On Wed, Nov 03, 2010 at 10:15:59AM +0100, Jan Kiszka wrote: > Am 03.11.2010 10:05, Michael S. Tsirkin wrote: > > On Wed, Nov 03, 2010 at 09:51:10AM +0100, Jan Kiszka wrote: > >> Am 03.11.2010 09:43, Michael S. Tsirkin wrote: > >>> On Wed, Nov 03, 2010 at 09:11:16AM +0100, Jan Kiszka wrote: > >>>> From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> > >>>> > >>>> PCI 2.3 allows to generically disable IRQ sources at device level. This > >>>> enables us to share IRQs of such devices between on the host side when > >>>> passing them to a guest. This feature is optional, user space has to > >>>> request it explicitly. > >>>> > >>>> Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> > >>> > >>> > >>> I just realized something. > >>> With this patch, if guest ever looks at > >>> interrupt disable bit, it will go crazy as that bit goes on/off by > >>> itself. I guess we could have an ioctl to set/clear the bit on > >>> device, and have qemu call that on config write into command/status > >>> register. > >> > >> I understand the problem, but I don't get why the kernel should bother. > >> User space has to filter the config space access, returning precisely > >> the value of the INTx disabled bit that the guest wrote. > > > > Yes but if guest disables INTx it should not get interrupts :) > > Right, got this meanwhile. KVM-in-KVM with nested device assignment > would break otherwise - intolerable. :) > > Jan > Or something simpler like WHQL :) -- MST -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
