From mboxrd@z Thu Jan 1 00:00:00 1970 From: Carsten Otte Subject: Re: Balloon driver? Date: Wed, 06 Jun 2007 18:04:35 +0200 Message-ID: <4666DB13.7080504@de.ibm.com> References: <64F9B87B6B770947A9F8391472E032160C1A61E8@ehost011-8.exch011.intermedia.net> <64F9B87B6B770947A9F8391472E032160C26F84A@ehost011-8.exch011.intermedia.net> <4666AB2E.8030502@de.ibm.com> <64F9B87B6B770947A9F8391472E032160C26F90E@ehost011-8.exch011.intermedia.net> Reply-To: carsteno-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: carsteno-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org, kvm-devel To: Dor Laor Return-path: In-Reply-To: <64F9B87B6B770947A9F8391472E032160C26F90E-yEcIvxbTEBqsx+V+t5oei8rau4O3wl8o3fe8/T/H7NteoWH0uzbU5w@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 Dor Laor wrote: > I agree that pci interface isn't ideal, the advantage is that platforms > that do support pci don't have to implement a virtualized bus, and pci > is PnP device. This was the motivation behind using it, especially for > Windows. In understand that requirement, and I think being able to surface paravirtual functions/devices to the guest as PCI device needs to be a key feature. For windows guests. > Now that more platforms are joining the KVM wagon, we should define a > common bus. PCI was a overkill anyway - its irq are shared and we don't > have to use its io/mmio areas. > Do you guys have something to start with? We do have something basic, our vdev bus. The bad thing is, it is platform specific. I really prefer to aim for an idea that Arnd came up with when discussing this issue: We could define a virtual device bus. We would have platform specific bus implementations which rely on hypercalls, interrupts, and shared memory in the pure paravirtual case. And we need a second bus driver, which is based on a pci device. Just similar to the situation where a PCI device is a USB host adapter. Now functionality like device drivers can sit on top of the abstraction layer. We need to invent a similar abstraction on the hypervisor side, which is a tricky task indeed. The best approach into this direction I have seen so far is not our own vdev thing but Rusty's virtio infrastructure. That's what I think I would start with. so long, Carsten ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/