Messages in this thread | | | Date | Wed, 16 Mar 2022 14:01:40 -0700 | From | Jacob Pan <> | Subject | Re: [PATCH v2 3/8] iommu/vt-d: Implement device_pasid domain attach ops |
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Hi Kevin,
On Wed, 16 Mar 2022 07:41:34 +0000, "Tian, Kevin" <kevin.tian@intel.com> wrote:
> > From: Jason Gunthorpe <jgg@nvidia.com> > > Sent: Tuesday, March 15, 2022 10:33 PM > > > > On Mon, Mar 14, 2022 at 10:07:07PM -0700, Jacob Pan wrote: > > > + /* > > > + * Each domain could have multiple devices attached with > > > shared or > > per > > > + * device PASIDs. At the domain level, we keep track of > > > unique PASIDs > > and > > > + * device user count. > > > + * E.g. If a domain has two devices attached, device A has > > > PASID 0, 1; > > > + * device B has PASID 0, 2. Then the domain would have PASID > > > 0, 1, 2. > > > + */ > > > > A 2d array of xarray's seems like a poor data structure for this task. > Perhaps i mis-presented here, I am not using 2D array. It is an 1D xarray for domain PASIDs only. Then I use the existing device list in each domain, adding another xa to track per-device-domain PASIDs. > besides that it also doesn't work when we support per-device PASID > allocation in the future. In that case merging device PASIDs together is > conceptually wrong. > Sorry, could you elaborate? If we do per-dev PASID allocation, we could use the ioasid_set for each pdev, right?
> > > > AFACIT this wants to store a list of (device, pasid) tuples, so a > > simple linked list, 1d xarray vector or a red black tree seems more > > appropriate.. > > > > this tuple can well serve per-device PASID. 😊 > I commented on the other email, but a simple list of tuples could have duplicated devices since each dev could attach multiple PASIDs, right? Should we still do two level then?
> Thanks > Kevin
Thanks,
Jacob
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