[PATCH v3 11/16] vfio: move global vfio_cfg to eal_vfio.c

[Jan Viktorin <viktorin@rehivetech.com>]

The vfio_cfg is a module-global variable and so together with this
variable, it is necessary to move functions:

* pci_vfio_get_group_fd
  - renamed to vfio_get_group_fd
  - pci_* version removed (no other call in EAL)

* pci_vfio_setup_device
  - renamed as vfio_setup_device

* pci_vfio_enable
  - renamed as vfio_enable
  - generalized to check for a specific vfio driver presence
  - pci_* specialization preserved as a wrapper

* pci_vfio_is_enabled
  - renamed as vfio_is_enabled
  - generalized to check for a specific vfio driver presence
    to preserve the semantics of VFIO + PCI
  - pci_* specialization preserved as a wrapper

* clear_current_group
  - private function, just moved

To stop GCC complaining about "defined but not used", the private
function pci_vfio_get_group_no has been removed entirely.

Signed-off-by: Jan Viktorin <viktorin@rehivetech.com>
---
 lib/librte_eal/linuxapp/eal/eal_pci_init.h         |   1 -
 lib/librte_eal/linuxapp/eal/eal_pci_vfio.c         | 297 +--------------------
 lib/librte_eal/linuxapp/eal/eal_pci_vfio_mp_sync.c |   2 +-
 lib/librte_eal/linuxapp/eal/eal_vfio.c             | 287 ++++++++++++++++++++
 lib/librte_eal/linuxapp/eal/eal_vfio.h             |  17 ++
 5 files changed, 309 insertions(+), 295 deletions(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal_pci_init.h b/lib/librte_eal/linuxapp/eal/eal_pci_init.h
index d34212b..d00bf7d 100644
--- a/lib/librte_eal/linuxapp/eal/eal_pci_init.h
+++ b/lib/librte_eal/linuxapp/eal/eal_pci_init.h
@@ -94,7 +94,6 @@ int pci_vfio_ioport_unmap(struct rte_pci_ioport *p);
 
 /* map VFIO resource prototype */
 int pci_vfio_map_resource(struct rte_pci_device *dev);
-int pci_vfio_get_group_fd(int iommu_group_fd);
 
 #endif
 
diff --git a/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c b/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
index 2792c23..46cd683 100644
--- a/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
+++ b/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
@@ -69,9 +69,6 @@ static struct rte_tailq_elem rte_vfio_tailq = {
 };
 EAL_REGISTER_TAILQ(rte_vfio_tailq)
 
-/* per-process VFIO config */
-static struct vfio_config vfio_cfg;
-
 int
 pci_vfio_read_config(const struct rte_intr_handle *intr_handle,
 		    void *buf, size_t len, off_t offs)
@@ -299,255 +296,6 @@ pci_vfio_setup_interrupts(struct rte_pci_device *dev, int vfio_dev_fd)
 	return -1;
 }
 
