From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [RFC] Next gen kvm api Date: Thu, 16 Feb 2012 12:26:33 +0200 Message-ID: <4F3CD9D9.2050900@redhat.com> References: <4F2AB552.2070909@redhat.com> <1328597934.6802.6.camel@concordia> <201202152221.36154.arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Alexander Graf , KVM list , linux-kernel , qemu-devel@nongnu.org, michael@ellerman.id.au, Eric Northup , Scott Wood To: Arnd Bergmann Return-path: In-Reply-To: <201202152221.36154.arnd@arndb.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org Sender: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org List-Id: kvm.vger.kernel.org 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