[dpdk-dev] [PATCH] vhost: initializing iotlb memory only when IOMMU feature is enabled DPDK 17.11 introduced the IOMMU feature which caused additional DPDK memory requirement per vhostuser device as part of iotlb_init(). Today this is done unconditionally (from DPDK 17.11 onwards) i.e. irrespective of IOMMU feature being enabled on the vhostuser device, iotlb is initialized. This breaks the backward compatibility for applications like OVS due to increase in the DPDK memory footprint and causes upgrade failures.

[Nitin Katiyar]

This patch is to do iotlb_init only if IOMMU feature is enabled on device.

Signed-off-by: Nitin Katiyar <nitin.katiyar at ericsson.com>
---
 lib/librte_vhost/iotlb.c      | 7 +++++++
 lib/librte_vhost/vhost_user.c | 7 +++++++
 2 files changed, 14 insertions(+)

diff --git a/lib/librte_vhost/iotlb.c b/lib/librte_vhost/iotlb.c
index c11ebca..0d7c820 100644
--- a/lib/librte_vhost/iotlb.c
+++ b/lib/librte_vhost/iotlb.c
@@ -310,6 +310,13 @@ struct vhost_iotlb_entry {
 	struct vhost_virtqueue *vq = dev->virtqueue[vq_index];
 	int socket = 0;
 
+	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)) {
+		RTE_LOG(ERR, VHOST_CONFIG,
+			"IOMMU feature is not enabled for this dev(%s)\n",
+			dev->ifname);
+		return -1;
+	}
+
 	if (vq->iotlb_pool) {
 		/*
 		 * The cache has already been initialized,
diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 26cfebe..ca787f3 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -1274,6 +1274,13 @@
 	uint16_t i;
 	uint64_t vva, len;
 
+	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)) {
+		RTE_LOG(ERR, VHOST_CONFIG,
+			"IOMMU feature is not enabled for this dev(%s)\n",
+			dev->ifname);
+		return -1;
+	}
+
 	switch (imsg->type) {
 	case VHOST_IOTLB_UPDATE:
 		len = imsg->size;
-- 
1.9.1