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Date:   Thu, 03 Jun 2021 14:05:20 +1000
From:   Nicholas Piggin <npiggin@gmail.com>
Subject: Re: [PATCH v4 03/16] powerpc/vas: Add platform specific user window
 operations
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:     haren@us.ibm.com, hbabu@us.ibm.com
References: <8d219c0816133a8643d650709066cf04c9c77322.camel@linux.ibm.com>
        <f4fb4b7bb98580ae3c025d83148a6406541de892.camel@linux.ibm.com>
In-Reply-To: <f4fb4b7bb98580ae3c025d83148a6406541de892.camel@linux.ibm.com>
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Excerpts from Haren Myneni's message of May 21, 2021 7:30 pm:
>=20
> PowerNV uses registers to open/close VAS windows, and getting the
> paste address. Whereas the hypervisor calls are used on PowerVM.
>=20
> This patch adds the platform specific user space window operations
> and register with the common VAS user space interface.

Basic idea makes sense. I don't understand this code in detail though.
A couple of things,

>=20
> Signed-off-by: Haren Myneni <haren@linux.ibm.com>
> ---
>  arch/powerpc/include/asm/vas.h              | 14 +++++-
>  arch/powerpc/platforms/book3s/vas-api.c     | 52 ++++++++++++---------
>  arch/powerpc/platforms/powernv/vas-window.c | 46 +++++++++++++++++-
>  3 files changed, 89 insertions(+), 23 deletions(-)
>=20
> diff --git a/arch/powerpc/include/asm/vas.h b/arch/powerpc/include/asm/va=
s.h
> index 6076adf9ab4f..668303198772 100644
> --- a/arch/powerpc/include/asm/vas.h
> +++ b/arch/powerpc/include/asm/vas.h
> @@ -5,6 +5,7 @@
> =20
>  #ifndef _ASM_POWERPC_VAS_H
>  #define _ASM_POWERPC_VAS_H
> +#include <uapi/asm/vas-api.h>
> =20
>  struct vas_window;
> =20
> @@ -48,6 +49,16 @@ enum vas_cop_type {
>  	VAS_COP_TYPE_MAX,
>  };
> =20
> +/*
> + * User space window operations used for powernv and powerVM
> + */
> +struct vas_user_win_ops {
> +	struct vas_window * (*open_win)(struct vas_tx_win_open_attr *,
> +				enum vas_cop_type);
> +	u64 (*paste_addr)(void *);
> +	int (*close_win)(void *);

Without looking further into the series, why do these two take void *=20
when the first returns a vas_window * which appears to be the required
argument to these?

> +static struct vas_user_win_ops vops =3D  {
> +	.open_win	=3D	vas_user_win_open,
> +	.paste_addr	=3D	vas_user_win_paste_addr,
> +	.close_win	=3D	vas_user_win_close,
> +};

const?

Thanks,
Nick