On Mon, Nov 16, 2015 at 12:39:45PM +0200, Marcel Apfelbaum wrote: > On 11/16/2015 12:37 PM, Michael S. Tsirkin wrote: > >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. > > OK, but this device will be both pci/pcie, depending on the machine type > right? > No need to split it too? > > Thanks, > Marcel
It's ok to have a single device but I don't like tying it to a machine type, much. It's always integrated within a RC, right? Can you go by the type of the parent device? > > > > >> > >>>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)
