linux-kernel - Re: [RFC PATCH v4 06/28] x86: Add support to enable SME during early boot processing

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Message-ID: <20170221151039.nheny3gazbnwaidp@pd.tnic>
Date:   Tue, 21 Feb 2017 16:10:39 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Tom Lendacky <thomas.lendacky@....com>
Cc:     linux-arch@...r.kernel.org, linux-efi@...r.kernel.org,
        kvm@...r.kernel.org, linux-doc@...r.kernel.org, x86@...nel.org,
        linux-kernel@...r.kernel.org, kasan-dev@...glegroups.com,
        linux-mm@...ck.org, iommu@...ts.linux-foundation.org,
        Rik van Riel <riel@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Toshimitsu Kani <toshi.kani@....com>,
        Arnd Bergmann <arnd@...db.de>,
        Jonathan Corbet <corbet@....net>,
        Matt Fleming <matt@...eblueprint.co.uk>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        Joerg Roedel <joro@...tes.org>,
        Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Brijesh Singh <brijesh.singh@....com>,
        Ingo Molnar <mingo@...hat.com>,
        Alexander Potapenko <glider@...gle.com>,
        Andy Lutomirski <luto@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Larry Woodman <lwoodman@...hat.com>,
        Dmitry Vyukov <dvyukov@...gle.com>
Subject: Re: [RFC PATCH v4 06/28] x86: Add support to enable SME during early
 boot processing

On Tue, Feb 21, 2017 at 08:55:30AM -0600, Tom Lendacky wrote:
> Actually, %rbp will have the encryption bit set in it at the time of the
> check so if SME is active we won't take the jump to .Lskip_fixup.

Ha, I didn't think of that! Do you see now what I mean with being
explicit in the asm boot code? :-)

Please note that in the comment above sme_encrypt_kernel().

Thanks.

-- 
Regards/Gruss,
    Boris.

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