X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=lib%2Flibrte_eal%2Flinuxapp%2Feal%2Feal_vfio.c;h=a2bbdfbf4a6ee43f283b3fde2bf755ed9a4b7098;hb=1bd9b61222f3a81ffe770fc00b70ded6e760c42b;hp=e44ae4d04a11605e9e928a5fa22bfd386593183e;hpb=bb4e158029645f37809fcf81a3acddd6fa11f88a;p=deb_dpdk.git

diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio.c b/lib/librte_eal/linuxapp/eal/eal_vfio.c
index e44ae4d0..a2bbdfbf 100644
--- a/lib/librte_eal/linuxapp/eal/eal_vfio.c
+++ b/lib/librte_eal/linuxapp/eal/eal_vfio.c
@@ -1,12 +1,14 @@
 /* SPDX-License-Identifier: BSD-3-Clause
- * Copyright(c) 2010-2014 Intel Corporation
+ * Copyright(c) 2010-2018 Intel Corporation
  */
 
+#include <inttypes.h>
 #include <string.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <sys/ioctl.h>
 
+#include <rte_errno.h>
 #include <rte_log.h>
 #include <rte_memory.h>
 #include <rte_eal_memconfig.h>
@@ -18,59 +20,294 @@
 
 #ifdef VFIO_PRESENT
 
+#define VFIO_MEM_EVENT_CLB_NAME "vfio_mem_event_clb"
+
+/* hot plug/unplug of VFIO groups may cause all DMA maps to be dropped. we can
+ * recreate the mappings for DPDK segments, but we cannot do so for memory that
+ * was registered by the user themselves, so we need to store the user mappings
+ * somewhere, to recreate them later.
+ */
+#define VFIO_MAX_USER_MEM_MAPS 256
+struct user_mem_map {
+	uint64_t addr;
+	uint64_t iova;
+	uint64_t len;
+};
+
+struct user_mem_maps {
+	rte_spinlock_recursive_t lock;
+	int n_maps;
+	struct user_mem_map maps[VFIO_MAX_USER_MEM_MAPS];
+};
+
+struct vfio_config {
+	int vfio_enabled;
+	int vfio_container_fd;
+	int vfio_active_groups;
+	const struct vfio_iommu_type *vfio_iommu_type;
+	struct vfio_group vfio_groups[VFIO_MAX_GROUPS];
+	struct user_mem_maps mem_maps;
+};
+
 /* per-process VFIO config */
-static struct vfio_config vfio_cfg;
+static struct vfio_config vfio_cfgs[VFIO_MAX_CONTAINERS];
+static struct vfio_config *default_vfio_cfg = &vfio_cfgs[0];
 
 static int vfio_type1_dma_map(int);
+static int vfio_type1_dma_mem_map(int, uint64_t, uint64_t, uint64_t, int);
 static int vfio_spapr_dma_map(int);
+static int vfio_spapr_dma_mem_map(int, uint64_t, uint64_t, uint64_t, int);
 static int vfio_noiommu_dma_map(int);
+static int vfio_noiommu_dma_mem_map(int, uint64_t, uint64_t, uint64_t, int);
+static int vfio_dma_mem_map(struct vfio_config *vfio_cfg, uint64_t vaddr,
+		uint64_t iova, uint64_t len, int do_map);
 
 /* IOMMU types we support */
 static const struct vfio_iommu_type iommu_types[] = {
 	/* x86 IOMMU, otherwise known as type 1 */
-	{ RTE_VFIO_TYPE1, "Type 1", &vfio_type1_dma_map},
+	{
+		.type_id = RTE_VFIO_TYPE1,
+		.name = "Type 1",
+		.dma_map_func = &vfio_type1_dma_map,
+		.dma_user_map_func = &vfio_type1_dma_mem_map
+	},
 	/* ppc64 IOMMU, otherwise known as spapr */
-	{ RTE_VFIO_SPAPR, "sPAPR", &vfio_spapr_dma_map},
+	{
+		.type_id = RTE_VFIO_SPAPR,
+		.name = "sPAPR",
+		.dma_map_func = &vfio_spapr_dma_map,
+		.dma_user_map_func = &vfio_spapr_dma_mem_map
+	},
 	/* IOMMU-less mode */
-	{ RTE_VFIO_NOIOMMU, "No-IOMMU", &vfio_noiommu_dma_map},
+	{
+		.type_id = RTE_VFIO_NOIOMMU,
+		.name = "No-IOMMU",
+		.dma_map_func = &vfio_noiommu_dma_map,
+		.dma_user_map_func = &vfio_noiommu_dma_mem_map
+	},
 };
 
-int
-vfio_get_group_fd(int iommu_group_no)
+/* for sPAPR IOMMU, we will need to walk memseg list, but we cannot use
+ * rte_memseg_walk() because by the time we enter callback we will be holding a
+ * write lock, so regular rte-memseg_walk will deadlock. copying the same
+ * iteration code everywhere is not ideal as well. so, use a lockless copy of
+ * memseg walk here.
+ */
+static int
+memseg_walk_thread_unsafe(rte_memseg_walk_t func, void *arg)
 {
-	int i;
-	int vfio_group_fd;
-	char filename[PATH_MAX];
-	struct vfio_group *cur_grp;
+	struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
+	int i, ms_idx, ret = 0;
 
-	/* check if we already have the group descriptor open */
-	for (i = 0; i < VFIO_MAX_GROUPS; i++)
-		if (vfio_cfg.vfio_groups[i].group_no == iommu_group_no)
-			return vfio_cfg.vfio_groups[i].fd;
+	for (i = 0; i < RTE_MAX_MEMSEG_LISTS; i++) {
+		struct rte_memseg_list *msl = &mcfg->memsegs[i];
+		const struct rte_memseg *ms;
+		struct rte_fbarray *arr;
 
-	/* Lets see first if there is room for a new group */
-	if (vfio_cfg.vfio_active_groups == VFIO_MAX_GROUPS) {
-		RTE_LOG(ERR, EAL, "Maximum number of VFIO groups reached!\n");
-		return -1;
-	}
+		if (msl->memseg_arr.count == 0)
+			continue;
 
-	/* Now lets get an index for the new group */
-	for (i = 0; i < VFIO_MAX_GROUPS; i++)
-		if (vfio_cfg.vfio_groups[i].group_no == -1) {
-			cur_grp = &vfio_cfg.vfio_groups[i];
-			break;
+		arr = &msl->memseg_arr;
+
+		ms_idx = rte_fbarray_find_next_used(arr, 0);
+		while (ms_idx >= 0) {
+			ms = rte_fbarray_get(arr, ms_idx);
+			ret = func(msl, ms, arg);
+			if (ret < 0)
+				return -1;
+			if (ret > 0)
+				return 1;
+			ms_idx = rte_fbarray_find_next_used(arr, ms_idx + 1);
 		}
+	}
+	return 0;
+}
 
