On 25-Jul-19 9:05 AM, David Marchand wrote:
On Wed, Jul 24, 2019 at 6:46 PM Anatoly Burakov
<anatoly.bura...@intel.com> wrote:
When IOMMU is not available, /sys/kernel/iommu_groups will not be
populated. This is happening since at least 3.6 when VFIO support
was added. If the directory is empty, EAL should not pick IOVA as
VA as the default IOVA mode.
We also assume that VFIO equals IOMMU, so if VFIO support is not
compiled, we always assume IOMMU support is not available.
Not sure I agree with this statement.
What about unknown (from eal pov) kernel drivers?
Are there any cases where we can use IOVA as VA mode without having VFIO
compiled?
Signed-off-by: Anatoly Burakov <anatoly.bura...@intel.com>
---
lib/librte_eal/linux/eal/eal.c | 11 ++++++--
lib/librte_eal/linux/eal/eal_vfio.c | 39 +++++++++++++++++++++++++++++
lib/librte_eal/linux/eal/eal_vfio.h | 2 ++
3 files changed, 50 insertions(+), 2 deletions(-)
diff --git a/lib/librte_eal/linux/eal/eal.c b/lib/librte_eal/linux/eal/eal.c
index 34db78753..584f97a96 100644
--- a/lib/librte_eal/linux/eal/eal.c
+++ b/lib/librte_eal/linux/eal/eal.c
@@ -1061,8 +1061,15 @@ rte_eal_init(int argc, char **argv)
enum rte_iova_mode iova_mode = rte_bus_get_iommu_class();
if (iova_mode == RTE_IOVA_DC) {
- iova_mode = RTE_IOVA_VA;
- RTE_LOG(DEBUG, EAL, "Buses did not request a specific IOVA
mode, select IOVA as VA mode.\n");
+ /* if we have an IOMMU, pick IOVA as VA mode */
+ if (vfio_iommu_enabled()) {
+ iova_mode = RTE_IOVA_VA;
+ RTE_LOG(DEBUG, EAL, "Buses did not request a
specific IOVA mode, selecting IOVA as VA mode.\n");
+ } else {
+ iova_mode = RTE_IOVA_PA;
+ RTE_LOG(DEBUG, EAL, "Buses did not request a
specific IOVA mode, but IOMMU is not available.\n");
+ RTE_LOG(DEBUG, EAL, "Selecting IOVA as PA
mode.\n");
+ }
Here, since the buses don't care, we can check for physical address
availability.
Good point, if PA are not available, we can't use IOVA as PA mode.
--
Thanks,
Anatoly
