RE: [PATCH v4 14/32] iommu: introduce iommu_domain_alloc_type and the KVM type

[Tian, Kevin]

> From: Robin Murphy
> Sent: Tuesday, March 15, 2022 6:49 PM
> 
> On 2022-03-14 19:44, Matthew Rosato wrote:
> > s390x will introduce an additional domain type that is used for
> > managing IOMMU owned by KVM.  Define the type here and add an
> > interface for allocating a specified type vs the default type.
> 
> I'm also not a huge fan of adding a new domain_alloc interface like
> this, however if it is justifiable, then please make it take struct
> device rather than struct bus_type as an argument.
> 
> It also sounds like there may be a degree of conceptual overlap here
> with what Jean-Philippe is working on for sharing pagetables between KVM
> and SMMU for Android pKVM, so it's probably worth some thought over
> whether there's any scope for common interfaces in terms of actual
> implementation.
> 

Same here. Yan Zhao is working on page table sharing between KVM
and VT-d. This is one important usage to build atop iommufd and
a set of common interfaces are definitely necessary here. 😊

Thanks
Kevin