Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752304Ab2BPK06 (ORCPT ); Thu, 16 Feb 2012 05:26:58 -0500 Received: from mx1.redhat.com ([209.132.183.28]:4842 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750814Ab2BPK0z (ORCPT ); Thu, 16 Feb 2012 05:26:55 -0500 Message-ID: <4F3CD9D9.2050900@redhat.com> Date: Thu, 16 Feb 2012 12:26:33 +0200 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:9.0) Gecko/20111222 Thunderbird/9.0 MIME-Version: 1.0 To: Arnd Bergmann CC: qemu-devel@nongnu.org, Alexander Graf , michael@ellerman.id.au, KVM list , linux-kernel , Eric Northup , Scott Wood Subject: Re: [Qemu-devel] [RFC] Next gen kvm api References: <4F2AB552.2070909@redhat.com> <1328597934.6802.6.camel@concordia> <201202152221.36154.arnd@arndb.de> In-Reply-To: <201202152221.36154.arnd@arndb.de> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1306 Lines: 28 On 02/16/2012 12:21 AM, Arnd Bergmann wrote: > ioctl is good for hardware devices and stuff that you want to enumerate > and/or control permissions on. For something like KVM that is really a > core kernel service, a syscall makes much more sense. > > I would certainly never mix the two concepts: If you use a chardev to get > a file descriptor, use ioctl to do operations on it, and if you use a > syscall to get the file descriptor then use other syscalls to do operations > on it. > > I don't really have a good recommendation whether or not to change from an > ioctl based interface to syscall for KVM now. On the one hand I believe it > would be significantly cleaner, on the other hand we cannot remove the > chardev interface any more since there are many existing users. > This sums up my feelings exactly. Moving to syscalls would be an improvement, but not so much an improvement as to warrant the thrashing and the pain from having to maintain the old interface for a long while. -- error compiling committee.c: too many arguments to function -- 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/