Re: [RFC v2 3/4] vduse: update the vq_info in ioctl

On Fri, Sep 29, 2023 at 5:12 PM Maxime Coquelin maxime.coquelin@redhat.com wrote:

On 9/12/23 09:39, Jason Wang wrote:

...

On Tue, Sep 12, 2023 at 11:00 AM Cindy Lu lulu@redhat.com wrote:

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In VDUSE_VQ_GET_INFO, the driver will sync the last_avail_idx with reconnect info, After mapping the reconnect pages to userspace The userspace App will update the reconnect_time in struct vhost_reconnect_vring, If this is not 0 then it means this vq is reconnected and will update the last_avail_idx

Signed-off-by: Cindy Lu lulu@redhat.com

drivers/vdpa/vdpa_user/vduse_dev.c | 13 +++++++++++++ include/uapi/linux/vduse.h | 6 ++++++ 2 files changed, 19 insertions(+)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c index 2c69f4004a6e..680b23dbdde2 100644 --- a/drivers/vdpa/vdpa_user/vduse_dev.c +++ b/drivers/vdpa/vdpa_user/vduse_dev.c @@ -1221,6 +1221,8 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd, struct vduse_vq_info vq_info; struct vduse_virtqueue *vq; u32 index;

•           struct vdpa_reconnect_info *area;
  

•           struct vhost_reconnect_vring *vq_reconnect;
  
             ret = -EFAULT;
             if (copy_from_user(&vq_info, argp, sizeof(vq_info)))
  

@@ -1252,6 +1254,17 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,

             vq_info.ready = vq->ready;

•           area = &vq->reconnect_info;
  

•           vq_reconnect = (struct vhost_reconnect_vring *)area->vaddr;
  

•           /*check if the vq is reconnect, if yes then update the last_avail_idx*/
  

•           if ((vq_reconnect->last_avail_idx !=
  

•                vq_info.split.avail_index) &&
  

•               (vq_reconnect->reconnect_time != 0)) {
  

•                   vq_info.split.avail_index =
  

•                           vq_reconnect->last_avail_idx;
  

•           }
  

•            ret = -EFAULT;
             if (copy_to_user(argp, &vq_info, sizeof(vq_info)))
                     break;
  

diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h index 11bd48c72c6c..d585425803fd 100644 --- a/include/uapi/linux/vduse.h +++ b/include/uapi/linux/vduse.h @@ -350,4 +350,10 @@ struct vduse_dev_response { }; };

+struct vhost_reconnect_vring {

•   __u16 reconnect_time;
  

•   __u16 last_avail_idx;
  

•   _Bool avail_wrap_counter;
  

Please add a comment for each field.

And I never saw _Bool is used in uapi before, maybe it's better to pack it with last_avail_idx into a __u32.

Better as two distincts __u16 IMHO.

Fine with me.

Thanks

Thanks, Maxime

...

Btw, do we need to track inflight descriptors as well?

Thanks

...

+};

• #endif /* _UAPI_VDUSE_H_ */

-- 2.34.3