-	/* This should not happen */
-	if (i == VFIO_MAX_GROUPS) {
-		RTE_LOG(ERR, EAL, "No VFIO group free slot found\n");
+static int
+is_null_map(const struct user_mem_map *map)
+{
+	return map->addr == 0 && map->iova == 0 && map->len == 0;
+}
+
+/* we may need to merge user mem maps together in case of user mapping/unmapping
+ * chunks of memory, so we'll need a comparator function to sort segments.
+ */
+static int
+user_mem_map_cmp(const void *a, const void *b)
+{
+	const struct user_mem_map *umm_a = a;
+	const struct user_mem_map *umm_b = b;
+
+	/* move null entries to end */
+	if (is_null_map(umm_a))
+		return 1;
+	if (is_null_map(umm_b))
+		return -1;
+
+	/* sort by iova first */
+	if (umm_a->iova < umm_b->iova)
+		return -1;
+	if (umm_a->iova > umm_b->iova)
+		return 1;
+
+	if (umm_a->addr < umm_b->addr)
+		return -1;
+	if (umm_a->addr > umm_b->addr)
+		return 1;
+
+	if (umm_a->len < umm_b->len)
 		return -1;
+	if (umm_a->len > umm_b->len)
+		return 1;
+
+	return 0;
+}
+
+/* adjust user map entry. this may result in shortening of existing map, or in
+ * splitting existing map in two pieces.
+ */
+static void
+adjust_map(struct user_mem_map *src, struct user_mem_map *end,
+		uint64_t remove_va_start, uint64_t remove_len)
+{
+	/* if va start is same as start address, we're simply moving start */
+	if (remove_va_start == src->addr) {
+		src->addr += remove_len;
+		src->iova += remove_len;
+		src->len -= remove_len;
+	} else if (remove_va_start + remove_len == src->addr + src->len) {
+		/* we're shrinking mapping from the end */
+		src->len -= remove_len;
+	} else {
+		/* we're blowing a hole in the middle */
+		struct user_mem_map tmp;
+		uint64_t total_len = src->len;
+
+		/* adjust source segment length */
+		src->len = remove_va_start - src->addr;
+
+		/* create temporary segment in the middle */
+		tmp.addr = src->addr + src->len;
+		tmp.iova = src->iova + src->len;
+		tmp.len = remove_len;
+
+		/* populate end segment - this one we will be keeping */
+		end->addr = tmp.addr + tmp.len;
+		end->iova = tmp.iova + tmp.len;
+		end->len = total_len - src->len - tmp.len;
+	}
+}
+
+/* try merging two maps into one, return 1 if succeeded */
+static int
+merge_map(struct user_mem_map *left, struct user_mem_map *right)
+{
+	if (left->addr + left->len != right->addr)
+		return 0;
+	if (left->iova + left->len != right->iova)
+		return 0;
+
+	left->len += right->len;
+
+	memset(right, 0, sizeof(*right));
+
+	return 1;
+}
+
+static struct user_mem_map *
+find_user_mem_map(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;
+
+		/* check start VA */
+		if (addr < map->addr || addr >= map_va_end)
+			continue;
+		/* check if VA end is within boundaries */
+		if (va_end <= map->addr || va_end > map_va_end)
+			continue;
+
+		/* check start IOVA */
+		if (iova < map->iova || iova >= map_iova_end)
+			continue;
+		/* check if IOVA end is within boundaries */
+		if (iova_end <= map->iova || iova_end > map_iova_end)
+			continue;
+
+		/* we've found our map */
+		return map;
+	}
+	return NULL;
+}
+
+/* this will sort all user maps, and merge/compact any adjacent maps */
+static void
+compact_user_maps(struct user_mem_maps *user_mem_maps)
+{
+	int i, n_merged, cur_idx;
+
+	qsort(user_mem_maps->maps, user_mem_maps->n_maps,
+			sizeof(user_mem_maps->maps[0]), user_mem_map_cmp);
+
+	/* we'll go over the list backwards when merging */
+	n_merged = 0;
+	for (i = user_mem_maps->n_maps - 2; i >= 0; i--) {
+		struct user_mem_map *l, *r;
+
+		l = &user_mem_maps->maps[i];
+		r = &user_mem_maps->maps[i + 1];
+
+		if (is_null_map(l) || is_null_map(r))
+			continue;
+
+		if (merge_map(l, r))
+			n_merged++;
+	}
+
+	/* the entries are still sorted, but now they have holes in them, so
+	 * walk through the list and remove the holes
+	 */
+	if (n_merged > 0) {
+		cur_idx = 0;
+		for (i = 0; i < user_mem_maps->n_maps; i++) {
+			if (!is_null_map(&user_mem_maps->maps[i])) {
+				struct user_mem_map *src, *dst;
+
+				src = &user_mem_maps->maps[i];
+				dst = &user_mem_maps->maps[cur_idx++];
+
+				if (src != dst) {
+					memcpy(dst, src, sizeof(*src));
+					memset(src, 0, sizeof(*src));
+				}
+			}
+		}
+		user_mem_maps->n_maps = cur_idx;
 	}
+}
+
+static int
+vfio_open_group_fd(int iommu_group_num)
+{
+	int vfio_group_fd;
+	char filename[PATH_MAX];
+	struct rte_mp_msg mp_req, *mp_rep;
+	struct rte_mp_reply mp_reply;
+	struct timespec ts = {.tv_sec = 5, .tv_nsec = 0};
+	struct vfio_mp_param *p = (struct vfio_mp_param *)mp_req.param;
+
 	/* if primary, try to open the group */
 	if (internal_config.process_type == RTE_PROC_PRIMARY) {
 		/* try regular group format */
 		snprintf(filename, sizeof(filename),
-				 VFIO_GROUP_FMT, iommu_group_no);
+				 VFIO_GROUP_FMT, iommu_group_num);
 		vfio_group_fd = open(filename, O_RDWR);
 		if (vfio_group_fd < 0) {
 			/* if file not found, it's not an error */
@@ -82,7 +319,8 @@ vfio_get_group_fd(int iommu_group_no)
 
 			/* special case: try no-IOMMU path as well */
 			snprintf(filename, sizeof(filename),
-					VFIO_NOIOMMU_GROUP_FMT, iommu_group_no);
+					VFIO_NOIOMMU_GROUP_FMT,
+					iommu_group_num);
 			vfio_group_fd = open(filename, O_RDWR);
 			if (vfio_group_fd < 0) {
 				if (errno != ENOENT) {
@@ -95,162 +333,293 @@ vfio_get_group_fd(int iommu_group_no)
 			/* noiommu group found */
 		}
 
-		cur_grp->group_no = iommu_group_no;
-		cur_grp->fd = vfio_group_fd;
-		vfio_cfg.vfio_active_groups++;
 		return vfio_group_fd;
 	}
 	/* if we're in a secondary process, request group fd from the primary
-	 * process via our socket
+	 * process via mp channel.
 	 */
-	else {
-		int socket_fd, ret;
+	p->req = SOCKET_REQ_GROUP;
+	p->group_num = iommu_group_num;
+	strcpy(mp_req.name, EAL_VFIO_MP);
+	mp_req.len_param = sizeof(*p);
+	mp_req.num_fds = 0;
+
+	vfio_group_fd = -1;
+	if (rte_mp_request_sync(&mp_req, &mp_reply, &ts) == 0 &&
+	    mp_reply.nb_received == 1) {
+		mp_rep = &mp_reply.msgs[0];
+		p = (struct vfio_mp_param *)mp_rep->param;
+		if (p->result == SOCKET_OK && mp_rep->num_fds == 1) {
+			vfio_group_fd = mp_rep->fds[0];
+		} else if (p->result == SOCKET_NO_FD) {
+			RTE_LOG(ERR, EAL, "  bad VFIO group fd\n");
+			vfio_group_fd = 0;
+		}
+		free(mp_reply.msgs);
+	}
 
-		socket_fd = vfio_mp_sync_connect_to_primary();
+	if (vfio_group_fd < 0)
+		RTE_LOG(ERR, EAL, "  cannot request group fd\n");
+	return vfio_group_fd;
+}
 
-		if (socket_fd < 0) {
-			RTE_LOG(ERR, EAL, "  cannot connect to primary process!\n");
-			return -1;
-		}
-		if (vfio_mp_sync_send_request(socket_fd, SOCKET_REQ_GROUP) < 0) {
-			RTE_LOG(ERR, EAL, "  cannot request container fd!\n");
-			close(socket_fd);
-			return -1;
-		}
-		if (vfio_mp_sync_send_request(socket_fd, iommu_group_no) < 0) {
-			RTE_LOG(ERR, EAL, "  cannot send group number!\n");
-			close(socket_fd);
-			return -1;
-		}
-		ret = vfio_mp_sync_receive_request(socket_fd);
-		switch (ret) {
-		case SOCKET_NO_FD:
-			close(socket_fd);
-			return 0;
-		case SOCKET_OK:
-			vfio_group_fd = vfio_mp_sync_receive_fd(socket_fd);
-			/* if we got the fd, store it and return it */
-			if (vfio_group_fd > 0) {
-				close(socket_fd);
-				cur_grp->group_no = iommu_group_no;
-				cur_grp->fd = vfio_group_fd;
-				vfio_cfg.vfio_active_groups++;
-				return vfio_group_fd;
-			}
-			/* fall-through on error */
-		default:
-			RTE_LOG(ERR, EAL, "  cannot get container fd!\n");
-			close(socket_fd);
-			return -1;
+static struct vfio_config *
+get_vfio_cfg_by_group_num(int iommu_group_num)
+{
+	struct vfio_config *vfio_cfg;
+	int i, j;
+
+	for (i = 0; i < VFIO_MAX_CONTAINERS; i++) {
+		vfio_cfg = &vfio_cfgs[i];
+		for (j = 0; j < VFIO_MAX_GROUPS; j++) {
+			if (vfio_cfg->vfio_groups[j].group_num ==
+					iommu_group_num)
+				return vfio_cfg;
 		}
 	}
-	return -1;
+
+	return NULL;
 }
 
+static struct vfio_config *
+get_vfio_cfg_by_group_fd(int vfio_group_fd)
+{
+	struct vfio_config *vfio_cfg;
+	int i, j;
+
+	for (i = 0; i < VFIO_MAX_CONTAINERS; i++) {
+		vfio_cfg = &vfio_cfgs[i];
+		for (j = 0; j < VFIO_MAX_GROUPS; j++)
+			if (vfio_cfg->vfio_groups[j].fd == vfio_group_fd)
+				return vfio_cfg;
+	}
 
