From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [Qemu-devel] [RFC] Next gen kvm api Date: Wed, 15 Feb 2012 15:39:41 +0200 Message-ID: <4F3BB59D.2020505@redhat.com> References: <4F2AB552.2070909@redhat.com> <20120205093723.GQ23536@redhat.com> <4F2E4F8B.8090504@redhat.com> <20120205095153.GA29265@redhat.com> <4F2EAFF6.7030006@codemonkey.ws> <4F2F9E89.7090607@redhat.com> <87vcnih5qt.fsf@rustcorp.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Anthony Liguori , Gleb Natapov , linux-kernel , KVM list , qemu-devel To: Rusty Russell Return-path: In-Reply-To: <87vcnih5qt.fsf@rustcorp.com.au> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 02/07/2012 08:12 PM, Rusty Russell wrote: > > I would really love to have this, but the problem is that we'd need a > > general purpose bytecode VM with binding to some kernel APIs. The > > bytecode VM, if made general enough to host more complicated devices, > > would likely be much larger than the actual code we have in the kernel now. > > We have the ability to upload bytecode into the kernel already. It's in > a great bytecode interpreted by the CPU itself. Unfortunately it's inflexible (has to come with the kernel) and open to security vulnerabilities. > If every user were emulating different machines, LPF this would make > sense. Are they? They aren't. > Or should we write those helpers once, in C, and > provide that for them. There are many of them: PIT/PIC/IOAPIC/MSIX tables/HPET/kvmclock/Hyper-V stuff/vhost-net/DMA remapping/IO remapping (just for x86), and some of them are quite complicated. However implementing them in bytecode amounts to exposing a stable kernel ABI, since they use such a vast range of kernel services. -- error compiling committee.c: too many arguments to function