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Date:   Thu, 28 Jul 2022 08:59:45 -0300
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     "Tian, Kevin" <kevin.tian@intel.com>
Cc:     Baolu Lu <baolu.lu@linux.intel.com>,
        Joerg Roedel <joro@8bytes.org>,
        Christoph Hellwig <hch@infradead.org>,
        "Raj, Ashok" <ashok.raj@intel.com>, Will Deacon <will@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Jean-Philippe Brucker <jean-philippe@linaro.com>,
        "Jiang, Dave" <dave.jiang@intel.com>,
        Vinod Koul <vkoul@kernel.org>,
        Eric Auger <eric.auger@redhat.com>,
        "Liu, Yi L" <yi.l.liu@intel.com>,
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        Zhangfei Gao <zhangfei.gao@linaro.org>,
        "Zhu, Tony" <tony.zhu@intel.com>,
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Subject: Re: [PATCH v10 04/12] iommu: Add attach/detach_dev_pasid iommu
 interface
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On Thu, Jul 28, 2022 at 03:06:47AM +0000, Tian, Kevin wrote:

> > Then we don't need this weirdo check in the core iommu code at all.
> 
> and then we could also move group->pasid_array to device->pasid_array
> with this approach. Though the end result doesn't change i.e. still only
> the singleton group can enable pasid the iommu core can just stick to
> the device manner now.

I don't see why, the group is still logically the unit of attachment
in the iommu area, and if we have a multi-device group it just means
we iterate over all the devices in the group when doing pasid set, no
different than a RID.

Jason