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:   Fri, 27 Nov 2020 12:31:56 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Juergen Gross <jgross@...e.com>
Cc:     xen-devel@...ts.xenproject.org, x86@...nel.org,
        linux-kernel@...r.kernel.org,
        virtualization@...ts.linux-foundation.org, peterz@...radead.org,
        luto@...nel.org, Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "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 12:46:21PM +0100, 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>
> ---
>  arch/x86/entry/entry_64.S             | 10 +++++-----
>  arch/x86/include/asm/irqflags.h       | 20 ++++++++------------
>  arch/x86/include/asm/paravirt.h       | 20 --------------------
>  arch/x86/include/asm/paravirt_types.h |  2 --
>  arch/x86/kernel/asm-offsets_64.c      |  1 -
>  arch/x86/kernel/paravirt.c            |  1 -
>  arch/x86/kernel/paravirt_patch.c      |  3 ---
>  arch/x86/xen/enlighten_pv.c           |  3 ---
>  8 files changed, 13 insertions(+), 47 deletions(-)

I love patches like this one! Give me more...

Reviewed-by: Borislav Petkov <bp@...e.de>

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette