linux-kernel - Re: SEV guest regression in 4.18

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20180825044749.GA19545@nazgul.tnic>
Date:   Sat, 25 Aug 2018 06:47:49 +0200
From:   Borislav Petkov <bp@...e.de>
To:     Brijesh Singh <brijesh.singh@....com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "Lendacky, Thomas" <Thomas.Lendacky@....com>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: SEV guest regression in 4.18

On Fri, Aug 24, 2018 at 01:47:10PM -0500, Brijesh Singh wrote:
> I am more inclined towards creating a new section with PMD aligned and
> sized. This section will contains the decrypted data. In early
> boot code we will update the mapping with C=0. If caller wants to create
> a shared variable then it can do so with:
> 
> static int foo __decrypted;

Right, and keeping the SEV-ES's GHCB in mind, you could make that
section extensible so that the GHCB's 4K page can land there too. Maybe
something like a PMD-aligned range of 4K pages which are fully defined
and which hypervisor and guest can share and can be used for all kinds of
communication in the future...

-- 
Regards/Gruss,
    Boris.

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