From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [RFC] Stable kvm userspace interface Date: Thu, 11 Jan 2007 10:32:22 +0200 Message-ID: <45A5F616.3040305@qumranet.com> References: <45A39A97.5060807@qumranet.com> <45A39D0D.7090007@garzik.org> <200701110834.43800.arnd@arndb.de> <45A5F4A5.9000408@garzik.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Andrew Morton , linux-kernel Return-path: To: Jeff Garzik In-Reply-To: <45A5F4A5.9000408-o2qLIJkoznsdnm+yROfE0A@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Jeff Garzik wrote: > Arnd Bergmann wrote: >> On Tuesday 09 January 2007 14:47, Jeff Garzik wrote: >>> Can we please avoid adding a ton of new ioctls? ioctls inevitably >>> require 64-bit compat code for certain architectures, whereas >>> sysfs/procfs does not. >> >> For performance reasons, an ascii string based interface is not >> desireable here, some of these calls should be optimized to >> the point of counting cycles. > > sysfs does not require ASCII... > The main kvm ioctl switches the execution mode to guest mode. Just like a syscall enters kernel mode, ioctl(vcpu_fd, KVM_VCPU_RUN) enters the guest address space and begins executing guest code. I don't see how to model that with sysfs. There are other objections as well. sysfs is a public interface, whereas kvm is a process private attribute. These objections don't apply to /proc though. -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV