linux-kernel - Re: [PATCH v5 2/5] KVM: x86: Add IBPB support

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, 1 Feb 2018 09:00:25 -0800
From:   "Raj, Ashok" <ashok.raj@...el.com>
To:     KarimAllah Ahmed <karahmed@...zon.de>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org, x86@...nel.org,
        Asit Mallick <asit.k.mallick@...el.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Arjan Van De Ven <arjan.van.de.ven@...el.com>,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Dan Williams <dan.j.williams@...el.com>,
        Jun Nakajima <jun.nakajima@...el.com>,
        Andy Lutomirski <luto@...nel.org>,
        Greg KH <gregkh@...uxfoundation.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        David Woodhouse <dwmw@...zon.co.uk>,
        Ashok Raj <ashok.raj@...el.com>
Subject: Re: [PATCH v5 2/5] KVM: x86: Add IBPB support

Hi Karim

Thanks for cracking at it through all the iterations.

On Wed, Jan 31, 2018 at 08:37:44PM +0100, KarimAllah Ahmed wrote:
> From: Ashok Raj <ashok.raj@...el.com>
> 
> The Indirect Branch Predictor Barrier (IBPB) is an indirect branch
> control mechanism. It keeps earlier branches from influencing
> later ones.

It might be better to split this patch into two parts.

- Just the place where we do IBPB barrier for VMX/SVM
- The msr get/set handling to comprehend guest, nested support etc.

The first part should be trivial so it can possibly make it into
tip/x86/pti branch sooner, while we rework the feedback to 
address this completely. 


Cheers,
Ashok