Hi Alex,
On 10/31/20 5:06 AM, Alex Williamson wrote:
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,
I focused too much on a feature and forgot about university. I should
apologize for this. Sorry about it!
Back to the original intention of this series. The aux domain was
allocated in vfio/mdev, but it's also needed by the vDCM component of a
device driver for mediated callbacks. Currently vfio/mdev or iommu core
has no support for this.
We had a proposal when we first did aux-domain support. But was not
discussed since there was no consumer at that time.
https://lore.kernel.org/linux-iommu/20181105073408.21815-7-baolu.lu@xxxxxxxxxxxxxxx/
Does it look good to you? I can send patches of such solution for
discussion if you think it's a right way.
Extending the iommu core for subdevice passthrough support sounds an
interesting topic, but it will take much time before we reach a
consensus. It sounds a good topic for the next year's LPC/MC :-).
Best regards,
baolu