-static int
-get_vfio_group_idx(int vfio_group_fd)
+	return NULL;
+}
+
+static struct vfio_config *
+get_vfio_cfg_by_container_fd(int container_fd)
+{
+	int i;
+
+	for (i = 0; i < VFIO_MAX_CONTAINERS; i++) {
+		if (vfio_cfgs[i].vfio_container_fd == container_fd)
+			return &vfio_cfgs[i];
+	}
+
+	return NULL;
+}
+
+int
+rte_vfio_get_group_fd(int iommu_group_num)
 {
 	int i;
+	int vfio_group_fd;
+	struct vfio_group *cur_grp;
+	struct vfio_config *vfio_cfg;
+
+	/* get the vfio_config it belongs to */
+	vfio_cfg = get_vfio_cfg_by_group_num(iommu_group_num);
+	vfio_cfg = vfio_cfg ? vfio_cfg : default_vfio_cfg;
+
+	/* check if we already have the group descriptor open */
+	for (i = 0; i < VFIO_MAX_GROUPS; i++)
+		if (vfio_cfg->vfio_groups[i].group_num == iommu_group_num)
+			return vfio_cfg->vfio_groups[i].fd;
+
+	/* Lets see first if there is room for a new group */
+	if (vfio_cfg->vfio_active_groups == VFIO_MAX_GROUPS) {
+		RTE_LOG(ERR, EAL, "Maximum number of VFIO groups reached!\n");
+		return -1;
+	}
+
+	/* Now lets get an index for the new group */
 	for (i = 0; i < VFIO_MAX_GROUPS; i++)
-		if (vfio_cfg.vfio_groups[i].fd == vfio_group_fd)
-			return i;
+		if (vfio_cfg->vfio_groups[i].group_num == -1) {
+			cur_grp = &vfio_cfg->vfio_groups[i];
+			break;
+		}
+
+	/* This should not happen */
+	if (i == VFIO_MAX_GROUPS) {
+		RTE_LOG(ERR, EAL, "No VFIO group free slot found\n");
+		return -1;
+	}
+
+	vfio_group_fd = vfio_open_group_fd(iommu_group_num);
+	if (vfio_group_fd < 0) {
+		RTE_LOG(ERR, EAL, "Failed to open group %d\n", iommu_group_num);
+		return -1;
+	}
+
+	cur_grp->group_num = iommu_group_num;
+	cur_grp->fd = vfio_group_fd;
+	vfio_cfg->vfio_active_groups++;
+
+	return vfio_group_fd;
+}
+
+static int
+get_vfio_group_idx(int vfio_group_fd)
+{
+	struct vfio_config *vfio_cfg;
+	int i, j;
+
+	for (i = 0; i < VFIO_MAX_CONTAINERS; i++) {
+		vfio_cfg = &vfio_cfgs[i];
+		for (j = 0; j < VFIO_MAX_GROUPS; j++)
+			if (vfio_cfg->vfio_groups[j].fd == vfio_group_fd)
+				return j;
+	}
+
 	return -1;
 }
 
 static void
 vfio_group_device_get(int vfio_group_fd)
 {
+	struct vfio_config *vfio_cfg;
 	int i;
 
+	vfio_cfg = get_vfio_cfg_by_group_fd(vfio_group_fd);
+	if (vfio_cfg == NULL) {
+		RTE_LOG(ERR, EAL, "  invalid group fd!\n");
+		return;
+	}
+
 	i = get_vfio_group_idx(vfio_group_fd);
 	if (i < 0 || i > (VFIO_MAX_GROUPS - 1))
 		RTE_LOG(ERR, EAL, "  wrong vfio_group index (%d)\n", i);
 	else
-		vfio_cfg.vfio_groups[i].devices++;
+		vfio_cfg->vfio_groups[i].devices++;
 }
 
 static void
 vfio_group_device_put(int vfio_group_fd)
 {
+	struct vfio_config *vfio_cfg;
 	int i;
 
+	vfio_cfg = get_vfio_cfg_by_group_fd(vfio_group_fd);
+	if (vfio_cfg == NULL) {
+		RTE_LOG(ERR, EAL, "  invalid group fd!\n");
+		return;
+	}
+
 	i = get_vfio_group_idx(vfio_group_fd);
 	if (i < 0 || i > (VFIO_MAX_GROUPS - 1))
 		RTE_LOG(ERR, EAL, "  wrong vfio_group index (%d)\n", i);
 	else
-		vfio_cfg.vfio_groups[i].devices--;
+		vfio_cfg->vfio_groups[i].devices--;
 }
 
 static int
 vfio_group_device_count(int vfio_group_fd)
 {
+	struct vfio_config *vfio_cfg;
 	int i;
 
+	vfio_cfg = get_vfio_cfg_by_group_fd(vfio_group_fd);
+	if (vfio_cfg == NULL) {
+		RTE_LOG(ERR, EAL, "  invalid group fd!\n");
+		return -1;
+	}
+
 	i = get_vfio_group_idx(vfio_group_fd);
 	if (i < 0 || i > (VFIO_MAX_GROUPS - 1)) {
 		RTE_LOG(ERR, EAL, "  wrong vfio_group index (%d)\n", i);
 		return -1;
 	}
 
-	return vfio_cfg.vfio_groups[i].devices;
+	return vfio_cfg->vfio_groups[i].devices;
+}
+
+static void
+vfio_mem_event_callback(enum rte_mem_event type, const void *addr, size_t len,
+		void *arg __rte_unused)
+{
+	struct rte_memseg_list *msl;
+	struct rte_memseg *ms;
+	size_t cur_len = 0;
+
+	msl = rte_mem_virt2memseg_list(addr);
+
+	/* for IOVA as VA mode, no need to care for IOVA addresses */
+	if (rte_eal_iova_mode() == RTE_IOVA_VA) {
+		uint64_t vfio_va = (uint64_t)(uintptr_t)addr;
+		if (type == RTE_MEM_EVENT_ALLOC)
+			vfio_dma_mem_map(default_vfio_cfg, vfio_va, vfio_va,
+					len, 1);
+		else
+			vfio_dma_mem_map(default_vfio_cfg, vfio_va, vfio_va,
+					len, 0);
+		return;
+	}
+
+	/* memsegs are contiguous in memory */
+	ms = rte_mem_virt2memseg(addr, msl);
+	while (cur_len < len) {
+		if (type == RTE_MEM_EVENT_ALLOC)
+			vfio_dma_mem_map(default_vfio_cfg, ms->addr_64,
+					ms->iova, ms->len, 1);
+		else
+			vfio_dma_mem_map(default_vfio_cfg, ms->addr_64,
+					ms->iova, ms->len, 0);
+
+		cur_len += ms->len;
+		++ms;
+	}
 }
 
 int
 rte_vfio_clear_group(int vfio_group_fd)
 {
 	int i;
-	int socket_fd, ret;
+	struct rte_mp_msg mp_req, *mp_rep;
+	struct rte_mp_reply mp_reply;
+	struct timespec ts = {.tv_sec = 5, .tv_nsec = 0};
+	struct vfio_mp_param *p = (struct vfio_mp_param *)mp_req.param;
+	struct vfio_config *vfio_cfg;
+
+	vfio_cfg = get_vfio_cfg_by_group_fd(vfio_group_fd);
+	if (vfio_cfg == NULL) {
+		RTE_LOG(ERR, EAL, "  invalid group fd!\n");
+		return -1;
+	}
 
 	if (internal_config.process_type == RTE_PROC_PRIMARY) {
 
 		i = get_vfio_group_idx(vfio_group_fd);
 		if (i < 0)
 			return -1;
-		vfio_cfg.vfio_groups[i].group_no = -1;
-		vfio_cfg.vfio_groups[i].fd = -1;
-		vfio_cfg.vfio_groups[i].devices = 0;
-		vfio_cfg.vfio_active_groups--;
+		vfio_cfg->vfio_groups[i].group_num = -1;
+		vfio_cfg->vfio_groups[i].fd = -1;
+		vfio_cfg->vfio_groups[i].devices = 0;
+		vfio_cfg->vfio_active_groups--;
 		return 0;
 	}
 
-	/* This is just for SECONDARY processes */
-	socket_fd = vfio_mp_sync_connect_to_primary();
-
-	if (socket_fd < 0) {
-		RTE_LOG(ERR, EAL, "  cannot connect to primary process!\n");
-		return -1;
-	}
-
-	if (vfio_mp_sync_send_request(socket_fd, SOCKET_CLR_GROUP) < 0) {
-		RTE_LOG(ERR, EAL, "  cannot request container fd!\n");
-		close(socket_fd);
-		return -1;
-	}
+	p->req = SOCKET_CLR_GROUP;
+	p->group_num = vfio_group_fd;
+	strcpy(mp_req.name, EAL_VFIO_MP);
+	mp_req.len_param = sizeof(*p);
+	mp_req.num_fds = 0;
+
+	if (rte_mp_request_sync(&mp_req, &mp_reply, &ts) == 0 &&
+	    mp_reply.nb_received == 1) {
+		mp_rep = &mp_reply.msgs[0];
+		p = (struct vfio_mp_param *)mp_rep->param;
+		if (p->result == SOCKET_OK) {
+			free(mp_reply.msgs);
+			return 0;
+		} else if (p->result == SOCKET_NO_FD)
+			RTE_LOG(ERR, EAL, "  BAD VFIO group fd!\n");
+		else
+			RTE_LOG(ERR, EAL, "  no such VFIO group fd!\n");
 
-	if (vfio_mp_sync_send_request(socket_fd, vfio_group_fd) < 0) {
-		RTE_LOG(ERR, EAL, "  cannot send group fd!\n");
-		close(socket_fd);
-		return -1;
+		free(mp_reply.msgs);
 	}
 
-	ret = vfio_mp_sync_receive_request(socket_fd);
-	switch (ret) {
-	case SOCKET_NO_FD:
-		RTE_LOG(ERR, EAL, "  BAD VFIO group fd!\n");
-		close(socket_fd);
-		break;
-	case SOCKET_OK:
-		close(socket_fd);
-		return 0;
-	case SOCKET_ERR:
-		RTE_LOG(ERR, EAL, "  Socket error\n");
-		close(socket_fd);
-		break;
-	default:
-		RTE_LOG(ERR, EAL, "  UNKNOWN reply, %d\n", ret);
-		close(socket_fd);
-	}
 	return -1;
 }
 
