[dpdk-dev] [RFC] vfio: only map regions VFIO supports

[Stephen Hemminger]

The FM10K driver has 3 BARS numbered 0, 4, and 8. But the kernel
VFIO driver only allows mapping 0-5 anything bigger than that will
return -EINVAL (see kernel source vfio_pci.c:vfio_pci_mmap).

The workaround is to limit the DPDK EAL VFIO support only map
the regions that will work. The FM10K driver is not using BAR8
in current code anyway.

Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
---
 lib/librte_eal/linuxapp/eal/eal_pci_vfio.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c b/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
index 426953a..e269e75 100644
--- a/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
+++ b/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
@@ -549,7 +549,7 @@ pci_vfio_map_resource(struct rte_pci_device *dev)
 	int iommu_group_no;
 	char pci_addr[PATH_MAX] = {0};
 	struct rte_pci_addr *loc = &dev->addr;
-	int i, ret, msix_bar;
+	int i, ret, msix_bar, nmaps;
 	struct mapped_pci_resource *vfio_res = NULL;
 	struct mapped_pci_res_list *vfio_res_list = RTE_TAILQ_CAST(rte_vfio_tailq.head, mapped_pci_res_list);
 
@@ -724,7 +724,9 @@ pci_vfio_map_resource(struct rte_pci_device *dev)
 	/* map BARs */
 	maps = vfio_res->maps;
 
-	for (i = 0; i < (int) vfio_res->nb_maps; i++) {
+	/* VFIO supports limited (0-5) maps */
+	nmaps = RTE_MIN(vfio_res->nb_maps, VFIO_PCI_ROM_REGION_INDEX - 1);
+	for (i = 0; i < nmaps; i++) {
 		struct vfio_region_info reg = { .argsz = sizeof(reg) };
 		void *bar_addr;
 		struct memreg {
-- 
2.1.4