Date: Mon, 21 Nov 2016 09:27:54 +0100
From: Borislav Petkov <bp@alien8.de>
To: Tom Lendacky <thomas.lendacky@amd.com>
Cc: linux-arch@vger.kernel.org, linux-efi@vger.kernel.org,
        kvm@vger.kernel.org, linux-doc@vger.kernel.org, x86@kernel.org,
        linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
        linux-mm@kvack.org, iommu@lists.linux-foundation.org,
        Rik van Riel <riel@redhat.com>,
        Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        Arnd Bergmann <arnd@arndb.de>, Jonathan Corbet <corbet@lwn.net>,
        Matt Fleming <matt@codeblueprint.co.uk>,
        Joerg Roedel <joro@8bytes.org>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Larry Woodman <lwoodman@redhat.com>, Ingo Molnar <mingo@redhat.com>,
        Andy Lutomirski <luto@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [RFC PATCH v3 11/20] x86: Add support for changing memory
 encryption attribute
Message-ID: <20161121082754.at6lhjhekbzjgyhc@pd.tnic>
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On Sat, Nov 19, 2016 at 12:48:27PM -0600, Tom Lendacky wrote:
> Should I move this functionality into the sme_set_mem_* functions or
> remove the sme_set_mem_* functions and use the set_memory_* functions
> directly.  The latter means calculating the number of pages, but makes
> it clear that this works on a page level while the former keeps
> everything the mem_encrypt.c file (and I can change that to take in a
> page count so that it is clear about the page boundary usage).

A user of that interface doesn't care, right?

All she wants to do is pass in an address and size and the code will
figure out everything. And I think address and size is the simplest two
args you can pass. numpages can be calculated from it. As you do in
sme_set_mem_*.

And you need to do it all in pageattr.c because it uses the cpa wankery
in there so you probably want to define

int set_memory_dec(unsigned long addr, size_t size)
int set_memory_enc(unsigned long addr, size_t size)

there which both simply call

__set_memory_enc_dec(unsigned long addr, size_t size, bool enc)

and it goes and figures out everything, builds the cpa_data and does the
mapping.

That looks very simple and clean to me.

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.