@@ -258,15 +627,20 @@ int
 rte_vfio_setup_device(const char *sysfs_base, const char *dev_addr,
 		int *vfio_dev_fd, struct vfio_device_info *device_info)
 {
+	struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
+	rte_rwlock_t *mem_lock = &mcfg->memory_hotplug_lock;
 	struct vfio_group_status group_status = {
 			.argsz = sizeof(group_status)
 	};
+	struct vfio_config *vfio_cfg;
+	struct user_mem_maps *user_mem_maps;
+	int vfio_container_fd;
 	int vfio_group_fd;
-	int iommu_group_no;
-	int ret;
+	int iommu_group_num;
+	int i, ret;
 
 	/* get group number */
-	ret = vfio_get_group_no(sysfs_base, dev_addr, &iommu_group_no);
+	ret = rte_vfio_get_group_num(sysfs_base, dev_addr, &iommu_group_num);
 	if (ret == 0) {
 		RTE_LOG(WARNING, EAL, "  %s not managed by VFIO driver, skipping\n",
 			dev_addr);
@@ -278,7 +652,7 @@ rte_vfio_setup_device(const char *sysfs_base, const char *dev_addr,
 		return -1;
 
 	/* get the actual group fd */
-	vfio_group_fd = vfio_get_group_fd(iommu_group_no);
+	vfio_group_fd = rte_vfio_get_group_fd(iommu_group_num);
 	if (vfio_group_fd < 0)
 		return -1;
 
@@ -309,12 +683,18 @@ rte_vfio_setup_device(const char *sysfs_base, const char *dev_addr,
 		return -1;
 	}
 
+	/* get the vfio_config it belongs to */
+	vfio_cfg = get_vfio_cfg_by_group_num(iommu_group_num);
+	vfio_cfg = vfio_cfg ? vfio_cfg : default_vfio_cfg;
+	vfio_container_fd = vfio_cfg->vfio_container_fd;
+	user_mem_maps = &vfio_cfg->mem_maps;
+
 	/* check if group does not have a container yet */
 	if (!(group_status.flags & VFIO_GROUP_FLAGS_CONTAINER_SET)) {
 
 		/* add group to a container */
 		ret = ioctl(vfio_group_fd, VFIO_GROUP_SET_CONTAINER,
-				&vfio_cfg.vfio_container_fd);
+				&vfio_container_fd);
 		if (ret) {
 			RTE_LOG(ERR, EAL, "  %s cannot add VFIO group to container, "
 					"error %i (%s)\n", dev_addr, errno, strerror(errno));
@@ -332,10 +712,12 @@ rte_vfio_setup_device(const char *sysfs_base, const char *dev_addr,
 		 * functionality.
 		 */
 		if (internal_config.process_type == RTE_PROC_PRIMARY &&
-				vfio_cfg.vfio_active_groups == 1) {
+				vfio_cfg->vfio_active_groups == 1 &&
+				vfio_group_device_count(vfio_group_fd) == 0) {
+			const struct vfio_iommu_type *t;
+
 			/* select an IOMMU type which we will be using */
-			const struct vfio_iommu_type *t =
-				vfio_set_iommu_type(vfio_cfg.vfio_container_fd);
+			t = vfio_set_iommu_type(vfio_container_fd);
 			if (!t) {
 				RTE_LOG(ERR, EAL,
 					"  %s failed to select IOMMU type\n",
@@ -344,15 +726,75 @@ rte_vfio_setup_device(const char *sysfs_base, const char *dev_addr,
 				rte_vfio_clear_group(vfio_group_fd);
 				return -1;
 			}
-			ret = t->dma_map_func(vfio_cfg.vfio_container_fd);
+			/* lock memory hotplug before mapping and release it
+			 * after registering callback, to prevent races
+			 */
+			rte_rwlock_read_lock(mem_lock);
+			if (vfio_cfg == default_vfio_cfg)
+				ret = t->dma_map_func(vfio_container_fd);
+			else
+				ret = 0;
 			if (ret) {
 				RTE_LOG(ERR, EAL,
 					"  %s DMA remapping failed, error %i (%s)\n",
 					dev_addr, errno, strerror(errno));
 				close(vfio_group_fd);
 				rte_vfio_clear_group(vfio_group_fd);
+				rte_rwlock_read_unlock(mem_lock);
+				return -1;
+			}
+
+			vfio_cfg->vfio_iommu_type = t;
+
+			/* re-map all user-mapped segments */
+			rte_spinlock_recursive_lock(&user_mem_maps->lock);
+
+			/* this IOMMU type may not support DMA mapping, but
+			 * if we have mappings in the list - that means we have
+			 * previously mapped something successfully, so we can
+			 * be sure that DMA mapping is supported.
+			 */
+			for (i = 0; i < user_mem_maps->n_maps; i++) {
+				struct user_mem_map *map;
+				map = &user_mem_maps->maps[i];
+
+				ret = t->dma_user_map_func(
+						vfio_container_fd,
+						map->addr, map->iova, map->len,
+						1);
+				if (ret) {
+					RTE_LOG(ERR, EAL, "Couldn't map user memory for DMA: "
+							"va: 0x%" PRIx64 " "
+							"iova: 0x%" PRIx64 " "
+							"len: 0x%" PRIu64 "\n",
+							map->addr, map->iova,
+							map->len);
+					rte_spinlock_recursive_unlock(
+							&user_mem_maps->lock);
+					rte_rwlock_read_unlock(mem_lock);
+					return -1;
+				}
+			}
+			rte_spinlock_recursive_unlock(&user_mem_maps->lock);
+
+			/* register callback for mem events */
+			if (vfio_cfg == default_vfio_cfg)
+				ret = rte_mem_event_callback_register(
+					VFIO_MEM_EVENT_CLB_NAME,
+					vfio_mem_event_callback, NULL);
+			else
+				ret = 0;
+			/* unlock memory hotplug */
+			rte_rwlock_read_unlock(mem_lock);
+
+			if (ret && rte_errno != ENOTSUP) {
+				RTE_LOG(ERR, EAL, "Could not install memory event callback for VFIO\n");
 				return -1;
 			}
+			if (ret)
+				RTE_LOG(DEBUG, EAL, "Memory event callbacks not supported\n");
+			else
+				RTE_LOG(DEBUG, EAL, "Installed memory event callback for VFIO\n");
 		}
 	}
 
@@ -390,30 +832,45 @@ int
 rte_vfio_release_device(const char *sysfs_base, const char *dev_addr,
 		    int vfio_dev_fd)
 {
+	struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
+	rte_rwlock_t *mem_lock = &mcfg->memory_hotplug_lock;
 	struct vfio_group_status group_status = {
 			.argsz = sizeof(group_status)
 	};
+	struct vfio_config *vfio_cfg;
 	int vfio_group_fd;
-	int iommu_group_no;
+	int iommu_group_num;
 	int ret;
 
+	/* we don't want any DMA mapping messages to come while we're detaching
+	 * VFIO device, because this might be the last device and we might need
+	 * to unregister the callback.
+	 */
+	rte_rwlock_read_lock(mem_lock);
+
 	/* get group number */
-	ret = vfio_get_group_no(sysfs_base, dev_addr, &iommu_group_no);
+	ret = rte_vfio_get_group_num(sysfs_base, dev_addr, &iommu_group_num);
 	if (ret <= 0) {
 		RTE_LOG(WARNING, EAL, "  %s not managed by VFIO driver\n",
 			dev_addr);
 		/* This is an error at this point. */
-		return -1;
+		ret = -1;
+		goto out;
 	}
 
 	/* get the actual group fd */
-	vfio_group_fd = vfio_get_group_fd(iommu_group_no);
+	vfio_group_fd = rte_vfio_get_group_fd(iommu_group_num);
 	if (vfio_group_fd <= 0) {
-		RTE_LOG(INFO, EAL, "vfio_get_group_fd failed for %s\n",
+		RTE_LOG(INFO, EAL, "rte_vfio_get_group_fd failed for %s\n",
 				   dev_addr);
-		return -1;
+		ret = -1;
+		goto out;
 	}
 
+	/* get the vfio_config it belongs to */
+	vfio_cfg = get_vfio_cfg_by_group_num(iommu_group_num);
+	vfio_cfg = vfio_cfg ? vfio_cfg : default_vfio_cfg;
+
 	/* At this point we got an active group. Closing it will make the
 	 * container detachment. If this is the last active group, VFIO kernel
 	 * code will unset the container and the IOMMU mappings.
@@ -423,7 +880,8 @@ rte_vfio_release_device(const char *sysfs_base, const char *dev_addr,
 	if (close(vfio_dev_fd) < 0) {
 		RTE_LOG(INFO, EAL, "Error when closing vfio_dev_fd for %s\n",
 				   dev_addr);
-		return -1;
+		ret = -1;
+		goto out;
 	}
 
 	/* An VFIO group can have several devices attached. Just when there is
@@ -435,30 +893,53 @@ rte_vfio_release_device(const char *sysfs_base, const char *dev_addr,
 		if (close(vfio_group_fd) < 0) {
 			RTE_LOG(INFO, EAL, "Error when closing vfio_group_fd for %s\n",
 				dev_addr);
-			return -1;
+			ret = -1;
+			goto out;
 		}
 
 		if (rte_vfio_clear_group(vfio_group_fd) < 0) {
 			RTE_LOG(INFO, EAL, "Error when clearing group for %s\n",
 					   dev_addr);
-			return -1;
+			ret = -1;
+			goto out;
 		}
 	}
 
