Messages in this thread | ![/](/images/icornerl.gif) | | Date | Thu, 11 Apr 2024 18:42:20 +0800 | Subject | Re: [PATCH v2 12/12] iommu/vt-d: Retire struct intel_svm | From | Baolu Lu <> |
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On 2024/4/11 16:32, Tian, Kevin wrote: >> From: Baolu Lu<baolu.lu@linux.intel.com> >> Sent: Thursday, April 11, 2024 3:56 PM >> >> On 2024/4/10 23:49, Jason Gunthorpe wrote: >>> On Wed, Apr 10, 2024 at 10:08:44AM +0800, Lu Baolu wrote: >>>> @@ -4388,14 +4386,8 @@ static void >> intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid) >>>> WARN_ON_ONCE(!dev_pasid); >>>> spin_unlock_irqrestore(&dmar_domain->lock, flags); >>>> >>>> - /* >>>> - * The SVA implementation needs to handle its own stuffs like the >> mm >>>> - * notification. Before consolidating that code into iommu core, let >>>> - * the intel sva code handle it. >>>> - */ >>>> if (domain->type == IOMMU_DOMAIN_SVA) { >>>> cache_tag_unassign_domain(dmar_domain, >> FLPT_DEFAULT_DID, dev, pasid); >>>> - intel_svm_remove_dev_pasid(domain); >>>> } else { >>>> did = domain_id_iommu(dmar_domain, iommu); >>>> cache_tag_unassign_domain(dmar_domain, did, dev, pasid); >>> It seems very strange that SVA has a different DID scheme, why is >>> this? PASID and SVA should not be different at this layer. >> The VT-d spec recommends that all SVA domains share a single domain ID. >> The PASID is unique to each SVA domain, hence the cache tags are unique. >> Currently, the Intel IOMMU driver assigns different domain IDs for all >> domains except the SVA type. >> >> Sharing a domain ID is not specific to SVA. In general, for devices >> under a single IOMMU, domains with unique PASIDs can share the same >> domain ID. >> >> In the long term (also on my task list), we will extend the cache tag >> code to support sharing domain IDs and remove the domain type check from >> the main code. This will also benefit the nesting case, where user >> domains nested on the same parent could share a domain ID. >> > at least above might be changed to a unified call with the helper > accepting an iommu parameter and then finding proper did > internally based on domain type, e.g. > > cache_tag_unassign_domain(domain, iommu, dev, pasid) > { > if (domain->type == IOMMU_DOMAIN_SVA) > did = FLPT_DEFAULT_DID; > else > did = domain_id_iommu(domain, iommu); > > ... > }
Yeah, your code is more graceful.
Best regards, baolu
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