Messages in this thread | | | Subject | Re: [PATCH v2 1/1] s390: virtio: let arch accept devices without IOMMU feature | From | Pierre Morel <> | Date | Tue, 16 Jun 2020 15:41:20 +0200 |
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On 2020-06-16 14:17, Cornelia Huck wrote: > On Tue, 16 Jun 2020 13:57:26 +0200 > Halil Pasic <pasic@linux.ibm.com> wrote: > >> On Tue, 16 Jun 2020 12:52:50 +0200 >> Pierre Morel <pmorel@linux.ibm.com> wrote: >> >>>>> int virtio_finalize_features(struct virtio_device *dev) >>>>> { >>>>> int ret = dev->config->finalize_features(dev); >>>>> @@ -179,6 +184,10 @@ int virtio_finalize_features(struct virtio_device *dev) >>>>> if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) >>>>> return 0; >>>>> >>>>> + if (arch_needs_iommu_platform(dev) && >>>>> + !virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) >>>>> + return -EIO; >>>>> + >>>> >>>> Why EIO? >>> >>> Because I/O can not occur correctly? >>> I am open to suggestions. >> >> We use -ENODEV if feature when the device rejects the features we >> tried to negotiate (see virtio_finalize_features()) and -EINVAL when >> the F_VERSION_1 and the virtio-ccw revision ain't coherent (in >> virtio_ccw_finalize_features()). Any of those seems more fitting >> that EIO to me. BTW does the error code itself matter in any way, >> or is it just OK vs some error? > > If I haven't lost my way, we end up in the driver core probe failure > handling; we probably should do -ENODEV if we just want probing to fail > and -EINVAL or -EIO if we want the code to moan. >
what about returning -ENODEV and add a dedicated warning here?
-- Pierre Morel IBM Lab Boeblingen
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