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Date:   Thu, 03 Jun 2021 13:32:16 +1000
From:   Nicholas Piggin <npiggin@gmail.com>
Subject: Re: [PATCH v4 01/16] powerpc/vas: Move VAS API to book3s common
 platform
To:     Haren Myneni <haren@linux.ibm.com>, herbert@gondor.apana.org.au,
        linux-crypto@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        mpe@ellerman.id.au
Cc:     hbabu@us.ibm.com
References: <8d219c0816133a8643d650709066cf04c9c77322.camel@linux.ibm.com>
        <5933dd793bf0d0d1389877715d936cc321ee86d1.camel@linux.ibm.com>
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Excerpts from Haren Myneni's message of May 21, 2021 7:28 pm:
>=20
> Using the same /dev/crypto/nx-gzip interface for both powerNV and
> pseries. So this patch creates platforms/book3s/ and moves VAS API
> to that directory. The actual functionality is not changed.
>=20
> Signed-off-by: Haren Myneni <haren@linux.ibm.com>
> ---
>  arch/powerpc/include/asm/vas.h                    |  3 +++
>  arch/powerpc/platforms/Kconfig                    |  1 +
>  arch/powerpc/platforms/Makefile                   |  1 +
>  arch/powerpc/platforms/book3s/Kconfig             | 15 +++++++++++++++
>  arch/powerpc/platforms/book3s/Makefile            |  2 ++

If Michael is happy with the new directory structure then fine by me.

>  .../platforms/{powernv =3D> book3s}/vas-api.c       |  2 +-
>  arch/powerpc/platforms/powernv/Kconfig            | 14 --------------
>  arch/powerpc/platforms/powernv/Makefile           |  2 +-
>  8 files changed, 24 insertions(+), 16 deletions(-)
>  create mode 100644 arch/powerpc/platforms/book3s/Kconfig
>  create mode 100644 arch/powerpc/platforms/book3s/Makefile
>  rename arch/powerpc/platforms/{powernv =3D> book3s}/vas-api.c (99%)
>=20
> diff --git a/arch/powerpc/include/asm/vas.h b/arch/powerpc/include/asm/va=
s.h
> index e33f80b0ea81..3be76e813e2d 100644
> --- a/arch/powerpc/include/asm/vas.h
> +++ b/arch/powerpc/include/asm/vas.h
> @@ -162,6 +162,9 @@ int vas_copy_crb(void *crb, int offset);
>   */
>  int vas_paste_crb(struct vas_window *win, int offset, bool re);
> =20
> +void vas_win_paste_addr(struct vas_window *window, u64 *addr,
> +			int *len);
> +
>  /*
>   * Register / unregister coprocessor type to VAS API which will be expor=
ted
>   * to user space. Applications can use this API to open / close window

If you do this, then the prototype should be removed from=20
arch/powerpc/platforms/powernv/vas.h

> diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kcon=
fig
> index 7a5e8f4541e3..594544a65b02 100644
> --- a/arch/powerpc/platforms/Kconfig
> +++ b/arch/powerpc/platforms/Kconfig
> @@ -20,6 +20,7 @@ source "arch/powerpc/platforms/embedded6xx/Kconfig"
>  source "arch/powerpc/platforms/44x/Kconfig"
>  source "arch/powerpc/platforms/40x/Kconfig"
>  source "arch/powerpc/platforms/amigaone/Kconfig"
> +source "arch/powerpc/platforms/book3s/Kconfig"
> =20
>  config KVM_GUEST
>  	bool "KVM Guest support"
> diff --git a/arch/powerpc/platforms/Makefile b/arch/powerpc/platforms/Mak=
efile
> index 143d4417f6cc..0e75d7df387b 100644
> --- a/arch/powerpc/platforms/Makefile
> +++ b/arch/powerpc/platforms/Makefile
> @@ -22,3 +22,4 @@ obj-$(CONFIG_PPC_CELL)		+=3D cell/
>  obj-$(CONFIG_PPC_PS3)		+=3D ps3/
>  obj-$(CONFIG_EMBEDDED6xx)	+=3D embedded6xx/
>  obj-$(CONFIG_AMIGAONE)		+=3D amigaone/
> +obj-$(CONFIG_PPC_BOOK3S)	+=3D book3s/
> diff --git a/arch/powerpc/platforms/book3s/Kconfig b/arch/powerpc/platfor=
ms/book3s/Kconfig
> new file mode 100644
> index 000000000000..bed21449e8e5
> --- /dev/null
> +++ b/arch/powerpc/platforms/book3s/Kconfig
> @@ -0,0 +1,15 @@
> +# SPDX-License-Identifier: GPL-2.0
> +config PPC_VAS
> +	bool "IBM Virtual Accelerator Switchboard (VAS)"
> +	depends on (PPC_POWERNV || PPC_PSERIES) && PPC_64K_PAGES
> +	default y
> +	help
> +	  This enables support for IBM Virtual Accelerator Switchboard (VAS).
> +
> +	  VAS allows accelerators in co-processors like NX-GZIP and NX-842
> +	  to be accessible to kernel subsystems and user processes.
> +	  VAS adapters are found in POWER9 and later based systems.
> +	  The user mode NX-GZIP support is added on P9 for powerNV and on
> +	  P10 for powerVM.

The changelog has changed. The last sentence is difficult to understand=20
(also please consistently capitalise PowerNV and PowerVM). Is it=20
supposed to say that PPC_VAS will provide user-mode NX-GZIP support on=20
P9 PowerNV systems and P10 PowerVM systems? If you respin the patch for
the prototype...

  This enables support for IBM Virtual Accelerator Switchboard (VAS).

  VAS devices are found in POWER9-based and later systems, they provide
  access to accelerator coprocessors such as NX-GZIP and NX-842. This
  driver allows the kernel to use NX-GZIP and NX-842 accelerators, and
  user-mode APIs for the NX-GZIP accelerator on POWER9 PowerNV and
  POWER10 PowerVM platforms. <here is a userspace library you can use>
  etc

Thanks,
Nick