Subject: Re: [PATCH v4 01/16] powerpc/vas: Move VAS API to book3s common platform

From: Nicholas Piggin <[email-masked]>
Date: Thu, 03 Jun 2021 13:32:16 +1000

Excerpts from Haren Myneni's message of May 21, 2021 7:28 pm:
> 
> 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.
> 
> Signed-off-by: Haren Myneni <[email-masked]>
> ---
>  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 => 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 => book3s}/vas-api.c (99%)
> 
> diff --git a/arch/powerpc/include/asm/vas.h b/arch/powerpc/include/asm/vas.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);
>  
> +void vas_win_paste_addr(struct vas_window *window, u64 *addr,
> +			int *len);
> +
>  /*
>   * Register / unregister coprocessor type to VAS API which will be exported
>   * to user space. Applications can use this API to open / close window

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

> diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig
> 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"
>  
>  config KVM_GUEST
>  	bool "KVM Guest support"
> diff --git a/arch/powerpc/platforms/Makefile b/arch/powerpc/platforms/Makefile
> index 143d4417f6cc..0e75d7df387b 100644
> --- a/arch/powerpc/platforms/Makefile
> +++ b/arch/powerpc/platforms/Makefile
> @@ -22,3 +22,4 @@ obj-$(CONFIG_PPC_CELL)		+= cell/
>  obj-$(CONFIG_PPC_PS3)		+= ps3/
>  obj-$(CONFIG_EMBEDDED6xx)	+= embedded6xx/
>  obj-$(CONFIG_AMIGAONE)		+= amigaone/
> +obj-$(CONFIG_PPC_BOOK3S)	+= book3s/
> diff --git a/arch/powerpc/platforms/book3s/Kconfig b/arch/powerpc/platforms/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 
(also please consistently capitalise PowerNV and PowerVM). Is it 
supposed to say that PPC_VAS will provide user-mode NX-GZIP support on 
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