Re: [PATCH 5/5] ioeventfd: Introduce KVM_IOEVENTFD_FLAG_SOCKET

Avi Kivity
2011-07-14T13:23:17Z

On 07/14/2011 04:17 PM, Pekka Enberg wrote:
> >
> > I still don't follow. The guest oopses? dmesg | less. An issue with
> > tools/kvm? gdb -p `pgrep kvm`.
>
> When I was debugging tools/kvm virtio code, I used to 'instrument' the
> guest kernel with printk() calls which helped a lot.
>

Sure, but do you really need it spewing out the serial port all the time?

> Also, a bug in tools/kvm can manifest in many interesting ways in the
> guest kernel during boot, for example. You can't do dmesg then and gdb
> won't save you. I think you've lived too long in the table KVM and Qemu
> land to remember how important reliable printk() is for development.

I guess. Also I've switched to trace_printk() since it's much nicer
(and intergrates with other ftrace features).

And again, I'm not against tools/kvm optimizing serial. I just want
better justification for socket-mmio.

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