Date: Mon, 4 Sep 2017 19:05:25 +0200
From: Borislav Petkov <bp@suse.de>
To: Brijesh Singh <brijesh.singh@amd.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
        linux-efi@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        kvm@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, "H . Peter Anvin" <hpa@zytor.com>,
        Andy Lutomirski <luto@kernel.org>, Tony Luck <tony.luck@intel.com>,
        Piotr Luc <piotr.luc@intel.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Fenghua Yu <fenghua.yu@intel.com>,
        Reza Arbab <arbab@linux.vnet.ibm.com>,
        David Howells <dhowells@redhat.com>,
        Matt Fleming <matt@codeblueprint.co.uk>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Laura Abbott <labbott@redhat.com>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Eric Biederman <ebiederm@xmission.com>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Jonathan Corbet <corbet@lwn.net>, Dave Airlie <airlied@redhat.com>,
        Kees Cook <keescook@chromium.org>, Paolo Bonzini <pbonzini@redhat.com>,
        Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        Arnd Bergmann <arnd@arndb.de>, Tejun Heo <tj@kernel.org>,
        Christoph Lameter <cl@linux.com>
Subject: Re: [RFC Part1 PATCH v3 16/17] X86/KVM: Provide support to create
 Guest and HV shared per-CPU variables
Message-ID: <20170904170525.toyulxwaevef42qe@pd.tnic>
References: <20170724190757.11278-1-brijesh.singh@amd.com>
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 <0810a732-9c77-a543-ffeb-7fd2d8f46266@amd.com>
 <20170830174655.ehrnmynotmp7laka@pd.tnic>
 <8155b5b2-b2b3-bc8f-33ae-b81b661a2e38@amd.com>
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On Fri, Sep 01, 2017 at 05:52:13PM -0500, Brijesh Singh wrote:
>  So far, we have not seen the need for having such functions except
> this cases. The approach we have right now works just fine and not
> sure if its worth adding new functions.

Then put the call to kvm_map_hv_shared_decrypted() into
kvm_smp_prepare_boot_cpu() to denote that you're executing this whole
stuff only once during guest init.

Now you're doing additional jumping-through-hoops with that once static
var just so you can force something which needs to execute only once but
gets called in a per-CPU path.

See what I mean?

> Thoughts ?
> 
> [1] Commit :7f8b7e7 x86/mm: Add support for early encryption/decryption of memory

Add

[core]
        abbrev = 12

to the core section of your .gitconfig.

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--