diff mbox series

[v3,4/8] vringh: support VA with iotlb

Message ID 20230321154228.182769-5-sgarzare@redhat.com (mailing list archive)
State Superseded
Headers show
Series vdpa_sim: add support for user VA | expand

Checks

Context Check Description
netdev/tree_selection success Not a local patch

Commit Message

Stefano Garzarella March 21, 2023, 3:42 p.m. UTC
vDPA supports the possibility to use user VA in the iotlb messages.
So, let's add support for user VA in vringh to use it in the vDPA
simulators.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---

Notes:
    v3:
    - refactored avoiding code duplication [Eugenio]
    v2:
    - replace kmap_atomic() with kmap_local_page() [see previous patch]
    - fix cast warnings when build with W=1 C=1

 include/linux/vringh.h            |   5 +-
 drivers/vdpa/mlx5/net/mlx5_vnet.c |   2 +-
 drivers/vdpa/vdpa_sim/vdpa_sim.c  |   4 +-
 drivers/vhost/vringh.c            | 153 +++++++++++++++++++++++-------
 4 files changed, 127 insertions(+), 37 deletions(-)

Comments

Jason Wang March 23, 2023, 3:36 a.m. UTC | #1
On Tue, Mar 21, 2023 at 11:43 PM Stefano Garzarella <sgarzare@redhat.com> wrote:
>
> vDPA supports the possibility to use user VA in the iotlb messages.
> So, let's add support for user VA in vringh to use it in the vDPA
> simulators.
>
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> ---
>
> Notes:
>     v3:
>     - refactored avoiding code duplication [Eugenio]
>     v2:
>     - replace kmap_atomic() with kmap_local_page() [see previous patch]
>     - fix cast warnings when build with W=1 C=1
>
>  include/linux/vringh.h            |   5 +-
>  drivers/vdpa/mlx5/net/mlx5_vnet.c |   2 +-
>  drivers/vdpa/vdpa_sim/vdpa_sim.c  |   4 +-
>  drivers/vhost/vringh.c            | 153 +++++++++++++++++++++++-------
>  4 files changed, 127 insertions(+), 37 deletions(-)
>
> diff --git a/include/linux/vringh.h b/include/linux/vringh.h
> index 1991a02c6431..d39b9f2dcba0 100644
> --- a/include/linux/vringh.h
> +++ b/include/linux/vringh.h
> @@ -32,6 +32,9 @@ struct vringh {
>         /* Can we get away with weak barriers? */
>         bool weak_barriers;
>
> +       /* Use user's VA */
> +       bool use_va;
> +
>         /* Last available index we saw (ie. where we're up to). */
>         u16 last_avail_idx;
>
> @@ -279,7 +282,7 @@ void vringh_set_iotlb(struct vringh *vrh, struct vhost_iotlb *iotlb,
>                       spinlock_t *iotlb_lock);
>
>  int vringh_init_iotlb(struct vringh *vrh, u64 features,
> -                     unsigned int num, bool weak_barriers,
> +                     unsigned int num, bool weak_barriers, bool use_va,
>                       struct vring_desc *desc,
>                       struct vring_avail *avail,
>                       struct vring_used *used);
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 520646ae7fa0..dfd0e000217b 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -2537,7 +2537,7 @@ static int setup_cvq_vring(struct mlx5_vdpa_dev *mvdev)
>
>         if (mvdev->actual_features & BIT_ULL(VIRTIO_NET_F_CTRL_VQ))
>                 err = vringh_init_iotlb(&cvq->vring, mvdev->actual_features,
> -                                       MLX5_CVQ_MAX_ENT, false,
> +                                       MLX5_CVQ_MAX_ENT, false, false,

To avoid those changes, would it be better to introduce
vringh_init_iotlb_va() so vringh_init_iotlb() can stick to pa.

>                                         (struct vring_desc *)(uintptr_t)cvq->desc_addr,
>                                         (struct vring_avail *)(uintptr_t)cvq->driver_addr,
>                                         (struct vring_used *)(uintptr_t)cvq->device_addr);
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> index eea23c630f7c..47cdf2a1f5b8 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> @@ -60,7 +60,7 @@ static void vdpasim_queue_ready(struct vdpasim *vdpasim, unsigned int idx)
>         struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
>         uint16_t last_avail_idx = vq->vring.last_avail_idx;
>
> -       vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true,
> +       vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true, false,
>                           (struct vring_desc *)(uintptr_t)vq->desc_addr,
>                           (struct vring_avail *)
>                           (uintptr_t)vq->driver_addr,
> @@ -92,7 +92,7 @@ static void vdpasim_vq_reset(struct vdpasim *vdpasim,
>         vq->cb = NULL;
>         vq->private = NULL;
>         vringh_init_iotlb(&vq->vring, vdpasim->dev_attr.supported_features,
> -                         VDPASIM_QUEUE_MAX, false, NULL, NULL, NULL);
> +                         VDPASIM_QUEUE_MAX, false, false, NULL, NULL, NULL);
>
>         vq->vring.notify = NULL;
>  }
> diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
> index 0ba3ef809e48..72c88519329a 100644
> --- a/drivers/vhost/vringh.c
> +++ b/drivers/vhost/vringh.c
> @@ -1094,10 +1094,18 @@ EXPORT_SYMBOL(vringh_need_notify_kern);
>
>  #if IS_REACHABLE(CONFIG_VHOST_IOTLB)
>
> +struct iotlb_vec {
> +       union {
> +               struct iovec *iovec;
> +               struct bio_vec *bvec;
> +       } iov;
> +       size_t count;
> +       bool is_iovec;

I wonder if this is needed (if vringh is passed to every iotlb_vec helper).

> +};
> +
>  static int iotlb_translate(const struct vringh *vrh,
>                            u64 addr, u64 len, u64 *translated,
> -                          struct bio_vec iov[],
> -                          int iov_size, u32 perm)
> +                          struct iotlb_vec *ivec, u32 perm)
>  {
>         struct vhost_iotlb_map *map;
>         struct vhost_iotlb *iotlb = vrh->iotlb;
> @@ -1107,9 +1115,9 @@ static int iotlb_translate(const struct vringh *vrh,
>         spin_lock(vrh->iotlb_lock);
>
>         while (len > s) {
> -               u64 size, pa, pfn;
> +               u64 size;
>
> -               if (unlikely(ret >= iov_size)) {
> +               if (unlikely(ret >= ivec->count)) {
>                         ret = -ENOBUFS;
>                         break;
>                 }
> @@ -1124,10 +1132,22 @@ static int iotlb_translate(const struct vringh *vrh,
>                 }
>
>                 size = map->size - addr + map->start;
> -               pa = map->addr + addr - map->start;
> -               pfn = pa >> PAGE_SHIFT;
> -               bvec_set_page(&iov[ret], pfn_to_page(pfn), min(len - s, size),
> -                             pa & (PAGE_SIZE - 1));
> +               if (ivec->is_iovec) {
> +                       struct iovec *iovec = ivec->iov.iovec;
> +
> +                       iovec[ret].iov_len = min(len - s, size);
> +                       iovec[ret].iov_base = (void __user *)(unsigned long)
> +                                             (map->addr + addr - map->start);

map->addr - map->start to avoid overflow?

> +               } else {
> +                       u64 pa = map->addr + addr - map->start;
> +                       u64 pfn = pa >> PAGE_SHIFT;
> +                       struct bio_vec *bvec = ivec->iov.bvec;
> +
> +                       bvec_set_page(&bvec[ret], pfn_to_page(pfn),
> +                                     min(len - s, size),
> +                                     pa & (PAGE_SIZE - 1));
> +               }
> +
>                 s += size;
>                 addr += size;
>                 ++ret;
> @@ -1141,26 +1161,42 @@ static int iotlb_translate(const struct vringh *vrh,
>         return ret;
>  }
>
> +#define IOTLB_IOV_SIZE 16
> +
>  static inline int copy_from_iotlb(const struct vringh *vrh, void *dst,
>                                   void *src, size_t len)
>  {
> +       struct iotlb_vec ivec;
> +       union {
> +               struct iovec iovec[IOTLB_IOV_SIZE];
> +               struct bio_vec bvec[IOTLB_IOV_SIZE];
> +       } iov;
>         u64 total_translated = 0;
>
> +       ivec.iov.iovec = iov.iovec;

ivc.iov = iov ?

Others look good.

