Re: [dpdk-dev] [PATCH] kni: increase kernel version requirement for VA

[Igor Ryzhov <iryzhov@nfware.com>]

Hi Ferruh,

There is a typo in "version incread to > 4.9.0 ...".
incread > increased

Igor

On Wed, Nov 20, 2019 at 7:00 PM Ferruh Yigit <ferruh.yigit@intel.com> wrote:

> A build error reported related to the selected
> 'get_user_pages_remote()' kernel API:
>
> .../kernel/linux/kni/kni_dev.h:113:8:
>   error: too few arguments to function ‘get_user_pages_remote’
>   ret = get_user_pages_remote(tsk, tsk->mm, iova, 1
>         ^~~~~~~~~~~~~~~~~~~~~
>
> Currently there are three version of the 'get_user_pages_remote()'
> supported, based on kernel version
> < 4.9, = 4.9, > 4.9
>
> These version based checks are not working fine with the distro kernels
> which is the cause of reported build error. The error reported by the
> kernel version 4.8, but it is using API defined in > 4.9.
>
> To be able to take control of this, and possible more, related build
> error, increasing the minimum supported kernel version for iova=va with
> KNI to kernel version 4.9.
>
> This leaves us with single version of the kernel API and more
> manageable.
>
> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> ---
> Cc: David Marchand <david.marchand@redhat.com>
> Cc: Vamsi Attunuru <vattunuru@marvell.com>
> Cc: Kiran Kumar K <kirankumark@marvell.com>
> Cc: Jerin Jacob <jerinj@marvell.com>
> ---
>  doc/guides/prog_guide/kernel_nic_interface.rst |  2 +-
>  doc/guides/rel_notes/release_19_11.rst         |  2 +-
>  kernel/linux/kni/compat.h                      | 16 +++++-----------
>  kernel/linux/kni/kni_dev.h                     | 10 ----------
>  lib/librte_eal/linux/eal/eal.c                 |  6 +++---
>  lib/librte_kni/rte_kni.c                       |  2 +-
>  6 files changed, 11 insertions(+), 27 deletions(-)
>
> diff --git a/doc/guides/prog_guide/kernel_nic_interface.rst
> b/doc/guides/prog_guide/kernel_nic_interface.rst
> index c4479ffbf..848b00253 100644
> --- a/doc/guides/prog_guide/kernel_nic_interface.rst
> +++ b/doc/guides/prog_guide/kernel_nic_interface.rst
> @@ -305,7 +305,7 @@ IOVA = VA: Support
>
>  KNI operates in IOVA_VA scheme when
>
> -- LINUX_VERSION_CODE >= KERNEL_VERSION(4, 6, 0) and
> +- LINUX_VERSION_CODE > KERNEL_VERSION(4, 9, 0) and
>  - EAL option `iova-mode=va` is passed or bus IOVA scheme in the DPDK is
> selected
>    as RTE_IOVA_VA.
>
> diff --git a/doc/guides/rel_notes/release_19_11.rst
> b/doc/guides/rel_notes/release_19_11.rst
> index 21be600ab..45b58190c 100644
> --- a/doc/guides/rel_notes/release_19_11.rst
> +++ b/doc/guides/rel_notes/release_19_11.rst
> @@ -299,7 +299,7 @@ New Features
>    * Added IOVA = VA support for KNI, KNI can operate in IOVA = VA mode
> when
>      `iova-mode=va` EAL option is passed to the application or when bus
> IOVA
>      scheme is selected as RTE_IOVA_VA. This mode only works on Linux
> Kernel
> -    versions 4.6.0 and above.
> +    versions above 4.9.0.
>
>    * Due to IOVA to KVA address translations, based on the KNI use case
> there
>      can be a performance impact. For mitigation, forcing IOVA to PA via
> EAL
> diff --git a/kernel/linux/kni/compat.h b/kernel/linux/kni/compat.h
> index 062b170ef..339dd25a7 100644
> --- a/kernel/linux/kni/compat.h
> +++ b/kernel/linux/kni/compat.h
> @@ -122,16 +122,10 @@
>  #define HAVE_SIGNAL_FUNCTIONS_OWN_HEADER
>  #endif
>
> -#if KERNEL_VERSION(4, 6, 0) <= LINUX_VERSION_CODE
> -
> +/*
> + * iova to kva mapping support can be provided since 4.6.0, but support
