From: "Tian, Kevin" <kevin.tian@intel.com>
To: Baolu Lu <baolu.lu@linux.intel.com>, Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
"Robin Murphy" <robin.murphy@arm.com>,
"Zhang, Tina" <tina.zhang@intel.com>,
"Liu, Yi L" <yi.l.liu@intel.com>,
"iommu@lists.linux.dev" <iommu@lists.linux.dev>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v2 12/12] iommu/vt-d: Retire struct intel_svm
Date: Thu, 11 Apr 2024 08:32:11 +0000 [thread overview]
Message-ID: <BN9PR11MB52767D3287A7E000AD17BC9B8C052@BN9PR11MB5276.namprd11.prod.outlook.com> (raw)
In-Reply-To: <b24f3380-1ac3-41c4-9163-56c1dcff6297@linux.intel.com>
> 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);
...
}
next prev parent reply other threads:[~2024-04-11 8:32 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-10 2:08 [PATCH v2 00/12] Consolidate domain cache invalidation Lu Baolu
2024-04-10 2:08 ` [PATCH v2 01/12] iommu/vt-d: Add cache tag assignment interface Lu Baolu
2024-04-10 2:08 ` [PATCH v2 02/12] iommu/vt-d: Add cache tag invalidation helpers Lu Baolu
2024-04-15 4:15 ` Zhang, Tina
2024-04-15 5:06 ` Baolu Lu
2024-04-15 6:46 ` Zhang, Tina
2024-04-10 2:08 ` [PATCH v2 03/12] iommu/vt-d: Add trace events for cache tag interface Lu Baolu
2024-04-10 2:08 ` [PATCH v2 04/12] iommu/vt-d: Use cache_tag_flush_all() in flush_iotlb_all Lu Baolu
2024-04-10 2:08 ` [PATCH v2 05/12] iommu/vt-d: Use cache_tag_flush_range() in tlb_sync Lu Baolu
2024-04-10 2:08 ` [PATCH v2 06/12] iommu/vt-d: Use cache_tag_flush_range_np() in iotlb_sync_map Lu Baolu
2024-04-10 2:08 ` [PATCH v2 07/12] iommu/vt-d: Cleanup use of iommu_flush_iotlb_psi() Lu Baolu
2024-04-10 2:08 ` [PATCH v2 08/12] iommu/vt-d: Use cache_tag_flush_range() in cache_invalidate_user Lu Baolu
2024-04-10 2:08 ` [PATCH v2 09/12] iommu/vt-d: Use cache helpers in arch_invalidate_secondary_tlbs Lu Baolu
2024-04-10 15:55 ` Jason Gunthorpe
2024-04-11 8:10 ` Baolu Lu
2024-04-10 2:08 ` [PATCH v2 10/12] iommu/vt-d: Retire intel_svm_dev Lu Baolu
2024-04-10 2:08 ` [PATCH v2 11/12] iommu: Add ops->domain_alloc_sva() Lu Baolu
2024-04-10 2:08 ` [PATCH v2 12/12] iommu/vt-d: Retire struct intel_svm Lu Baolu
2024-04-10 15:49 ` Jason Gunthorpe
2024-04-11 7:55 ` Baolu Lu
2024-04-11 8:32 ` Tian, Kevin [this message]
2024-04-11 10:42 ` Baolu Lu
2024-04-11 13:07 ` Jason Gunthorpe
2024-04-11 13:13 ` Baolu Lu
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