From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55722) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W60pY-0006YU-OS for qemu-devel@nongnu.org; Wed, 22 Jan 2014 11:39:14 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W60pQ-0003al-Oj for qemu-devel@nongnu.org; Wed, 22 Jan 2014 11:39:08 -0500 Received: from mx1.redhat.com ([209.132.183.28]:29812) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W60pQ-0003a0-Fe for qemu-devel@nongnu.org; Wed, 22 Jan 2014 11:39:00 -0500 Message-ID: <52DFF353.1060307@redhat.com> Date: Wed, 22 Jan 2014 17:35:31 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <1390224336-27009-1-git-send-email-pbonzini@redhat.com> <20140122152917.GA22855@amt.cnet> In-Reply-To: <20140122152917.GA22855@amt.cnet> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH uq/master] kvm: always update the MPX model specific register List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Marcelo Tosatti Cc: Liu Jinsong , qemu-devel@nongnu.org, kvm@vger.kernel.org Il 22/01/2014 16:29, Marcelo Tosatti ha scritto: > > The original patch from Liu Jinsong restricted them to reset or full > > state updates, but that's unnecessary (and wrong) since the BNDCFGS > > MSR has no side effects. > > Why is it necessary to save/restore BNDCFGS MSR on states other > than FULL and RESET? Yes, nothing in QEMU except reset will touch the MSR, but this applies also to all the other MSRs that are saved unconditionally. It's nice to be able to poke them with gdb, and saving/restoring the MSR provides that. Paolo