On Wed, Aug 3, 2022 at 12:56 PM Xie Yongji <xieyongji@xxxxxxxxxxxxx> wrote:
>
> This introduces a new ioctl: VDUSE_IOTLB_GET_INFO to
> support querying some information of IOVA regions.
>
> Now it can be used to query whether the IOVA region
> supports userspace memory registration.
>
> Signed-off-by: Xie Yongji <xieyongji@xxxxxxxxxxxxx>
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
> ---
> drivers/vdpa/vdpa_user/vduse_dev.c | 39 ++++++++++++++++++++++++++++++
> include/uapi/linux/vduse.h | 24 ++++++++++++++++++
> 2 files changed, 63 insertions(+)
>
> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> index eedff0a3885a..41c0b29739f1 100644
> --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> @@ -1228,6 +1228,45 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
> umem.size);
> break;
> }
> + case VDUSE_IOTLB_GET_INFO: {
> + struct vduse_iova_info info;
> + struct vhost_iotlb_map *map;
> + struct vduse_iova_domain *domain = dev->domain;
> +
> + ret = -EFAULT;
> + if (copy_from_user(&info, argp, sizeof(info)))
> + break;
> +
> + ret = -EINVAL;
> + if (info.start > info.last)
> + break;
> +
> + if (!is_mem_zero((const char *)info.reserved,
> + sizeof(info.reserved)))
> + break;
> +
> + spin_lock(&domain->iotlb_lock);
> + map = vhost_iotlb_itree_first(domain->iotlb,
> + info.start, info.last);
> + if (map) {
> + info.start = map->start;
> + info.last = map->last;
> + info.capability = 0;
> + if (domain->bounce_map && map->start == 0 &&
> + map->last == domain->bounce_size - 1)
> + info.capability |= VDUSE_IOVA_CAP_UMEM;
> + }
> + spin_unlock(&domain->iotlb_lock);
> + if (!map)
> + break;
> +
> + ret = -EFAULT;
> + if (copy_to_user(argp, &info, sizeof(info)))
> + break;
> +
> + ret = 0;
> + break;
> + }
> default:
> ret = -ENOIOCTLCMD;
> break;
> diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
> index 9885e0571f09..11bd48c72c6c 100644
> --- a/include/uapi/linux/vduse.h
> +++ b/include/uapi/linux/vduse.h
> @@ -233,6 +233,30 @@ struct vduse_iova_umem {
> /* De-register the userspace memory. Caller should set iova and size field. */
> #define VDUSE_IOTLB_DEREG_UMEM _IOW(VDUSE_BASE, 0x19, struct vduse_iova_umem)
>
> +/**
> + * struct vduse_iova_info - information of one IOVA region
> + * @start: start of the IOVA region
> + * @last: last of the IOVA region
> + * @capability: capability of the IOVA regsion
> + * @reserved: for future use, needs to be initialized to zero
> + *
> + * Structure used by VDUSE_IOTLB_GET_INFO ioctl to get information of
> + * one IOVA region.
> + */
> +struct vduse_iova_info {
> + __u64 start;
> + __u64 last;
> +#define VDUSE_IOVA_CAP_UMEM (1 << 0)
> + __u64 capability;
> + __u64 reserved[3];
> +};
> +
> +/*
> + * Find the first IOVA region that overlaps with the range [start, last]
> + * and return some information on it. Caller should set start and last fields.
> + */
> +#define VDUSE_IOTLB_GET_INFO _IOWR(VDUSE_BASE, 0x1a, struct vduse_iova_info)
> +
> /* The control messages definition for read(2)/write(2) on /dev/vduse/$NAME */
>
> /**
> --
> 2.20.1
>
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