linux-kernel - Re: [PATCH v1 2/2] acpi, x86: Remove encryption mask from ACPI page protection type

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Date:   Fri, 28 Jul 2017 08:28:07 +0200
From:   Ingo Molnar <mingo@...nel.org>
To:     Tom Lendacky <thomas.lendacky@....com>
Cc:     Borislav Petkov <bp@...en8.de>, x86@...nel.org,
        linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
        Andy Lutomirski <luto@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Dave Young <dyoung@...hat.com>,
        Brijesh Singh <brijesh.singh@....com>
Subject: Re: [PATCH v1 2/2] acpi, x86: Remove encryption mask from ACPI page
 protection type


* Tom Lendacky <thomas.lendacky@....com> wrote:

> > > +	 * in memory in an encrypted state so return a protection attribute
> > > +	 * that does not have the encryption bit set.
> > >   	 */
> > > -	 return PAGE_KERNEL;
> > > +	 return sme_active() ? PAGE_KERNEL_IO : PAGE_KERNEL;
> > 
> > Why isn't there a PAGE_KERNEL_NOENC define which you can simply return
> > instead of testing?
> 
> Sounds like something I should add to pgtable_types.h (which has a
> #define for PAGE_KERNEL_EXEC_NOENC, but not PAGE_KERNEL_NOENC). I'll
> create that #define.
> 
> As for the sme_active() check I was getting ahead of myself since
> under SEV the encryption mask is needed.  I'll change it to just
> return PAGE_KERNEL_NOENC and then worry about the SEV change in
> the SEV patches.

Ok, that works for me too, as we at least don't sprinke the code with repeated 
sme_active() toggles.

Thanks,

	Ingo