Hi Alex, I've noticed that when doing device passthrough with VFIO, if an IRQ in the host machine is associated with a PCI device that's being passed to the guest, then the IRQ is automatically forwarded into the guest by kvm/vfio. Is is possible to tell qemu to forward arbitrary IRQs to the guest as well?
My situation is that I am trying to make a touchpad device work in the VM guest. This device sits behind an i2c controller on the host. When I pass through the i2c controller (PCI device), its IRQ automatically gets passed to the guest as well, so everything works on this level. My problem is that the touchpad device behind the i2c controller is wired up to use a specific IRQ for interrupts, and since qemu has no idea this needs to be forwarded along with the i2c controller, it doesn't get forwarded. Everything else with the i2c controller and touchpad works as intended in the guest, including aspects of the touchpad functionality that don't require interrupts. I was hoping there was an easy way to tell qemu to forward this IRQ to the guest (maybe in the same code path where the IRQ for the i2c controller is forwarded?) -- even though it is not associated with any PCI device in the host. If not, maybe you could point me to where in the code I would need to hack to pass an extra IRQ to the guest? Or is it much more complicated and intractable than I'm making it out to be? Thanks! P.S. I've seen a couple threads you're on that are related, but don't totally answer my question: [1] https://www.redhat.com/archives/vfio-users/2017-October/msg00019.html [2] https://stackoverflow.com/questions/29461518/interrupt-handling-for-assigned-device-through-vfio _______________________________________________ vfio-users mailing list vfio-users@redhat.com https://www.redhat.com/mailman/listinfo/vfio-users
