Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1956115AbdDZGgP (ORCPT ); Wed, 26 Apr 2017 02:36:15 -0400 Received: from mail.skyhub.de ([5.9.137.197]:53638 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1956098AbdDZGgH (ORCPT ); Wed, 26 Apr 2017 02:36:07 -0400 Date: Wed, 26 Apr 2017 08:35:56 +0200 From: Borislav Petkov To: Juergen Gross Cc: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, boris.ostrovsky@oracle.com, hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com Subject: Re: [PATCH] x86/amd: don't set X86_BUG_SYSRET_SS_ATTRS if forced to zero Message-ID: <20170426063556.vc2zmns3uscubuim@pd.tnic> References: <20170425180014.7533-1-jgross@suse.com> <20170425182443.3ab75tkfosol2yk4@pd.tnic> <20170425191809.uvdt4jimnbvqbyf2@pd.tnic> <24b7ab61-69e6-192e-5bb7-2ef5cdaa28c3@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <24b7ab61-69e6-192e-5bb7-2ef5cdaa28c3@suse.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 704 Lines: 21 On Wed, Apr 26, 2017 at 06:45:42AM +0200, Juergen Gross wrote: > The really clean solution would be to add this test to set_cpu_bug() No, the really clean solution is to set it once and not play toggle games. > This would work. OTOH I'd prefer to test whether the bit should be > forced to remain zero than use the knowledge _who_ is trying to force > it. Because we're in the business of investigating who did? Nah, we should set it or clear it once and not do funky toggle games. Especially if in the future something else changes and timing windows grow and we refactor stuff and yadda yadda... -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.