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?
>
> 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.
--
David Marchand
