On Mon, Nov 16, 2015 at 12:34:11PM +0200, Marcel Apfelbaum wrote: > On 11/16/2015 12:11 PM, Paolo Bonzini wrote: > > > > > >On 16/11/2015 11:10, Marcel Apfelbaum wrote: > >>>What would you lose? Hotplug? > >> > >>Without the bridge? Yes. However the user can add it manually the > >>pci-bridge and have it anyway. > > > >Ok, I guess that's more or less acceptable. It's still ugly however, to > >the point that I wonder if we should rename the device and call the old > >one a failed experiment. > > > > I guess we can rename the pxb to extra-root or something, but in this way > will have a deprecated/duplicated device to support and kill in the future. > > Why not use the compat property as it is? > Again, the command line *remains* the same, the difference is where the > devices associated with the pxb will land: on the secondary bus (for QEMU < > 2.5) > or on the root bus itself (QEMU >= 2.5). > > I know is guest visible, but the guest will see one of them depending on the > machine type. > > Regarding the splitting of pxb into 2 devices (pci/pcie), I have nothing > against it, > but because the implementation is *exactly* the same I think we should gain > more > by maintaining one device. > > > Thanks, > Marcel
Yes, I think you want a new "pci-extender" device which is just the extender. Then existing pxb will create both it and the bridge behind it. Maybe creating pxb which is extender+bridge was a mistake, I don't know, but we shipped it in QEMU so we support it. > > >Paolo > > > >>I wanted to get rid of the internal pci-bridge as a default, and this > >>is why pxb and pxb-pcie are he same device now (except bus type)