From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40664) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDuBj-0003zQ-21 for qemu-devel@nongnu.org; Fri, 17 Jun 2016 09:52:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bDuBe-0002YI-TI for qemu-devel@nongnu.org; Fri, 17 Jun 2016 09:51:58 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44882) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDuBe-0002Y7-NU for qemu-devel@nongnu.org; Fri, 17 Jun 2016 09:51:54 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2D2BA64070 for ; Fri, 17 Jun 2016 13:51:54 +0000 (UTC) Date: Fri, 17 Jun 2016 14:51:50 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20160617135150.GH2273@work-vm> References: <1466097133-5489-1-git-send-email-dgilbert@redhat.com> <1466097133-5489-4-git-send-email-dgilbert@redhat.com> <20160616201408.GX18662@thinpad.lan.raisama.net> <20160617124641.GZ18662@thinpad.lan.raisama.net> <4371f52c-335b-95dd-0a50-432d876f0784@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4371f52c-335b-95dd-0a50-432d876f0784@redhat.com> Subject: Re: [Qemu-devel] [PATCH 3/5] x86: fill high bits of mtrr mask List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: Eduardo Habkost , aarcange@redhat.com, qemu-devel@nongnu.org * Paolo Bonzini (pbonzini@redhat.com) wrote: > Note that the failure mode is pretty brutal since KVM reports an > internal error right after restarting on the destination, and who knows > what used to happen before the assertion was introduced. All MSRs after > MTRRs would be ignored by KVM! I think we got lucky because the MTRRs were close to the last MSRs in the list, there was only some MCG/MCE stuff after it which probably wouldn't have been missed; if the MTRR wasn't set I'm guessing someone would have just had a behaviour that looked like dreadful performance after migration perhaps? Dave > Migrating and checking the configuration complicates the code and, > because it's only for a warning, doesn't save you from massaging the > values to make things work. > > Paolo -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK