Re: [PATCH v6 0/9] vfio/mdev: IOMMU aware mediated device

From: Jean-Philippe Brucker
Date: Fri Feb 15 2019 - 13:46:26 EST

On 14/02/2019 20:14, Alex Williamson wrote:
>> This patch series extends both IOMMU and vfio components to support
>> mdev device passing through when it could be isolated and protected
>> by the IOMMU units. The first part of this series (PATCH 1/09~6/09)
>> adds the interfaces and implementation of the multiple domains per
>> device. The second part (PATCH 7/09~9/09) adds the iommu device
>> attribute to each mdev, determines isolation type according to the
>> existence of an iommu device when attaching group in vfio type1 iommu
>> module, and attaches the domain to iommu aware mediated devices.
>> References:
>> [1]
>> [2]
>> [3]
>> Best regards,
>> Lu Baolu
>> Change log:
>>   v5->v6:
> This looks pretty reasonable with Jean-Philippe's nit fixups.  Where do
> we go from here?  I think we need an ack from Kirti since they have an
> interest here.  Presumably this looks ok to the ARM folks.

Looks great from my point of view. I focused on patch 1 since I'm
planning to reuse iommu_dev_features for SVA. I don't have time to test
auxd and mdev on SMMUv3 at the moment but I had a better look and, if it
helps, for patches 1 and 7-9:

Reviewed-by: Jean-Philippe Brucker <jean-philippe.brucker@xxxxxxx>

That said, are you planning to add back the mdev_get_iommu_domain()
function, in a separate patch? Because I think the parent driver still
needs a way to retrieve the PASID for an mdev?


> Do we have
> any consumers of this code yet?  Theoretically I think a vfio-pci-like
> meta driver could be written as an mdev vendor driver with this support
> (restricted to type1 iommu use cases).  Thanks,
> Alex