-/* open group fd or get an existing one */
-int
-pci_vfio_get_group_fd(int iommu_group_no)
-{
-	int i;
-	int vfio_group_fd;
-	char filename[PATH_MAX];
-
-	/* check if we already have the group descriptor open */
-	for (i = 0; i < vfio_cfg.vfio_group_idx; i++)
-		if (vfio_cfg.vfio_groups[i].group_no == iommu_group_no)
-			return vfio_cfg.vfio_groups[i].fd;
-
-	/* 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_fd = open(filename, O_RDWR);
-		if (vfio_group_fd < 0) {
-			/* if file not found, it's not an error */
-			if (errno != ENOENT) {
-				RTE_LOG(ERR, EAL, "Cannot open %s: %s\n", filename,
-						strerror(errno));
-				return -1;
-			}
-
-			/* special case: try no-IOMMU path as well */
-			snprintf(filename, sizeof(filename),
-					VFIO_NOIOMMU_GROUP_FMT, iommu_group_no);
-			vfio_group_fd = open(filename, O_RDWR);
-			if (vfio_group_fd < 0) {
-				if (errno != ENOENT) {
-					RTE_LOG(ERR, EAL, "Cannot open %s: %s\n", filename,
-							strerror(errno));
-					return -1;
-				}
-				return 0;
-			}
-			/* noiommu group found */
-		}
-
-		/* if the fd is valid, create a new group for it */
-		if (vfio_cfg.vfio_group_idx == VFIO_MAX_GROUPS) {
-			RTE_LOG(ERR, EAL, "Maximum number of VFIO groups reached!\n");
-			close(vfio_group_fd);
-			return -1;
-		}
-		vfio_cfg.vfio_groups[vfio_cfg.vfio_group_idx].group_no = iommu_group_no;
-		vfio_cfg.vfio_groups[vfio_cfg.vfio_group_idx].fd = vfio_group_fd;
-		return vfio_group_fd;
-	}
-	/* if we're in a secondary process, request group fd from the primary
-	 * process via our socket
-	 */
-	else {
-		int socket_fd, ret;
-
-		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_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, return it */
-			if (vfio_group_fd > 0) {
-				close(socket_fd);
-				return vfio_group_fd;
-			}
-			/* fall-through on error */
-		default:
-			RTE_LOG(ERR, EAL, "  cannot get container fd!\n");
-			close(socket_fd);
-			return -1;
-		}
-	}
-	return -1;
-}
-
-/* parse IOMMU group number for a PCI device
- * returns 1 on success, -1 for errors, 0 for non-existent group
- */
-static int
-pci_vfio_get_group_no(const char *pci_addr, int *iommu_group_no)
-{
-	return vfio_get_group_no(pci_get_sysfs_path(), pci_addr, iommu_group_no);
-}
-
-static void
-clear_current_group(void)
-{
-	vfio_cfg.vfio_groups[vfio_cfg.vfio_group_idx].group_no = 0;
-	vfio_cfg.vfio_groups[vfio_cfg.vfio_group_idx].fd = -1;
-}
-
-/**
- * Setup vfio_cfg for the device indentified by its address. It discovers
- * the configured I/O MMU groups or sets a new one for the device. If a new
- * groups is assigned, the DMA mapping is performed.
- * Returns 0 on success, a negative value on failure and a positive value in
- * case the given device cannot be managed this way.
- */
-static int pci_vfio_setup_device(const char *pci_addr, int *vfio_dev_fd,
-		struct vfio_device_info *device_info)
-{
-	struct vfio_group_status group_status = {
-			.argsz = sizeof(group_status)
-	};
-	int vfio_group_fd;
-	int iommu_group_no;
-	int ret;
-
-	/* get group number */
-	ret = pci_vfio_get_group_no(pci_addr, &iommu_group_no);
-	if (ret == 0) {
-		RTE_LOG(WARNING, EAL, "  %s not managed by VFIO driver, skipping\n",
-			pci_addr);
-		return 1;
-	}
-
-	/* if negative, something failed */
-	if (ret < 0)
-		return -1;
-
-	/* get the actual group fd */
-	vfio_group_fd = pci_vfio_get_group_fd(iommu_group_no);
-	if (vfio_group_fd < 0)
-		return -1;
-
-	/* store group fd */
-	vfio_cfg.vfio_groups[vfio_cfg.vfio_group_idx].group_no = iommu_group_no;
-	vfio_cfg.vfio_groups[vfio_cfg.vfio_group_idx].fd = vfio_group_fd;
-
-	/* if group_fd == 0, that means the device isn't managed by VFIO */
-	if (vfio_group_fd == 0) {
-		RTE_LOG(WARNING, EAL, "  %s not managed by VFIO driver, skipping\n",
-				pci_addr);
-		/* we store 0 as group fd to distinguish between existing but
-		 * unbound VFIO groups, and groups that don't exist at all.
-		 */
-		vfio_cfg.vfio_group_idx++;
-		return 1;
-	}
-
-	/*
-	 * at this point, we know that this group is viable (meaning, all devices
-	 * are either bound to VFIO or not bound to anything)
-	 */
-
-	/* check if the group is viable */
-	ret = ioctl(vfio_group_fd, VFIO_GROUP_GET_STATUS, &group_status);
-	if (ret) {
-		RTE_LOG(ERR, EAL, "  %s cannot get group status, "
-				"error %i (%s)\n", pci_addr, errno, strerror(errno));
-		close(vfio_group_fd);
-		clear_current_group();
-		return -1;
-	} else if (!(group_status.flags & VFIO_GROUP_FLAGS_VIABLE)) {
-		RTE_LOG(ERR, EAL, "  %s VFIO group is not viable!\n", pci_addr);
-		close(vfio_group_fd);
-		clear_current_group();
-		return -1;
-	}
-
-	/* 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);
-		if (ret) {
-			RTE_LOG(ERR, EAL, "  %s cannot add VFIO group to container, "
-					"error %i (%s)\n", pci_addr, errno, strerror(errno));
-			close(vfio_group_fd);
-			clear_current_group();
-			return -1;
-		}
-		/*
-		 * at this point we know that this group has been successfully
-		 * initialized, so we increment vfio_group_idx to indicate that we can
-		 * add new groups.
-		 */
-		vfio_cfg.vfio_group_idx++;
-	}
-
-	/*
-	 * pick an IOMMU type and set up DMA mappings for container
-	 *
-	 * needs to be done only once, only when at least one group is assigned to
-	 * a container and only in primary process
-	 */
-	if (internal_config.process_type == RTE_PROC_PRIMARY &&
-			vfio_cfg.vfio_container_has_dma == 0) {
-		/* select an IOMMU type which we will be using */
-		const struct vfio_iommu_type *t =
-				vfio_set_iommu_type(vfio_cfg.vfio_container_fd);
-		if (!t) {
-			RTE_LOG(ERR, EAL, "  %s failed to select IOMMU type\n", pci_addr);
-			return -1;
-		}
-		ret = t->dma_map_func(vfio_cfg.vfio_container_fd);
-		if (ret) {
-			RTE_LOG(ERR, EAL, "  %s DMA remapping failed, "
-					"error %i (%s)\n", pci_addr, errno, strerror(errno));
-			return -1;
-		}
-		vfio_cfg.vfio_container_has_dma = 1;
-	}
-
-	/* get a file descriptor for the device */
-	*vfio_dev_fd = ioctl(vfio_group_fd, VFIO_GROUP_GET_DEVICE_FD, pci_addr);
-	if (*vfio_dev_fd < 0) {
-		/* if we cannot get a device fd, this simply means that this
-		 * particular port is not bound to VFIO
-		 */
-		RTE_LOG(WARNING, EAL, "  %s not managed by VFIO driver, skipping\n",
-				pci_addr);
-		return 1;
-	}
-
-	/* test and setup the device */
-	ret = ioctl(*vfio_dev_fd, VFIO_DEVICE_GET_INFO, device_info);
-	if (ret) {
-		RTE_LOG(ERR, EAL, "  %s cannot get device info, "
-				"error %i (%s)\n", pci_addr, errno, strerror(errno));
-		close(*vfio_dev_fd);
-		return -1;
-	}
-
-	return 0;
-}
-
 /*
  * map the PCI resources of a PCI device in virtual memory (VFIO version).
  * primary and secondary processes follow almost exactly the same path
@@ -575,7 +323,8 @@ pci_vfio_map_resource(struct rte_pci_device *dev)
 	snprintf(pci_addr, sizeof(pci_addr), PCI_PRI_FMT,
 			loc->domain, loc->bus, loc->devid, loc->function);
 
