_addr_t *)&iova, flag, attrs); >>> + if (!addr) >>> + return NULL; >>> + >>> + *dma_addr = (dma_addr_t)iova; >>> + >>> + return addr; >>> +} >>> + >>> +static void vduse_dev_free_coherent(struct device *dev, size_t size, >>> + void *vaddr, dma_addr_t dma_addr, >>> + unsigned long attrs) >>> +{ >>> + struct vduse_dev *vdev = dev_to_vduse(dev); >>> + struct vduse_iova_domain *domain = vdev->domain; >>> + >>> + vduse_domain_free_coherent(domain, size, vaddr, dma_addr, attrs); >>> +} >>> + >>> +static size_t vduse_dev_max_mapping_size(struct device *dev) >>> +{ >>> + struct vduse_dev *vdev = dev_to_vduse(dev); >>> + struct vduse_iova_domain *domain = vdev->domain; >>> + >>> + return domain->bounce_size; >>> +} >>> + >>> +static const struct dma_map_ops vduse_dev_dma_ops = { >>> + .map_page = vduse_dev_map_page, >>> + .unmap_page = vduse_dev_unmap_page, >>> + .alloc = vduse_dev_alloc_coherent, >>> + .free = vduse_dev_free_coherent, >>> + .max_mapping_size = vduse_dev_max_mapping_size, >>> +}; >>> + >>> +static unsigned int perm_to_file_flags(u8 perm) >>> +{ >>> + unsigned int flags = 0; >>> + >>> + switch (perm) { >>> + case VDUSE_ACCESS_WO: >>> + flags |= O_WRONLY; >>> + break; >>> + case VDUSE_ACCESS_RO: >>> + flags |= O_RDONLY; >>> + break; >>> + case VDUSE_ACCESS_RW: >>> + flags |= O_RDWR; >>> + break; >>> + default: >>> + WARN(1, "invalidate vhost IOTLB permission\n"); >>> + break; >>> + } >>> + >>> + return flags; >>> +} >>> + >>> +static int vduse_kickfd_setup(struct vduse_dev *dev, >>> + struct vduse_vq_eventfd *eventfd) >>> +{ >>> + struct eventfd_ctx *ctx = NULL; >>> + struct vduse_virtqueue *vq; >>> + u32 index; >>> + >>> + if (eventfd->index >= dev->vq_num) >>> + return -EINVAL; >>> + >>> + index = array_index_nospec(eventfd->index, dev->vq_num); >>> + vq = &dev->vqs[index]; >>> + if (eventfd->fd >= 0) { >>> + ctx = eventfd_ctx_fdget(eventfd->fd); >>> + if (IS_ERR(ctx)) >>> + return PTR_ERR(ctx); >>> + } else if (eventfd->fd != VDUSE_EVENTFD_DEASSIGN) >>> + return 0; >>> + >>> + spin_lock(&vq->kick_lock); >>> + if (vq->kickfd) >>> + eventfd_ctx_put(vq->kickfd); >>> + vq->kickfd = ctx; >>> + if (vq->ready && vq->kicked && vq->kickfd) { >>> + eventfd_signal(vq->kickfd, 1); >>> + vq->kicked = false; >>> + } >>> + spin_unlock(&vq->kick_lock); >>> + >>> + return 0; >>> +} >>> + >>> +static bool vduse_dev_is_ready(struct vduse_dev *dev) >>> +{ >>> + int i; >>> + >>> + for (i = 0; i < dev->vq_num; i++) >>> + if (!dev->vqs[i].num_max) >>> + return false; >>> + >>> + return true; >>> +} >>> + >>> +static void vduse_dev_irq_inject(struct work_struct *work) >>> +{ >>> + struct vduse_dev *dev = container_of(work, struct vduse_dev, inject); >>> + >>> + spin_lock_irq(&dev->irq_lock); >>> + if (dev->config_cb.callback) >>> + dev->config_cb.callback(dev->config_cb.private); >>> + spin_unlock_irq(&dev->irq_lock); >>> +} >>> + >>> +static