linux-kernel - Re: [PATCH] x86/pti: don't report XenPV as vulnerable

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Message-ID: <nycvar.YFH.7.76.1806150815440.6203@cbobk.fhfr.pm>
Date:   Fri, 15 Jun 2018 08:16:33 +0200 (CEST)
From:   Jiri Kosina <jikos@...nel.org>
To:     Juergen Gross <jgross@...e.com>
cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...e.de>,
        Mike Latimer <mlatimer@...e.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86/pti: don't report XenPV as vulnerable

On Fri, 15 Jun 2018, Juergen Gross wrote:

> >> wrong for 64-bit, too, in case the mitigation is disabled at hypervisor 
> >> level.
> > 
> > If that is indeed possible (is it?), then the check we have in 
> > pti_check_boottime_disable() is wrong as well.
> 
> No, it isn't. PTI for 32-bit kernels isn't paravirtualized, so it has to
> be disabled.

I was talking about this "mitigation disabled at Xen hypervisor level for 
64-bit" situation though.

-- 
Jiri Kosina
SUSE Labs