-	if ((ret = pci_vfio_setup_device(pci_addr, &vfio_dev_fd, &device_info)))
+	if ((ret = vfio_setup_device(pci_get_sysfs_path(), pci_addr,
+					&vfio_dev_fd, &device_info)))
 		return ret;
 
 	/* get MSI-X BAR, if any (we have to know where it is because we can't
@@ -834,50 +583,12 @@ pci_vfio_ioport_unmap(struct rte_pci_ioport *p)
 int
 pci_vfio_enable(void)
 {
-	/* initialize group list */
-	int i;
-	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;
-	}
-
-	/* inform the user that we are probing for VFIO */
-	RTE_LOG(INFO, EAL, "Probing VFIO support...\n");
-
-	/* check if vfio-pci module is loaded */
-	vfio_available = rte_eal_check_module("vfio_pci");
-
-	/* return error directly */
-	if (vfio_available == -1) {
-		RTE_LOG(INFO, EAL, "Could not get loaded module details!\n");
-		return -1;
-	}
-
-	/* return 0 if VFIO modules not loaded */
-	if (vfio_available == 0) {
-		RTE_LOG(DEBUG, EAL, "VFIO modules not loaded, "
-			"skipping VFIO support...\n");
-		return 0;
-	}
-
-	vfio_cfg.vfio_container_fd = vfio_get_container_fd();
-
-	/* check if we have VFIO driver enabled */
-	if (vfio_cfg.vfio_container_fd != -1) {
-		RTE_LOG(NOTICE, EAL, "VFIO support initialized\n");
-		vfio_cfg.vfio_enabled = 1;
-	} else {
-		RTE_LOG(NOTICE, EAL, "VFIO support could not be initialized\n");
-	}
-
-	return 0;
+	return vfio_enable("vfio_pci");
 }
 