void vduse_vq_irq_inject(struct work_struct *work) >>> +{ >>> + struct vduse_virtqueue *vq = container_of(work, >>> + struct vduse_virtqueue, inject); >>> + >>> + spin_lock_irq(&vq->irq_lock); >>> + if (vq->ready && vq->cb.callback) >>> + vq->cb.callback(vq->cb.private); >>> + spin_unlock_irq(&vq->irq_lock); >>> +} >>> + >>> +static long vduse_dev_ioctl(struct file *file, unsigned int cmd, >>> + unsigned long arg) >>> +{ >>> + struct vduse_dev *dev = file->private_data; >>> + void __user *argp = (void __user *)arg; >>> + int ret; >>> + >>> + switch (cmd) { >>> + case VDUSE_IOTLB_GET_FD: { >>> + struct vduse_iotlb_entry entry; >>> + struct vhost_iotlb_map *map; >>> + struct vdpa_map_file *map_file; >>> + struct vduse_iova_domain *domain = dev->domain; >>> + struct file *f = NULL; >>> + >>> + ret = -EFAULT; >>> + if (copy_from_user(&entry, argp, sizeof(entry))) >>> + break; >>> + >>> + ret = -EINVAL; >>> + if (entry.start > entry.last) >>> + break; >>> + >>> + spin_lock(&domain->iotlb_lock); >>> + map = vhost_iotlb_itree_first(domain->iotlb, >>> + entry.start, entry.last); >>> + if (map) { >>> + map_file = (struct vdpa_map_file *)map->opaque; >>> + f = get_file(map_file->file); >>> + entry.offset = map_file->offset; >>> + entry.start = map->start; >>> + entry.last = map->last; >>> + entry.perm = map->perm; >>> + } >>> + spin_unlock(&domain->iotlb_lock); >>> + ret = -EINVAL; >>> + if (!f) >>> + break; >>> + >>> + ret = -EFAULT; >>> + if (copy_to_user(argp, &entry, sizeof(entry))) { >>> + fput(f); >>> + break; >>> + } >>> + ret = receive_fd(f, perm_to_file_flags(entry.perm)); >>> + fput(f); >>> + break; >>> + } >>> + case VDUSE_DEV_GET_FEATURES: >> >> Let's add a comment to explain here. E.g we just mirror what driver >> wrote and the drier is expected to check FEATURE_OK. >> > I already document some details in include/uapi/linux/vduse.h and > Documentation/userspace-api/vduse.rst
The point is the behavior of "mirroring" is one of the choice:
"
The device MUST present any valid feature bits the driver has written indriver_feature, starting at bitdriver_feature_select∗32 for anydriver_feature_selectwritten by the driver. Valid feature bits are those which are subset of the correspondingdevice_featurebits. The device MAY present invalid bits written by the driver.Note:This means that a device can ignore writes for feature bits it never offers, and simply present 0 on reads. Or it can just mirror what the driver wrote (but it will still have to check them when the driver sets FEATURES_OK).Note:A driver shouldn’t write invalid bits anyway, as per3.1.1 <https://docs.oasis-open.org/virtio/virtio/v1.1/csprd01/virtio-v1.1-csprd01.html#x1-930001>, but this attempts to handle it.
"
It would be helpful to add a comment here or people may check whether it follows the spec.
