[dpdk-dev] [PATCH v2 1/3] eal/freebsd: fix IOVA mode selection

[Dmitry Kozlyuk <dkozlyuk@oss.nvidia.com>]

FreeBSD EAL selected IOVA mode PA even in --no-huge mode
where PA are not available. Memory zones were created with IOVA
equal to RTE_BAD_IOVA with no indication this field is not usable.

Change IOVA mode detection:
1. Always allow to force --iova-mode=va.
2. In --no-huge mode, disallow forcing --iova-mode=pa, and select VA.
3. Otherwise select IOVA mode according to bus requests, default to PA.
In case contigmem is inaccessible, memory initialization will fail
with a message indicating the cause.

Fixes: c2361bab70c5 ("eal: compute IOVA mode based on PA availability")
Cc: benjamin.walker@intel.com
Cc: stable@dpdk.org

Signed-off-by: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
---
 lib/eal/freebsd/eal.c | 37 +++++++++++++++++++++++++------------
 1 file changed, 25 insertions(+), 12 deletions(-)

diff --git a/lib/eal/freebsd/eal.c b/lib/eal/freebsd/eal.c
index 9935356ed4..519a645344 100644
--- a/lib/eal/freebsd/eal.c
+++ b/lib/eal/freebsd/eal.c
@@ -677,6 +677,8 @@ rte_eal_init(int argc, char **argv)
 	const struct rte_config *config = rte_eal_get_configuration();
 	struct internal_config *internal_conf =
 		eal_get_internal_configuration();
+	bool has_phys_addr;
+	enum rte_iova_mode iova_mode;
 
 	/* checks if the machine is adequate */
 	if (!rte_cpu_is_supported()) {
@@ -777,21 +779,32 @@ rte_eal_init(int argc, char **argv)
 		return -1;
 	}
 
-	/* if no EAL option "--iova-mode=<pa|va>", use bus IOVA scheme */
-	if (internal_conf->iova_mode == RTE_IOVA_DC) {
-		/* autodetect the IOVA mapping mode (default is RTE_IOVA_PA) */
-		enum rte_iova_mode iova_mode = rte_bus_get_iommu_class();
-
-		if (iova_mode == RTE_IOVA_DC)
-			iova_mode = RTE_IOVA_PA;
-		rte_eal_get_configuration()->iova_mode = iova_mode;
-	} else {
-		rte_eal_get_configuration()->iova_mode =
-			internal_conf->iova_mode;
+	/*
+	 * PA are only available for hugepages via contigmem.
+	 * If contigmem is inaccessible, rte_eal_hugepage_init() will fail
+	 * with a message describing the cause.
+	 */
+	has_phys_addr = internal_conf->no_hugetlbfs == 0;
+	iova_mode = internal_conf->iova_mode;
+	if (iova_mode == RTE_IOVA_PA && !has_phys_addr) {
+		rte_eal_init_alert("Cannot use IOVA as 'PA' since physical addresses are not available");
+		rte_errno = EINVAL;
+		return -1;
+	}
+	if (iova_mode == RTE_IOVA_DC) {
+		RTE_LOG(DEBUG, EAL, "Specific IOVA mode is not requested, autodetecting\n");
+		if (has_phys_addr) {
+			RTE_LOG(DEBUG, EAL, "Selecting IOVA mode according to bus requests\n");
+			iova_mode = rte_bus_get_iommu_class();
+			if (iova_mode == RTE_IOVA_DC)
+				iova_mode = RTE_IOVA_PA;
+		} else {
+			iova_mode = RTE_IOVA_VA;
+		}
 	}
-
 	RTE_LOG(INFO, EAL, "Selected IOVA mode '%s'\n",
 		rte_eal_iova_mode() == RTE_IOVA_PA ? "PA" : "VA");
+	rte_eal_get_configuration()->iova_mode = iova_mode;
 
 	if (internal_conf->no_hugetlbfs == 0) {
 		/* rte_config isn't initialized yet */
-- 
2.25.1