Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932323AbbKQTh2 (ORCPT ); Tue, 17 Nov 2015 14:37:28 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:33017 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932274AbbKQThY (ORCPT ); Tue, 17 Nov 2015 14:37:24 -0500 Subject: Re: [Xen-devel] [PATCH] xen/x86: Adjust stack pointer in xen_sysexit To: Andy Lutomirski , Andrew Cooper References: <1447456706-24347-1-git-send-email-boris.ostrovsky@oracle.com> <56468D24.8030801@oracle.com> <564A0371.2040104@oracle.com> <20151116195906.GB20137@pd.tnic> <20151116202232.GC20137@pd.tnic> <564A50C3.1000200@zytor.com> <564B3C57.5000002@oracle.com> <564B7C2B.5030901@citrix.com> Cc: "linux-kernel@vger.kernel.org" , xen-devel , Borislav Petkov , David Vrabel , "H. Peter Anvin" From: Boris Ostrovsky Message-ID: <564B81DE.90909@oracle.com> Date: Tue, 17 Nov 2015 14:37:02 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: aserv0021.oracle.com [141.146.126.233] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 660 Lines: 16 On 11/17/2015 02:16 PM, Andy Lutomirski wrote: >>> Looks good to me. Does Xen have any sysexit/sysret32 equivalent to >>> return to 32-bit user mode? If so, it could be worth trying to wire >>> it up by patching the jz instead of the test instruction. We can actually make patching a little bit more efficient by replacing the test instruction with 'xor %eax,%eax'. That way we won't need any 'nop's. -boris -- 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/