 int
 pci_vfio_is_enabled(void)
 {
-	return vfio_cfg.vfio_enabled;
+	return vfio_is_enabled("vfio_pci");
 }
 #endif
diff --git a/lib/librte_eal/linuxapp/eal/eal_pci_vfio_mp_sync.c b/lib/librte_eal/linuxapp/eal/eal_pci_vfio_mp_sync.c
index a759f02..b3f4c51 100644
--- a/lib/librte_eal/linuxapp/eal/eal_pci_vfio_mp_sync.c
+++ b/lib/librte_eal/linuxapp/eal/eal_pci_vfio_mp_sync.c
@@ -310,7 +310,7 @@ pci_vfio_mp_sync_thread(void __rte_unused * arg)
 				continue;
 			}
 
-			fd = pci_vfio_get_group_fd(vfio_group_no);
+			fd = vfio_get_group_fd(vfio_group_no);
 
 			if (fd < 0)
 				vfio_mp_sync_send_request(conn_sock, SOCKET_ERR);
diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio.c b/lib/librte_eal/linuxapp/eal/eal_vfio.c
index 2bf810e..d11f723 100644
--- a/lib/librte_eal/linuxapp/eal/eal_vfio.c
+++ b/lib/librte_eal/linuxapp/eal/eal_vfio.c
@@ -42,9 +42,296 @@
 
 #include "eal_filesystem.h"
 #include "eal_vfio.h"
+#include "eal_private.h"
 