Thanks

> +       ivec.count = IOTLB_IOV_SIZE;
> +       ivec.is_iovec = vrh->use_va;
> +
>         while (total_translated < len) {
> -               struct bio_vec iov[16];
>                 struct iov_iter iter;
>                 u64 translated;
>                 int ret;
>
>                 ret = iotlb_translate(vrh, (u64)(uintptr_t)src,
>                                       len - total_translated, &translated,
> -                                     iov, ARRAY_SIZE(iov), VHOST_MAP_RO);
> +                                     &ivec, VHOST_MAP_RO);
>                 if (ret == -ENOBUFS)
> -                       ret = ARRAY_SIZE(iov);
> +                       ret = IOTLB_IOV_SIZE;
>                 else if (ret < 0)
>                         return ret;
>
> -               iov_iter_bvec(&iter, ITER_SOURCE, iov, ret, translated);
> +               if (ivec.is_iovec) {
> +                       iov_iter_init(&iter, ITER_SOURCE, ivec.iov.iovec, ret,
> +                                     translated);
> +               } else {
> +                       iov_iter_bvec(&iter, ITER_SOURCE, ivec.iov.bvec, ret,
> +                                     translated);
> +               }
>
>                 ret = copy_from_iter(dst, translated, &iter);
>                 if (ret < 0)
> @@ -1177,23 +1213,37 @@ static inline int copy_from_iotlb(const struct vringh *vrh, void *dst,
>  static inline int copy_to_iotlb(const struct vringh *vrh, void *dst,
>                                 void *src, size_t len)
>  {
> +       struct iotlb_vec ivec;
> +       union {
> +               struct iovec iovec[IOTLB_IOV_SIZE];
> +               struct bio_vec bvec[IOTLB_IOV_SIZE];
> +       } iov;
>         u64 total_translated = 0;
>
> +       ivec.iov.iovec = iov.iovec;
> +       ivec.count = IOTLB_IOV_SIZE;
> +       ivec.is_iovec = vrh->use_va;
> +
>         while (total_translated < len) {
> -               struct bio_vec iov[16];
>                 struct iov_iter iter;
>                 u64 translated;
>                 int ret;
>
>                 ret = iotlb_translate(vrh, (u64)(uintptr_t)dst,
>                                       len - total_translated, &translated,
> -                                     iov, ARRAY_SIZE(iov), VHOST_MAP_WO);
> +                                     &ivec, VHOST_MAP_WO);
>                 if (ret == -ENOBUFS)
> -                       ret = ARRAY_SIZE(iov);
> +                       ret = IOTLB_IOV_SIZE;
>                 else if (ret < 0)
>                         return ret;
>
> -               iov_iter_bvec(&iter, ITER_DEST, iov, ret, translated);
> +               if (ivec.is_iovec) {
> +                       iov_iter_init(&iter, ITER_DEST, ivec.iov.iovec, ret,
> +                                     translated);
> +               } else {
> +                       iov_iter_bvec(&iter, ITER_DEST, ivec.iov.bvec, ret,
> +                                     translated);
> +               }
>
>                 ret = copy_to_iter(src, translated, &iter);
>                 if (ret < 0)
> @@ -1210,20 +1260,37 @@ static inline int copy_to_iotlb(const struct vringh *vrh, void *dst,
>  static inline int getu16_iotlb(const struct vringh *vrh,
>                                u16 *val, const __virtio16 *p)
>  {
> -       struct bio_vec iov;
> -       void *kaddr, *from;
> +       struct iotlb_vec ivec;
> +       union {
> +               struct iovec iovec[1];
> +               struct bio_vec bvec[1];
> +       } iov;
> +       __virtio16 tmp;
>         int ret;
>
> +       ivec.iov.iovec = iov.iovec;
> +       ivec.count = 1;
> +       ivec.is_iovec = vrh->use_va;
> +
>         /* Atomic read is needed for getu16 */
> -       ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p), NULL,
> -                             &iov, 1, VHOST_MAP_RO);
> +       ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p),
> +                             NULL, &ivec, VHOST_MAP_RO);
>         if (ret < 0)
>                 return ret;
>
> -       kaddr = kmap_local_page(iov.bv_page);
> -       from = kaddr + iov.bv_offset;
> -       *val = vringh16_to_cpu(vrh, READ_ONCE(*(__virtio16 *)from));
> -       kunmap_local(kaddr);
> +       if (ivec.is_iovec) {
> +               ret = __get_user(tmp, (__virtio16 __user *)ivec.iov.iovec[0].iov_base);
> +               if (ret)
> +                       return ret;
> +       } else {
> +               void *kaddr = kmap_local_page(ivec.iov.bvec[0].bv_page);
> +               void *from = kaddr + ivec.iov.bvec[0].bv_offset;
> +
> +               tmp = READ_ONCE(*(__virtio16 *)from);
> +               kunmap_local(kaddr);
> +       }
> +
> +       *val = vringh16_to_cpu(vrh, tmp);
>
>         return 0;
>  }
> @@ -1231,20 +1298,37 @@ static inline int getu16_iotlb(const struct vringh *vrh,
>  static inline int putu16_iotlb(const struct vringh *vrh,
>                                __virtio16 *p, u16 val)
>  {
> -       struct bio_vec iov;
> -       void *kaddr, *to;
> +       struct iotlb_vec ivec;
> +       union {
> +               struct iovec iovec;
> +               struct bio_vec bvec;
> +       } iov;
> +       __virtio16 tmp;
>         int ret;
>
> +       ivec.iov.iovec = &iov.iovec;
> +       ivec.count = 1;
> +       ivec.is_iovec = vrh->use_va;
> +
>         /* Atomic write is needed for putu16 */
> -       ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p), NULL,
> -                             &iov, 1, VHOST_MAP_WO);
> +       ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p),
> +                             NULL, &ivec, VHOST_MAP_RO);
>         if (ret < 0)
>                 return ret;
>
> -       kaddr = kmap_local_page(iov.bv_page);
> -       to = kaddr + iov.bv_offset;
> -       WRITE_ONCE(*(__virtio16 *)to, cpu_to_vringh16(vrh, val));
> -       kunmap_local(kaddr);
> +       tmp = cpu_to_vringh16(vrh, val);
> +
> +       if (ivec.is_iovec) {
> +               ret = __put_user(tmp, (__virtio16 __user *)ivec.iov.iovec[0].iov_base);
> +               if (ret)
> +                       return ret;
> +       } else {
> +               void *kaddr = kmap_local_page(ivec.iov.bvec[0].bv_page);
> +               void *to = kaddr + ivec.iov.bvec[0].bv_offset;
> +
> +               WRITE_ONCE(*(__virtio16 *)to, tmp);
> +               kunmap_local(kaddr);
> +       }
>
>         return 0;
>  }
> @@ -1306,6 +1390,7 @@ static inline int putused_iotlb(const struct vringh *vrh,
>   * @features: the feature bits for this ring.
>   * @num: the number of elements.
>   * @weak_barriers: true if we only need memory barriers, not I/O.
> + * @use_va: true if IOTLB contains user VA
>   * @desc: the userpace descriptor pointer.
>   * @avail: the userpace avail pointer.
>   * @used: the userpace used pointer.
> @@ -1313,11 +1398,13 @@ static inline int putused_iotlb(const struct vringh *vrh,
>   * Returns an error if num is invalid.
>   */
>  int vringh_init_iotlb(struct vringh *vrh, u64 features,
> -                     unsigned int num, bool weak_barriers,
> +                     unsigned int num, bool weak_barriers, bool use_va,
>                       struct vring_desc *desc,
>                       struct vring_avail *avail,
>                       struct vring_used *used)
>  {
> +       vrh->use_va = use_va;
> +
>         return vringh_init_kern(vrh, features, num, weak_barriers,
>                                 desc, avail, used);
>  }
> --
> 2.39.2
>
Eugenio Perez Martin March 23, 2023, 8:09 a.m. UTC | #2
On Tue, Mar 21, 2023 at 4:43 PM Stefano Garzarella <sgarzare@redhat.com> wrote:
>
> vDPA supports the possibility to use user VA in the iotlb messages.
> So, let's add support for user VA in vringh to use it in the vDPA
> simulators.
>
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> ---
>
> Notes:
>     v3:
>     - refactored avoiding code duplication [Eugenio]
>     v2:
>     - replace kmap_atomic() with kmap_local_page() [see previous patch]
>     - fix cast warnings when build with W=1 C=1
>
>  include/linux/vringh.h            |   5 +-
>  drivers/vdpa/mlx5/net/mlx5_vnet.c |   2 +-
>  drivers/vdpa/vdpa_sim/vdpa_sim.c  |   4 +-
>  drivers/vhost/vringh.c            | 153 +++++++++++++++++++++++-------
>  4 files changed, 127 insertions(+), 37 deletions(-)
>
> diff --git a/include/linux/vringh.h b/include/linux/vringh.h
> index 1991a02c6431..d39b9f2dcba0 100644
> --- a/include/linux/vringh.h
> +++ b/include/linux/vringh.h
> @@ -32,6 +32,9 @@ struct vringh {
>         /* Can we get away with weak barriers? */
>         bool weak_barriers;
>
> +       /* Use user's VA */
> +       bool use_va;
> +
>         /* Last available index we saw (ie. where we're up to). */
>         u16 last_avail_idx;
>
> @@ -279,7 +282,7 @@ void vringh_set_iotlb(struct vringh *vrh, struct vhost_iotlb *iotlb,
>                       spinlock_t *iotlb_lock);
>
>  int vringh_init_iotlb(struct vringh *vrh, u64 features,
> -                     unsigned int num, bool weak_barriers,
> +                     unsigned int num, bool weak_barriers, bool use_va,
>                       struct vring_desc *desc,
>                       struct vring_avail *avail,
>                       struct vring_used *used);
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 520646ae7fa0..dfd0e000217b 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -2537,7 +2537,7 @@ static int setup_cvq_vring(struct mlx5_vdpa_dev *mvdev)
>
>         if (mvdev->actual_features & BIT_ULL(VIRTIO_NET_F_CTRL_VQ))
>                 err = vringh_init_iotlb(&cvq->vring, mvdev->actual_features,
> -                                       MLX5_CVQ_MAX_ENT, false,
> +                                       MLX5_CVQ_MAX_ENT, false, false,
>                                         (struct vring_desc *)(uintptr_t)cvq->desc_addr,
>                                         (struct vring_avail *)(uintptr_t)cvq->driver_addr,
>                                         (struct vring_used *)(uintptr_t)cvq->device_addr);
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> index eea23c630f7c..47cdf2a1f5b8 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> @@ -60,7 +60,7 @@ static void vdpasim_queue_ready(struct vdpasim *vdpasim, unsigned int idx)
>         struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
>         uint16_t last_avail_idx = vq->vring.last_avail_idx;
>
> -       vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true,
> +       vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true, false,
>                           (struct vring_desc *)(uintptr_t)vq->desc_addr,
>                           (struct vring_avail *)
>                           (uintptr_t)vq->driver_addr,
> @@ -92,7 +92,7 @@ static void vdpasim_vq_reset(struct vdpasim *vdpasim,
>         vq->cb = NULL;
>         vq->private = NULL;
>         vringh_init_iotlb(&vq->vring, vdpasim->dev_attr.supported_features,
> -                         VDPASIM_QUEUE_MAX, false, NULL, NULL, NULL);
> +                         VDPASIM_QUEUE_MAX, false, false, NULL, NULL, NULL);
>
>         vq->vring.notify = NULL;
>  }
> diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
> index 0ba3ef809e48..72c88519329a 100644
> --- a/drivers/vhost/vringh.c
> +++ b/drivers/vhost/vringh.c
> @@ -1094,10 +1094,18 @@ EXPORT_SYMBOL(vringh_need_notify_kern);
>
>  #if IS_REACHABLE(CONFIG_VHOST_IOTLB)
>
> +struct iotlb_vec {
> +       union {
> +               struct iovec *iovec;
> +               struct bio_vec *bvec;
> +       } iov;
> +       size_t count;
> +       bool is_iovec;
> +};
> +
>  static int iotlb_translate(const struct vringh *vrh,
>                            u64 addr, u64 len, u64 *translated,
> -                          struct bio_vec iov[],
> -                          int iov_size, u32 perm)
> +                          struct iotlb_vec *ivec, u32 perm)
>  {
>         struct vhost_iotlb_map *map;
>         struct vhost_iotlb *iotlb = vrh->iotlb;
> @@ -1107,9 +1115,9 @@ static int iotlb_translate(const struct vringh *vrh,
>         spin_lock(vrh->iotlb_lock);
>
>         while (len > s) {
> -               u64 size, pa, pfn;
> +               u64 size;
>
> -               if (unlikely(ret >= iov_size)) {
> +               if (unlikely(ret >= ivec->count)) {
>                         ret = -ENOBUFS;
>                         break;
>                 }
> @@ -1124,10 +1132,22 @@ static int iotlb_translate(const struct vringh *vrh,
>                 }
>
>                 size = map->size - addr + map->start;
> -               pa = map->addr + addr - map->start;
> -               pfn = pa >> PAGE_SHIFT;
> -               bvec_set_page(&iov[ret], pfn_to_page(pfn), min(len - s, size),
> -                             pa & (PAGE_SIZE - 1));
> +               if (ivec->is_iovec) {
> +                       struct iovec *iovec = ivec->iov.iovec;
> +
> +                       iovec[ret].iov_len = min(len - s, size);
> +                       iovec[ret].iov_base = (void __user *)(unsigned long)

