Re: [dpdk-dev] [PATCH v3 1/3] eal/linux: select iova-mode va with no-huge option

[Jerin Jacob <jerinjacobk@gmail.com>]

On Fri, Feb 21, 2020 at 4:22 AM David Wilder <dwilder@us.ibm.com> wrote:
>
> If --no-huge is set and iova-mode has not been specified force VA mode.
> If --no-huge and --iova-mode=PA is requested error out as this is
> an impossible configuration.
>
> Signed-off-by: David Wilder <dwilder@us.ibm.com>
> ---
>  lib/librte_eal/linux/eal/eal.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
>
> diff --git a/lib/librte_eal/linux/eal/eal.c b/lib/librte_eal/linux/eal/eal.c
> index 9530ee55f..d3a0a1731 100644
> --- a/lib/librte_eal/linux/eal/eal.c
> +++ b/lib/librte_eal/linux/eal/eal.c
> @@ -1062,9 +1062,16 @@ rte_eal_init(int argc, char **argv)
>
>         /* if no EAL option "--iova-mode=<pa|va>", use bus IOVA scheme */
>         if (internal_config.iova_mode == RTE_IOVA_DC) {
> +
>                 /* autodetect the IOVA mapping mode */
>                 enum rte_iova_mode iova_mode = rte_bus_get_iommu_class();
>
> +               if (iova_mode == RTE_IOVA_PA && !rte_eal_has_hugepages()) {
> +                       iova_mode = RTE_IOVA_VA;

What if igb_uio or vfio_nommu has been loaded(i.e no iommu support
enabled from the driver)? This would fail.

> +                       RTE_LOG(WARNING, EAL, "Some buses want 'PA' but forcing 'VA' because --no-huge is requested.\n");
> +                       RTE_LOG(WARNING, EAL, "Not all buses may be able to initialize.\n");
> +               }
> +
>                 if (iova_mode == RTE_IOVA_DC) {
>                         RTE_LOG(DEBUG, EAL, "Buses did not request a specific IOVA mode.\n");
>
> @@ -1111,6 +1118,13 @@ rte_eal_init(int argc, char **argv)
>                         internal_config.iova_mode;
>         }
>
> +       if (rte_eal_iova_mode() == RTE_IOVA_PA &&
> +           rte_eal_has_hugepages() == 0) {
> +               rte_eal_init_alert("Cannot use IOVA as 'PA' with --no-huge");

Top of the tree already detecting this case. am I missing anything?

[master]dell[dpdk.org] $ sudo ./build/app/test/dpdk-test  -c 0x3
--no-huge --iova-mode=pa
EAL: Detected 56 lcore(s)
EAL: Detected 2 NUMA nodes
EAL: Static memory layout is selected, amount of reserved memory can
be adjusted with -m or --socket-mem
EAL: Multi-process socket /var/run/dpdk/rte/mp_socket
EAL: FATAL: Cannot use IOVA as 'PA' since physical addresses are not available
EAL: Cannot use IOVA as 'PA' since physical addresses are not available

> +               rte_errno = EINVAL;
> +               return -1;
> +       }
> +
>         if (rte_eal_iova_mode() == RTE_IOVA_PA && !phys_addrs) {
>                 rte_eal_init_alert("Cannot use IOVA as 'PA' since physical addresses are not available");
>                 rte_errno = EINVAL;
> --
> 2.25.0
>