Re: [PATCH v6 5/5] vfio/type1: Use mdev bus iommu_ops for IOMMU callbacks

[Alex Williamson]

On Fri, 30 Oct 2020 06:16:28 +0000
"Tian, Kevin" <kevin.tian@xxxxxxxxx> wrote:

> > From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> > Sent: Friday, October 30, 2020 12:58 PM
> > 
> > With the IOMMU driver registering iommu_ops for the mdev_bus, the
> > IOMMU
> > operations on an mdev could be done in the same way as any normal device
> > (for example, PCI/PCIe). There's no need to distinguish an mdev from
> > others for iommu operations. Remove the unnecessary code.  
> 
> This is really a nice cleanup as the output of this change! :)

It's easy to remove a bunch of code when the result is breaking
everyone else.  Please share with me how SR-IOV backed mdevs continue
to work on AMD platforms, or how they might work on ARM platforms, when
siov_iommu_ops (VT-d only) becomes the one and only provider of
iommu_ops on the mdev bus.  Hard NAK on this series.  Thanks,

Alex