s/unsigned long/uintptr_t ?



> +                                             (map->addr + addr - map->start);
> +               } else {
> +                       u64 pa = map->addr + addr - map->start;
> +                       u64 pfn = pa >> PAGE_SHIFT;
> +                       struct bio_vec *bvec = ivec->iov.bvec;
> +
> +                       bvec_set_page(&bvec[ret], pfn_to_page(pfn),
> +                                     min(len - s, size),
> +                                     pa & (PAGE_SIZE - 1));
> +               }
> +
>                 s += size;
>                 addr += size;
>                 ++ret;
> @@ -1141,26 +1161,42 @@ static int iotlb_translate(const struct vringh *vrh,
>         return ret;
>  }
>
> +#define IOTLB_IOV_SIZE 16

I'm fine with defining here, but maybe it is better to isolate the
change in a previous patch or reuse another well known macro?

Other looks good, and I agree with Jason's comments so even if the
macro declaration is not moved:

Acked-by: Eugenio Pérez <eperezma@redhat.com>

> +
>  static inline int copy_from_iotlb(const struct vringh *vrh, void *dst,
>                                   void *src, size_t len)
>  {
> +       struct iotlb_vec ivec;
> +       union {
> +               struct iovec iovec[IOTLB_IOV_SIZE];
> +               struct bio_vec bvec[IOTLB_IOV_SIZE];
> +       } iov;
>         u64 total_translated = 0;
>
> +       ivec.iov.iovec = iov.iovec;
> +       ivec.count = IOTLB_IOV_SIZE;
> +       ivec.is_iovec = vrh->use_va;
> +
>         while (total_translated < len) {
> -               struct bio_vec iov[16];
>                 struct iov_iter iter;
>                 u64 translated;
>                 int ret;
>
>                 ret = iotlb_translate(vrh, (u64)(uintptr_t)src,
>                                       len - total_translated, &translated,
> -                                     iov, ARRAY_SIZE(iov), VHOST_MAP_RO);
> +                                     &ivec, VHOST_MAP_RO);
>                 if (ret == -ENOBUFS)
> -                       ret = ARRAY_SIZE(iov);
> +                       ret = IOTLB_IOV_SIZE;
>                 else if (ret < 0)
>                         return ret;
>
> -               iov_iter_bvec(&iter, ITER_SOURCE, iov, ret, translated);
> +               if (ivec.is_iovec) {
> +                       iov_iter_init(&iter, ITER_SOURCE, ivec.iov.iovec, ret,
> +                                     translated);
> +               } else {
> +                       iov_iter_bvec(&iter, ITER_SOURCE, ivec.iov.bvec, ret,
> +                                     translated);
> +               }
>
>                 ret = copy_from_iter(dst, translated, &iter);
>                 if (ret < 0)
> @@ -1177,23 +1213,37 @@ static inline int copy_from_iotlb(const struct vringh *vrh, void *dst,
>  static inline int copy_to_iotlb(const struct vringh *vrh, void *dst,
>                                 void *src, size_t len)
>  {
> +       struct iotlb_vec ivec;
> +       union {
> +               struct iovec iovec[IOTLB_IOV_SIZE];
> +               struct bio_vec bvec[IOTLB_IOV_SIZE];
> +       } iov;
>         u64 total_translated = 0;
>
> +       ivec.iov.iovec = iov.iovec;
> +       ivec.count = IOTLB_IOV_SIZE;
> +       ivec.is_iovec = vrh->use_va;
> +
>         while (total_translated < len) {
> -               struct bio_vec iov[16];
>                 struct iov_iter iter;
>                 u64 translated;
>                 int ret;
>
>                 ret = iotlb_translate(vrh, (u64)(uintptr_t)dst,
>                                       len - total_translated, &translated,
> -                                     iov, ARRAY_SIZE(iov), VHOST_MAP_WO);
> +                                     &ivec, VHOST_MAP_WO);
>                 if (ret == -ENOBUFS)
> -                       ret = ARRAY_SIZE(iov);
> +                       ret = IOTLB_IOV_SIZE;
>                 else if (ret < 0)
>                         return ret;
>
> -               iov_iter_bvec(&iter, ITER_DEST, iov, ret, translated);
> +               if (ivec.is_iovec) {
> +                       iov_iter_init(&iter, ITER_DEST, ivec.iov.iovec, ret,
> +                                     translated);
> +               } else {
> +                       iov_iter_bvec(&iter, ITER_DEST, ivec.iov.bvec, ret,
> +                                     translated);
> +               }
>
>                 ret = copy_to_iter(src, translated, &iter);
>                 if (ret < 0)
> @@ -1210,20 +1260,37 @@ static inline int copy_to_iotlb(const struct vringh *vrh, void *dst,
>  static inline int getu16_iotlb(const struct vringh *vrh,
>                                u16 *val, const __virtio16 *p)
>  {
> -       struct bio_vec iov;
> -       void *kaddr, *from;
> +       struct iotlb_vec ivec;
> +       union {
> +               struct iovec iovec[1];
> +               struct bio_vec bvec[1];
> +       } iov;
> +       __virtio16 tmp;
>         int ret;
>
> +       ivec.iov.iovec = iov.iovec;
> +       ivec.count = 1;
> +       ivec.is_iovec = vrh->use_va;
> +
>         /* Atomic read is needed for getu16 */
> -       ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p), NULL,
> -                             &iov, 1, VHOST_MAP_RO);
> +       ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p),
> +                             NULL, &ivec, VHOST_MAP_RO);
>         if (ret < 0)
>                 return ret;
>
> -       kaddr = kmap_local_page(iov.bv_page);
> -       from = kaddr + iov.bv_offset;
> -       *val = vringh16_to_cpu(vrh, READ_ONCE(*(__virtio16 *)from));
> -       kunmap_local(kaddr);
> +       if (ivec.is_iovec) {
> +               ret = __get_user(tmp, (__virtio16 __user *)ivec.iov.iovec[0].iov_base);
> +               if (ret)
> +                       return ret;
> +       } else {
> +               void *kaddr = kmap_local_page(ivec.iov.bvec[0].bv_page);
> +               void *from = kaddr + ivec.iov.bvec[0].bv_offset;
> +
> +               tmp = READ_ONCE(*(__virtio16 *)from);
> +               kunmap_local(kaddr);
> +       }
> +
> +       *val = vringh16_to_cpu(vrh, tmp);
>
>         return 0;
>  }
> @@ -1231,20 +1298,37 @@ static inline int getu16_iotlb(const struct vringh *vrh,
>  static inline int putu16_iotlb(const struct vringh *vrh,
>                                __virtio16 *p, u16 val)
>  {
> -       struct bio_vec iov;
> -       void *kaddr, *to;
> +       struct iotlb_vec ivec;
> +       union {
> +               struct iovec iovec;
> +               struct bio_vec bvec;
> +       } iov;
> +       __virtio16 tmp;
>         int ret;
>
> +       ivec.iov.iovec = &iov.iovec;
> +       ivec.count = 1;
> +       ivec.is_iovec = vrh->use_va;
> +
>         /* Atomic write is needed for putu16 */
> -       ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p), NULL,
> -                             &iov, 1, VHOST_MAP_WO);
> +       ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p),
> +                             NULL, &ivec, VHOST_MAP_RO);
>         if (ret < 0)
>                 return ret;
>
> -       kaddr = kmap_local_page(iov.bv_page);
> -       to = kaddr + iov.bv_offset;
> -       WRITE_ONCE(*(__virtio16 *)to, cpu_to_vringh16(vrh, val));
> -       kunmap_local(kaddr);
> +       tmp = cpu_to_vringh16(vrh, val);
> +
> +       if (ivec.is_iovec) {
> +               ret = __put_user(tmp, (__virtio16 __user *)ivec.iov.iovec[0].iov_base);
> +               if (ret)
> +                       return ret;
> +       } else {
> +               void *kaddr = kmap_local_page(ivec.iov.bvec[0].bv_page);
> +               void *to = kaddr + ivec.iov.bvec[0].bv_offset;
> +
> +               WRITE_ONCE(*(__virtio16 *)to, tmp);
> +               kunmap_local(kaddr);
> +       }
>
>         return 0;
>  }
> @@ -1306,6 +1390,7 @@ static inline int putused_iotlb(const struct vringh *vrh,
>   * @features: the feature bits for this ring.
>   * @num: the number of elements.
>   * @weak_barriers: true if we only need memory barriers, not I/O.
> + * @use_va: true if IOTLB contains user VA
>   * @desc: the userpace descriptor pointer.
>   * @avail: the userpace avail pointer.
>   * @used: the userpace used pointer.
> @@ -1313,11 +1398,13 @@ static inline int putused_iotlb(const struct vringh *vrh,
>   * Returns an error if num is invalid.
>   */
>  int vringh_init_iotlb(struct vringh *vrh, u64 features,
> -                     unsigned int num, bool weak_barriers,
> +                     unsigned int num, bool weak_barriers, bool use_va,
>                       struct vring_desc *desc,
>                       struct vring_avail *avail,
>                       struct vring_used *used)
>  {
> +       vrh->use_va = use_va;
> +
>         return vringh_init_kern(vrh, features, num, weak_barriers,
>                                 desc, avail, used);
>  }
> --
> 2.39.2
>
Stefano Garzarella March 23, 2023, 10:37 a.m. UTC | #3
On Thu, Mar 23, 2023 at 11:36:28AM +0800, Jason Wang wrote:
>On Tue, Mar 21, 2023 at 11:43 PM Stefano Garzarella <sgarzare@redhat.com> wrote:
>>
>> vDPA supports the possibility to use user VA in the iotlb messages.
>> So, let's add support for user VA in vringh to use it in the vDPA
>> simulators.
>>
>> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
>> ---
>>
>> Notes:
>>     v3:
>>     - refactored avoiding code duplication [Eugenio]
>>     v2:
>>     - replace kmap_atomic() with kmap_local_page() [see previous patch]
>>     - fix cast warnings when build with W=1 C=1
>>
>>  include/linux/vringh.h            |   5 +-
>>  drivers/vdpa/mlx5/net/mlx5_vnet.c |   2 +-
>>  drivers/vdpa/vdpa_sim/vdpa_sim.c  |   4 +-
>>  drivers/vhost/vringh.c            | 153 +++++++++++++++++++++++-------
>>  4 files changed, 127 insertions(+), 37 deletions(-)
>>
>> diff --git a/include/linux/vringh.h b/include/linux/vringh.h
>> index 1991a02c6431..d39b9f2dcba0 100644
>> --- a/include/linux/vringh.h
>> +++ b/include/linux/vringh.h
>> @@ -32,6 +32,9 @@ struct vringh {
>>         /* Can we get away with weak barriers? */
>>         bool weak_barriers;
>>
>> +       /* Use user's VA */
>> +       bool use_va;
>> +
>>         /* Last available index we saw (ie. where we're up to). */
>>         u16 last_avail_idx;
>>
>> @@ -279,7 +282,7 @@ void vringh_set_iotlb(struct vringh *vrh, struct vhost_iotlb *iotlb,
>>                       spinlock_t *iotlb_lock);
>>
>>  int vringh_init_iotlb(struct vringh *vrh, u64 features,
>> -                     unsigned int num, bool weak_barriers,
>> +                     unsigned int num, bool weak_barriers, bool use_va,
>>                       struct vring_desc *desc,
>>                       struct vring_avail *avail,
>>                       struct vring_used *used);
>> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
>> index 520646ae7fa0..dfd0e000217b 100644
>> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
>> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
>> @@ -2537,7 +2537,7 @@ static int setup_cvq_vring(struct mlx5_vdpa_dev *mvdev)
>>
>>         if (mvdev->actual_features & BIT_ULL(VIRTIO_NET_F_CTRL_VQ))
>>                 err = vringh_init_iotlb(&cvq->vring, mvdev->actual_features,
>> -                                       MLX5_CVQ_MAX_ENT, false,
>> +                                       MLX5_CVQ_MAX_ENT, false, false,
>
>To avoid those changes, would it be better to introduce
>vringh_init_iotlb_va() so vringh_init_iotlb() can stick to pa.

