[dpdk-dev] [PATCH v8 5/5] kni: modify IOVA mode checks to support VA

[<vattunuru@marvell.com>]

From: Vamsi Attunuru <vattunuru@marvell.com>

Patch addresses checks in KNI and eal that enforce IOVA=PA when
IOVA=VA mode is enabled, since KNI kernel module supports VA
mode for kernel versions >= 4.4.0.

Updated KNI documentation with above details.

Signed-off-by: Vamsi Attunuru <vattunuru@marvell.com>
Signed-off-by: Kiran Kumar K <kirankumark@marvell.com>
---
 doc/guides/prog_guide/kernel_nic_interface.rst | 8 ++++++++
 lib/librte_eal/linux/eal/eal.c                 | 4 +++-
 lib/librte_kni/rte_kni.c                       | 5 -----
 3 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/doc/guides/prog_guide/kernel_nic_interface.rst b/doc/guides/prog_guide/kernel_nic_interface.rst
index 38369b3..fd2ce63 100644
--- a/doc/guides/prog_guide/kernel_nic_interface.rst
+++ b/doc/guides/prog_guide/kernel_nic_interface.rst
@@ -291,6 +291,14 @@ The sk_buff is then freed and the mbuf sent in the tx_q FIFO.
 The DPDK TX thread dequeues the mbuf and sends it to the PMD via ``rte_eth_tx_burst()``.
 It then puts the mbuf back in the cache.
 
+IOVA = VA: Support
+------------------
+
+KNI can be operated in IOVA as VA scheme when following criteria are fullfilled
+
+- LINUX_VERSION_CODE >= KERNEL_VERSION(4, 4, 0)
+- eal param `--iova-mode va` is passed or bus IOVA scheme is set to RTE_IOVA_VA
+
 Ethtool
 -------
 
diff --git a/lib/librte_eal/linux/eal/eal.c b/lib/librte_eal/linux/eal/eal.c
index 2e5499f..9705243 100644
--- a/lib/librte_eal/linux/eal/eal.c
+++ b/lib/librte_eal/linux/eal/eal.c
@@ -1070,12 +1070,14 @@ rte_eal_init(int argc, char **argv)
 		/* Workaround for KNI which requires physical address to work */
 		if (iova_mode == RTE_IOVA_VA &&
 				rte_eal_check_module("rte_kni") == 1) {
+#if KERNEL_VERSION(4, 4, 0) > LINUX_VERSION_CODE
 			if (phys_addrs) {
 				iova_mode = RTE_IOVA_PA;
-				RTE_LOG(WARNING, EAL, "Forcing IOVA as 'PA' because KNI module is loaded\n");
+				RTE_LOG(WARNING, EAL, "Forcing IOVA as 'PA' because KNI module does not support VA\n");
 			} else {
 				RTE_LOG(DEBUG, EAL, "KNI can not work since physical addresses are unavailable\n");
 			}
+#endif
 		}
 #endif
 		rte_eal_get_configuration()->iova_mode = iova_mode;
diff --git a/lib/librte_kni/rte_kni.c b/lib/librte_kni/rte_kni.c
index 897a5bb..6a95230 100644
--- a/lib/librte_kni/rte_kni.c
+++ b/lib/librte_kni/rte_kni.c
@@ -98,11 +98,6 @@ static volatile int kni_fd = -1;
 int
 rte_kni_init(unsigned int max_kni_ifaces __rte_unused)
 {
-	if (rte_eal_iova_mode() != RTE_IOVA_PA) {
-		RTE_LOG(ERR, KNI, "KNI requires IOVA as PA\n");
-		return -1;
-	}
-
 	/* Check FD and open */
 	if (kni_fd < 0) {
 		kni_fd = open("/dev/" KNI_DEVICE, O_RDWR);
-- 
2.8.4