linux-kernel - Re: [PATCH v5 5/5] x86/kvm: Avoid dynamic allocation of pvclock data when SEV is active

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Message-ID: <20180906183334.GF11144@zn.tnic>
Date:   Thu, 6 Sep 2018 20:33:34 +0200
From:   Borislav Petkov <bp@...e.de>
To:     Sean Christopherson <sean.j.christopherson@...el.com>
Cc:     Brijesh Singh <brijesh.singh@....com>, x86@...nel.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        Tom Lendacky <thomas.lendacky@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>
Subject: Re: [PATCH v5 5/5] x86/kvm: Avoid dynamic allocation of pvclock data
 when SEV is active

On Thu, Sep 06, 2018 at 08:54:52AM -0700, Sean Christopherson wrote:
> My thought was that we could simply define a second array for the SEV
> case to statically allocate for NR_CPUS since __decrypted has a big
> chunk of memory that would be ununsed anyways[1]. And since the second
> array is only used for SEV it can be freed if !SEV.

Lemme see if I get it straight:

__decrypted:

 4K

__decrypted_XXX:

 ((num_possible_cpus() * 32) / 4K) pages

__decrypted_end:

Am I close?

-- 
Regards/Gruss,
    Boris.

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