> + * version incread to > 4.9.0 because of the updates in
> get_user_pages_remote()
> + */
> +#if KERNEL_VERSION(4, 9, 0) < LINUX_VERSION_CODE
>  #define HAVE_IOVA_TO_KVA_MAPPING_SUPPORT
> -
> -#if KERNEL_VERSION(4, 9, 0) > LINUX_VERSION_CODE
> -#define GET_USER_PAGES_REMOTE_API_V1
> -#elif KERNEL_VERSION(4, 9, 0) == LINUX_VERSION_CODE
> -#define GET_USER_PAGES_REMOTE_API_V2
> -#else
> -#define GET_USER_PAGES_REMOTE_API_V3
> -#endif
> -
>  #endif
> diff --git a/kernel/linux/kni/kni_dev.h b/kernel/linux/kni/kni_dev.h
> index fb641b696..5e75c6371 100644
> --- a/kernel/linux/kni/kni_dev.h
> +++ b/kernel/linux/kni/kni_dev.h
> @@ -101,18 +101,8 @@ static inline phys_addr_t iova_to_phys(struct
> task_struct *tsk,
>         offset = iova & (PAGE_SIZE - 1);
>
>         /* Read one page struct info */
> -#ifdef GET_USER_PAGES_REMOTE_API_V3
>         ret = get_user_pages_remote(tsk, tsk->mm, iova, 1,
>                                     FOLL_TOUCH, &page, NULL, NULL);
> -#endif
> -#ifdef GET_USER_PAGES_REMOTE_API_V2
> -       ret = get_user_pages_remote(tsk, tsk->mm, iova, 1,
> -                                   FOLL_TOUCH, &page, NULL);
> -#endif
> -#ifdef GET_USER_PAGES_REMOTE_API_V1
> -       ret = get_user_pages_remote(tsk, tsk->mm, iova, 1
> -                                   0, 0, &page, NULL);
> -#endif
>         if (ret < 0)
>                 return 0;
>
> diff --git a/lib/librte_eal/linux/eal/eal.c
> b/lib/librte_eal/linux/eal/eal.c
> index b5b71500c..5879e33e5 100644
> --- a/lib/librte_eal/linux/eal/eal.c
> +++ b/lib/librte_eal/linux/eal/eal.c
> @@ -1073,7 +1073,7 @@ rte_eal_init(int argc, char **argv)
>                                  */
>                                 iova_mode = RTE_IOVA_VA;
>                                 RTE_LOG(DEBUG, EAL, "Physical addresses
> are unavailable, selecting IOVA as VA mode.\n");
> -#if defined(RTE_LIBRTE_KNI) && LINUX_VERSION_CODE >= KERNEL_VERSION(4, 6,
> 0)
> +#if defined(RTE_LIBRTE_KNI) && LINUX_VERSION_CODE > KERNEL_VERSION(4, 9,
> 0)
>                         } else if (rte_eal_check_module("rte_kni") == 1) {
>                                 iova_mode = RTE_IOVA_PA;
>                                 RTE_LOG(DEBUG, EAL, "KNI is loaded,
> selecting IOVA as PA mode for better KNI perfomance.\n");
> @@ -1090,9 +1090,9 @@ rte_eal_init(int argc, char **argv)
>                                 RTE_LOG(DEBUG, EAL, "IOMMU is not
> available, selecting IOVA as PA mode.\n");
>                         }
>                 }
> -#if defined(RTE_LIBRTE_KNI) && LINUX_VERSION_CODE < KERNEL_VERSION(4, 6,
> 0)
> +#if defined(RTE_LIBRTE_KNI) && LINUX_VERSION_CODE <= KERNEL_VERSION(4, 9,
> 0)
>                 /* Workaround for KNI which requires physical address to
> work
> -                * in kernels < 4.6
> +                * in kernels <= 4.9
>                  */
>                 if (iova_mode == RTE_IOVA_VA &&
>                                 rte_eal_check_module("rte_kni") == 1) {
> diff --git a/lib/librte_kni/rte_kni.c b/lib/librte_kni/rte_kni.c
> index 86995fc81..b564482fe 100644
> --- a/lib/librte_kni/rte_kni.c
> +++ b/lib/librte_kni/rte_kni.c
> @@ -98,7 +98,7 @@ static volatile int kni_fd = -1;
>  int
>  rte_kni_init(unsigned int max_kni_ifaces __rte_unused)
>  {
> -#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 6, 0)
> +#if LINUX_VERSION_CODE <= KERNEL_VERSION(4, 9, 0)
>         if (rte_eal_iova_mode() != RTE_IOVA_PA) {
>                 RTE_LOG(ERR, KNI, "KNI requires IOVA as PA\n");
>                 return -1;
> --
> 2.21.0
>
>