Date:   Mon, 13 Feb 2023 19:18:51 -0400
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc:     Jean-Philippe Brucker <jean-philippe@linaro.org>,
        LKML <linux-kernel@vger.kernel.org>, iommu@lists.linux.dev,
        Lu Baolu <baolu.lu@linux.intel.com>,
        Joerg Roedel <joro@8bytes.org>,
        Jean-Philippe Brucker <jean-philippe@linaro.com>,
        Robin Murphy <robin.murphy@arm.com>,
        David Woodhouse <dwmw2@infradead.org>,
        Raj Ashok <ashok.raj@intel.com>,
        "Tian, Kevin" <kevin.tian@intel.com>, Yi Liu <yi.l.liu@intel.com>
Subject: Re: [PATCH 2/2] iommu/ioasid: Remove custom IOASID allocator
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On Mon, Feb 13, 2023 at 01:44:02PM -0800, Jacob Pan wrote:
> > Your DMA API PASID thing will simply need one new API to alloc/free a
> > PASID from the iommu_global_pasid_ida
> It should satisfy what we need right now.
> Just wondering if we were to do resource management of global PASIDs, say
> with the new misc cgroup controller, do we plan to expand in iommu sva code?
> If yes, do we keep DMA API PASID in a separate range/set?

I would say all shared PASIDs held by userspace should be captured by
by a resource limit, it doesn't matter if they are global PASIDs or
device local shared PASIDs.

So if a cgroup comes it is just a matter of putting charges in the
right place which is auditable by looking at calls to attach pasid
functions.

Jason