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

Duan, Zhenzhong
2026-03-27T09:13:03Z

>-----Original Message-----
>From: Tian, Kevin <kevin.tian@intel.com>
>Subject: RE: [PATCH 2/3] iommupt/vtd: Support dirty tracking on PASID
>
>> From: Duan, Zhenzhong <zhenzhong.duan@intel.com>
>> 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.

Make sense, will send v2 with the bug fix as first patch.

Thanks
Zhenzhong