-	return 0;
+	/* if there are no active device groups, unregister the callback to
+	 * avoid spurious attempts to map/unmap memory from VFIO.
+	 */
+	if (vfio_cfg == default_vfio_cfg && vfio_cfg->vfio_active_groups == 0)
+		rte_mem_event_callback_unregister(VFIO_MEM_EVENT_CLB_NAME,
+				NULL);
+
+	/* success */
+	ret = 0;
+
+out:
+	rte_rwlock_read_unlock(mem_lock);
+	return ret;
 }
 
 int
 rte_vfio_enable(const char *modname)
 {
 	/* initialize group list */
-	int i;
+	int i, j;
 	int vfio_available;
 
-	for (i = 0; i < VFIO_MAX_GROUPS; i++) {
-		vfio_cfg.vfio_groups[i].fd = -1;
-		vfio_cfg.vfio_groups[i].group_no = -1;
-		vfio_cfg.vfio_groups[i].devices = 0;
+	rte_spinlock_recursive_t lock = RTE_SPINLOCK_RECURSIVE_INITIALIZER;
+
+	for (i = 0; i < VFIO_MAX_CONTAINERS; i++) {
+		vfio_cfgs[i].vfio_container_fd = -1;
+		vfio_cfgs[i].vfio_active_groups = 0;
+		vfio_cfgs[i].vfio_iommu_type = NULL;
+		vfio_cfgs[i].mem_maps.lock = lock;
+
+		for (j = 0; j < VFIO_MAX_GROUPS; j++) {
+			vfio_cfgs[i].vfio_groups[j].fd = -1;
+			vfio_cfgs[i].vfio_groups[j].group_num = -1;
+			vfio_cfgs[i].vfio_groups[j].devices = 0;
+		}
 	}
 
 	/* inform the user that we are probing for VFIO */
@@ -480,12 +961,12 @@ rte_vfio_enable(const char *modname)
 		return 0;
 	}
 
-	vfio_cfg.vfio_container_fd = vfio_get_container_fd();
+	default_vfio_cfg->vfio_container_fd = rte_vfio_get_container_fd();
 
 	/* check if we have VFIO driver enabled */
-	if (vfio_cfg.vfio_container_fd != -1) {
+	if (default_vfio_cfg->vfio_container_fd != -1) {
 		RTE_LOG(NOTICE, EAL, "VFIO support initialized\n");
-		vfio_cfg.vfio_enabled = 1;
+		default_vfio_cfg->vfio_enabled = 1;
 	} else {
 		RTE_LOG(NOTICE, EAL, "VFIO support could not be initialized\n");
 	}
@@ -497,7 +978,7 @@ int
 rte_vfio_is_enabled(const char *modname)
 {
 	const int mod_available = rte_eal_check_module(modname) > 0;
-	return vfio_cfg.vfio_enabled && mod_available;
+	return default_vfio_cfg->vfio_enabled && mod_available;
 }
 
 const struct vfio_iommu_type *
@@ -558,9 +1039,14 @@ vfio_has_supported_extensions(int vfio_container_fd)
 }
 
 int
-vfio_get_container_fd(void)
+rte_vfio_get_container_fd(void)
 {
 	int ret, vfio_container_fd;
+	struct rte_mp_msg mp_req, *mp_rep;
+	struct rte_mp_reply mp_reply;
+	struct timespec ts = {.tv_sec = 5, .tv_nsec = 0};
+	struct vfio_mp_param *p = (struct vfio_mp_param *)mp_req.param;
+
 
 	/* if we're in a primary process, try to open the container */
 	if (internal_config.process_type == RTE_PROC_PRIMARY) {
@@ -591,39 +1077,35 @@ vfio_get_container_fd(void)
 		}
 
 		return vfio_container_fd;
-	} else {
-		/*
-		 * if we're in a secondary process, request container fd from the
-		 * primary process via our socket
-		 */
-		int socket_fd;
-
-		socket_fd = vfio_mp_sync_connect_to_primary();
-		if (socket_fd < 0) {
-			RTE_LOG(ERR, EAL, "  cannot connect to primary process!\n");
-			return -1;
-		}
-		if (vfio_mp_sync_send_request(socket_fd, SOCKET_REQ_CONTAINER) < 0) {
-			RTE_LOG(ERR, EAL, "  cannot request container fd!\n");
-			close(socket_fd);
-			return -1;
-		}
-		vfio_container_fd = vfio_mp_sync_receive_fd(socket_fd);
-		if (vfio_container_fd < 0) {
-			RTE_LOG(ERR, EAL, "  cannot get container fd!\n");
-			close(socket_fd);
-			return -1;
+	}
+	/*
+	 * if we're in a secondary process, request container fd from the
+	 * primary process via mp channel
+	 */
+	p->req = SOCKET_REQ_CONTAINER;
+	strcpy(mp_req.name, EAL_VFIO_MP);
+	mp_req.len_param = sizeof(*p);
+	mp_req.num_fds = 0;
+
+	vfio_container_fd = -1;
+	if (rte_mp_request_sync(&mp_req, &mp_reply, &ts) == 0 &&
+	    mp_reply.nb_received == 1) {
+		mp_rep = &mp_reply.msgs[0];
+		p = (struct vfio_mp_param *)mp_rep->param;
+		if (p->result == SOCKET_OK && mp_rep->num_fds == 1) {
+			free(mp_reply.msgs);
+			return mp_rep->fds[0];
 		}
-		close(socket_fd);
-		return vfio_container_fd;
+		free(mp_reply.msgs);
 	}
 
+	RTE_LOG(ERR, EAL, "  cannot request container fd\n");
 	return -1;
 }
 
 int
-vfio_get_group_no(const char *sysfs_base,
-		const char *dev_addr, int *iommu_group_no)
+rte_vfio_get_group_num(const char *sysfs_base,
+		const char *dev_addr, int *iommu_group_num)
 {
 	char linkname[PATH_MAX];
 	char filename[PATH_MAX];
@@ -655,7 +1137,7 @@ vfio_get_group_no(const char *sysfs_base,
 	errno = 0;
 	group_tok = tok[ret - 1];
 	end = group_tok;
-	*iommu_group_no = strtol(group_tok, &end, 10);
+	*iommu_group_num = strtol(group_tok, &end, 10);
 	if ((end != group_tok && *end != '\0') || errno != 0) {
 		RTE_LOG(ERR, EAL, "  %s error parsing IOMMU number!\n", dev_addr);
 		return -1;
@@ -665,60 +1147,158 @@ vfio_get_group_no(const char *sysfs_base,
 }
 
 static int
-vfio_type1_dma_map(int vfio_container_fd)
+type1_map(const struct rte_memseg_list *msl __rte_unused,
+		const struct rte_memseg *ms, void *arg)
 {
-	const struct rte_memseg *ms = rte_eal_get_physmem_layout();
-	int i, ret;
+	int *vfio_container_fd = arg;
 
-	/* map all DPDK segments for DMA. use 1:1 PA to IOVA mapping */
-	for (i = 0; i < RTE_MAX_MEMSEG; i++) {
-		struct vfio_iommu_type1_dma_map dma_map;
+	return vfio_type1_dma_mem_map(*vfio_container_fd, ms->addr_64, ms->iova,
+			ms->len, 1);
+}
 
-		if (ms[i].addr == NULL)
-			break;
+static int
+vfio_type1_dma_mem_map(int vfio_container_fd, uint64_t vaddr, uint64_t iova,
+		uint64_t len, int do_map)
+{
+	struct vfio_iommu_type1_dma_map dma_map;
+	struct vfio_iommu_type1_dma_unmap dma_unmap;
+	int ret;
 
+	if (do_map != 0) {
 		memset(&dma_map, 0, sizeof(dma_map));
 		dma_map.argsz = sizeof(struct vfio_iommu_type1_dma_map);
-		dma_map.vaddr = ms[i].addr_64;
-		dma_map.size = ms[i].len;
-		if (rte_eal_iova_mode() == RTE_IOVA_VA)
-			dma_map.iova = dma_map.vaddr;
-		else
-			dma_map.iova = ms[i].iova;
-		dma_map.flags = VFIO_DMA_MAP_FLAG_READ | VFIO_DMA_MAP_FLAG_WRITE;
+		dma_map.vaddr = vaddr;
+		dma_map.size = len;
+		dma_map.iova = iova;
+		dma_map.flags = VFIO_DMA_MAP_FLAG_READ |
+				VFIO_DMA_MAP_FLAG_WRITE;
 
 		ret = ioctl(vfio_container_fd, VFIO_IOMMU_MAP_DMA, &dma_map);
-
 		if (ret) {
-			RTE_LOG(ERR, EAL, "  cannot set up DMA remapping, "
-					  "error %i (%s)\n", errno,
-					  strerror(errno));
-			return -1;
+			RTE_LOG(ERR, EAL, "  cannot set up DMA remapping, error %i (%s)\n",
+				errno, strerror(errno));
+				return -1;
 		}
-	}
+	} else {
+		memset(&dma_unmap, 0, sizeof(dma_unmap));
+		dma_unmap.argsz = sizeof(struct vfio_iommu_type1_dma_unmap);
+		dma_unmap.size = len;
+		dma_unmap.iova = iova;
+
+		ret = ioctl(vfio_container_fd, VFIO_IOMMU_UNMAP_DMA,
+				&dma_unmap);
+		if (ret) {
+			RTE_LOG(ERR, EAL, "  cannot clear DMA remapping, error %i (%s)\n",
+					errno, strerror(errno));
+			return -1;
+		}
+	}
 
 	return 0;
 }
 
 static int
-vfio_spapr_dma_map(int vfio_container_fd)
+vfio_type1_dma_map(int vfio_container_fd)
 {
-	const struct rte_memseg *ms = rte_eal_get_physmem_layout();
-	int i, ret;
+	return rte_memseg_walk(type1_map, &vfio_container_fd);
+}
+
+static int
+vfio_spapr_dma_do_map(int vfio_container_fd, uint64_t vaddr, uint64_t iova,
+		uint64_t len, int do_map)
+{
+	struct vfio_iommu_type1_dma_map dma_map;
+	struct vfio_iommu_type1_dma_unmap dma_unmap;
+	int ret;
+
+	if (do_map != 0) {
+		memset(&dma_map, 0, sizeof(dma_map));
+		dma_map.argsz = sizeof(struct vfio_iommu_type1_dma_map);
+		dma_map.vaddr = vaddr;
+		dma_map.size = len;
+		dma_map.iova = iova;
+		dma_map.flags = VFIO_DMA_MAP_FLAG_READ |
+				VFIO_DMA_MAP_FLAG_WRITE;
+
+		ret = ioctl(vfio_container_fd, VFIO_IOMMU_MAP_DMA, &dma_map);
+		if (ret) {
+			RTE_LOG(ERR, EAL, "  cannot set up DMA remapping, error %i (%s)\n",
+				errno, strerror(errno));
+				return -1;
+		}
+
+	} else {
+		struct vfio_iommu_spapr_register_memory reg = {
+			.argsz = sizeof(reg),
+			.flags = 0
+		};
+		reg.vaddr = (uintptr_t) vaddr;
+		reg.size = len;
+
+		ret = ioctl(vfio_container_fd,
+				VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY, &reg);
+		if (ret) {
+			RTE_LOG(ERR, EAL, "  cannot unregister vaddr for IOMMU, error %i (%s)\n",
+					errno, strerror(errno));
+			return -1;
+		}
+
+		memset(&dma_unmap, 0, sizeof(dma_unmap));
+		dma_unmap.argsz = sizeof(struct vfio_iommu_type1_dma_unmap);
+		dma_unmap.size = len;
+		dma_unmap.iova = iova;
+
+		ret = ioctl(vfio_container_fd, VFIO_IOMMU_UNMAP_DMA,
+				&dma_unmap);
+		if (ret) {
+			RTE_LOG(ERR, EAL, "  cannot clear DMA remapping, error %i (%s)\n",
+					errno, strerror(errno));
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+static int
+vfio_spapr_map_walk(const struct rte_memseg_list *msl __rte_unused,
+		const struct rte_memseg *ms, void *arg)
+{
+	int *vfio_container_fd = arg;
 
-	struct vfio_iommu_spapr_register_memory reg = {
-		.argsz = sizeof(reg),
-		.flags = 0
+	return vfio_spapr_dma_mem_map(*vfio_container_fd, ms->addr_64, ms->iova,
+			ms->len, 1);
+}
+
+struct spapr_walk_param {
+	uint64_t window_size;
+	uint64_t hugepage_sz;
+};
+static int
+vfio_spapr_window_size_walk(const struct rte_memseg_list *msl __rte_unused,
+		const struct rte_memseg *ms, void *arg)
+{
+	struct spapr_walk_param *param = arg;
+	uint64_t max = ms->iova + ms->len;
+
+	if (max > param->window_size) {
+		param->hugepage_sz = ms->hugepage_sz;
+		param->window_size = max;
+	}
+
+	return 0;
+}
+
+static int
+vfio_spapr_create_new_dma_window(int vfio_container_fd,
+		struct vfio_iommu_spapr_tce_create *create) {
+	struct vfio_iommu_spapr_tce_remove remove = {
+		.argsz = sizeof(remove),
 	};
 	struct vfio_iommu_spapr_tce_info info = {
 		.argsz = sizeof(info),
 	};
-	struct vfio_iommu_spapr_tce_create create = {
-		.argsz = sizeof(create),
-	};
-	struct vfio_iommu_spapr_tce_remove remove = {
-		.argsz = sizeof(remove),
-	};
+	int ret;
 
 	/* query spapr iommu info */
 	ret = ioctl(vfio_container_fd, VFIO_IOMMU_SPAPR_TCE_GET_INFO, &info);
@@ -737,70 +1317,156 @@ vfio_spapr_dma_map(int vfio_container_fd)
 		return -1;
 	}
 
-	/* create DMA window from 0 to max(phys_addr + len) */
-	for (i = 0; i < RTE_MAX_MEMSEG; i++) {
-		if (ms[i].addr == NULL)
-			break;
-
-		create.window_size = RTE_MAX(create.window_size,
-				ms[i].iova + ms[i].len);
-	}
-
-	/* sPAPR requires window size to be a power of 2 */
-	create.window_size = rte_align64pow2(create.window_size);
-	create.page_shift = __builtin_ctzll(ms->hugepage_sz);
-	create.levels = 1;
-
-	ret = ioctl(vfio_container_fd, VFIO_IOMMU_SPAPR_TCE_CREATE, &create);
+	/* create new DMA window */
+	ret = ioctl(vfio_container_fd, VFIO_IOMMU_SPAPR_TCE_CREATE, create);
 	if (ret) {
 		RTE_LOG(ERR, EAL, "  cannot create new DMA window, "
 				"error %i (%s)\n", errno, strerror(errno));
 		return -1;
 	}
 
-	if (create.start_addr != 0) {
+	if (create->start_addr != 0) {
 		RTE_LOG(ERR, EAL, "  DMA window start address != 0\n");
 		return -1;
 	}
 
-	/* map all DPDK segments for DMA. use 1:1 PA to IOVA mapping */
-	for (i = 0; i < RTE_MAX_MEMSEG; i++) {
-		struct vfio_iommu_type1_dma_map dma_map;
+	return 0;
+}
 
-		if (ms[i].addr == NULL)
-			break;
+static int
+vfio_spapr_dma_mem_map(int vfio_container_fd, uint64_t vaddr, uint64_t iova,
+		uint64_t len, int do_map)
+{
+	struct spapr_walk_param param;
+	struct vfio_iommu_spapr_tce_create create = {
+		.argsz = sizeof(create),
+	};
+	struct vfio_config *vfio_cfg;
+	struct user_mem_maps *user_mem_maps;
+	int i, ret = 0;
 
-		reg.vaddr = (uintptr_t) ms[i].addr;
-		reg.size = ms[i].len;
-		ret = ioctl(vfio_container_fd,
-			VFIO_IOMMU_SPAPR_REGISTER_MEMORY, &reg);
-		if (ret) {
-			RTE_LOG(ERR, EAL, "  cannot register vaddr for IOMMU, "
-				"error %i (%s)\n", errno, strerror(errno));
-			return -1;
-		}
+	vfio_cfg = get_vfio_cfg_by_container_fd(vfio_container_fd);
+	if (vfio_cfg == NULL) {
+		RTE_LOG(ERR, EAL, "  invalid container fd!\n");
+		return -1;
+	}
 
-		memset(&dma_map, 0, sizeof(dma_map));
-		dma_map.argsz = sizeof(struct vfio_iommu_type1_dma_map);
-		dma_map.vaddr = ms[i].addr_64;
-		dma_map.size = ms[i].len;
-		if (rte_eal_iova_mode() == RTE_IOVA_VA)
-			dma_map.iova = dma_map.vaddr;
-		else
-			dma_map.iova = ms[i].iova;
-		dma_map.flags = VFIO_DMA_MAP_FLAG_READ |
-				 VFIO_DMA_MAP_FLAG_WRITE;
+	user_mem_maps = &vfio_cfg->mem_maps;
+	rte_spinlock_recursive_lock(&user_mem_maps->lock);
 
-		ret = ioctl(vfio_container_fd, VFIO_IOMMU_MAP_DMA, &dma_map);
+	/* check if window size needs to be adjusted */
+	memset(&param, 0, sizeof(param));
 
-		if (ret) {
-			RTE_LOG(ERR, EAL, "  cannot set up DMA remapping, "
-				"error %i (%s)\n", errno, strerror(errno));
-			return -1;
+	if (memseg_walk_thread_unsafe(vfio_spapr_window_size_walk,
+				&param) < 0) {
+		RTE_LOG(ERR, EAL, "Could not get window size\n");
+		ret = -1;
+		goto out;
+	}
+
+	/* also check user maps */
+	for (i = 0; i < user_mem_maps->n_maps; i++) {
+		uint64_t max = user_mem_maps->maps[i].iova +
+				user_mem_maps->maps[i].len;
+		create.window_size = RTE_MAX(create.window_size, max);
+	}
+
+	/* sPAPR requires window size to be a power of 2 */
+	create.window_size = rte_align64pow2(param.window_size);
+	create.page_shift = __builtin_ctzll(param.hugepage_sz);
+	create.levels = 1;
+
+	if (do_map) {
+		void *addr;
+		/* re-create window and remap the entire memory */
+		if (iova > create.window_size) {
+			if (vfio_spapr_create_new_dma_window(vfio_container_fd,
+					&create) < 0) {
+				RTE_LOG(ERR, EAL, "Could not create new DMA window\n");
+				ret = -1;
+				goto out;
+			}
+			if (memseg_walk_thread_unsafe(vfio_spapr_map_walk,
+					&vfio_container_fd) < 0) {
+				RTE_LOG(ERR, EAL, "Could not recreate DMA maps\n");
+				ret = -1;
+				goto out;
+			}
+			/* remap all user maps */
+			for (i = 0; i < user_mem_maps->n_maps; i++) {
+				struct user_mem_map *map =
+						&user_mem_maps->maps[i];
+				if (vfio_spapr_dma_do_map(vfio_container_fd,
+						map->addr, map->iova, map->len,
+						1)) {
+					RTE_LOG(ERR, EAL, "Could not recreate user DMA maps\n");
+					ret = -1;
+					goto out;
+				}
+			}
 		}
 