Okay, I don't have a strong opinion, I'll add vringh_init_iotlb_va().

>
>>                                         (struct vring_desc *)(uintptr_t)cvq->desc_addr,
>>                                         (struct vring_avail *)(uintptr_t)cvq->driver_addr,
>>                                         (struct vring_used *)(uintptr_t)cvq->device_addr);
>> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
>> index eea23c630f7c..47cdf2a1f5b8 100644
>> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
>> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
>> @@ -60,7 +60,7 @@ static void vdpasim_queue_ready(struct vdpasim *vdpasim, unsigned int idx)
>>         struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
>>         uint16_t last_avail_idx = vq->vring.last_avail_idx;
>>
>> -       vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true,
>> +       vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true, false,
>>                           (struct vring_desc *)(uintptr_t)vq->desc_addr,
>>                           (struct vring_avail *)
>>                           (uintptr_t)vq->driver_addr,
>> @@ -92,7 +92,7 @@ static void vdpasim_vq_reset(struct vdpasim *vdpasim,
>>         vq->cb = NULL;
>>         vq->private = NULL;
>>         vringh_init_iotlb(&vq->vring, vdpasim->dev_attr.supported_features,
>> -                         VDPASIM_QUEUE_MAX, false, NULL, NULL, NULL);
>> +                         VDPASIM_QUEUE_MAX, false, false, NULL, NULL, NULL);
>>
>>         vq->vring.notify = NULL;
>>  }
>> diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
>> index 0ba3ef809e48..72c88519329a 100644
>> --- a/drivers/vhost/vringh.c
>> +++ b/drivers/vhost/vringh.c
>> @@ -1094,10 +1094,18 @@ EXPORT_SYMBOL(vringh_need_notify_kern);
>>
>>  #if IS_REACHABLE(CONFIG_VHOST_IOTLB)
>>
>> +struct iotlb_vec {
>> +       union {
>> +               struct iovec *iovec;
>> +               struct bio_vec *bvec;
>> +       } iov;
>> +       size_t count;
>> +       bool is_iovec;
>
>I wonder if this is needed (if vringh is passed to every iotlb_vec helper).

Yep, I can use vringh->use_va.

>
>> +};
>> +
>>  static int iotlb_translate(const struct vringh *vrh,
>>                            u64 addr, u64 len, u64 *translated,
>> -                          struct bio_vec iov[],
>> -                          int iov_size, u32 perm)
>> +                          struct iotlb_vec *ivec, u32 perm)
>>  {
>>         struct vhost_iotlb_map *map;
>>         struct vhost_iotlb *iotlb = vrh->iotlb;
>> @@ -1107,9 +1115,9 @@ static int iotlb_translate(const struct vringh *vrh,
>>         spin_lock(vrh->iotlb_lock);
>>
>>         while (len > s) {
>> -               u64 size, pa, pfn;
>> +               u64 size;
>>
>> -               if (unlikely(ret >= iov_size)) {
>> +               if (unlikely(ret >= ivec->count)) {
>>                         ret = -ENOBUFS;
>>                         break;
>>                 }
>> @@ -1124,10 +1132,22 @@ static int iotlb_translate(const struct vringh *vrh,
>>                 }
>>
>>                 size = map->size - addr + map->start;
>> -               pa = map->addr + addr - map->start;
>> -               pfn = pa >> PAGE_SHIFT;
>> -               bvec_set_page(&iov[ret], pfn_to_page(pfn), min(len - s, size),
>> -                             pa & (PAGE_SIZE - 1));
>> +               if (ivec->is_iovec) {
>> +                       struct iovec *iovec = ivec->iov.iovec;
>> +
>> +                       iovec[ret].iov_len = min(len - s, size);
>> +                       iovec[ret].iov_base = (void __user *)(unsigned long)
>> +                                             (map->addr + addr - map->start);
>
>map->addr - map->start to avoid overflow?

Right, it was pre-existing, but I'll fix since I'm here (also in the
else branch).
And since it's duplicate code, I'll declare it outside!

>
>> +               } else {
>> +                       u64 pa = map->addr + addr - map->start;
>> +                       u64 pfn = pa >> PAGE_SHIFT;
>> +                       struct bio_vec *bvec = ivec->iov.bvec;
>> +
>> +                       bvec_set_page(&bvec[ret], pfn_to_page(pfn),
>> +                                     min(len - s, size),
>> +                                     pa & (PAGE_SIZE - 1));
>> +               }
>> +
>>                 s += size;
>>                 addr += size;
>>                 ++ret;
>> @@ -1141,26 +1161,42 @@ static int iotlb_translate(const struct vringh *vrh,
>>         return ret;
>>  }
>>
>> +#define IOTLB_IOV_SIZE 16
>> +
>>  static inline int copy_from_iotlb(const struct vringh *vrh, void *dst,
>>                                   void *src, size_t len)
>>  {
>> +       struct iotlb_vec ivec;
>> +       union {
>> +               struct iovec iovec[IOTLB_IOV_SIZE];
>> +               struct bio_vec bvec[IOTLB_IOV_SIZE];
>> +       } iov;
>>         u64 total_translated = 0;
>>
>> +       ivec.iov.iovec = iov.iovec;
>
>ivc.iov = iov ?

