[dpdk-dev] [PATCH v7 07/26] vfio: avoid enabling while the module is not loaded

[Neil Horman <nhorman@tuxdriver.com>]

From: Michael Qiu <michael.qiu@intel.com>

When vfio module is not loaded when kernel support vfio feature,
the routine still try to open the container to get file
description.

This action is not safe, and of course got error messages:

EAL: Detected 40 lcore(s)
EAL:   unsupported IOMMU type!
EAL: VFIO support could not be initialized
EAL: Setting up memory...

This may make user confuse, this patch make it reasonable
and much more smooth to user.

Signed-off-by: Michael Qiu <michael.qiu@intel.com>
Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>
---
 lib/librte_eal/common/eal_private.h        | 14 ++++++++++++++
 lib/librte_eal/linuxapp/eal/eal.c          | 27 +++++++++++++++++++++++++++
 lib/librte_eal/linuxapp/eal/eal_pci_vfio.c | 24 ++++++++++++++++++++++--
 3 files changed, 63 insertions(+), 2 deletions(-)

diff --git a/lib/librte_eal/common/eal_private.h b/lib/librte_eal/common/eal_private.h
index 232fcec..159cd66 100644
--- a/lib/librte_eal/common/eal_private.h
+++ b/lib/librte_eal/common/eal_private.h
@@ -203,4 +203,18 @@ int rte_eal_alarm_init(void);
  */
 int rte_eal_dev_init(void);
 
+/**
+ * Function is to check if the kernel module(like, vfio, vfio_iommu_type1,
+ * etc.) loaded.
+ *
+ * @param module_name
+ *	The module's name which need to be checked
+ *
+ * @return
+ *	-1 means some error happens(NULL pointer or open failure)
+ *	0  means the module not loaded
+ *	1  means the module loaded
+ */
+int rte_eal_check_module(const char *module_name);
+
 #endif /* _EAL_PRIVATE_H_ */
diff --git a/lib/librte_eal/linuxapp/eal/eal.c b/lib/librte_eal/linuxapp/eal/eal.c
index 2fb1acc..648ef81 100644
--- a/lib/librte_eal/linuxapp/eal/eal.c
+++ b/lib/librte_eal/linuxapp/eal/eal.c
@@ -859,3 +859,30 @@ int rte_eal_has_hugepages(void)
 {
 	return ! internal_config.no_hugetlbfs;
 }
+
+int
+rte_eal_check_module(const char *module_name)
+{
+	char mod_name[30]; /* Any module names can be longer than 30 bytes? */
+	int ret = 0;
+
+	if (NULL == module_name)
+		return -1;
+
+	FILE *fd = fopen("/proc/modules", "r");
+	if (NULL == fd) {
+		RTE_LOG(ERR, EAL, "Open /proc/modules failed!"
+			" error %i (%s)\n", errno, strerror(errno));
+		return -1;
+	}
+	while (!feof(fd)) {
+		fscanf(fd, "%29s %*[^\n]", mod_name);
+		if (!strcmp(mod_name, module_name)) {
+			ret = 1;
+			break;
+		}
+	}
+	fclose(fd);
+
+	return ret;
+}
diff --git a/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c b/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
index c1246e8..20e0977 100644
--- a/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
+++ b/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
@@ -44,6 +44,7 @@
 #include <rte_tailq.h>
 #include <rte_eal_memconfig.h>
 #include <rte_malloc.h>
+#include <eal_private.h>
 
 #include "eal_filesystem.h"
 #include "eal_pci_init.h"
@@ -340,9 +341,11 @@ pci_vfio_get_container_fd(void)
 		if (ret != 1) {
 			if (ret < 0)
 				RTE_LOG(ERR, EAL, "  could not get IOMMU type, "
-						"error %i (%s)\n", errno, strerror(errno));
+					"error %i (%s)\n", errno,
+					strerror(errno));
 			else
-				RTE_LOG(ERR, EAL, "  unsupported IOMMU type!\n");
+				RTE_LOG(ERR, EAL, "  unsupported IOMMU type "
+					"detected in VFIO\n");
 			close(vfio_container_fd);
 			return -1;
 		}
@@ -783,11 +786,28 @@ pci_vfio_enable(void)
 {
 	/* initialize group list */
 	int i;
+	int module_vfio_type1;
 
 	for (i = 0; i < VFIO_MAX_GROUPS; i++) {
 		vfio_cfg.vfio_groups[i].fd = -1;
 		vfio_cfg.vfio_groups[i].group_no = -1;
 	}
+
+	module_vfio_type1 = rte_eal_check_module("vfio_iommu_type1");
+
+	/* return error directly */
+	if (module_vfio_type1 == -1) {
+		RTE_LOG(INFO, EAL, "Could not get loaded module details!\n");
+		return -1;
+	}
+
+	/* return 0 if VFIO modules not loaded */
+	if (module_vfio_type1 == 0) {
+		RTE_LOG(INFO, EAL, "VFIO modules not all loaded, "
+			"skip VFIO support...\n");
+		return 0;
+	}
+
 	vfio_cfg.vfio_container_fd = pci_vfio_get_container_fd();
 
 	/* check if we have VFIO driver enabled */
-- 
2.1.0