From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758319AbZCROjU (ORCPT ); Wed, 18 Mar 2009 10:39:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757169AbZCROjL (ORCPT ); Wed, 18 Mar 2009 10:39:11 -0400 Received: from ti-out-0910.google.com ([209.85.142.184]:51944 "EHLO ti-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756345AbZCROjL (ORCPT ); Wed, 18 Mar 2009 10:39:11 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=N26drVvO9S8lp8jA/GvZoTX1sht2uYPbXsDTAujxCF5Rhb0Kh/r4GkWWW21fFCjN4E OM3Kt7IRlazlIRl+trq9j13H6WrUA+td4hz/Mhw/sHlm7ngIjJ/HJ1LZhdvHOS+Nvi3P Rn+xt1O2YLUxyepfPe216R9X8VaPY8zRw8jFo= Date: Wed, 18 Mar 2009 22:39:39 +0800 From: =?utf-8?Q?Am=C3=A9rico?= Wang To: Renzo Davoli Cc: Am??rico Wang , Ingo Molnar , linux-kernel@vger.kernel.org, Jeff Dike , user-mode-linux-devel@lists.sourceforge.net Subject: Re: [PATCH 2/2] ptrace_vm: ptrace for syscall emulation virtual machines Message-ID: <20090318143939.GA3986@hack> References: <20090204080256.GC17452@cs.unibo.it> <20090310214456.GE5213@cs.unibo.it> <20090310220241.GC30475@elte.hu> <20090311134138.GD12753@cs.unibo.it> <20090316081508.GE3360@hack> <20090316121732.GC22978@cs.unibo.it> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090316121732.GC22978@cs.unibo.it> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 16, 2009 at 01:17:32PM +0100, Renzo Davoli wrote: >Dear Cong, > >Thank you for the detailed analysis of the code. >I'll change the code taking care of your observations asap. You are so welcome. :) > >On Mon, Mar 16, 2009 at 04:15:08PM +0800, Am??rico Wang wrote: >> >I have updated the patch, now it should be (more) consistent >> >with the Coding Style specifications. >> You can use scripts/checkpatch.pl to check it before sending. >I read the coding style document and I used the perl script. >However, the script is not able to cope with all the style specifications >and I may have missed something more. >> >> >UML tests at startup which features are provided and uses PTRACE_VM or >> >PTRACE_SYSEMU (or nothing). PTRACE_VM and/or PTRACE_SYSEMU support can be >> >disabled by command line flags. >> So what? PTRACE_VM is only supported in UML with this patch, >> UML still has to use PTRACE_SYSEMU on x86_32. >> >> Am I missing something? :) >This patch [2/2] is for UML (host and guest). Patch #1 provides PTRACE_VM >for all the architectures supporting ptrace via tracehook. >By applying both patches PTRACE_VM is available in the following architectures: >x86*, sparc*, s390, powerpc*, ia64, sh* and um. >(I have not tested all these architectures, but the patch applies to the core ptrace >code, shared by all of them). Ok then. I am not familiar with tracehooks. >Ptrace_vm then provides the same speedup of PTRACE_SYSEMU extending its support: >- to other architectures: ports of UML or similar code for other architectures can >use it >- to other applications: PTRACE_SYSEMU supports the virtualization of all the system calls >while by PTRACE_VM the VM monitor can virtualize some of the system calls, depending on >some condition e.g. the value of a parameter. It is possible in this way give a faster >implementation to partial virtual machines like my umview. > >With patch #2 user-mode linux also uses ptrace_vm where available. > Thanks for your explanations! -- Do what you love, f**k the rest! F**k the regulations!