+		/* now that we've remapped all of the memory that was present
+		 * before, map the segment that we were requested to map.
+		 *
+		 * however, if we were called by the callback, the memory we
+		 * were called with was already in the memseg list, so previous
+		 * mapping should've mapped that segment already.
+		 *
+		 * virt2memseg_list is a relatively cheap check, so use that. if
+		 * memory is within any memseg list, it's a memseg, so it's
+		 * already mapped.
+		 */
+		addr = (void *)(uintptr_t)vaddr;
+		if (rte_mem_virt2memseg_list(addr) == NULL &&
+				vfio_spapr_dma_do_map(vfio_container_fd,
+					vaddr, iova, len, 1) < 0) {
+			RTE_LOG(ERR, EAL, "Could not map segment\n");
+			ret = -1;
+			goto out;
+		}
+	} else {
+		/* for unmap, check if iova within DMA window */
+		if (iova > create.window_size) {
+			RTE_LOG(ERR, EAL, "iova beyond DMA window for unmap");
+			ret = -1;
+			goto out;
+		}
+
+		vfio_spapr_dma_do_map(vfio_container_fd, vaddr, iova, len, 0);
+	}
+out:
+	rte_spinlock_recursive_unlock(&user_mem_maps->lock);
+	return ret;
+}
+
+static int
+vfio_spapr_dma_map(int vfio_container_fd)
+{
+	struct vfio_iommu_spapr_tce_create create = {
+		.argsz = sizeof(create),
+	};
+	struct spapr_walk_param param;
+
+	memset(&param, 0, sizeof(param));
+
+	/* create DMA window from 0 to max(phys_addr + len) */
+	rte_memseg_walk(vfio_spapr_window_size_walk, &param);
+
+	/* sPAPR requires window size to be a power of 2 */
+	create.window_size = rte_align64pow2(param.window_size);
+	create.page_shift = __builtin_ctzll(param.hugepage_sz);
+	create.levels = 1;
+
+	if (vfio_spapr_create_new_dma_window(vfio_container_fd, &create) < 0) {
+		RTE_LOG(ERR, EAL, "Could not create new DMA window\n");
+		return -1;
 	}
 
+	/* map all DPDK segments for DMA. use 1:1 PA to IOVA mapping */
+	if (rte_memseg_walk(vfio_spapr_map_walk, &vfio_container_fd) < 0)
+		return -1;
+
 	return 0;
 }
 
@@ -811,6 +1477,175 @@ vfio_noiommu_dma_map(int __rte_unused vfio_container_fd)
 	return 0;
 }
 
+static int
+vfio_noiommu_dma_mem_map(int __rte_unused vfio_container_fd,
+			 uint64_t __rte_unused vaddr,
+			 uint64_t __rte_unused iova, uint64_t __rte_unused len,
+			 int __rte_unused do_map)
+{
+	/* No-IOMMU mode does not need DMA mapping */
+	return 0;
+}
+
+static int
+vfio_dma_mem_map(struct vfio_config *vfio_cfg, uint64_t vaddr, uint64_t iova,
+		uint64_t len, int do_map)
+{
+	const struct vfio_iommu_type *t = vfio_cfg->vfio_iommu_type;
+
+	if (!t) {
+		RTE_LOG(ERR, EAL, "  VFIO support not initialized\n");
+		rte_errno = ENODEV;
+		return -1;
+	}
+
+	if (!t->dma_user_map_func) {
+		RTE_LOG(ERR, EAL,
+			"  VFIO custom DMA region maping not supported by IOMMU %s\n",
+			t->name);
+		rte_errno = ENOTSUP;
+		return -1;
+	}
+
+	return t->dma_user_map_func(vfio_cfg->vfio_container_fd, vaddr, iova,
+			len, do_map);
+}
+
+static int
+container_dma_map(struct vfio_config *vfio_cfg, uint64_t vaddr, uint64_t iova,
+		uint64_t len)
+{
+	struct user_mem_map *new_map;
+	struct user_mem_maps *user_mem_maps;
+	int ret = 0;
+
+	user_mem_maps = &vfio_cfg->mem_maps;
+	rte_spinlock_recursive_lock(&user_mem_maps->lock);
+	if (user_mem_maps->n_maps == VFIO_MAX_USER_MEM_MAPS) {
+		RTE_LOG(ERR, EAL, "No more space for user mem maps\n");
+		rte_errno = ENOMEM;
+		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
+		 * plugged in, even if a device were added later, this mapping
+		 * might have succeeded. however, since we cannot verify if this
+		 * is a valid mapping without having a device attached, consider
+		 * this to be unsupported, because we can't just store any old
+		 * mapping and pollute list of active mappings willy-nilly.
+		 */
+		RTE_LOG(ERR, EAL, "Couldn't map new region for DMA\n");
+		ret = -1;
+		goto out;
+	}
+	/* create new user mem map entry */
+	new_map = &user_mem_maps->maps[user_mem_maps->n_maps++];
+	new_map->addr = vaddr;
+	new_map->iova = iova;
+	new_map->len = len;
+
+	compact_user_maps(user_mem_maps);
+out:
+	rte_spinlock_recursive_unlock(&user_mem_maps->lock);
+	return ret;
+}
+
+static int
+container_dma_unmap(struct vfio_config *vfio_cfg, uint64_t vaddr, uint64_t iova,
+		uint64_t len)
+{
+	struct user_mem_map *map, *new_map = NULL;
+	struct user_mem_maps *user_mem_maps;
+	int ret = 0;
+
+	user_mem_maps = &vfio_cfg->mem_maps;
+	rte_spinlock_recursive_lock(&user_mem_maps->lock);
+
+	/* find our mapping */
+	map = find_user_mem_map(user_mem_maps, vaddr, iova, len);
+	if (!map) {
+		RTE_LOG(ERR, EAL, "Couldn't find previously mapped region\n");
+		rte_errno = EINVAL;
+		ret = -1;
+		goto out;
+	}
+	if (map->addr != vaddr || map->iova != iova || map->len != len) {
+		/* we're partially unmapping a previously mapped region, so we
+		 * need to split entry into two.
+		 */
+		if (user_mem_maps->n_maps == VFIO_MAX_USER_MEM_MAPS) {
+			RTE_LOG(ERR, EAL, "Not enough space to store partial mapping\n");
+			rte_errno = ENOMEM;
+			ret = -1;
+			goto out;
+		}
+		new_map = &user_mem_maps->maps[user_mem_maps->n_maps++];
+	}
+
+	/* unmap the entry */
+	if (vfio_dma_mem_map(vfio_cfg, vaddr, iova, len, 0)) {
+		/* there may not be any devices plugged in, so unmapping will
+		 * fail with ENODEV/ENOTSUP rte_errno values, but that doesn't
+		 * stop us from removing the mapping, as the assumption is we
+		 * won't be needing this memory any more and thus will want to
+		 * prevent it from being remapped again on hotplug. so, only
+		 * fail if we indeed failed to unmap (e.g. if the mapping was
+		 * within our mapped range but had invalid alignment).
+		 */
+		if (rte_errno != ENODEV && rte_errno != ENOTSUP) {
+			RTE_LOG(ERR, EAL, "Couldn't unmap region for DMA\n");
+			ret = -1;
+			goto out;
+		} else {
+			RTE_LOG(DEBUG, EAL, "DMA unmapping failed, but removing mappings anyway\n");
+		}
+	}
+	/* remove map from the list of active mappings */
+	if (new_map != NULL) {
+		adjust_map(map, new_map, vaddr, len);
+
+		/* if we've created a new map by splitting, sort everything */
+		if (!is_null_map(new_map)) {
+			compact_user_maps(user_mem_maps);
+		} else {
+			/* we've created a new mapping, but it was unused */
+			user_mem_maps->n_maps--;
+		}
+	} else {
+		memset(map, 0, sizeof(*map));
+		compact_user_maps(user_mem_maps);
+		user_mem_maps->n_maps--;
+	}
+
+out:
+	rte_spinlock_recursive_unlock(&user_mem_maps->lock);
+	return ret;
+}
+
+int __rte_experimental
+rte_vfio_dma_map(uint64_t vaddr, uint64_t iova, uint64_t len)
+{
+	if (len == 0) {
+		rte_errno = EINVAL;
+		return -1;
+	}
+
+	return container_dma_map(default_vfio_cfg, vaddr, iova, len);
+}
+
+int __rte_experimental
+rte_vfio_dma_unmap(uint64_t vaddr, uint64_t iova, uint64_t len)
+{
+	if (len == 0) {
+		rte_errno = EINVAL;
+		return -1;
+	}
+
+	return container_dma_unmap(default_vfio_cfg, vaddr, iova, len);
+}
+
 int
 rte_vfio_noiommu_is_enabled(void)
 {
@@ -843,4 +1678,299 @@ rte_vfio_noiommu_is_enabled(void)
 	return c == 'Y';
 }
 
