Re: [dpdk-dev] [PATCH v1 1/1] bus/vdev: add get iommu class callback

[Jerin Jacob <jerinjacobk@gmail.com>]

On Wed, Oct 16, 2019 at 7:59 PM <vattunuru@marvell.com> wrote:
>
> From: Vamsi Attunuru <vattunuru@marvell.com>
>
> When DPDK application is run with vdevs, EAL decides
> the iommu mode and accordingly application runs in
> either of the modes.
>
> For KNI kind of functionality with vdevs, since there
> is no backed device structure in kernel, iommu_mode = PA
> needs to be enforced during eal init.
>
> Patch adds get_iommu_class callback in vdev bus driver
> and returns iommu mode as PA when vdevs are used for
> kni functionality, callback returns iommu mode as DC
> in normal cases.
>
> Signed-off-by: Vamsi Attunuru <vattunuru@marvell.com>
> ---
>
> Below support fixes the following patchset(add iova=va mode support in KNI)
> which is currently failing to create KNI devices when vdevs are passed.
> http://patches.dpdk.org/patch/57720/
>
>  drivers/bus/vdev/vdev.c                 | 15 +++++++++++++++
>  lib/librte_eal/common/eal_private.h     | 14 --------------
>  lib/librte_eal/common/include/rte_eal.h | 14 ++++++++++++++
>  3 files changed, 29 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/bus/vdev/vdev.c b/drivers/bus/vdev/vdev.c
> index a89ea23..ab07738 100644
> --- a/drivers/bus/vdev/vdev.c
> +++ b/drivers/bus/vdev/vdev.c
> @@ -546,6 +546,20 @@ vdev_unplug(struct rte_device *dev)
>         return rte_vdev_uninit(dev->name);
>  }
>
> +static enum rte_iova_mode
> +rte_vdev_get_iommu_class(void)
> +{
> +       struct rte_devargs *devargs = NULL;
> +
> +       if (rte_eal_check_module("rte_kni") == 1) {
> +               RTE_EAL_DEVARGS_FOREACH("vdev", devargs) {
> +                       return RTE_IOVA_PA;
> +               }
> +       }
> +
> +       return RTE_IOVA_DC;
> +}

This will fix KNI + vdev issue.

# Move the check under #ifdef RTE_LIBRTE_KNI
# Please add a comment in the code such as
"vdev based KNI needs IOVA as PA to work"


>  static struct rte_bus rte_vdev_bus = {
>         .scan = vdev_scan,
>         .probe = vdev_probe,
> @@ -554,6 +568,7 @@ static struct rte_bus rte_vdev_bus = {
>         .unplug = vdev_unplug,
>         .parse = vdev_parse,
>         .dev_iterate = rte_vdev_dev_iterate,
> +       .get_iommu_class = rte_vdev_get_iommu_class,
>  };
>
>  RTE_REGISTER_BUS(vdev, rte_vdev_bus);
> diff --git a/lib/librte_eal/common/eal_private.h b/lib/librte_eal/common/eal_private.h
> index 798ede5..4207bdb 100644
> --- a/lib/librte_eal/common/eal_private.h
> +++ b/lib/librte_eal/common/eal_private.h
> @@ -133,20 +133,6 @@ int rte_eal_intr_init(void);
>  int rte_eal_alarm_init(void);
>
>  /**
> - * Function is to check if the kernel module(like, vfio, vfio_iommu_type1,
> - * etc.) loaded.
> - *
> - * @param module_name
> - *     The module's name which need to be checked
> - *
> - * @return
> - *     -1 means some error happens(NULL pointer or open failure)
> - *     0  means the module not loaded
> - *     1  means the module loaded
> - */
> -int rte_eal_check_module(const char *module_name);
> -
> -/**
>   * Get virtual area of specified size from the OS.
>   *
>   * This function is private to the EAL.
> diff --git a/lib/librte_eal/common/include/rte_eal.h b/lib/librte_eal/common/include/rte_eal.h
> index b7cf912..4ea98e6 100644
> --- a/lib/librte_eal/common/include/rte_eal.h
> +++ b/lib/librte_eal/common/include/rte_eal.h
> @@ -531,6 +531,20 @@ rte_eal_mbuf_user_pool_ops(void);
>  const char *
>  rte_eal_get_runtime_dir(void);
>
> +/**
> + * Function is to check if the kernel module(like, vfio, vfio_iommu_type1,
> + * etc.) loaded.
> + *
> + * @param module_name
> + *     The module's name which need to be checked
> + *
> + * @return
> + *     -1 means some error happens(NULL pointer or open failure)
> + *     0  means the module not loaded
> + *     1  means the module loaded
> + */
> +int rte_eal_check_module(const char *module_name);

Please move, promoting rte_eal_check_module() as public API in a
different patch.

And update
1) lib/librte_eal/rte_eal_version.map
2) Add FreeBSD support as well, it can return always zero


> +
>  #ifdef __cplusplus
>  }
>  #endif
> --
> 2.8.4
>