linux-kernel - Re: [regression/bisected] Add IBPB decreases performance in two times

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Message-ID: <20230813111425.GEZNi7EXyHOLQTNzFg@fat_crate.local>
Date:   Sun, 13 Aug 2023 13:14:25 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Mikhail Gavrilov <mikhail.v.gavrilov@...il.com>
Cc:     Linux List Kernel Mailing <linux-kernel@...r.kernel.org>,
        x86@...nel.org
Subject: Re: [regression/bisected] Add IBPB decreases performance in two times

On Sun, Aug 13, 2023 at 03:57:03PM +0500, Mikhail Gavrilov wrote:
> Sure, I checked and got the same results as on the kernel with reverted commits.
> I suppose when new BIOS update will release the kernel would use
> automatically path `spec_rstack_overflow=microcode` and all users who
> faced with this issue not needed add `spec_rstack_overflow=microcode`
> to their kernel command line, right?

No, you have to specify it explicitly. The default mitigation is still
safe RET.

-- 
Regards/Gruss,
    Boris.

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