iommu/vt-d: Add cache tag assignment interface

Caching tag is a combination of tags used by the hardware to cache various
translations. Whenever a mapping in a domain is changed, the IOMMU driver
should invalidate the caches with the caching tags. The VT-d specification
describes caching tags in section 6.2.1, Tagging of Cached Translations.

Add interface to assign caching tags to an IOMMU domain when attached to a
RID or PASID, and unassign caching tags when a domain is detached from a
RID or PASID. All caching tags are listed in the per-domain tag list and
are protected by a dedicated lock.

In addition to the basic IOTLB and devTLB caching tag types, NESTING_IOTLB
and NESTING_DEVTLB tag types are also introduced. These tags are used for
caches that store translations for DMA accesses through a nested user
domain. They are affected by changes to mappings in the parent domain.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20240416080656.60968-2-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

1 files changed, 9 insertions, 1 deletions

diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index e05c6c4cb8c3..2e627fbd5adb 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -366,17 +366,23 @@ static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
 			sdev->qdep = 0;
 	}
 
+	ret = cache_tag_assign_domain(to_dmar_domain(domain), dev, pasid);
+	if (ret)
+		goto free_sdev;
+
 	/* Setup the pasid table: */
 	sflags = cpu_feature_enabled(X86_FEATURE_LA57) ? PASID_FLAG_FL5LP : 0;
 	ret = intel_pasid_setup_first_level(iommu, dev, mm->pgd, pasid,
 					    FLPT_DEFAULT_DID, sflags);
 	if (ret)
-		goto free_sdev;
+		goto unassign_tag;
 
 	list_add_rcu(&sdev->list, &svm->devs);
 
 	return 0;
 
+unassign_tag:
+	cache_tag_unassign_domain(to_dmar_domain(domain), dev, pasid);
 free_sdev:
 	kfree(sdev);
 free_svm:
@@ -741,6 +747,8 @@ struct iommu_domain *intel_svm_domain_alloc(void)
 	if (!domain)
 		return NULL;
 	domain->domain.ops = &intel_svm_domain_ops;
+	INIT_LIST_HEAD(&domain->cache_tags);
+	spin_lock_init(&domain->cache_lock);
 
 	return &domain->domain;
 }