RE: [PATCH 2/3] iommupt/vtd: Support dirty tracking on PASID

[Tian, Kevin]

> From: Duan, Zhenzhong <zhenzhong.duan@xxxxxxxxx>
> Sent: Thursday, February 5, 2026 10:34 AM
> 
> In order to support passthrough device with PASID capability in QEMU,
> e.g., DSA device, kernel needs to support attaching PASID to a domain.
> 
> But attaching is not allowed if the domain is a second stage domain with
> dirty tracking, this is the use case when guest configures 'iommu=pt'.
> 
> The reason is kernel lacking support for dirty tracking on such domain
> attached to PASID. Same for nested domain even though there is no such
> checking.

no check for nested domain is a bug. We should first add a check and
backport it to stable kernel. Then have this series to allow it in new
kernels.