Re: [Qemu-devel] [PATCH] virtio: Introduce virtio-testdev

[Peter Maydell]

On 15 October 2013 10:47, Anup Patel <address@hidden> wrote:
> On Tue, Oct 15, 2013 at 2:06 PM, Andrew Jones <address@hidden> wrote:
>> I'm not opposed to it, but at the moment I'm not sure how we would
>> utilize it within kvm-unit-tests. Maybe it would be useful for another
>> application though? So maybe we can add it as an add-on patch at the
>> time we come up with its use case?
>
> I suggested it because we have "machvirt" machine in QEMU for
> KVM ARM/ARM64 which has only VirtIO devices. In "machvirt", we
> don't have mechanism to reset the system because none of the
> VirtIO devices have such a mechanism. Now since you are introducing
> a "testdev", we can have a RESET command in VirtIO and implement
> VirtIO REBOOT driver in Linux kernel to use it.
>
> Currently, due to no RESET support in "machvirt" we are not able
> to reboot Guest Linux from Guest console.

We shouldn't be abusing a device intended for testing to
provide necessary features. If we need guest reboot support
(which seems like an obvious thing to want) then we need
to implement a sensible mechanism for it.

-- PMM