Unmap fails when there are duplicate entries in user_mem_maps.

The fix is to validate if the input VA, IOVA exists or
overlaps in user_mem_maps before creating map.

Fixes: 73a63908 ("vfio: allow to map other memory regions")
Cc: sta...@dpdk.org

Signed-off-by: Chaitanya Babu Talluri <tallurix.chaitanya.b...@intel.com>
---
 lib/librte_eal/linux/eal/eal_vfio.c | 46 +++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/lib/librte_eal/linux/eal/eal_vfio.c 
b/lib/librte_eal/linux/eal/eal_vfio.c
index 501c74f23..104912077 100644
--- a/lib/librte_eal/linux/eal/eal_vfio.c
+++ b/lib/librte_eal/linux/eal/eal_vfio.c
@@ -212,6 +212,41 @@ find_user_mem_map(struct user_mem_maps *user_mem_maps, 
uint64_t addr,
        return NULL;
 }
 
+static int
+find_user_mem_map_overlap(struct user_mem_maps *user_mem_maps, uint64_t addr,
+               uint64_t iova, uint64_t len)
+{
+       uint64_t va_end = addr + len;
+       uint64_t iova_end = iova + len;
+       int i;
+
+       for (i = 0; i < user_mem_maps->n_maps; i++) {
+               struct user_mem_map *map = &user_mem_maps->maps[i];
+               uint64_t map_va_end = map->addr + map->len;
+               uint64_t map_iova_end = map->iova + map->len;
+
+               bool no_lo_va_overlap = addr < map->addr && va_end <= map->addr;
+               bool no_hi_va_overlap = addr >= map_va_end &&
+                       va_end > map_va_end;
+               bool no_lo_iova_overlap = iova < map->iova &&
+                       iova_end <= map->iova;
+               bool no_hi_iova_overlap = iova >= map_iova_end &&
+                       iova_end > map_iova_end;
+
+               /* check input VA and iova is not within the
+                * existing map's range
+                */
+               if ((no_lo_va_overlap || no_hi_va_overlap) &&
+                               (no_lo_iova_overlap || no_hi_iova_overlap))
+                       continue;
+               else
+                       /* map overlaps */
+                       return 1;
+       }
+       /* map doesn't overlap */
+       return 0;
+}
+
 /* this will sort all user maps, and merge/compact any adjacent maps */
 static void
 compact_user_maps(struct user_mem_maps *user_mem_maps)
@@ -1732,6 +1767,17 @@ container_dma_map(struct vfio_config *vfio_cfg, uint64_t 
vaddr, uint64_t iova,
                ret = -1;
                goto out;
        }
+
+       /* check whether vaddr and iova exists in user_mem_maps */
+       ret = find_user_mem_map_overlap(user_mem_maps, vaddr, iova, len);
+       if (ret) {
+               RTE_LOG(ERR, EAL, "Mapping overlaps with a previously "
+                               "existing mapping\n");
+               rte_errno = EEXIST;
+               ret = -1;
+               goto out;
+       }
+
        /* map the entry */
        if (vfio_dma_mem_map(vfio_cfg, vaddr, iova, len, 1)) {
                /* technically, this will fail if there are currently no devices
-- 
2.17.2

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