Date: Sat, 13 Jan 2018 14:10:10 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: David Woodhouse <dwmw2@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Borislav Petkov <bp@alien8.de>,
        Laura Abbott <labbott@redhat.com>, X86 ML <x86@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        stable <stable@vger.kernel.org>
Subject: Re: Yet another KPTI regression with 4.14.x series in a VM
Message-ID: <20180113131010.GJ3397@worktop>
References: <c7ecacdc-993e-d24f-b8d9-2af7615fd6f6@redhat.com>
 <alpine.DEB.2.20.1801121949220.2371@nanos>
 <9eb15489-da09-7a4c-0700-7b6eb99e6f7b@redhat.com>
 <alpine.DEB.2.20.1801122250080.2371@nanos>
 <CALCETrWOpg_OXThyMC66JQu7JF=TxzRwFrEgunUZt3H+VUfxrQ@mail.gmail.com>
 <20180113120847.GI3397@worktop>
 <1515846611.22302.567.camel@infradead.org>
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On Sat, Jan 13, 2018 at 12:30:11PM +0000, David Woodhouse wrote:
> On Sat, 2018-01-13 at 13:08 +0100, Peter Zijlstra wrote:
> > 
> > ????????ALTERNATIVE "orq $(PTI_SWITCH_PGTABLE_MASK), \scratch_reg",
> > ??????????????????? "orq $(PTI_SWITCH_MASK), \scratch_reg", X86_FEATURE_PCID
> > 
> > Is not wanting to compile though; probably that whole alternative vs
> > macro thing again :/
> 
> Welcome to my world. Try
> 
> ?ALTERNATIVE __stringify(orq $(PTI_SWITCH_PGTABLE_MASK), \scratch_reg), \
>              __stringify(orq $(PTI_SWITCH_MASK), \scratch_reg), \
>              X86_FEATURE_PCID

Doesn't seem to work, gets literal __stringy() crud in the .s file.