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, 14 insertions, 5 deletions

diff --git a/drivers/iommu/intel/nested.c b/drivers/iommu/intel/nested.c
index a7d68f3d518a..13406ee742bf 100644
--- a/drivers/iommu/intel/nested.c
+++ b/drivers/iommu/intel/nested.c
@@ -52,13 +52,14 @@ static int intel_nested_attach_dev(struct iommu_domain *domain,
 		return ret;
 	}
 
+	ret = cache_tag_assign_domain(dmar_domain, dev, IOMMU_NO_PASID);
+	if (ret)
+		goto detach_iommu;
+
 	ret = intel_pasid_setup_nested(iommu, dev,
 				       IOMMU_NO_PASID, dmar_domain);
-	if (ret) {
-		domain_detach_iommu(dmar_domain, iommu);
-		dev_err_ratelimited(dev, "Failed to setup pasid entry\n");
-		return ret;
-	}
+	if (ret)
+		goto unassign_tag;
 
 	info->domain = dmar_domain;
 	spin_lock_irqsave(&dmar_domain->lock, flags);
@@ -68,6 +69,12 @@ static int intel_nested_attach_dev(struct iommu_domain *domain,
 	domain_update_iotlb(dmar_domain);
 
 	return 0;
+unassign_tag:
+	cache_tag_unassign_domain(dmar_domain, dev, IOMMU_NO_PASID);
+detach_iommu:
+	domain_detach_iommu(dmar_domain, iommu);
+
+	return ret;
 }
 
 static void intel_nested_domain_free(struct iommu_domain *domain)
@@ -206,7 +213,9 @@ struct iommu_domain *intel_nested_domain_alloc(struct iommu_domain *parent,
 	domain->domain.type = IOMMU_DOMAIN_NESTED;
 	INIT_LIST_HEAD(&domain->devices);
 	INIT_LIST_HEAD(&domain->dev_pasids);
+	INIT_LIST_HEAD(&domain->cache_tags);
 	spin_lock_init(&domain->lock);
+	spin_lock_init(&domain->cache_lock);
 	xa_init(&domain->iommu_array);
 
 	spin_lock(&s2_domain->s1_lock);