From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:37017) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TGxx3-0007xt-42 for qemu-devel@nongnu.org; Wed, 26 Sep 2012 16:11:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TGxwv-00020m-LT for qemu-devel@nongnu.org; Wed, 26 Sep 2012 16:11:21 -0400 Received: from terminus.zytor.com ([198.137.202.10]:58257 helo=mail.zytor.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TGxwv-00020g-Cy for qemu-devel@nongnu.org; Wed, 26 Sep 2012 16:11:13 -0400 Message-ID: <50636153.3070200@zytor.com> Date: Wed, 26 Sep 2012 13:10:59 -0700 From: "H. Peter Anvin" MIME-Version: 1.0 References: <1348684238-6555-1-git-send-email-hpa@linux.intel.com> <873924wokp.fsf@codemonkey.ws> In-Reply-To: <873924wokp.fsf@codemonkey.ws> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] x86: Implement SMEP and SMAP List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Linda Wang , Thomas Gleixner , "H. Peter Anvin" , Qemu devel , Ingo Molnar On 09/26/2012 12:50 PM, Anthony Liguori wrote: > > The patch looks good except for these two chunks. This would break live > migration from a new QEMU to an old one because CPUs are currently not > versioned. > > If you just remove these two chunks, the patch can be applied and you > can still test with: > > qemu-system-x86_64 -cpu qemu64,+smep,+smap > > We're working vcpu versioning and will hopefully have it in place for > 1.3. If we get there, we can enable these features unconditionally and > add the appropriate backwards compatibility code. > OK. I had to add a chunk to up the minimum CPUID level to 7 if any of the level 7 features were enabled, however. > > scripts/checkpatch.pl will complain about lack of curly braces with ifs. > > I know this file does not use them consistently. Since you have to > respin anyway, please run checkpatch and fixup the errors. > Actually, several of the files are very consistent about *not* using them. I'll respin the patch, but it ain't pretty. -hpa