Cc: brijesh.singh@amd.com, 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>,
        =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <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
To: Borislav Petkov <bp@suse.de>
References: <20170724190757.11278-1-brijesh.singh@amd.com>
 <20170724190757.11278-17-brijesh.singh@amd.com>
 <20170829102258.gxk227js4yw47qi3@pd.tnic>
 <0810a732-9c77-a543-ffeb-7fd2d8f46266@amd.com>
 <20170830174655.ehrnmynotmp7laka@pd.tnic>
 <8155b5b2-b2b3-bc8f-33ae-b81b661a2e38@amd.com>
 <20170904170525.toyulxwaevef42qe@pd.tnic>
From: Brijesh Singh <brijesh.singh@amd.com>
Message-ID: <a059fbc9-5eb7-41c9-bcdc-86ae069f21a5@amd.com>
Date: Mon, 4 Sep 2017 12:47:15 -0500
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On 9/4/17 12:05 PM, Borislav Petkov wrote:
> 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?

Yes, I see your point. I will address this issue in next rev.


-Brijesh