linux-kernel - Re: [PATCH v2 03/12] x86/pv: switch SWAPGS to ALTERNATIVE

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:   Wed, 09 Dec 2020 22:07:12 +0100
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Juergen Gross <jgross@...e.com>, xen-devel@...ts.xenproject.org,
        x86@...nel.org, linux-kernel@...r.kernel.org,
        virtualization@...ts.linux-foundation.org
Cc:     peterz@...radead.org, luto@...nel.org,
        Juergen Gross <jgross@...e.com>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>, Deep Shah <sdeep@...are.com>,
        "VMware\, Inc." <pv-drivers@...are.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Stefano Stabellini <sstabellini@...nel.org>
Subject: Re: [PATCH v2 03/12] x86/pv: switch SWAPGS to ALTERNATIVE

On Fri, Nov 20 2020 at 12:46, Juergen Gross wrote:
> SWAPGS is used only for interrupts coming from user mode or for
> returning to user mode. So there is no reason to use the PARAVIRT
> framework, as it can easily be replaced by an ALTERNATIVE depending
> on X86_FEATURE_XENPV.
>
> There are several instances using the PV-aware SWAPGS macro in paths
> which are never executed in a Xen PV guest. Replace those with the
> plain swapgs instruction. For SWAPGS_UNSAFE_STACK the same applies.
>
> Signed-off-by: Juergen Gross <jgross@...e.com>
> Acked-by: Andy Lutomirski <luto@...nel.org>
> Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org>

Reviewed-by: Thomas Gleixner <tglx@...utronix.de>