[dpdk-dev] [PATCH v2 3/3] net: vhost: add iommu-support parameter to enable IOMMU feature

[Maxime Coquelin <maxime.coquelin@redhat.com>]

Introduce a new iommu-support parameter to Vhost PMD that
passes the RTE_VHOST_USER_IOMMU_SUPPORT flag at vhost
device register time.

Default value is 0, meaning that IOMMU support is disabled
if not specified explicitly.

Example to enable IOMMU support for a given device:

--vdev 'net_vhost0,iface=/tmp/vhost-user2,iommu-support=1'

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 doc/guides/nics/vhost.rst         |  5 +++++
 drivers/net/vhost/rte_eth_vhost.c | 13 +++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/doc/guides/nics/vhost.rst b/doc/guides/nics/vhost.rst
index e651a1661..4f7ae8990 100644
--- a/doc/guides/nics/vhost.rst
+++ b/doc/guides/nics/vhost.rst
@@ -66,6 +66,11 @@ The user can specify below arguments in `--vdev` option.
     It is used to specify the number of queues virtio-net device has.
     (Default: 1)
 
+#.  ``iommu-support``:
+
+    It is used to enable iommu support in vhost library.
+    (Default: 0 (disabled))
+
 Vhost PMD event handling
 ------------------------
 
diff --git a/drivers/net/vhost/rte_eth_vhost.c b/drivers/net/vhost/rte_eth_vhost.c
index f98c98067..a28cc3b9a 100644
--- a/drivers/net/vhost/rte_eth_vhost.c
+++ b/drivers/net/vhost/rte_eth_vhost.c
@@ -52,6 +52,7 @@ enum {VIRTIO_RXQ, VIRTIO_TXQ, VIRTIO_QNUM};
 #define ETH_VHOST_QUEUES_ARG		"queues"
 #define ETH_VHOST_CLIENT_ARG		"client"
 #define ETH_VHOST_DEQUEUE_ZERO_COPY	"dequeue-zero-copy"
+#define ETH_VHOST_IOMMU_SUPPORT		"iommu-support"
 #define VHOST_MAX_PKT_BURST 32
 
 static const char *valid_arguments[] = {
@@ -59,6 +60,7 @@ static const char *valid_arguments[] = {
 	ETH_VHOST_QUEUES_ARG,
 	ETH_VHOST_CLIENT_ARG,
 	ETH_VHOST_DEQUEUE_ZERO_COPY,
+	ETH_VHOST_IOMMU_SUPPORT,
 	NULL
 };
 
@@ -1164,6 +1166,7 @@ rte_pmd_vhost_probe(struct rte_vdev_device *dev)
 	uint64_t flags = 0;
 	int client_mode = 0;
 	int dequeue_zero_copy = 0;
+	int iommu_support = 0;
 
 	RTE_LOG(INFO, PMD, "Initializing pmd_vhost for %s\n",
 		rte_vdev_device_name(dev));
@@ -1211,6 +1214,16 @@ rte_pmd_vhost_probe(struct rte_vdev_device *dev)
 			flags |= RTE_VHOST_USER_DEQUEUE_ZERO_COPY;
 	}
 
+	if (rte_kvargs_count(kvlist, ETH_VHOST_IOMMU_SUPPORT) == 1) {
+		ret = rte_kvargs_process(kvlist, ETH_VHOST_IOMMU_SUPPORT,
+					 &open_int, &iommu_support);
+		if (ret < 0)
+			goto out_free;
+
+		if (iommu_support)
+			flags |= RTE_VHOST_USER_IOMMU_SUPPORT;
+	}
+
 	if (dev->device.numa_node == SOCKET_ID_ANY)
 		dev->device.numa_node = rte_socket_id();
 
-- 
2.13.6