From: Eric Zhang <eric.zhang@windriver.com>
Date: Wed, 3 Oct 2018 20:53:13 +0000 (-0400)
Subject: eal: force IOVA to a particular mode
X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=075b182b54ce;p=dpdk.git

eal: force IOVA to a particular mode

This patch uses EAL option "--iova-mode" to force the IOVA mode to a
particular value. There exists virtual devices that are not directly
attached to the PCI bus, and therefore the auto detection of the IOVA
mode based on probing the PCI bus and IOMMU configuration may not
report the required addressing mode. Using the EAL option permits the
mode to be explicitly configured in this scenario.

Signed-off-by: Eric Zhang <eric.zhang@windriver.com>
Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>
Reviewed-by: Marko Kovacevic <marko.kovacevic@intel.com>
---

diff --git a/doc/guides/prog_guide/env_abstraction_layer.rst b/doc/guides/prog_guide/env_abstraction_layer.rst
index 00ce64ceba..4f8612a241 100644
--- a/doc/guides/prog_guide/env_abstraction_layer.rst
+++ b/doc/guides/prog_guide/env_abstraction_layer.rst
@@ -358,6 +358,14 @@ Misc Functions
 
 Locks and atomic operations are per-architecture (i686 and x86_64).
 
+IOVA Mode Configuration
+~~~~~~~~~~~~~~~~~~~~~~~
+
+Auto detection of the IOVA mode, based on probing the bus and IOMMU configuration, may not report
+the desired addressing mode when virtual devices that are not directly attached to the bus are present.
+To facilitate forcing the IOVA mode to a specific value the EAL command line option ``--iova-mode`` can
+be used to select either physical addressing('pa') or virtual addressing('va').
+
 Memory Segments and Memory Zones (memzone)
 ------------------------------------------
 
diff --git a/doc/guides/testpmd_app_ug/run_app.rst b/doc/guides/testpmd_app_ug/run_app.rst
index 851df65daf..c79fd0d0ba 100644
--- a/doc/guides/testpmd_app_ug/run_app.rst
+++ b/doc/guides/testpmd_app_ug/run_app.rst
@@ -133,6 +133,10 @@ See the DPDK Getting Started Guides for more information on these options.
 
     Use malloc instead of hugetlbfs.
 
+*   ``--iova-mode <pa|va>``
+
+    Force IOVA mode to a specific value.
+
 
 Testpmd Command-line Options
 ----------------------------
diff --git a/lib/librte_eal/bsdapp/eal/eal.c b/lib/librte_eal/bsdapp/eal/eal.c
index 21997ced85..508cbc46fd 100644
--- a/lib/librte_eal/bsdapp/eal/eal.c
+++ b/lib/librte_eal/bsdapp/eal/eal.c
@@ -656,8 +656,15 @@ rte_eal_init(int argc, char **argv)
 		return -1;
 	}
 
-	/* autodetect the iova mapping mode (default is iova_pa) */
-	rte_eal_get_configuration()->iova_mode = rte_bus_get_iommu_class();
+	/* if no EAL option "--iova-mode=<pa|va>", use bus IOVA scheme */
+	if (internal_config.iova_mode == RTE_IOVA_DC) {
+		/* autodetect the IOVA mapping mode (default is RTE_IOVA_PA) */
+		rte_eal_get_configuration()->iova_mode =
+			rte_bus_get_iommu_class();
+	} else {
+		rte_eal_get_configuration()->iova_mode =
+			internal_config.iova_mode;
+	}
 
 	if (internal_config.no_hugetlbfs == 0) {
 		/* rte_config isn't initialized yet */
diff --git a/lib/librte_eal/linuxapp/eal/eal.c b/lib/librte_eal/linuxapp/eal/eal.c
index 6a3395f3c9..361744d409 100644
--- a/lib/librte_eal/linuxapp/eal/eal.c
+++ b/lib/librte_eal/linuxapp/eal/eal.c
@@ -912,16 +912,23 @@ rte_eal_init(int argc, char **argv)
 		return -1;
 	}
 
-	/* autodetect the iova mapping mode (default is iova_pa) */
-	rte_eal_get_configuration()->iova_mode = rte_bus_get_iommu_class();
-
-	/* Workaround for KNI which requires physical address to work */
-	if (rte_eal_get_configuration()->iova_mode == RTE_IOVA_VA &&
-			rte_eal_check_module("rte_kni") == 1) {
-		rte_eal_get_configuration()->iova_mode = RTE_IOVA_PA;
-		RTE_LOG(WARNING, EAL,
-			"Some devices want IOVA as VA but PA will be used because.. "
-			"KNI module inserted\n");
+	/* if no EAL option "--iova-mode=<pa|va>", use bus IOVA scheme */
+	if (internal_config.iova_mode == RTE_IOVA_DC) {
+		/* autodetect the IOVA mapping mode (default is RTE_IOVA_PA) */
+		rte_eal_get_configuration()->iova_mode =
+			rte_bus_get_iommu_class();
+
+		/* Workaround for KNI which requires physical address to work */
+		if (rte_eal_get_configuration()->iova_mode == RTE_IOVA_VA &&
+				rte_eal_check_module("rte_kni") == 1) {
+			rte_eal_get_configuration()->iova_mode = RTE_IOVA_PA;
+			RTE_LOG(WARNING, EAL,
+				"Some devices want IOVA as VA but PA will be used because.. "
+				"KNI module inserted\n");
+		}
+	} else {
+		rte_eal_get_configuration()->iova_mode =
+			internal_config.iova_mode;
 	}
 
 	if (internal_config.no_hugetlbfs == 0) {