> >>> + ret = put_user(dev->driver_features, (u64 __user *)argp); >>> + break; >>> + case VDUSE_DEV_SET_CONFIG: { >>> + struct vduse_config_data config; >>> + unsigned long size = offsetof(struct vduse_config_data, >>> + buffer); >>> + >>> + ret = -EFAULT; >>> + if (copy_from_user(&config, argp, size)) >>> + break; >>> + >>> + ret = -EINVAL; >>> + if (config.length == 0 || >>> + config.length > dev->config_size - config.offset) >>> + break; >>> + >>> + ret = -EFAULT; >>> + if (copy_from_user(dev->config + config.offset, argp + size, >>> + config.length)) >>> + break; >>> + >>> + ret = 0; >>> + break; >>> + } >>> + case VDUSE_DEV_INJECT_IRQ: >> >> It's better to have "config" in the name. >> > OK. > >>> + ret = 0; >>> + queue_work(vduse_irq_wq, &dev->inject); >>> + break; >>> + case VDUSE_VQ_SETUP: { >>> + struct vduse_vq_config config; >>> + u32 index; >>> + >>> + ret = -EFAULT; >>> + if (copy_from_user(&config, argp, sizeof(config))) >>> + break; >>> + >>> + ret = -EINVAL; >>> + if (config.index >= dev->vq_num) >>> + break; >>> + >>> + index = array_index_nospec(config.index, dev->vq_num); >>> + dev->vqs[index].num_max = config.max_size; >>> + ret = 0; >>> + break; >>> + } >>> + case VDUSE_VQ_GET_INFO: { >>> + struct vduse_vq_info vq_info; >>> + struct vduse_virtqueue *vq; >>> + u32 index; >>> + >>> + ret = -EFAULT; >>> + if (copy_from_user(&vq_info, argp, sizeof(vq_info))) >>> + break; >>> + >>> + ret = -EINVAL; >>> + if (vq_info.index >= dev->vq_num) >>> + break; >>> + >>> + index = array_index_nospec(vq_info.index, dev->vq_num); >>> + vq = &dev->vqs[index]; >>> + vq_info.desc_addr = vq->desc_addr; >>> + vq_info.driver_addr = vq->driver_addr; >>> + vq_info.device_addr = vq->device_addr; >>> + vq_info.num = vq->num; >>> + >>> + if (dev->driver_features & BIT_ULL(VIRTIO_F_RING_PACKED)) { >>> + vq_info.packed.last_avail_counter = >>> + vq->state.packed.last_avail_counter; >>> + vq_info.packed.last_avail_idx = >>> + vq->state.packed.last_avail_idx; >>> + vq_info.packed.last_used_counter = >>> + vq->state.packed.last_used_counter; >>> + vq_info.packed.last_used_idx = >>> + vq->state.packed.last_used_idx; >>> + } else >>> + vq_info.split.avail_index = >>> + vq->state.split.avail_index; >>> + >>> + vq_info.ready = vq->ready; >>> + >>> + ret = -EFAULT; >>> + if (copy_to_user(argp, &vq_info, sizeof(vq_info))) >>> + break; >>> + >>> + ret = 0; >>> + break; >>> + } >>> + case VDUSE_VQ_SETUP_KICKFD: { >>> + struct vduse_vq_eventfd eventfd; >>> + >>> + ret = -EFAULT; >>> + if (copy_from_user(&eventfd, argp, sizeof(eventfd))) >>> + break; >>> + >>> + ret = vduse_kickfd_setup(dev, &eventfd); >>> + break; >>> + } >>> + case VDUSE_VQ_INJECT_IRQ: { >>> + u32 index; >>> + >>> + ret = -EFAULT; >>> + if (get_user(index, (u32 __user *)argp)) >>> + break; >>> + >>> + ret = -EINVAL; >>> + if (index >= dev->vq_num) >>> + break; >>> + >>> + ret = 0; >>> + index = array_index_nospec(index, dev->vq_num); >>> + queue_work(vduse_irq_wq, &dev->vqs[index].inject); >>> + break; >>> + } >>> + default: >>> + ret = -ENOIOCTLCMD; >>> + break; >>> + } >>> + >>> + return ret; >>> +} >>> + >>> +static int vduse_dev_release(struct inode *inode, struct file *file) >>> +{ >>> + struct vduse_dev *dev = file->private_data; >>> + >>> + spin_lock(&dev->msg_lock); >>> + /* Make sure the inflight messages can processed after reconncection */ >>> + list_splice_init(&dev->recv_list, &dev->send_list); >>> + spin_unlock(&dev->msg_lock); >>> + dev->connected = false; >>> + >>> + return 0; >>> +} >>> + >>> +static struct vduse_dev *vduse_dev_get_from_minor(int minor) >>> +{ >>> + struct vduse_dev *dev; >>> + >>> + mutex_lock(&vduse_lock); >>> + dev = idr_find(&vduse_idr, minor); >>> + mutex_unlock(&vduse_lock); >>> + >>> + return dev; >>> +} >>> + >>> +static int vduse_dev_open(struct inode *inode, struct file *file) >>> +{ >>> + int ret; >>> + struct vduse_dev *dev = vduse_dev_get_from_minor(iminor(inode)); >>> + >>> + if (!dev) >>> + return -ENODEV; >>> + >>> + ret = -EBUSY; >>> + mutex_lock(&dev->lock); >>> + if (dev->connected) >>> + goto unlock; >>> + >>> + ret = 0; >>> + dev->connected = true; >>> + file->private_data = dev; >>> +unlock: >>> + mutex_unlock(&dev->lock); >>> + >>> + return ret; >>> +} >>> + >>> +static const struct file_operations vduse_dev_fops = { >>> + .owner = THIS_MODULE, >>> + .open = vduse_dev_open, >>> + .release = vduse_dev_release, >>> + .read_iter = vduse_dev_read_iter, >>> + .write_iter = vduse_dev_write_iter, >>> + .poll = vduse_dev_poll, >>> + .unlocked_ioctl = vduse_dev_ioctl, >>> + .compat_ioctl = compat_ptr_ioctl, >>> + .llseek = noop_llseek, >>> +}; >>> + >>> +static struct vduse_dev *vduse_dev_create(void) >>> +{ >>> + struct vduse_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL); >>> + >>> + if (!dev) >>> + return NULL; >>> + >>> + mutex_init(&dev->lock); >>> + spin_lock_init(&dev->msg_lock); >>> + INIT_LIST_HEAD(&dev->send_list); >>> + INIT_LIST_HEAD(&dev->recv_list); >>> + spin_lock_init(&dev->irq_lock); >>> + >>> + INIT_WORK(&dev->inject, vduse_dev_irq_inject); >>> + init_waitqueue_head(&dev->waitq); >>> + >>> + return dev; >>> +} >>> + >>> +static void vduse_dev_destroy(struct vduse_dev *dev) >>> +{ >>> + kfree(dev); >>> +} >>> + >>> +static struct vduse_dev *vduse_find_dev(const char *name) >>> +{ >>> + struct vduse_dev *dev; >>> + int id; >>> + >>> + idr_for_each_entry(&vduse_idr, dev, id) >>> + if (!strcmp(dev->name, name)) >>> + return dev; >>> + >>> + return NULL; >>> +} >>> + >>> +static int vduse_destroy_dev(char *name) >>> +{ >>> + struct vduse_dev *dev = vduse_find_dev(name); >>> + >>> + if (!dev) >>> + return -EINVAL; >>> + >>> + mutex_lock(&dev->lock); >>> + if (dev->vdev || dev->connected) { >>> + mutex_unlock(&dev->lock); >>> + return -EBUSY; >>> + } >>> + dev->connected = true; >>> + mutex_unlock(&dev->lock); >>> + >>> + vduse_dev_reset(dev); >>> + device_destroy(vduse_class, MKDEV(MAJOR(vduse_major), dev->minor)); >>> + idr_remove(&vduse_idr, dev->minor); >>> + kvfree(dev->config); >>> + kfree(dev->vqs); >>> + vduse_domain_destroy(dev->domain); >>> + kfree(dev->name); >>> + vduse_dev_destroy(dev); >>> + module_put(THIS_MODULE); >>> + >>> + return 0; >>> +} >>> + >>> +static bool device_is_allowed(u32 device_id) >>> +{ >>> + int i; >>> + >>> + for (i = 0; i < ARRAY_SIZE(allowed_device_id); i++) >>> + if (allowed_device_id[i] == device_id) >>> + return true; >>> + >>> + return false; >>> +} >>> + >>> +static bool features_is_valid(u64 features) >>> +{ >>> + if (!(features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) >>> + return false; >>> + >>> + /* Now we only support read-only configuration space */ >>> + if (features & (1ULL << VIRTIO_BLK_F_CONFIG_WCE)) >>> + return false; >>> + >>> + return true; >>> +} >>> + >>> +static bool vduse_validate_config(struct vduse_dev_config *config) >>> +{ >>> + if (config->bounce_size > VDUSE_MAX_BOUNCE_SIZE) >>> + return false; >>> + >>> + if (config->vq_align > PAGE_SIZE) >>> + return false; >>> + >>> + if (config->config_size > PAGE_SIZE) >>> + return false; >> >> Any reason for this check? >> > To limit the kernel buffer size for configuration space. Is the > PAGE_SIZE enough?
Should be sufficient for now.
Thanks
> > Thanks, > Yongji >
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