From: David Wilder <dwil...@us.ibm.com>
When using --no-huge option physical address are not guaranteed
to be persistent.
This change effectively makes "--no-huge" the same as
"--no-huge --iova-mode=va".
When --no-huge is used (or any other condition making physical
addresses unavailable) setting --iova-mode=pa will have no effect.
Signed-off-by: Christian Ehrhardt <christian.ehrha...@canonical.com>
---
doc/guides/prog_guide/env_abstraction_layer.rst | 9 ++++++---
lib/eal/linux/eal.c | 16 ++++++++++------
2 files changed, 16 insertions(+), 9 deletions(-)
diff --git a/doc/guides/prog_guide/env_abstraction_layer.rst
b/doc/guides/prog_guide/env_abstraction_layer.rst
index 6debf54efb..20c7355e0f 100644
--- a/doc/guides/prog_guide/env_abstraction_layer.rst
+++ b/doc/guides/prog_guide/env_abstraction_layer.rst
@@ -559,9 +559,12 @@ IOVA Mode is selected by considering what the current
usable Devices on the
system require and/or support.
On FreeBSD, RTE_IOVA_PA is always the default. On Linux, the IOVA mode is
-detected based on a 2-step heuristic detailed below.
+detected based on a heuristic detailed below.
-For the first step, EAL asks each bus its requirement in terms of IOVA mode
+For the first step, if no Physical Addresses are available RTE_IOVA_VA is
+selected.
+
+Then EAL asks each bus its requirement in terms of IOVA mode
and decides on a preferred IOVA mode.
- if all buses report RTE_IOVA_PA, then the preferred IOVA mode is RTE_IOVA_PA,
@@ -575,7 +578,7 @@ and decides on a preferred IOVA mode.
If the buses have expressed no preference on which IOVA mode to pick, then a
default is selected using the following logic:
-- if physical addresses are not available, RTE_IOVA_VA mode is used
+- if enable_iova_as_pa was not set at build RTE_IOVA_VA mode is used
- if /sys/kernel/iommu_groups is not empty, RTE_IOVA_VA mode is used
- otherwise, RTE_IOVA_PA mode is used
diff --git a/lib/eal/linux/eal.c b/lib/eal/linux/eal.c
index 57da058cec..2f1fce3c54 100644
--- a/lib/eal/linux/eal.c
+++ b/lib/eal/linux/eal.c
@@ -1067,6 +1067,16 @@ rte_eal_init(int argc, char **argv)
phys_addrs = rte_eal_using_phys_addrs() != 0;
+ if (!phys_addrs) {
+ /* if we have no access to physical addresses, pick IOVA as VA
mode. */
+ if (internal_conf->iova_mode == RTE_IOVA_PA)
+ RTE_LOG(WARNING, EAL, "WARNING: --iova-mode=pa, but
Physical addresses are unavailable, selecting IOVA as VA mode.\n");
+ else
+ RTE_LOG(DEBUG, EAL, "Physical addresses are
unavailable, selecting IOVA as VA mode.\n");
+ internal_conf->iova_mode = RTE_IOVA_VA;
+ rte_eal_get_configuration()->iova_mode =
internal_conf->iova_mode;
+ }
+
/* 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 */
@@ -1078,12 +1088,6 @@ rte_eal_init(int argc, char **argv)
if (!RTE_IOVA_IN_MBUF) {
iova_mode = RTE_IOVA_VA;
RTE_LOG(DEBUG, EAL, "IOVA as VA mode is forced
by build option.\n");
- } else if (!phys_addrs) {
- /* if we have no access to physical addresses,
- * pick IOVA as VA mode.
- */
- iova_mode = RTE_IOVA_VA;
- RTE_LOG(DEBUG, EAL, "Physical addresses are
unavailable, selecting IOVA as VA mode.\n");
} else if (is_iommu_enabled()) {
/* we have an IOMMU, pick IOVA as VA mode */
iova_mode = RTE_IOVA_VA;
--
2.34.1
