Re: [Qemu-devel] Re: [PATCH] virtio-pci: Disable virtio-ioeventfd when !CONFIG_IOTHREAD

[Stefan Hajnoczi]

On Tue, Jan 25, 2011 at 2:13 PM, Michael S. Tsirkin <address@hidden> wrote:
> On Tue, Jan 25, 2011 at 01:58:08PM +0000, Stefan Hajnoczi wrote:
>> It is not possible to use virtio-ioeventfd when building without an I/O
>> thread.  We rely on a signal to kick us out of vcpu execution.  Timers
>> and AIO use SIGALRM and SIGUSR2 respectively.  Unfortunately eventfd
>> does not support O_ASYNC (SIGIO) so eventfd cannot be used in a signal
>> driven manner.
>>
>> Signed-off-by: Stefan Hajnoczi <address@hidden>
>
> I'd rather have the CONFIG_ ... mess contained in kvm-all.c
> which tests CONFIG_IOTHREAD anyway, than spread out
> to devices. Can we make kvm_has_many_ioeventfds check this?

Good idea.

Stefan