I tried, but they are both anonymous unions, so I cannot assign them.

Also, this inner union I need to allocate space in the stack to hold
both arrays, while the union in iotlb_vec to carry both pointers.

I don't know whether to add a third field (e.g. `void *raw`) to both and
assign it.

>
>Others look good.

Thanks,
Stefano
Stefano Garzarella March 23, 2023, 10:46 a.m. UTC | #4
On Thu, Mar 23, 2023 at 09:09:14AM +0100, Eugenio Perez Martin wrote:
>On Tue, Mar 21, 2023 at 4:43 PM Stefano Garzarella <sgarzare@redhat.com> wrote:
>>
>> vDPA supports the possibility to use user VA in the iotlb messages.
>> So, let's add support for user VA in vringh to use it in the vDPA
>> simulators.
>>
>> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
>> ---
>>
>> Notes:
>>     v3:
>>     - refactored avoiding code duplication [Eugenio]
>>     v2:
>>     - replace kmap_atomic() with kmap_local_page() [see previous patch]
>>     - fix cast warnings when build with W=1 C=1
>>
>>  include/linux/vringh.h            |   5 +-
>>  drivers/vdpa/mlx5/net/mlx5_vnet.c |   2 +-
>>  drivers/vdpa/vdpa_sim/vdpa_sim.c  |   4 +-
>>  drivers/vhost/vringh.c            | 153 +++++++++++++++++++++++-------
>>  4 files changed, 127 insertions(+), 37 deletions(-)
>>
>> diff --git a/include/linux/vringh.h b/include/linux/vringh.h
>> index 1991a02c6431..d39b9f2dcba0 100644
>> --- a/include/linux/vringh.h
>> +++ b/include/linux/vringh.h
>> @@ -32,6 +32,9 @@ struct vringh {
>>         /* Can we get away with weak barriers? */
>>         bool weak_barriers;
>>
>> +       /* Use user's VA */
>> +       bool use_va;
>> +
>>         /* Last available index we saw (ie. where we're up to). */
>>         u16 last_avail_idx;
>>
>> @@ -279,7 +282,7 @@ void vringh_set_iotlb(struct vringh *vrh, struct vhost_iotlb *iotlb,
>>                       spinlock_t *iotlb_lock);
>>
>>  int vringh_init_iotlb(struct vringh *vrh, u64 features,
>> -                     unsigned int num, bool weak_barriers,
>> +                     unsigned int num, bool weak_barriers, bool use_va,
>>                       struct vring_desc *desc,
>>                       struct vring_avail *avail,
>>                       struct vring_used *used);
>> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
>> index 520646ae7fa0..dfd0e000217b 100644
>> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
>> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
>> @@ -2537,7 +2537,7 @@ static int setup_cvq_vring(struct mlx5_vdpa_dev *mvdev)
>>
>>         if (mvdev->actual_features & BIT_ULL(VIRTIO_NET_F_CTRL_VQ))
>>                 err = vringh_init_iotlb(&cvq->vring, mvdev->actual_features,
>> -                                       MLX5_CVQ_MAX_ENT, false,
>> +                                       MLX5_CVQ_MAX_ENT, false, false,
>>                                         (struct vring_desc *)(uintptr_t)cvq->desc_addr,
>>                                         (struct vring_avail *)(uintptr_t)cvq->driver_addr,
>>                                         (struct vring_used *)(uintptr_t)cvq->device_addr);
>> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
>> index eea23c630f7c..47cdf2a1f5b8 100644
>> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
>> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
>> @@ -60,7 +60,7 @@ static void vdpasim_queue_ready(struct vdpasim *vdpasim, unsigned int idx)
>>         struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
>>         uint16_t last_avail_idx = vq->vring.last_avail_idx;
>>
>> -       vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true,
>> +       vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true, false,
>>                           (struct vring_desc *)(uintptr_t)vq->desc_addr,
>>                           (struct vring_avail *)
>>                           (uintptr_t)vq->driver_addr,
>> @@ -92,7 +92,7 @@ static void vdpasim_vq_reset(struct vdpasim *vdpasim,
>>         vq->cb = NULL;
>>         vq->private = NULL;
>>         vringh_init_iotlb(&vq->vring, vdpasim->dev_attr.supported_features,
>> -                         VDPASIM_QUEUE_MAX, false, NULL, NULL, NULL);
>> +                         VDPASIM_QUEUE_MAX, false, false, NULL, NULL, NULL);
>>
>>         vq->vring.notify = NULL;
>>  }
>> diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
>> index 0ba3ef809e48..72c88519329a 100644
>> --- a/drivers/vhost/vringh.c
>> +++ b/drivers/vhost/vringh.c
>> @@ -1094,10 +1094,18 @@ EXPORT_SYMBOL(vringh_need_notify_kern);
>>
>>  #if IS_REACHABLE(CONFIG_VHOST_IOTLB)
>>
>> +struct iotlb_vec {
>> +       union {
>> +               struct iovec *iovec;
>> +               struct bio_vec *bvec;
>> +       } iov;
>> +       size_t count;
>> +       bool is_iovec;
>> +};
>> +
>>  static int iotlb_translate(const struct vringh *vrh,
>>                            u64 addr, u64 len, u64 *translated,
>> -                          struct bio_vec iov[],
>> -                          int iov_size, u32 perm)
>> +                          struct iotlb_vec *ivec, u32 perm)
>>  {
>>         struct vhost_iotlb_map *map;
>>         struct vhost_iotlb *iotlb = vrh->iotlb;
>> @@ -1107,9 +1115,9 @@ static int iotlb_translate(const struct vringh *vrh,
>>         spin_lock(vrh->iotlb_lock);
>>
>>         while (len > s) {
>> -               u64 size, pa, pfn;
>> +               u64 size;
>>
>> -               if (unlikely(ret >= iov_size)) {
>> +               if (unlikely(ret >= ivec->count)) {
>>                         ret = -ENOBUFS;
>>                         break;
>>                 }
>> @@ -1124,10 +1132,22 @@ static int iotlb_translate(const struct vringh *vrh,
>>                 }
>>
>>                 size = map->size - addr + map->start;
>> -               pa = map->addr + addr - map->start;
>> -               pfn = pa >> PAGE_SHIFT;
>> -               bvec_set_page(&iov[ret], pfn_to_page(pfn), min(len - s, size),
>> -                             pa & (PAGE_SIZE - 1));
>> +               if (ivec->is_iovec) {
>> +                       struct iovec *iovec = ivec->iov.iovec;
>> +
>> +                       iovec[ret].iov_len = min(len - s, size);
>> +                       iovec[ret].iov_base = (void __user *)(unsigned long)
>
>s/unsigned long/uintptr_t ?
>

yep, good catch!

As I wrote to Jason, I think I'll take it out of the if and just declare 
an uintptr_t variable, since I'm using it also in the else branch.

>
>
>> +                                             (map->addr + addr - map->start);
>> +               } else {
>> +                       u64 pa = map->addr + addr - map->start;
>> +                       u64 pfn = pa >> PAGE_SHIFT;
>> +                       struct bio_vec *bvec = ivec->iov.bvec;
>> +
>> +                       bvec_set_page(&bvec[ret], pfn_to_page(pfn),
>> +                                     min(len - s, size),
>> +                                     pa & (PAGE_SIZE - 1));
>> +               }
>> +
>>                 s += size;
>>                 addr += size;
>>                 ++ret;
>> @@ -1141,26 +1161,42 @@ static int iotlb_translate(const struct vringh *vrh,
>>         return ret;
>>  }
>>
>> +#define IOTLB_IOV_SIZE 16
>
>I'm fine with defining here, but maybe it is better to isolate the
>change in a previous patch or reuse another well known macro?

Yep, good point!

Do you have any well known macro to suggest?

>
>Other looks good, and I agree with Jason's comments so even if the
>macro declaration is not moved:
>
>Acked-by: Eugenio Pérez <eperezma@redhat.com>

Thanks,
Stefano
Eugenio Perez Martin March 23, 2023, 2:43 p.m. UTC | #5
On Thu, Mar 23, 2023 at 11:46 AM Stefano Garzarella <sgarzare@redhat.com> wrote:
>
> On Thu, Mar 23, 2023 at 09:09:14AM +0100, Eugenio Perez Martin wrote:
> >On Tue, Mar 21, 2023 at 4:43 PM Stefano Garzarella <sgarzare@redhat.com> wrote:
> >>
> >> vDPA supports the possibility to use user VA in the iotlb messages.
> >> So, let's add support for user VA in vringh to use it in the vDPA
> >> simulators.
> >>
> >> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> >> ---
> >>
> >> Notes:
> >>     v3:
> >>     - refactored avoiding code duplication [Eugenio]
> >>     v2:
> >>     - replace kmap_atomic() with kmap_local_page() [see previous patch]
> >>     - fix cast warnings when build with W=1 C=1
> >>
> >>  include/linux/vringh.h            |   5 +-
> >>  drivers/vdpa/mlx5/net/mlx5_vnet.c |   2 +-
> >>  drivers/vdpa/vdpa_sim/vdpa_sim.c  |   4 +-
> >>  drivers/vhost/vringh.c            | 153 +++++++++++++++++++++++-------
> >>  4 files changed, 127 insertions(+), 37 deletions(-)
> >>
> >> diff --git a/include/linux/vringh.h b/include/linux/vringh.h
> >> index 1991a02c6431..d39b9f2dcba0 100644
> >> --- a/include/linux/vringh.h
> >> +++ b/include/linux/vringh.h
> >> @@ -32,6 +32,9 @@ struct vringh {
> >>         /* Can we get away with weak barriers? */
> >>         bool weak_barriers;
> >>
> >> +       /* Use user's VA */
> >> +       bool use_va;
> >> +
> >>         /* Last available index we saw (ie. where we're up to). */
> >>         u16 last_avail_idx;
> >>
> >> @@ -279,7 +282,7 @@ void vringh_set_iotlb(struct vringh *vrh, struct vhost_iotlb *iotlb,
> >>                       spinlock_t *iotlb_lock);
> >>
> >>  int vringh_init_iotlb(struct vringh *vrh, u64 features,
> >> -                     unsigned int num, bool weak_barriers,
> >> +                     unsigned int num, bool weak_barriers, bool use_va,
> >>                       struct vring_desc *desc,
> >>                       struct vring_avail *avail,
> >>                       struct vring_used *used);
> >> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> >> index 520646ae7fa0..dfd0e000217b 100644
> >> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> >> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> >> @@ -2537,7 +2537,7 @@ static int setup_cvq_vring(struct mlx5_vdpa_dev *mvdev)
> >>
> >>         if (mvdev->actual_features & BIT_ULL(VIRTIO_NET_F_CTRL_VQ))
> >>                 err = vringh_init_iotlb(&cvq->vring, mvdev->actual_features,
> >> -                                       MLX5_CVQ_MAX_ENT, false,
> >> +                                       MLX5_CVQ_MAX_ENT, false, false,
> >>                                         (struct vring_desc *)(uintptr_t)cvq->desc_addr,
> >>                                         (struct vring_avail *)(uintptr_t)cvq->driver_addr,
> >>                                         (struct vring_used *)(uintptr_t)cvq->device_addr);
> >> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> >> index eea23c630f7c..47cdf2a1f5b8 100644
> >> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
> >> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> >> @@ -60,7 +60,7 @@ static void vdpasim_queue_ready(struct vdpasim *vdpasim, unsigned int idx)
> >>         struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
> >>         uint16_t last_avail_idx = vq->vring.last_avail_idx;
> >>
> >> -       vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true,
> >> +       vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true, false,
> >>                           (struct vring_desc *)(uintptr_t)vq->desc_addr,
> >>                           (struct vring_avail *)
> >>                           (uintptr_t)vq->driver_addr,
> >> @@ -92,7 +92,7 @@ static void vdpasim_vq_reset(struct vdpasim *vdpasim,
> >>         vq->cb = NULL;
> >>         vq->private = NULL;
> >>         vringh_init_iotlb(&vq->vring, vdpasim->dev_attr.supported_features,
> >> -                         VDPASIM_QUEUE_MAX, false, NULL, NULL, NULL);
> >> +                         VDPASIM_QUEUE_MAX, false, false, NULL, NULL, NULL);
> >>
> >>         vq->vring.notify = NULL;
> >>  }
> >> diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
> >> index 0ba3ef809e48..72c88519329a 100644
> >> --- a/drivers/vhost/vringh.c
> >> +++ b/drivers/vhost/vringh.c
> >> @@ -1094,10 +1094,18 @@ EXPORT_SYMBOL(vringh_need_notify_kern);
> >>
> >>  #if IS_REACHABLE(CONFIG_VHOST_IOTLB)
> >>
> >> +struct iotlb_vec {
> >> +       union {
> >> +               struct iovec *iovec;
> >> +               struct bio_vec *bvec;
> >> +       } iov;
> >> +       size_t count;
> >> +       bool is_iovec;
> >> +};
> >> +
> >>  static int iotlb_translate(const struct vringh *vrh,
> >>                            u64 addr, u64 len, u64 *translated,
> >> -                          struct bio_vec iov[],
> >> -                          int iov_size, u32 perm)
> >> +                          struct iotlb_vec *ivec, u32 perm)
> >>  {
> >>         struct vhost_iotlb_map *map;
> >>         struct vhost_iotlb *iotlb = vrh->iotlb;
> >> @@ -1107,9 +1115,9 @@ static int iotlb_translate(const struct vringh *vrh,
> >>         spin_lock(vrh->iotlb_lock);
> >>
> >>         while (len > s) {
> >> -               u64 size, pa, pfn;
> >> +               u64 size;
> >>
> >> -               if (unlikely(ret >= iov_size)) {
> >> +               if (unlikely(ret >= ivec->count)) {
> >>                         ret = -ENOBUFS;
> >>                         break;
> >>                 }
> >> @@ -1124,10 +1132,22 @@ static int iotlb_translate(const struct vringh *vrh,
> >>                 }
> >>
> >>                 size = map->size - addr + map->start;
> >> -               pa = map->addr + addr - map->start;
> >> -               pfn = pa >> PAGE_SHIFT;
> >> -               bvec_set_page(&iov[ret], pfn_to_page(pfn), min(len - s, size),
> >> -                             pa & (PAGE_SIZE - 1));
> >> +               if (ivec->is_iovec) {
> >> +                       struct iovec *iovec = ivec->iov.iovec;
> >> +
> >> +                       iovec[ret].iov_len = min(len - s, size);
> >> +                       iovec[ret].iov_base = (void __user *)(unsigned long)
> >
> >s/unsigned long/uintptr_t ?
> >
>
> yep, good catch!
>
> As I wrote to Jason, I think I'll take it out of the if and just declare
> an uintptr_t variable, since I'm using it also in the else branch.
>
> >
> >
> >> +                                             (map->addr + addr - map->start);
> >> +               } else {
> >> +                       u64 pa = map->addr + addr - map->start;
> >> +                       u64 pfn = pa >> PAGE_SHIFT;
> >> +                       struct bio_vec *bvec = ivec->iov.bvec;
> >> +
> >> +                       bvec_set_page(&bvec[ret], pfn_to_page(pfn),
> >> +                                     min(len - s, size),
> >> +                                     pa & (PAGE_SIZE - 1));
> >> +               }
> >> +
> >>                 s += size;
> >>                 addr += size;
> >>                 ++ret;
> >> @@ -1141,26 +1161,42 @@ static int iotlb_translate(const struct vringh *vrh,
> >>         return ret;
> >>  }
> >>
> >> +#define IOTLB_IOV_SIZE 16
> >
> >I'm fine with defining here, but maybe it is better to isolate the
> >change in a previous patch or reuse another well known macro?
>
> Yep, good point!
>
> Do you have any well known macro to suggest?
>

Not really, 16 seems like a convenience value here actually :). Maybe
replace _SIZE with _STRIDE or similar?

I keep the Acked-by even if the final name is IOTLB_IOV_SIZE though.

