On Mon, 21 May 2007 13:28:03 +0200, Arnd Bergmann <[EMAIL PROTECTED]> wrote:
> We've had the same discussion about PCI as virtual device abstraction > recently when hpa made the suggestions to get a set of PCI device > numbers registered for Linux. (If you want to read it up, it's the thread at http://marc.info/?t=117554525400003&r=1&w=2) > > IIRC, the conclusion to which we came was that it is indeed helpful > for most architecture to have a PCI device as one way to probe for > the functionality, but not to rely on it. s390 is the obvious > example where you can't have PCI, but you may also want to build > a guest kernel without PCI support because of space constraints > in a many-guests machine. > > What I think would be ideal is to have a new bus type in Linux > that does not have any dependency on PCI itself, but can be > easily implemented as a child of a PCI device. > > If we only need the stuff mentioned by Anthony, the interface could > look like > > struct vmchannel_device { > struct resource virt_mem; > struct vm_device_id id; > int irq; ^^^^^^^^ > int (*signal)(struct vmchannel_device *); > int (*irq_ack)(struct vmchannel_device *); > struct device dev; > }; IRQ numbers are evil :) It should be more like a void *vmchannel_device_handle; which could be different things depending on what we want the vmchannel_device to be a child of (it could be an IRQ number for PCI devices, or something like subchannel_id if we wanted to support channel devices). > > Such a device can easily be provided as a child of a PCI device, > or as something that is purely virtual based on an hcall interface. This looks like a flexible approach. ------------------------------------------------------------------------- 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/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
