linux-kernel - Re: [PATCH] KVM: x86: Expose Predictive Store Forwarding Disable

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Message-ID: <YVGz0HXe+WNAXfdF@zn.tnic>
Date:   Mon, 27 Sep 2021 14:06:40 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Babu Moger <babu.moger@....com>, tglx@...utronix.de,
        mingo@...hat.com, x86@...nel.org, hpa@...or.com, seanjc@...gle.com,
        vkuznets@...hat.com, wanpengli@...cent.com, jmattson@...gle.com,
        joro@...tes.org, tony.luck@...el.com, peterz@...radead.org,
        kyung.min.park@...el.com, wei.huang2@....com, jgross@...e.com,
        andrew.cooper3@...rix.com, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Subject: Re: [PATCH] KVM: x86: Expose Predictive Store Forwarding Disable

On Mon, Sep 27, 2021 at 01:13:26PM +0200, Paolo Bonzini wrote:
> Because the guest kernel needs to know which MSRs to write when you touch
> the SSBD prctl, so that PSFD is properly disabled *inside the guest*.

It already knows which - the same one which disables SSB. PSF is
disabled *together* with SSB, for now...

-- 
Regards/Gruss,
    Boris.

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