Thanks!
Stefano Garzarella March 24, 2023, 2:39 p.m. UTC | #6
On Thu, Mar 23, 2023 at 03:43:34PM +0100, Eugenio Perez Martin wrote:
>On Thu, Mar 23, 2023 at 11:46 AM Stefano Garzarella <sgarzare@redhat.com> wrote:
>>
>> On Thu, Mar 23, 2023 at 09:09:14AM +0100, Eugenio Perez Martin wrote:
>> >On Tue, Mar 21, 2023 at 4:43 PM Stefano Garzarella <sgarzare@redhat.com> wrote:
>> >>
>> >> vDPA supports the possibility to use user VA in the iotlb messages.
>> >> So, let's add support for user VA in vringh to use it in the vDPA
>> >> simulators.
>> >>
>> >> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
>> >> ---
>> >>
>> >> Notes:
>> >>     v3:
>> >>     - refactored avoiding code duplication [Eugenio]
>> >>     v2:
>> >>     - replace kmap_atomic() with kmap_local_page() [see previous patch]
>> >>     - fix cast warnings when build with W=1 C=1
>> >>
>> >>  include/linux/vringh.h            |   5 +-
>> >>  drivers/vdpa/mlx5/net/mlx5_vnet.c |   2 +-
>> >>  drivers/vdpa/vdpa_sim/vdpa_sim.c  |   4 +-
>> >>  drivers/vhost/vringh.c            | 153 +++++++++++++++++++++++-------
>> >>  4 files changed, 127 insertions(+), 37 deletions(-)
>> >>
>> >> diff --git a/include/linux/vringh.h b/include/linux/vringh.h
>> >> index 1991a02c6431..d39b9f2dcba0 100644
>> >> --- a/include/linux/vringh.h
>> >> +++ b/include/linux/vringh.h
>> >> @@ -32,6 +32,9 @@ struct vringh {
>> >>         /* Can we get away with weak barriers? */
>> >>         bool weak_barriers;
>> >>
>> >> +       /* Use user's VA */
>> >> +       bool use_va;
>> >> +
>> >>         /* Last available index we saw (ie. where we're up to). */
>> >>         u16 last_avail_idx;
>> >>
>> >> @@ -279,7 +282,7 @@ void vringh_set_iotlb(struct vringh *vrh, struct vhost_iotlb *iotlb,
>> >>                       spinlock_t *iotlb_lock);
>> >>
>> >>  int vringh_init_iotlb(struct vringh *vrh, u64 features,
>> >> -                     unsigned int num, bool weak_barriers,
>> >> +                     unsigned int num, bool weak_barriers, bool use_va,
>> >>                       struct vring_desc *desc,
>> >>                       struct vring_avail *avail,
>> >>                       struct vring_used *used);
>> >> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
>> >> index 520646ae7fa0..dfd0e000217b 100644
>> >> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
>> >> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
>> >> @@ -2537,7 +2537,7 @@ static int setup_cvq_vring(struct mlx5_vdpa_dev *mvdev)
>> >>
>> >>         if (mvdev->actual_features & BIT_ULL(VIRTIO_NET_F_CTRL_VQ))
>> >>                 err = vringh_init_iotlb(&cvq->vring, mvdev->actual_features,
>> >> -                                       MLX5_CVQ_MAX_ENT, false,
>> >> +                                       MLX5_CVQ_MAX_ENT, false, false,
>> >>                                         (struct vring_desc *)(uintptr_t)cvq->desc_addr,
>> >>                                         (struct vring_avail *)(uintptr_t)cvq->driver_addr,
>> >>                                         (struct vring_used *)(uintptr_t)cvq->device_addr);
>> >> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
>> >> index eea23c630f7c..47cdf2a1f5b8 100644
>> >> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
>> >> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
>> >> @@ -60,7 +60,7 @@ static void vdpasim_queue_ready(struct vdpasim *vdpasim, unsigned int idx)
>> >>         struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
>> >>         uint16_t last_avail_idx = vq->vring.last_avail_idx;
>> >>
>> >> -       vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true,
>> >> +       vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true, false,
>> >>                           (struct vring_desc *)(uintptr_t)vq->desc_addr,
>> >>                           (struct vring_avail *)
>> >>                           (uintptr_t)vq->driver_addr,
>> >> @@ -92,7 +92,7 @@ static void vdpasim_vq_reset(struct vdpasim *vdpasim,
>> >>         vq->cb = NULL;
>> >>         vq->private = NULL;
>> >>         vringh_init_iotlb(&vq->vring, vdpasim->dev_attr.supported_features,
>> >> -                         VDPASIM_QUEUE_MAX, false, NULL, NULL, NULL);
>> >> +                         VDPASIM_QUEUE_MAX, false, false, NULL, NULL, NULL);
>> >>
>> >>         vq->vring.notify = NULL;
>> >>  }
>> >> diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
>> >> index 0ba3ef809e48..72c88519329a 100644
>> >> --- a/drivers/vhost/vringh.c
>> >> +++ b/drivers/vhost/vringh.c
>> >> @@ -1094,10 +1094,18 @@ EXPORT_SYMBOL(vringh_need_notify_kern);
>> >>
>> >>  #if IS_REACHABLE(CONFIG_VHOST_IOTLB)
>> >>
>> >> +struct iotlb_vec {
>> >> +       union {
>> >> +               struct iovec *iovec;
>> >> +               struct bio_vec *bvec;
>> >> +       } iov;
>> >> +       size_t count;
>> >> +       bool is_iovec;
>> >> +};
>> >> +
>> >>  static int iotlb_translate(const struct vringh *vrh,
>> >>                            u64 addr, u64 len, u64 *translated,
>> >> -                          struct bio_vec iov[],
>> >> -                          int iov_size, u32 perm)
>> >> +                          struct iotlb_vec *ivec, u32 perm)
>> >>  {
>> >>         struct vhost_iotlb_map *map;
>> >>         struct vhost_iotlb *iotlb = vrh->iotlb;
>> >> @@ -1107,9 +1115,9 @@ static int iotlb_translate(const struct vringh *vrh,
>> >>         spin_lock(vrh->iotlb_lock);
>> >>
>> >>         while (len > s) {
>> >> -               u64 size, pa, pfn;
>> >> +               u64 size;
>> >>
>> >> -               if (unlikely(ret >= iov_size)) {
>> >> +               if (unlikely(ret >= ivec->count)) {
>> >>                         ret = -ENOBUFS;
>> >>                         break;
>> >>                 }
>> >> @@ -1124,10 +1132,22 @@ static int iotlb_translate(const struct vringh *vrh,
>> >>                 }
>> >>
>> >>                 size = map->size - addr + map->start;
>> >> -               pa = map->addr + addr - map->start;
>> >> -               pfn = pa >> PAGE_SHIFT;
>> >> -               bvec_set_page(&iov[ret], pfn_to_page(pfn), min(len - s, size),
>> >> -                             pa & (PAGE_SIZE - 1));
>> >> +               if (ivec->is_iovec) {
>> >> +                       struct iovec *iovec = ivec->iov.iovec;
>> >> +
>> >> +                       iovec[ret].iov_len = min(len - s, size);
>> >> +                       iovec[ret].iov_base = (void __user *)(unsigned long)
>> >
>> >s/unsigned long/uintptr_t ?
>> >
>>
>> yep, good catch!
>>
>> As I wrote to Jason, I think I'll take it out of the if and just declare
>> an uintptr_t variable, since I'm using it also in the else branch.
>>
>> >
>> >
>> >> +                                             (map->addr + addr - map->start);
>> >> +               } else {
>> >> +                       u64 pa = map->addr + addr - map->start;
>> >> +                       u64 pfn = pa >> PAGE_SHIFT;
>> >> +                       struct bio_vec *bvec = ivec->iov.bvec;
>> >> +
>> >> +                       bvec_set_page(&bvec[ret], pfn_to_page(pfn),
>> >> +                                     min(len - s, size),
>> >> +                                     pa & (PAGE_SIZE - 1));
>> >> +               }
>> >> +
>> >>                 s += size;
>> >>                 addr += size;
>> >>                 ++ret;
>> >> @@ -1141,26 +1161,42 @@ static int iotlb_translate(const struct vringh *vrh,
>> >>         return ret;
>> >>  }
>> >>
>> >> +#define IOTLB_IOV_SIZE 16
>> >
>> >I'm fine with defining here, but maybe it is better to isolate the
>> >change in a previous patch or reuse another well known macro?
>>
>> Yep, good point!
>>
>> Do you have any well known macro to suggest?
>>
>
>Not really, 16 seems like a convenience value here actually :). Maybe
>replace _SIZE with _STRIDE or similar?

Ack, I will add IOTLB_IOV_STRIDE in a preparation patch before this
one.

>
>I keep the Acked-by even if the final name is IOTLB_IOV_SIZE though.

Thanks,
I changed a bit this patch following Jason's and your suggestions.

I'd like an explicit Acked-by on the next version if it is okay with 
you.

Thanks,
Stefano
diff mbox series

Patch

diff --git a/include/linux/vringh.h b/include/linux/vringh.h
index 1991a02c6431..d39b9f2dcba0 100644
--- a/include/linux/vringh.h
+++ b/include/linux/vringh.h
@@ -32,6 +32,9 @@  struct vringh {
 	/* Can we get away with weak barriers? */
 	bool weak_barriers;
 
+	/* Use user's VA */
+	bool use_va;
+
 	/* Last available index we saw (ie. where we're up to). */
 	u16 last_avail_idx;
 
@@ -279,7 +282,7 @@  void vringh_set_iotlb(struct vringh *vrh, struct vhost_iotlb *iotlb,
 		      spinlock_t *iotlb_lock);
 
 int vringh_init_iotlb(struct vringh *vrh, u64 features,
-		      unsigned int num, bool weak_barriers,
+		      unsigned int num, bool weak_barriers, bool use_va,
 		      struct vring_desc *desc,
 		      struct vring_avail *avail,
 		      struct vring_used *used);
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 520646ae7fa0..dfd0e000217b 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -2537,7 +2537,7 @@  static int setup_cvq_vring(struct mlx5_vdpa_dev *mvdev)
 
 	if (mvdev->actual_features & BIT_ULL(VIRTIO_NET_F_CTRL_VQ))
 		err = vringh_init_iotlb(&cvq->vring, mvdev->actual_features,
-					MLX5_CVQ_MAX_ENT, false,
+					MLX5_CVQ_MAX_ENT, false, false,
 					(struct vring_desc *)(uintptr_t)cvq->desc_addr,
 					(struct vring_avail *)(uintptr_t)cvq->driver_addr,
 					(struct vring_used *)(uintptr_t)cvq->device_addr);
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index eea23c630f7c..47cdf2a1f5b8 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -60,7 +60,7 @@  static void vdpasim_queue_ready(struct vdpasim *vdpasim, unsigned int idx)
 	struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
 	uint16_t last_avail_idx = vq->vring.last_avail_idx;
 
-	vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true,
+	vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true, false,
 			  (struct vring_desc *)(uintptr_t)vq->desc_addr,
 			  (struct vring_avail *)
 			  (uintptr_t)vq->driver_addr,
@@ -92,7 +92,7 @@  static void vdpasim_vq_reset(struct vdpasim *vdpasim,
 	vq->cb = NULL;
 	vq->private = NULL;
 	vringh_init_iotlb(&vq->vring, vdpasim->dev_attr.supported_features,
-			  VDPASIM_QUEUE_MAX, false, NULL, NULL, NULL);
+			  VDPASIM_QUEUE_MAX, false, false, NULL, NULL, NULL);
 
 	vq->vring.notify = NULL;
 }
diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
index 0ba3ef809e48..72c88519329a 100644
--- a/drivers/vhost/vringh.c
+++ b/drivers/vhost/vringh.c
@@ -1094,10 +1094,18 @@  EXPORT_SYMBOL(vringh_need_notify_kern);
 
 #if IS_REACHABLE(CONFIG_VHOST_IOTLB)
 
