linux - How to add a new device in QEMU source code?

Question

What could be the step wise approach to emulate/add a new device in qemu using QOM approach?

What and where could be the changes with respect to DeviceState/BusState and other properties?

Answer 1

edu in-tree educational PCI device

• https://github.com/qemu/qemu/blob/v2.7.0/hw/misc/edu.c
• https://github.com/qemu/qemu/blob/v2.7.0/docs/specs/edu.txt

It is very easy to understand and well documented, so I recommend that you study it.

It exposes a minimal PCI device, with basic IO, interrupt generation, and DMA.

I've written a minimal Linux kernel module + userland tests to play with it at:

• https://github.com/cirosantilli/linux-kernel-module-cheat/blob/6788a577c394a2fc512d8f3df0806d84dc09f355/rootfs_overlay/pci.sh
• https://github.com/cirosantilli/linux-kernel-module-cheat/blob/6788a577c394a2fc512d8f3df0806d84dc09f355/kernel_module/pci.c

Out-of-tree devices

I asked if it is possible to make out-of-tree devices at: How to create out-of-tree QEMU devices? but it does not look like it.