pcisim

Overview ¶

Package pcisim puts a gpudev.Device behind an emulated virtio-pci modern transport, in process: it implements go-virtio/common.Transport, so the go-virtio/gpu guest driver (or any driver written against that interface) can bring the device up and drive it with no VM.

Guest memory is a gpudev.RAM: AllocatePages hands out its pages, and the device reads the virtqueues and buffers from it by guest-physical address, as a hypervisor would. A doorbell write runs the queue synchronously, so the driver finds the used ring updated when its notify returns.

Reference: the virtio spec, transport-pci.tex — struct virtio_pci_cap (:143-153), struct virtio_pci_common_cfg (:302-328), the notification address cap.offset + queue_notify_off * notify_off_multiplier (:551).