linux-kernel - Re: [PATCH v2 0/2] INVD intercept change to skip instruction

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

Date:   Thu, 24 Sep 2020 14:20:33 -0700
From:   Jim Mattson <jmattson@...gle.com>
To:     Tom Lendacky <thomas.lendacky@....com>
Cc:     kvm list <kvm@...r.kernel.org>,
        "the arch/x86 maintainers" <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Joerg Roedel <joro@...tes.org>,
        Brijesh Singh <brijesh.singh@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH v2 0/2] INVD intercept change to skip instruction

On Thu, Sep 24, 2020 at 11:42 AM Tom Lendacky <thomas.lendacky@....com> wrote:
>
> From: Tom Lendacky <thomas.lendacky@....com>
>
> This series updates the INVD intercept support for both SVM and VMX to
> skip the instruction rather than emulating it, since emulation of this
> instruction is just a NOP.

Isn't INVD a serializing instruction, whereas NOP isn't? IIRC, Intel
doesn't architect VM-entry or VM-exit as serializing, though they
probably are in practice. I'm not sure what AMD's stance on this is.