Are virtio-1.0 PCI IDs accounted for?
Not sure this is a bug or not because I'm not familiar with NSIS at all, but looking at win-guest-tools.nsis I see that is has references to PCI IDs associated with each driver. However I only see a single reference per virtio device, and nowadays virtio drivers now will apply to two PCI IDs: the original device, and virtio 1.0 variants. For example the viostor driver also works for PCI\VEN_1AF4&DEV_1042&SUBSYS_11001AF4&REV_01. See .inf files in the latest virtio-win ISO. If those IDs are used in some way to determine whether to install the driver or not then this is probably a bug