[dpdk-dev] [PATCH v3 1/2] vfio: open VFIO container at startup rather than during init

[Anatoly Burakov <anatoly.burakov@intel.com>]

Currently, VFIO only checks for being able to access the /dev/vfio
directory when initializing VFIO, deferring actual VFIO container
initialization to VFIO binding code. This doesn't bode well for when
VFIO container cannot be initialized for whatever reason, because
it results in unrecoverable error even if the user didn't set up
VFIO and didn't even want to use it in the first place.

This patch fixes this by moving container initialization into the
code that checks if VFIO is available at runtime. Therefore, any
issues with the container will be known at initialization stage and
VFIO will simply be turned off if container could not be set up.

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
---
 lib/librte_eal/linuxapp/eal/eal_pci_vfio.c | 15 ++-------------
 1 file changed, 2 insertions(+), 13 deletions(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c b/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
index 4de6061..9eb5dcd 100644
--- a/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
+++ b/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
@@ -523,17 +523,6 @@ pci_vfio_map_resource(struct rte_pci_device *dev)
 	rte_snprintf(pci_addr, sizeof(pci_addr), PCI_PRI_FMT,
 			loc->domain, loc->bus, loc->devid, loc->function);
 
-	/* get container fd (needs to be done only once per initialization) */
-	if (vfio_cfg.vfio_container_fd == -1) {
-		int vfio_container_fd = pci_vfio_get_container_fd();
-		if (vfio_container_fd < 0) {
-			RTE_LOG(ERR, EAL, "  %s cannot open VFIO container!\n", pci_addr);
-			return -1;
-		}
-
-		vfio_cfg.vfio_container_fd = vfio_container_fd;
-	}
-
 	/* get group number */
 	iommu_group_no = pci_vfio_get_group_no(pci_addr);
 
@@ -770,10 +759,10 @@ pci_vfio_enable(void)
 		vfio_cfg.vfio_groups[i].fd = -1;
 		vfio_cfg.vfio_groups[i].group_no = -1;
 	}
-	vfio_cfg.vfio_container_fd = -1;
+	vfio_cfg.vfio_container_fd = pci_vfio_get_container_fd();
 
 	/* check if we have VFIO driver enabled */
-	if (access(VFIO_DIR, F_OK) == 0)
+	if (vfio_cfg.vfio_container_fd != -1)
 		vfio_cfg.vfio_enabled = 1;
 	else
 		RTE_LOG(INFO, EAL, "VFIO driver not loaded or wrong permissions\n");
-- 
1.8.1.4