[dpdk-dev] [PATCH] vfio: fix device unplug when several devices per vfio group

[Alejandro Lucero]

VFIO allows a secure way of assigning devices to user space and those
devices which can not be isolated from other ones are set in same VFIO
group. Releasing or unplugging a device should be aware of remaining
devices is the same group for avoiding to close such a group.

Fixes: 94c0776b1bad ("vfio: support hotplug")

Signed-off-by: Alejandro Lucero <alejandro.lucero at netronome.com>
---
 lib/librte_eal/linuxapp/eal/eal_vfio.c | 32 ++++++++++++++++++++++++--------
 lib/librte_eal/linuxapp/eal/eal_vfio.h |  1 +
 2 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio.c b/lib/librte_eal/linuxapp/eal/eal_vfio.c
index 6e2e84c..6e24273 100644
--- a/lib/librte_eal/linuxapp/eal/eal_vfio.c
+++ b/lib/librte_eal/linuxapp/eal/eal_vfio.c
@@ -184,6 +184,7 @@
 			if (vfio_cfg.vfio_groups[i].fd == vfio_group_fd) {
 				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--;
 				return 0;
 			}
@@ -353,6 +354,7 @@
 		clear_group(vfio_group_fd);
 		return -1;
 	}
+	vfio_cfg.vfio_groups[vfio_group_fd].devices++;
 
 	return 0;
 }
@@ -390,17 +392,30 @@
 	 * code will unset the container and the IOMMU mappings.
 	 */
 
-	if (close(vfio_group_fd) < 0)
-		RTE_LOG(INFO, EAL, "Error when closing vfio_group_fd for %s\n",
-				   dev_addr);
-
-	if (close(vfio_dev_fd) < 0)
+	/* Closing a device */
+	if (close(vfio_dev_fd) < 0) {
 		RTE_LOG(INFO, EAL, "Error when closing vfio_dev_fd for %s\n",
 				   dev_addr);
+		return -1;
+	}
 
-	if (clear_group(vfio_group_fd) < 0)
-		RTE_LOG(INFO, EAL, "Error when clearing group for %s\n",
-				   dev_addr);
+	/* An VFIO group can have several devices attached. Just when there is
+	 * no devices remaining should the group be closed.
+	 */
+	if (--vfio_cfg.vfio_groups[vfio_group_fd].devices == 0) {
+
+		if (close(vfio_group_fd) < 0) {
+			RTE_LOG(INFO, EAL, "Error when closing vfio_group_fd for %s\n",
+				dev_addr);
+			return -1;
+		}
+
+		if (clear_group(vfio_group_fd) < 0) {
+			RTE_LOG(INFO, EAL, "Error when clearing group for %s\n",
+					   dev_addr);
+			return -1;
+		}
+	}
 
 	return 0;
 }
@@ -415,6 +430,7 @@
 	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;
 	}
 
 	/* inform the user that we are probing for VFIO */
diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio.h b/lib/librte_eal/linuxapp/eal/eal_vfio.h
index 7fcec2c..2c7cb94 100644
--- a/lib/librte_eal/linuxapp/eal/eal_vfio.h
+++ b/lib/librte_eal/linuxapp/eal/eal_vfio.h
@@ -103,6 +103,7 @@ struct vfio_iommu_spapr_tce_remove {
 struct vfio_group {
 	int group_no;
 	int fd;
+	int devices;
 };
 
 struct vfio_config {
-- 
1.9.1