Re: [dpdk-dev] [PATCH v2 2/2] eal: force IOVA to particular mode

["Zhang, Qing Long (Eric)" <Eric.Zhang@windriver.com>]

Hi Santosh/Anatoly,
Any comments on the v2 patch which uses EAL option to let user configure 
iova mode as suggested?

Thanks
Eric 

-----Original Message-----
From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of eric zhang
Sent: Tuesday, September 18, 2018 3:10 PM
To: anatoly.burakov@intel.com; santosh.shukla@caviumnetworks.com
Cc: dev@dpdk.org; Legacy, Allain; Peters, Matt
Subject: [dpdk-dev] [PATCH v2 2/2] eal: force IOVA to 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 detectioni 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>

---
v2:
* use eal option instead of compilation option to configure IOVA
* apply http://patchwork.dpdk.org/patch/25192/
---
 lib/librte_eal/bsdapp/eal/eal.c   | 11 +++++++++--
 lib/librte_eal/linuxapp/eal/eal.c | 27 +++++++++++++++++----------
 2 files changed, 26 insertions(+), 12 deletions(-)

diff --git a/lib/librte_eal/bsdapp/eal/eal.c b/lib/librte_eal/bsdapp/eal/eal.c
index 369a682..52a1547 100644
--- a/lib/librte_eal/bsdapp/eal/eal.c
+++ b/lib/librte_eal/bsdapp/eal/eal.c
@@ -569,8 +569,15 @@ static void rte_eal_init_alert(const char *msg)
 		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 == -1) {
+		/* autodetect the iova mapping mode (default is 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 &&
 			internal_config.process_type != RTE_PROC_SECONDARY &&
diff --git a/lib/librte_eal/linuxapp/eal/eal.c b/lib/librte_eal/linuxapp/eal/eal.c
index e0b5ae1..51208df 100644
--- a/lib/librte_eal/linuxapp/eal/eal.c
+++ b/lib/librte_eal/linuxapp/eal/eal.c
@@ -805,16 +805,23 @@ static void rte_eal_init_alert(const char *msg)
 		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 == -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");
+		}
+	} else {
+		rte_eal_get_configuration()->iova_mode =
+			internal_config.iova_mode;
 	}
 
 	if (internal_config.no_hugetlbfs == 0 &&
-- 
1.8.3.1