 #ifdef VFIO_PRESENT
 
+/* per-process VFIO config */
+static struct vfio_config vfio_cfg;
+
+int
+vfio_get_group_fd(int iommu_group_no)
+{
+	int i;
+	int vfio_group_fd;
+	char filename[PATH_MAX];
+
+	/* check if we already have the group descriptor open */
+	for (i = 0; i < vfio_cfg.vfio_group_idx; i++)
+		if (vfio_cfg.vfio_groups[i].group_no == iommu_group_no)
+			return vfio_cfg.vfio_groups[i].fd;
+
+	/* 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_fd = open(filename, O_RDWR);
+		if (vfio_group_fd < 0) {
+			/* if file not found, it's not an error */
+			if (errno != ENOENT) {
+				RTE_LOG(ERR, EAL, "Cannot open %s: %s\n", filename,
+						strerror(errno));
+				return -1;
+			}
+
+			/* special case: try no-IOMMU path as well */
+			snprintf(filename, sizeof(filename),
+					VFIO_NOIOMMU_GROUP_FMT, iommu_group_no);
+			vfio_group_fd = open(filename, O_RDWR);
+			if (vfio_group_fd < 0) {
+				if (errno != ENOENT) {
+					RTE_LOG(ERR, EAL, "Cannot open %s: %s\n", filename,
+							strerror(errno));
+					return -1;
+				}
+				return 0;
+			}
+			/* noiommu group found */
+		}
+
+		/* if the fd is valid, create a new group for it */
+		if (vfio_cfg.vfio_group_idx == VFIO_MAX_GROUPS) {
+			RTE_LOG(ERR, EAL, "Maximum number of VFIO groups reached!\n");
+			close(vfio_group_fd);
+			return -1;
+		}
+		vfio_cfg.vfio_groups[vfio_cfg.vfio_group_idx].group_no = iommu_group_no;
+		vfio_cfg.vfio_groups[vfio_cfg.vfio_group_idx].fd = vfio_group_fd;
+		return vfio_group_fd;
+	}
+	/* if we're in a secondary process, request group fd from the primary
+	 * process via our socket
+	 */
+	else {
+		int socket_fd, ret;
+
+		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_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, return it */
+			if (vfio_group_fd > 0) {
+				close(socket_fd);
+				return vfio_group_fd;
+			}
+			/* fall-through on error */
+		default:
+			RTE_LOG(ERR, EAL, "  cannot get container fd!\n");
+			close(socket_fd);
+			return -1;
+		}
+	}
+	return -1;
+}
+
+static void
+clear_current_group(void)
+{
+	vfio_cfg.vfio_groups[vfio_cfg.vfio_group_idx].group_no = 0;
+	vfio_cfg.vfio_groups[vfio_cfg.vfio_group_idx].fd = -1;
+}
+
+int vfio_setup_device(const char *sysfs_base, const char *dev_addr,
+		int *vfio_dev_fd, struct vfio_device_info *device_info)
+{
+	struct vfio_group_status group_status = {
+			.argsz = sizeof(group_status)
+	};
+	int vfio_group_fd;
+	int iommu_group_no;
+	int ret;
+
+	/* get group number */
+	ret = vfio_get_group_no(sysfs_base, dev_addr, &iommu_group_no);
+	if (ret == 0) {
+		RTE_LOG(WARNING, EAL, "  %s not managed by VFIO driver, skipping\n",
+			dev_addr);
+		return 1;
+	}
+
+	/* if negative, something failed */
+	if (ret < 0)
+		return -1;
+
+	/* get the actual group fd */
+	vfio_group_fd = vfio_get_group_fd(iommu_group_no);
+	if (vfio_group_fd < 0)
+		return -1;
+
+	/* store group fd */
+	vfio_cfg.vfio_groups[vfio_cfg.vfio_group_idx].group_no = iommu_group_no;
+	vfio_cfg.vfio_groups[vfio_cfg.vfio_group_idx].fd = vfio_group_fd;
+
+	/* if group_fd == 0, that means the device isn't managed by VFIO */
+	if (vfio_group_fd == 0) {
+		RTE_LOG(WARNING, EAL, "  %s not managed by VFIO driver, skipping\n",
+				dev_addr);
+		/* we store 0 as group fd to distinguish between existing but
+		 * unbound VFIO groups, and groups that don't exist at all.
+		 */
+		vfio_cfg.vfio_group_idx++;
+		return 1;
+	}
+
+	/*
+	 * at this point, we know that this group is viable (meaning, all devices
+	 * are either bound to VFIO or not bound to anything)
+	 */
+
+	/* check if the group is viable */
+	ret = ioctl(vfio_group_fd, VFIO_GROUP_GET_STATUS, &group_status);
+	if (ret) {
+		RTE_LOG(ERR, EAL, "  %s cannot get group status, "
+				"error %i (%s)\n", dev_addr, errno, strerror(errno));
+		close(vfio_group_fd);
+		clear_current_group();
+		return -1;
+	} else if (!(group_status.flags & VFIO_GROUP_FLAGS_VIABLE)) {
+		RTE_LOG(ERR, EAL, "  %s VFIO group is not viable!\n", dev_addr);
+		close(vfio_group_fd);
+		clear_current_group();
+		return -1;
+	}
+
+	/* 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);
+		if (ret) {
+			RTE_LOG(ERR, EAL, "  %s cannot add VFIO group to container, "