-#endif
+int __rte_experimental
+rte_vfio_container_create(void)
+{
+	int i;
+
+	/* Find an empty slot to store new vfio config */
+	for (i = 1; i < VFIO_MAX_CONTAINERS; i++) {
+		if (vfio_cfgs[i].vfio_container_fd == -1)
+			break;
+	}
+
+	if (i == VFIO_MAX_CONTAINERS) {
+		RTE_LOG(ERR, EAL, "exceed max vfio container limit\n");
+		return -1;
+	}
+
+	vfio_cfgs[i].vfio_container_fd = rte_vfio_get_container_fd();
+	if (vfio_cfgs[i].vfio_container_fd < 0) {
+		RTE_LOG(NOTICE, EAL, "fail to create a new container\n");
+		return -1;
+	}
+
+	return vfio_cfgs[i].vfio_container_fd;
+}
+
+int __rte_experimental
+rte_vfio_container_destroy(int container_fd)
+{
+	struct vfio_config *vfio_cfg;
+	int i;
+
+	vfio_cfg = get_vfio_cfg_by_container_fd(container_fd);
+	if (vfio_cfg == NULL) {
+		RTE_LOG(ERR, EAL, "Invalid container fd\n");
+		return -1;
+	}
+
+	for (i = 0; i < VFIO_MAX_GROUPS; i++)
+		if (vfio_cfg->vfio_groups[i].group_num != -1)
+			rte_vfio_container_group_unbind(container_fd,
+				vfio_cfg->vfio_groups[i].group_num);
+
+	close(container_fd);
+	vfio_cfg->vfio_container_fd = -1;
+	vfio_cfg->vfio_active_groups = 0;
+	vfio_cfg->vfio_iommu_type = NULL;
+
+	return 0;
+}
+
+int __rte_experimental
+rte_vfio_container_group_bind(int container_fd, int iommu_group_num)
+{
+	struct vfio_config *vfio_cfg;
+	struct vfio_group *cur_grp;
+	int vfio_group_fd;
+	int i;
+
+	vfio_cfg = get_vfio_cfg_by_container_fd(container_fd);
+	if (vfio_cfg == NULL) {
+		RTE_LOG(ERR, EAL, "Invalid container fd\n");
+		return -1;
+	}
+
+	/* Check room for new group */
+	if (vfio_cfg->vfio_active_groups == VFIO_MAX_GROUPS) {
+		RTE_LOG(ERR, EAL, "Maximum number of VFIO groups reached!\n");
+		return -1;
+	}
+
+	/* Get an index for the new group */
+	for (i = 0; i < VFIO_MAX_GROUPS; i++)
+		if (vfio_cfg->vfio_groups[i].group_num == -1) {
+			cur_grp = &vfio_cfg->vfio_groups[i];
+			break;
+		}
+
+	/* This should not happen */
+	if (i == VFIO_MAX_GROUPS) {
+		RTE_LOG(ERR, EAL, "No VFIO group free slot found\n");
+		return -1;
+	}
+
+	vfio_group_fd = vfio_open_group_fd(iommu_group_num);
+	if (vfio_group_fd < 0) {
+		RTE_LOG(ERR, EAL, "Failed to open group %d\n", iommu_group_num);
+		return -1;
+	}
+	cur_grp->group_num = iommu_group_num;
+	cur_grp->fd = vfio_group_fd;
+	cur_grp->devices = 0;
+	vfio_cfg->vfio_active_groups++;
+
+	return vfio_group_fd;
+}
+
+int __rte_experimental
+rte_vfio_container_group_unbind(int container_fd, int iommu_group_num)
+{
+	struct vfio_config *vfio_cfg;
+	struct vfio_group *cur_grp;
+	int i;
+
+	vfio_cfg = get_vfio_cfg_by_container_fd(container_fd);
+	if (vfio_cfg == NULL) {
+		RTE_LOG(ERR, EAL, "Invalid container fd\n");
+		return -1;
+	}
+
+	for (i = 0; i < VFIO_MAX_GROUPS; i++) {
+		if (vfio_cfg->vfio_groups[i].group_num == iommu_group_num) {
+			cur_grp = &vfio_cfg->vfio_groups[i];
+			break;
+		}
+	}
+
+	/* This should not happen */
+	if (i == VFIO_MAX_GROUPS) {
+		RTE_LOG(ERR, EAL, "Specified group number not found\n");
+		return -1;
+	}
+
+	if (cur_grp->fd >= 0 && close(cur_grp->fd) < 0) {
+		RTE_LOG(ERR, EAL, "Error when closing vfio_group_fd for"
+			" iommu_group_num %d\n", iommu_group_num);
+		return -1;
+	}
+	cur_grp->group_num = -1;
+	cur_grp->fd = -1;
+	cur_grp->devices = 0;
+	vfio_cfg->vfio_active_groups--;
+
+	return 0;
+}
+
+int __rte_experimental
+rte_vfio_container_dma_map(int container_fd, uint64_t vaddr, uint64_t iova,
+		uint64_t len)
+{
+	struct vfio_config *vfio_cfg;
+
+	if (len == 0) {
+		rte_errno = EINVAL;
+		return -1;
+	}
+
+	vfio_cfg = get_vfio_cfg_by_container_fd(container_fd);
+	if (vfio_cfg == NULL) {
+		RTE_LOG(ERR, EAL, "Invalid container fd\n");
+		return -1;
+	}
+
+	return container_dma_map(vfio_cfg, vaddr, iova, len);
+}
+
+int __rte_experimental
+rte_vfio_container_dma_unmap(int container_fd, uint64_t vaddr, uint64_t iova,
+		uint64_t len)
+{
+	struct vfio_config *vfio_cfg;
+
+	if (len == 0) {
+		rte_errno = EINVAL;
+		return -1;
+	}
+
+	vfio_cfg = get_vfio_cfg_by_container_fd(container_fd);
+	if (vfio_cfg == NULL) {
+		RTE_LOG(ERR, EAL, "Invalid container fd\n");
+		return -1;
+	}
+
+	return container_dma_unmap(vfio_cfg, vaddr, iova, len);
+}
+
+#else
+
+int __rte_experimental
+rte_vfio_dma_map(uint64_t __rte_unused vaddr, __rte_unused uint64_t iova,
+		  __rte_unused uint64_t len)
+{
+	return -1;
+}
+
+int __rte_experimental
+rte_vfio_dma_unmap(uint64_t __rte_unused vaddr, uint64_t __rte_unused iova,
+		    __rte_unused uint64_t len)
+{
+	return -1;
+}
+
+int
+rte_vfio_setup_device(__rte_unused const char *sysfs_base,
+		__rte_unused const char *dev_addr,
+		__rte_unused int *vfio_dev_fd,
+		__rte_unused struct vfio_device_info *device_info)
+{
+	return -1;
+}
+
+int
+rte_vfio_release_device(__rte_unused const char *sysfs_base,
+		__rte_unused const char *dev_addr, __rte_unused int fd)
+{
+	return -1;
+}
+
+int
+rte_vfio_enable(__rte_unused const char *modname)
+{
+	return -1;
+}
+
+int
+rte_vfio_is_enabled(__rte_unused const char *modname)
+{
+	return -1;
+}
+
+int
+rte_vfio_noiommu_is_enabled(void)
+{
+	return -1;
+}
+
+int
+rte_vfio_clear_group(__rte_unused int vfio_group_fd)
+{
+	return -1;
+}
+
+int __rte_experimental
+rte_vfio_get_group_num(__rte_unused const char *sysfs_base,
+		__rte_unused const char *dev_addr,
+		__rte_unused int *iommu_group_num)
+{
+	return -1;
+}
+
+int __rte_experimental
+rte_vfio_get_container_fd(void)
+{
+	return -1;
+}
+
+int __rte_experimental
+rte_vfio_get_group_fd(__rte_unused int iommu_group_num)
+{
+	return -1;
+}
+
+int __rte_experimental
+rte_vfio_container_create(void)
+{
+	return -1;
+}
+
+int __rte_experimental
+rte_vfio_container_destroy(__rte_unused int container_fd)
+{
+	return -1;
+}
+
+int __rte_experimental
+rte_vfio_container_group_bind(__rte_unused int container_fd,
+		__rte_unused int iommu_group_num)
+{
+	return -1;
+}
+
+int __rte_experimental
+rte_vfio_container_group_unbind(__rte_unused int container_fd,
+		__rte_unused int iommu_group_num)
+{
+	return -1;
+}
+
+int __rte_experimental
+rte_vfio_container_dma_map(__rte_unused int container_fd,
+		__rte_unused uint64_t vaddr,
+		__rte_unused uint64_t iova,
+		__rte_unused uint64_t len)
+{
+	return -1;
+}
+
+int __rte_experimental
+rte_vfio_container_dma_unmap(__rte_unused int container_fd,
+		__rte_unused uint64_t vaddr,
+		__rte_unused uint64_t iova,
+		__rte_unused uint64_t len)
+{
+	return -1;
+}
+
+#endif /* VFIO_PRESENT */