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 <sgarz...@redhat.com>
---

Notes:
    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            | 247 ++++++++++++++++++++++++------
 4 files changed, 205 insertions(+), 53 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 3a0e721aef05..babc8dd171a6 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 6a0a65814626..481eb156658b 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,
@@ -81,7 +81,7 @@ 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..61c79cea44ca 100644
--- a/drivers/vhost/vringh.c
+++ b/drivers/vhost/vringh.c
@@ -1094,15 +1094,99 @@ EXPORT_SYMBOL(vringh_need_notify_kern);
 
 #if IS_REACHABLE(CONFIG_VHOST_IOTLB)
 
-static int iotlb_translate(const struct vringh *vrh,
-                          u64 addr, u64 len, u64 *translated,
-                          struct bio_vec iov[],
-                          int iov_size, u32 perm)
+static int iotlb_translate_va(const struct vringh *vrh,
+                             u64 addr, u64 len, u64 *translated,
+                             struct iovec iov[],
+                             int iov_size, u32 perm)
 {
        struct vhost_iotlb_map *map;
        struct vhost_iotlb *iotlb = vrh->iotlb;
+       u64 s = 0, last = addr + len - 1;
        int ret = 0;
+
+       spin_lock(vrh->iotlb_lock);
+
+       while (len > s) {
+               u64 size;
+
+               if (unlikely(ret >= iov_size)) {
+                       ret = -ENOBUFS;
+                       break;
+               }
+
+               map = vhost_iotlb_itree_first(iotlb, addr, last);
+               if (!map || map->start > addr) {
+                       ret = -EINVAL;
+                       break;
+               } else if (!(map->perm & perm)) {
+                       ret = -EPERM;
+                       break;
+               }
+
+               size = map->size - addr + map->start;
+               iov[ret].iov_len = min(len - s, size);
+               iov[ret].iov_base = (void __user *)(unsigned long)
+                                   (map->addr + addr - map->start);
+               s += size;
+               addr += size;
+               ++ret;
+       }
+
+       spin_unlock(vrh->iotlb_lock);
+
+       if (translated)
+               *translated = min(len, s);
+
+       return ret;
+}
+
+static inline int copy_from_va(const struct vringh *vrh, void *dst, void *src,
+                              u64 len, u64 *translated)
+{
+       struct iovec iov[16];
+       struct iov_iter iter;
+       int ret;
+
+       ret = iotlb_translate_va(vrh, (u64)(uintptr_t)src, len, translated, iov,
+                                ARRAY_SIZE(iov), VHOST_MAP_RO);
+       if (ret == -ENOBUFS)
+               ret = ARRAY_SIZE(iov);
+       else if (ret < 0)
+               return ret;
+
+       iov_iter_init(&iter, ITER_SOURCE, iov, ret, *translated);
+
+       return copy_from_iter(dst, *translated, &iter);
+}
+
+static inline int copy_to_va(const struct vringh *vrh, void *dst, void *src,
+                            u64 len, u64 *translated)
+{
+       struct iovec iov[16];
+       struct iov_iter iter;
+       int ret;
+
+       ret = iotlb_translate_va(vrh, (u64)(uintptr_t)dst, len, translated, iov,
+                                ARRAY_SIZE(iov), VHOST_MAP_WO);
+       if (ret == -ENOBUFS)
+               ret = ARRAY_SIZE(iov);
+       else if (ret < 0)
+               return ret;
+
+       iov_iter_init(&iter, ITER_DEST, iov, ret, *translated);
+
+       return copy_to_iter(src, *translated, &iter);
+}
+
+static int iotlb_translate_pa(const struct vringh *vrh,
+                             u64 addr, u64 len, u64 *translated,
+                             struct bio_vec iov[],
+                             int iov_size, u32 perm)
+{
+       struct vhost_iotlb_map *map;
+       struct vhost_iotlb *iotlb = vrh->iotlb;
        u64 s = 0, last = addr + len - 1;
+       int ret = 0;
 
        spin_lock(vrh->iotlb_lock);
 
@@ -1141,28 +1225,61 @@ static int iotlb_translate(const struct vringh *vrh,
        return ret;
 }
 
