Messages in this thread | | | Date | Tue, 15 Mar 2022 15:36:20 -0700 | From | Jacob Pan <> | Subject | Re: [PATCH v2 3/8] iommu/vt-d: Implement device_pasid domain attach ops |
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Hi Jason,
On Tue, 15 Mar 2022 11:33:22 -0300, Jason Gunthorpe <jgg@nvidia.com> wrote:
> 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. > > 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.. > Agreed. It might need some surgery for dmar_domain and device_domain_info, which already has a simple device list. I am trying to leverage the existing data struct, let me take a closer look.
> > + if (entry) { > > + pinfo = entry; > > + } else { > > + pinfo = kzalloc(sizeof(*pinfo), GFP_ATOMIC); > > + if (!pinfo) > > + return -ENOMEM; > > + pinfo->pasid = pasid; > > + /* Store the new PASID info in the per domain array */ > > + ret = xa_err(__xa_store(&dmar_domain->pasids, pasid, > > pinfo, > > + GFP_ATOMIC)); > > + if (ret) > > + goto xa_store_err; > > + } > > + /* Store PASID in per device-domain array, this is for > > tracking devTLB */ > > + ret = xa_err(xa_store(&info->pasids, pasid, pinfo, > > GFP_ATOMIC)); > > + if (ret) > > + goto xa_store_err; > > + > > + atomic_inc(&pinfo->users); > > + xa_unlock(&dmar_domain->pasids); > > + > > + return 0; > > + > > +xa_store_err: > > + xa_unlock(&dmar_domain->pasids); > > + spin_lock_irqsave(&iommu->lock, flags); > > + intel_pasid_tear_down_entry(iommu, dev, pasid, false); > > + spin_unlock_irqrestore(&iommu->lock, flags); > > + > > + if (!atomic_read(&pinfo->users)) { > > + __xa_erase(&dmar_domain->pasids, pasid); > > This isn't locked right > good catch! need to move under xa_unlock.
Thanks,
Jacob
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