[1/3] lib/eal: fix vfio unmap that fails unexpectedly
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Commit Message
Unmap of multiple pages fails after a sequence of partial map/unmaps.
The scenario is that multiple maps are created in user_mem_maps,
after multiple map/unmap/remap sequences.
For an example,
Steps:
1. Map 3 pages together
2. Un-map page1
3. Re-map page 1
4. Un-map page 2
5. Re-map page 2
6. Un-map page 3
7. Re-map page 3
8. Un-map all pages
Unmap fails when there are duplicate entries in user_mem_maps.
The fix is to validate if the input VA, IOVA exists in
user_mem_maps before creating map.
Fixes: 73a63908 ("vfio: allow to map other memory regions")
Cc: stable@dpdk.org
Signed-off-by: Chaitanya Babu Talluri <tallurix.chaitanya.babu@intel.com>
---
lib/librte_eal/linux/eal/eal_vfio.c | 46 +++++++++++++++++++++++++++++
1 file changed, 46 insertions(+)
Comments
On 21-Aug-19 2:02 PM, Chaitanya Babu Talluri wrote:
> Unmap of multiple pages fails after a sequence of partial map/unmaps.
> The scenario is that multiple maps are created in user_mem_maps,
> after multiple map/unmap/remap sequences.
>
> For an example,
> Steps:
> 1. Map 3 pages together
> 2. Un-map page1
> 3. Re-map page 1
> 4. Un-map page 2
> 5. Re-map page 2
> 6. Un-map page 3
> 7. Re-map page 3
> 8. Un-map all pages
I don't think this description is correct in relation to what is being
fixed here. The code attempts to prevent overlaps, but there are no
overlaps in the above example - none of the above operations would
trigger the added code.
@@ -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