On Wed, Jan 19, 2022 at 04:41:56PM -0500, Jagannathan Raman wrote: > Signed-off-by: Elena Ufimtseva <elena.ufimts...@oracle.com> > Signed-off-by: John G Johnson <john.g.john...@oracle.com> > Signed-off-by: Jagannathan Raman <jag.ra...@oracle.com> > --- > hw/remote/machine.c | 57 +++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 57 insertions(+) > > diff --git a/hw/remote/machine.c b/hw/remote/machine.c > index 220ff01aa9..221a8430c1 100644 > --- a/hw/remote/machine.c > +++ b/hw/remote/machine.c > @@ -22,6 +22,60 @@ > #include "hw/pci/pci_host.h" > #include "hw/remote/iohub.h" > > +static bool remote_machine_get_bus(const char *type, BusState **bus, > + Error **errp) > +{ > + ERRP_GUARD(); > + RemoteMachineState *s = REMOTE_MACHINE(current_machine); > + BusState *root_bus = NULL; > + PCIBus *new_pci_bus = NULL; > + > + if (!bus) { > + error_setg(errp, "Invalid argument"); > + return false; > + } > + > + if (strcmp(type, TYPE_PCI_BUS) && strcmp(type, TYPE_PCI_BUS)) { > + return true; > + } > + > + root_bus = qbus_find_recursive(sysbus_get_default(), NULL, > TYPE_PCIE_BUS); > + if (!root_bus) { > + error_setg(errp, "Unable to find root PCI device"); > + return false; > + } > + > + new_pci_bus = pci_isol_bus_new(root_bus, type, errp); > + if (!new_pci_bus) { > + return false; > + } > + > + *bus = BUS(new_pci_bus); > + > + pci_bus_irqs(new_pci_bus, remote_iohub_set_irq, remote_iohub_map_irq, > + &s->iohub, REMOTE_IOHUB_NB_PIRQS); > + > + return true; > +}
Can the user create the same PCI bus via QMP commands? If so, then this is just a convenience that saves the extra step. Or is there some magic that cannot be done via QMP device_add? I'm asking because there are 3 objects involved and I'd like to understand the lifecycle/dependencies: 1. The PCIDevice we wish to export. 2. The PCIBus with isolated address spaces that contains the PCIDevice. 3. The vfio-user server that exports a given PCIDevice. Users can already create the PCIDevice via hotplug and the vfio-user server via object-add. So if there's no magic they could also create the PCI bus: 1. device_add ...some PCI bus stuff here...,id=isol-pci-bus0 2. device_add ...the PCIDevice...,bus=isol-pci-bus0,id=mydev 3. object-add x-vfio-user-server,device=mydev Unplug would work in the reverse order. It may be more convenient to automatically create a PCIBus when the PCIDevice is hotplugged, but this kind of magic also has drawbacks (hidden devices, naming collisions, etc). > + > +static bool remote_machine_put_bus(BusState *bus, Error **errp) > +{ > + PCIBus *pci_bus = NULL; > + > + if (!bus) { > + error_setg(errp, "Invalid argument"); > + return false; > + } > + > + if (!object_dynamic_cast(OBJECT(bus), TYPE_PCI_BUS)) { > + return true; > + } > + > + pci_bus = PCI_BUS(bus); > + > + return pci_isol_bus_free(pci_bus, errp); > +} > + > static void remote_machine_init(MachineState *machine) > { > MemoryRegion *system_memory, *system_io, *pci_memory; > @@ -56,6 +110,9 @@ static void remote_machine_init(MachineState *machine) > &s->iohub, REMOTE_IOHUB_NB_PIRQS); > > qbus_set_hotplug_handler(BUS(pci_host->bus), OBJECT(s)); > + > + qdev_set_bus_cbs(remote_machine_get_bus, remote_machine_put_bus, > + &error_fatal); > } > > static void remote_machine_pre_plug_cb(HotplugHandler *hotplug_dev, > -- > 2.20.1 >
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