[Qemu-devel] Question: can we hot plug a PCIe switch on machine "virt"

[Heyi Guo]

Hi folks,

In physical world, a PCIe switch including one upstream port and several 
downstream ports is a single physical device, however we treat each port as a 
device in qemu world. In qemu docs/pcie.txt, we have below statements:

Line 230: Be aware that PCI Express Downstream Ports can't be hot-plugged into
Line 231: an existing PCI Express Upstream Port.

To my understanding, it implies PCIe downstream ports *can* be hot-plugged into 
something which is not an existing upstream port. If it is true, how can we do 
that? AFAIK monitor command device_add can only add one device at a time.

Please help to show the truth.

Thanks,

Heyi