+					"error %i (%s)\n", dev_addr, errno, strerror(errno));
+			close(vfio_group_fd);
+			clear_current_group();
+			return -1;
+		}
+		/*
+		 * at this point we know that this group has been successfully
+		 * initialized, so we increment vfio_group_idx to indicate that we can
+		 * add new groups.
+		 */
+		vfio_cfg.vfio_group_idx++;
+	}
+
+	/*
+	 * pick an IOMMU type and set up DMA mappings for container
+	 *
+	 * needs to be done only once, only when at least one group is assigned to
+	 * a container and only in primary process
+	 */
+	if (internal_config.process_type == RTE_PROC_PRIMARY &&
+			vfio_cfg.vfio_container_has_dma == 0) {
+		/* select an IOMMU type which we will be using */
+		const struct vfio_iommu_type *t =
+				vfio_set_iommu_type(vfio_cfg.vfio_container_fd);
+		if (!t) {
+			RTE_LOG(ERR, EAL, "  %s failed to select IOMMU type\n", dev_addr);
+			return -1;
+		}
+		ret = t->dma_map_func(vfio_cfg.vfio_container_fd);
+		if (ret) {
+			RTE_LOG(ERR, EAL, "  %s DMA remapping failed, "
+					"error %i (%s)\n", dev_addr, errno, strerror(errno));
+			return -1;
+		}
+		vfio_cfg.vfio_container_has_dma = 1;
+	}
+
+	/* get a file descriptor for the device */
+	*vfio_dev_fd = ioctl(vfio_group_fd, VFIO_GROUP_GET_DEVICE_FD, dev_addr);
+	if (*vfio_dev_fd < 0) {
+		/* if we cannot get a device fd, this simply means that this
+		* particular port is not bound to VFIO
+		*/
+		RTE_LOG(WARNING, EAL, "  %s not managed by VFIO driver, skipping\n",
+				dev_addr);
+		return 1;
+	}
+
+	/* test and setup the device */
+	ret = ioctl(*vfio_dev_fd, VFIO_DEVICE_GET_INFO, device_info);
+	if (ret) {
+		RTE_LOG(ERR, EAL, "  %s cannot get device info, "
+				"error %i (%s)\n", dev_addr, errno, strerror(errno));
+		close(*vfio_dev_fd);
+		return -1;
+	}
+
+	return 0;
+}
+
+int
+vfio_enable(const char *modname)
+{
+	/* initialize group list */
+	int i;
+	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;
+	}
+
+	/* inform the user that we are probing for VFIO */
+	RTE_LOG(INFO, EAL, "Probing VFIO support...\n");
+
+	/* check if vfio-pci module is loaded */
+	vfio_available = rte_eal_check_module(modname);
+
+	/* return error directly */
+	if (vfio_available == -1) {
+		RTE_LOG(INFO, EAL, "Could not get loaded module details!\n");
+		return -1;
+	}
+
+	/* return 0 if VFIO modules not loaded */
+	if (vfio_available == 0) {
+		RTE_LOG(DEBUG, EAL, "VFIO modules not loaded, "
+			"skipping VFIO support...\n");
+		return 0;
+	}
+
+	vfio_cfg.vfio_container_fd = vfio_get_container_fd();
+
+	/* check if we have VFIO driver enabled */
+	if (vfio_cfg.vfio_container_fd != -1) {
+		RTE_LOG(NOTICE, EAL, "VFIO support initialized\n");
+		vfio_cfg.vfio_enabled = 1;
+	} else {
+		RTE_LOG(NOTICE, EAL, "VFIO support could not be initialized\n");
+	}
+
+	return 0;
+}
+
+int
+vfio_is_enabled(const char *modname)
+{
+	const int mod_available = rte_eal_check_module(modname);
+	return vfio_cfg.vfio_enabled && mod_available;
+}
+
 const struct vfio_iommu_type *
 vfio_set_iommu_type(int vfio_container_fd) {
 	unsigned idx;
diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio.h b/lib/librte_eal/linuxapp/eal/eal_vfio.h
index 619cd6b..d4532a5 100644
--- a/lib/librte_eal/linuxapp/eal/eal_vfio.h
+++ b/lib/librte_eal/linuxapp/eal/eal_vfio.h
@@ -126,6 +126,23 @@ int
 vfio_get_group_no(const char *sysfs_base,
 		const char *dev_addr, int *iommu_group_no);
 
+/* open group fd or get an existing one */
+int
+vfio_get_group_fd(int iommu_group_no);
+
+/**
+ * Setup vfio_cfg for the device indentified by its address. It discovers
+ * the configured I/O MMU groups or sets a new one for the device. If a new
+ * groups is assigned, the DMA mapping is performed.
+ * Returns 0 on success, a negative value on failure and a positive value in
+ * case the given device cannot be managed this way.
+ */
+int vfio_setup_device(const char *sysfs_base, const char *dev_addr,
+		int *vfio_dev_fd, struct vfio_device_info *device_info);
+
+int vfio_enable(const char *modname);
+int vfio_is_enabled(const char *modname);
+
 #define SOCKET_REQ_CONTAINER 0x100
 #define SOCKET_REQ_GROUP 0x200
 #define SOCKET_OK 0x0
-- 
2.8.0