[v4,1/4] lib/eal: fix vfio unmap that fails unexpectedly
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Message ID 1567598682-2225-2-git-send-email-tallurix.chaitanya.babu@intel.com
State New
Delegated to: David Marchand
Headers show
Series
  • add unit tests for eal vfio library
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Checks

Context Check Description
ci/checkpatch success coding style OK
ci/Intel-compilation success Compilation OK

Commit Message

Chaitanya Babu, TalluriX Sept. 4, 2019, 12:04 p.m. UTC
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: 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(+)

Patch
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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