+struct iotlb_vec {
+	union {
+		struct iovec *iovec;
+		struct bio_vec *bvec;
+	} iov;
+	size_t count;
+	bool is_iovec;
+};
+
 static int iotlb_translate(const struct vringh *vrh,
 			   u64 addr, u64 len, u64 *translated,
-			   struct bio_vec iov[],
-			   int iov_size, u32 perm)
+			   struct iotlb_vec *ivec, u32 perm)
 {
 	struct vhost_iotlb_map *map;
 	struct vhost_iotlb *iotlb = vrh->iotlb;
@@ -1107,9 +1115,9 @@  static int iotlb_translate(const struct vringh *vrh,
 	spin_lock(vrh->iotlb_lock);
 
 	while (len > s) {
-		u64 size, pa, pfn;
+		u64 size;
 
-		if (unlikely(ret >= iov_size)) {
+		if (unlikely(ret >= ivec->count)) {
 			ret = -ENOBUFS;
 			break;
 		}
@@ -1124,10 +1132,22 @@  static int iotlb_translate(const struct vringh *vrh,
 		}
 
 		size = map->size - addr + map->start;
-		pa = map->addr + addr - map->start;
-		pfn = pa >> PAGE_SHIFT;
-		bvec_set_page(&iov[ret], pfn_to_page(pfn), min(len - s, size),
-			      pa & (PAGE_SIZE - 1));
+		if (ivec->is_iovec) {
+			struct iovec *iovec = ivec->iov.iovec;
+
+			iovec[ret].iov_len = min(len - s, size);
+			iovec[ret].iov_base = (void __user *)(unsigned long)
+					      (map->addr + addr - map->start);
+		} else {
+			u64 pa = map->addr + addr - map->start;
+			u64 pfn = pa >> PAGE_SHIFT;
+			struct bio_vec *bvec = ivec->iov.bvec;
+
+			bvec_set_page(&bvec[ret], pfn_to_page(pfn),
+				      min(len - s, size),
+				      pa & (PAGE_SIZE - 1));
+		}
+
 		s += size;
 		addr += size;
 		++ret;
@@ -1141,26 +1161,42 @@  static int iotlb_translate(const struct vringh *vrh,
 	return ret;
 }
 
+#define IOTLB_IOV_SIZE 16
+
 static inline int copy_from_iotlb(const struct vringh *vrh, void *dst,
 				  void *src, size_t len)
 {
+	struct iotlb_vec ivec;
+	union {
+		struct iovec iovec[IOTLB_IOV_SIZE];
+		struct bio_vec bvec[IOTLB_IOV_SIZE];
+	} iov;
 	u64 total_translated = 0;
 
+	ivec.iov.iovec = iov.iovec;
+	ivec.count = IOTLB_IOV_SIZE;
+	ivec.is_iovec = vrh->use_va;
+
 	while (total_translated < len) {
-		struct bio_vec iov[16];
 		struct iov_iter iter;
 		u64 translated;
 		int ret;
 
 		ret = iotlb_translate(vrh, (u64)(uintptr_t)src,
 				      len - total_translated, &translated,
-				      iov, ARRAY_SIZE(iov), VHOST_MAP_RO);
+				      &ivec, VHOST_MAP_RO);
 		if (ret == -ENOBUFS)
-			ret = ARRAY_SIZE(iov);
+			ret = IOTLB_IOV_SIZE;
 		else if (ret < 0)
 			return ret;
 
-		iov_iter_bvec(&iter, ITER_SOURCE, iov, ret, translated);
+		if (ivec.is_iovec) {
+			iov_iter_init(&iter, ITER_SOURCE, ivec.iov.iovec, ret,
+				      translated);
+		} else {
+			iov_iter_bvec(&iter, ITER_SOURCE, ivec.iov.bvec, ret,
+				      translated);
+		}
 
 		ret = copy_from_iter(dst, translated, &iter);
 		if (ret < 0)
@@ -1177,23 +1213,37 @@  static inline int copy_from_iotlb(const struct vringh *vrh, void *dst,
 static inline int copy_to_iotlb(const struct vringh *vrh, void *dst,
 				void *src, size_t len)
 {
+	struct iotlb_vec ivec;
+	union {
+		struct iovec iovec[IOTLB_IOV_SIZE];
+		struct bio_vec bvec[IOTLB_IOV_SIZE];
+	} iov;
 	u64 total_translated = 0;
 
+	ivec.iov.iovec = iov.iovec;
+	ivec.count = IOTLB_IOV_SIZE;
+	ivec.is_iovec = vrh->use_va;
+
 	while (total_translated < len) {
-		struct bio_vec iov[16];
 		struct iov_iter iter;
 		u64 translated;
 		int ret;
 
 		ret = iotlb_translate(vrh, (u64)(uintptr_t)dst,
 				      len - total_translated, &translated,
-				      iov, ARRAY_SIZE(iov), VHOST_MAP_WO);
+				      &ivec, VHOST_MAP_WO);
 		if (ret == -ENOBUFS)
-			ret = ARRAY_SIZE(iov);
+			ret = IOTLB_IOV_SIZE;
 		else if (ret < 0)
 			return ret;
 
-		iov_iter_bvec(&iter, ITER_DEST, iov, ret, translated);
+		if (ivec.is_iovec) {
+			iov_iter_init(&iter, ITER_DEST, ivec.iov.iovec, ret,
+				      translated);
+		} else {
+			iov_iter_bvec(&iter, ITER_DEST, ivec.iov.bvec, ret,
+				      translated);
+		}
 
 		ret = copy_to_iter(src, translated, &iter);
 		if (ret < 0)
@@ -1210,20 +1260,37 @@  static inline int copy_to_iotlb(const struct vringh *vrh, void *dst,
 static inline int getu16_iotlb(const struct vringh *vrh,
 			       u16 *val, const __virtio16 *p)
 {
-	struct bio_vec iov;
-	void *kaddr, *from;
+	struct iotlb_vec ivec;
+	union {
+		struct iovec iovec[1];
+		struct bio_vec bvec[1];
+	} iov;
+	__virtio16 tmp;
 	int ret;
 
+	ivec.iov.iovec = iov.iovec;
+	ivec.count = 1;
+	ivec.is_iovec = vrh->use_va;
+
 	/* Atomic read is needed for getu16 */
-	ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p), NULL,
-			      &iov, 1, VHOST_MAP_RO);
+	ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p),
+			      NULL, &ivec, VHOST_MAP_RO);
 	if (ret < 0)
 		return ret;
 
-	kaddr = kmap_local_page(iov.bv_page);
-	from = kaddr + iov.bv_offset;
-	*val = vringh16_to_cpu(vrh, READ_ONCE(*(__virtio16 *)from));
-	kunmap_local(kaddr);
+	if (ivec.is_iovec) {
+		ret = __get_user(tmp, (__virtio16 __user *)ivec.iov.iovec[0].iov_base);
+		if (ret)
+			return ret;
+	} else {
+		void *kaddr = kmap_local_page(ivec.iov.bvec[0].bv_page);
+		void *from = kaddr + ivec.iov.bvec[0].bv_offset;
+
+		tmp = READ_ONCE(*(__virtio16 *)from);
+		kunmap_local(kaddr);
+	}
+
+	*val = vringh16_to_cpu(vrh, tmp);
 
 	return 0;
 }
@@ -1231,20 +1298,37 @@  static inline int getu16_iotlb(const struct vringh *vrh,
 static inline int putu16_iotlb(const struct vringh *vrh,
 			       __virtio16 *p, u16 val)
 {
-	struct bio_vec iov;
-	void *kaddr, *to;
+	struct iotlb_vec ivec;
+	union {
+		struct iovec iovec;
+		struct bio_vec bvec;
+	} iov;
+	__virtio16 tmp;
 	int ret;
 
+	ivec.iov.iovec = &iov.iovec;
+	ivec.count = 1;
+	ivec.is_iovec = vrh->use_va;
+
 	/* Atomic write is needed for putu16 */
-	ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p), NULL,
-			      &iov, 1, VHOST_MAP_WO);
+	ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p),
+			      NULL, &ivec, VHOST_MAP_RO);
 	if (ret < 0)
 		return ret;
 
-	kaddr = kmap_local_page(iov.bv_page);
-	to = kaddr + iov.bv_offset;
-	WRITE_ONCE(*(__virtio16 *)to, cpu_to_vringh16(vrh, val));
-	kunmap_local(kaddr);
+	tmp = cpu_to_vringh16(vrh, val);
+
+	if (ivec.is_iovec) {
+		ret = __put_user(tmp, (__virtio16 __user *)ivec.iov.iovec[0].iov_base);
+		if (ret)
+			return ret;
+	} else {
+		void *kaddr = kmap_local_page(ivec.iov.bvec[0].bv_page);
+		void *to = kaddr + ivec.iov.bvec[0].bv_offset;
+
+		WRITE_ONCE(*(__virtio16 *)to, tmp);
+		kunmap_local(kaddr);
+	}
 
 	return 0;
 }
@@ -1306,6 +1390,7 @@  static inline int putused_iotlb(const struct vringh *vrh,
  * @features: the feature bits for this ring.
  * @num: the number of elements.
  * @weak_barriers: true if we only need memory barriers, not I/O.
+ * @use_va: true if IOTLB contains user VA
  * @desc: the userpace descriptor pointer.
  * @avail: the userpace avail pointer.
  * @used: the userpace used pointer.
@@ -1313,11 +1398,13 @@  static inline int putused_iotlb(const struct vringh *vrh,
  * Returns an error if num is invalid.
  */
 int vringh_init_iotlb(struct vringh *vrh, u64 features,
-		      unsigned int num, bool weak_barriers,
+		      unsigned int num, bool weak_barriers, bool use_va,
 		      struct vring_desc *desc,
 		      struct vring_avail *avail,
 		      struct vring_used *used)
 {
+	vrh->use_va = use_va;
+
 	return vringh_init_kern(vrh, features, num, weak_barriers,
 				desc, avail, used);
 }