Re: [RFC v4 PATCH 09/49] multi-process: setup PCI host bridge for remote device

[Jag Raman]

On 11/13/2019 11:07 AM, Stefan Hajnoczi wrote:
> On Thu, Oct 24, 2019 at 05:08:50AM -0400, Jagannathan Raman wrote:
> > +static void remote_host_realize(DeviceState *dev, Error **errp)
> > +{
> > +    PCIHostState *pci = PCI_HOST_BRIDGE(dev);
> > +    RemPCIHost *s = REMOTE_HOST_DEVICE(dev);
> > +
> > +    /*
> > +     * TODO: the name of the bus would be provided by QEMU. Use
> > +     * "pcie.0" for now.
> > +     */
> > +    pci->bus = pci_root_bus_new(DEVICE(s), "pcie.0",
> > +                                s->mr_pci_mem, s->mr_sys_io,
> > +                                0, TYPE_PCIE_BUS);
>
> The PCI bus name could be a property and then whatever instantiates
> RemPCIHost could set it.
>
> Machine types usually hardcode the name because they assume there is
> only one machine instance.  In the case of mpqemu this is an okay
> starting point, but maybe multiple busses will become necessary if the
> device emulation process handles multiple device instances - especially
> if they are served to multiple guests like in a software-defined network
> switch use case.

Are you referring to a case where a single remote process will emulate
devices from multiple guests?

We haven't thought about that application. But we will certainly add the
ability to specify the name of the bus as a parameter.

Thank you very much!
--
Jag

>