linux-kernel - Re: [PATCH v1] x86: Pin cr4 FSGSBASE

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Date:   Wed, 27 May 2020 12:31:47 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Andi Kleen <andi@...stfloor.org>
Cc:     Kees Cook <keescook@...omium.org>,
        Greg KH <gregkh@...uxfoundation.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org, sashal@...nel.org,
        Andi Kleen <ak@...ux.intel.com>, stable@...r.kernel.org
Subject: Re: [PATCH v1] x86: Pin cr4 FSGSBASE

On Tue, May 26, 2020 at 04:14:25PM -0700, Andi Kleen wrote:
> > And if this is going to be more permanent, we can separate the mask
> > (untested):
> 
> The FSGSBASE one should not be permanent, it will be replaced
> with the full FSGSBASE patches that set that bit correctly.

Well, even with full FSGSBASE patches on, that CR4 bit should never get
changed after boot.