Re: [PATCH v3 1/1] s390: virtio: let arch accept devices without IOMMU feature

Pierre Morel
2020-06-29T18:49:28Z

On 2020-06-19 14:02, Halil Pasic wrote:
> On Fri, 19 Jun 2020 11:20:51 +0200
> Cornelia Huck <cohuck@redhat.com> wrote:
>
>>>> + if (arch_needs_virtio_iommu_platform(dev) &&
>>>> + !virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) {
>>>> + dev_warn(&dev->dev,
>>>> + "virtio: device must provide VIRTIO_F_IOMMU_PLATFORM\n");
>>>
>>> I'm not sure, divulging the current Linux name of this feature bit is a
>>> good idea, but if everybody else is fine with this, I don't care that
>>
>> Not sure if that feature name will ever change, as it is exported in
>> headers. At most, we might want to add the new ACCESS_PLATFORM define
>> and keep the old one, but that would still mean some churn.
>>
>>> much. An alternative would be:
>>> "virtio: device falsely claims to have full access to the memory,
>>> aborting the device"
>>
>> "virtio: device does not work with limited memory access" ?
>>
>> But no issue with keeping the current message.
>
> I think I prefer Conny's version, but no strong feelings here.
>

The reason why the device is not accepted without IOMMU_PLATFORM is arch
specific, I think it should be clearly stated.
If no strong oposition...

Thanks,
Pierre

--
Pierre Morel
IBM Lab Boeblingen