linux-kernel - Re: [PATCH v7 1/4] x86/insn-eval: Add support for 64-bit kernel mode

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Message-ID: <20200102092733.GA8345@zn.tnic>
Date:   Thu, 2 Jan 2020 10:27:33 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Andy Lutomirski <luto@...capital.net>
Cc:     "Kirill A. Shutemov" <kirill@...temov.name>,
        Jann Horn <jannh@...gle.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Alexander Potapenko <glider@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>, kasan-dev@...glegroups.com,
        linux-kernel@...r.kernel.org,
        Andrey Konovalov <andreyknvl@...gle.com>,
        Andy Lutomirski <luto@...nel.org>,
        Sean Christopherson <sean.j.christopherson@...el.com>
Subject: Re: [PATCH v7 1/4] x86/insn-eval: Add support for 64-bit kernel mode

On Thu, Jan 02, 2020 at 04:55:22PM +0900, Andy Lutomirski wrote:
> > In most cases you have struct insn around (or can easily pass it down to
> > the place). Why not use insn->x86_64?
> 
> What populates that?

insn_init() AFAICT.

However, you have cases where you don't have struct insn:
fixup_umip_exception() uses it and it calls insn_get_seg_base() which
does use it too.

> FWIW, this code is a bit buggy: it gets EFI mixed mode wrong. I’m
> not entirely sure we care.

We'll cross that bridge when we get there, I'd say.

Thx.

-- 
Regards/Gruss,
    Boris.

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