+static inline int copy_from_pa(const struct vringh *vrh, void *dst, void *src,
+                              u64 len, u64 *translated)
+{
+       struct bio_vec iov[16];
+       struct iov_iter iter;
+       int ret;
+
+       ret = iotlb_translate_pa(vrh, (u64)(uintptr_t)src, len, translated, iov,
+                                ARRAY_SIZE(iov), VHOST_MAP_RO);
+       if (ret == -ENOBUFS)
+               ret = ARRAY_SIZE(iov);
+       else if (ret < 0)
+               return ret;
+
+       iov_iter_bvec(&iter, ITER_SOURCE, iov, ret, *translated);
+
+       return copy_from_iter(dst, *translated, &iter);
+}
+
+static inline int copy_to_pa(const struct vringh *vrh, void *dst, void *src,
+                            u64 len, u64 *translated)
+{
+       struct bio_vec iov[16];
+       struct iov_iter iter;
+       int ret;
+
+       ret = iotlb_translate_pa(vrh, (u64)(uintptr_t)dst, len, translated, iov,
+                                ARRAY_SIZE(iov), VHOST_MAP_WO);
+       if (ret == -ENOBUFS)
+               ret = ARRAY_SIZE(iov);
+       else if (ret < 0)
+               return ret;
+
+       iov_iter_bvec(&iter, ITER_DEST, iov, ret, *translated);
+
+       return copy_to_iter(src, *translated, &iter);
+}
+
 static inline int copy_from_iotlb(const struct vringh *vrh, void *dst,
                                  void *src, size_t len)
 {
        u64 total_translated = 0;
 
        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);
-               if (ret == -ENOBUFS)
-                       ret = ARRAY_SIZE(iov);
-               else if (ret < 0)
-                       return ret;
-
-               iov_iter_bvec(&iter, ITER_SOURCE, iov, ret, translated);
+               if (vrh->use_va) {
+                       ret = copy_from_va(vrh, dst, src,
+                                          len - total_translated, &translated);
+               } else {
+                       ret = copy_from_pa(vrh, dst, src,
+                                          len - total_translated, &translated);
+               }
 
-               ret = copy_from_iter(dst, translated, &iter);
                if (ret < 0)
                        return ret;
 
@@ -1180,22 +1297,17 @@ static inline int copy_to_iotlb(const struct vringh 
*vrh, void *dst,
        u64 total_translated = 0;
 
        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);
-               if (ret == -ENOBUFS)
-                       ret = ARRAY_SIZE(iov);
-               else if (ret < 0)
-                       return ret;
-
-               iov_iter_bvec(&iter, ITER_DEST, iov, ret, translated);
+               if (vrh->use_va) {
+                       ret = copy_to_va(vrh, dst, src,
+                                        len - total_translated, &translated);
+               } else {
+                       ret = copy_to_pa(vrh, dst, src,
+                                        len - total_translated, &translated);
+               }
 
-               ret = copy_to_iter(src, translated, &iter);
                if (ret < 0)
                        return ret;
 
@@ -1210,20 +1322,37 @@ 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;
        int ret;
 
        /* Atomic read is needed for getu16 */
-       ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p), NULL,
-                             &iov, 1, VHOST_MAP_RO);
-       if (ret < 0)
-               return ret;
+       if (vrh->use_va) {
+               struct iovec iov;
+               __virtio16 tmp;
+
+               ret = iotlb_translate_va(vrh, (u64)(uintptr_t)p, sizeof(*p),
+                                        NULL, &iov, 1, 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);
+               ret = __get_user(tmp, (__virtio16 __user *)iov.iov_base);
+               if (ret)
+                       return ret;
+
+               *val = vringh16_to_cpu(vrh, tmp);
+       } else {
+               struct bio_vec iov;
+               void *kaddr, *from;
+
+               ret = iotlb_translate_pa(vrh, (u64)(uintptr_t)p, sizeof(*p),
+                                        NULL, &iov, 1, 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);
+       }
 
        return 0;
 }
@@ -1231,20 +1360,37 @@ 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;
        int ret;
 
        /* Atomic write is needed for putu16 */
-       ret = iotlb_translate(vrh, (u64)(uintptr_t)p, sizeof(*p), NULL,
-                             &iov, 1, VHOST_MAP_WO);
-       if (ret < 0)
-               return ret;
+       if (vrh->use_va) {
+               struct iovec iov;
+               __virtio16 tmp;
 
-       kaddr = kmap_local_page(iov.bv_page);
-       to = kaddr + iov.bv_offset;
-       WRITE_ONCE(*(__virtio16 *)to, cpu_to_vringh16(vrh, val));
-       kunmap_local(kaddr);
+               ret = iotlb_translate_va(vrh, (u64)(uintptr_t)p, sizeof(*p),
+                                        NULL, &iov, 1, VHOST_MAP_RO);
+               if (ret < 0)
+                       return ret;
+
+               tmp = cpu_to_vringh16(vrh, val);
+
+               ret = __put_user(tmp, (__virtio16 __user *)iov.iov_base);
+               if (ret)
+                       return ret;
+       } else {
+               struct bio_vec iov;
+               void *kaddr, *to;
+
+               ret = iotlb_translate_pa(vrh, (u64)(uintptr_t)p, sizeof(*p), 
NULL,
+                                        &iov, 1, VHOST_MAP_WO);
+               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);
+       }
 
        return 0;
 }
@@ -1306,6 +1452,7 @@ 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 +1460,13 @@ 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

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