Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752558AbbKPT7T (ORCPT ); Mon, 16 Nov 2015 14:59:19 -0500 Received: from mail.skyhub.de ([78.46.96.112]:60908 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751646AbbKPT7Q (ORCPT ); Mon, 16 Nov 2015 14:59:16 -0500 Date: Mon, 16 Nov 2015 20:59:06 +0100 From: Borislav Petkov To: Andy Lutomirski Cc: Boris Ostrovsky , "linux-kernel@vger.kernel.org" , xen-devel , David Vrabel , Konrad Rzeszutek Wilk Subject: Re: [PATCH] xen/x86: Adjust stack pointer in xen_sysexit Message-ID: <20151116195906.GB20137@pd.tnic> References: <1447456706-24347-1-git-send-email-boris.ostrovsky@oracle.com> <56468D24.8030801@oracle.com> <564A0371.2040104@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1262 Lines: 33 On Mon, Nov 16, 2015 at 11:03:22AM -0800, Andy Lutomirski wrote: > ... > The reader surely doesn't remember that this isn't guaranteed to be a > swapgs instruction on native. Using: > > ALTERNATIVE "swapgs" "" X86_FEATURE_XENPV > > would be safer (it would get rid of the SWAPGS_UNSAFE_STACK mess) and > much clearer. We could hide *that* behind a macro and no one would be > confused. (Well, they'd be confused by the fact that Xen PV handles > gsbase very differently from native, but that has nothing to do with > the macro.) > > I think we could convert piecemeal, and I wonder if this new patch for > 32-bit native on 4.4 (this is needed for 4.4, right?) would be a good > starting point. Borislav, what do you think? Would you be okay with > adding a Xen PV pseudofeature? AFAICT, I'd prefer this becomes rather a jump label which gets enabled on xen. Especially if a single pseudofeature might not be enough, apprently... -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/