Re: [PATCH v5 2/2] s390: virtio: PV needs VIRTIO I/O device protection

[Halil Pasic <pasic@linux.ibm.com>]

On Thu, 9 Jul 2020 12:51:58 +0200
Pierre Morel <pmorel@linux.ibm.com> wrote:

> >> +int arch_validate_virtio_features(struct virtio_device *dev)
> >> +{
> >> +	if (!is_prot_virt_guest())
> >> +		return 0;
> >> +
> >> +	if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
> >> +		dev_warn(&dev->dev, "device must provide VIRTIO_F_VERSION_1\n");  
> > 
> > I'd probably use "legacy virtio not supported with protected
> > virtualization".
> >   
> >> +		return -ENODEV;
> >> +	}
> >> +
> >> +	if (!virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) {
> >> +		dev_warn(&dev->dev,
> >> +			 "device must provide VIRTIO_F_IOMMU_PLATFORM\n");  
> > 
> > "support for limited memory access required for protected
> > virtualization"
> > 
> > ?
> > 
> > Mentioning the feature flag is shorter in both cases, though.  
> 
> And I think easier to look for in case of debugging purpose.
> I change it if there is more demands.

Not all our end users are kernel and/or qemu developers. I find the
messages from v4 less technical, more informative, and way better.

Regards,
Halil