[Qemu-devel] error "kvm: virtio: trying to map MMIO memory"

[Stéphanie Ouillon]

Hello,

I am porting virtio device drivers for DragonFly BSD for a GSoC project. [1]

I have been facing a problem for 3-4 days with my virtio network device driver in qemu: when I load the driver, I get the following error:
kvm: virtio: trying to map MMIO memory

And then the machine crashes immediately (I started the vm in a screen to see this message).

It seems to be linked with the call of a bus_space_write_2 function [2] inside a virtio_enqueue_commit function in virtio.c [3]. But without more information about this type of error message (I found some patches or bug reports on the net, but I am not sure they match in my case), I found it difficult to locate it.

Would anybody have a clue about what kind of bug would provoke this error in qemu ?


Thank you !


Stéphanie Ouillon


[1] http://github.com/arroway/virtio_DragonFlyBSD/tree/dev-net/net
[2] source code in DragonFly BSD http://fxr.watson.org/fxr/source/cpu/i386/include/bus_at386.h?v=DFBSD;im=bigexcerpts#L887
[3] at l.465: http://github.com/arroway/virtio_DragonFlyBSD/blob/dev-net/virtio.c