[v6,05/12] iommu/vt-d: Reserve a domain id for FL and PT modes
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Message ID 20181210015906.27929-6-baolu.lu@linux.intel.com
State Accepted
Commit 3b33d4ab3217337f648f7ff3e57e755e6444c748
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Series
  • iommu/vt-d: Add scalable mode support
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Commit Message

Lu Baolu Dec. 10, 2018, 1:58 a.m. UTC
Vt-d spec rev3.0 (section 6.2.3.1) requires that each pasid
entry for first-level or pass-through translation should be
programmed with a domain id different from those used for
second-level or nested translation. It is recommended that
software could use a same domain id for all first-only and
pass-through translations.

This reserves a domain id for first-level and pass-through
translations.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Liu Yi L <yi.l.liu@intel.com>
Cc: Sanjay Kumar <sanjay.k.kumar@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel-iommu.c | 10 ++++++++++
 drivers/iommu/intel-pasid.h |  6 ++++++
 2 files changed, 16 insertions(+)

Patch
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diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 52cdb0e077f2..5e924bc8ebec 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1621,6 +1621,16 @@  static int iommu_init_domains(struct intel_iommu *iommu)
 	 */
 	set_bit(0, iommu->domain_ids);
 
+	/*
+	 * Vt-d spec rev3.0 (section 6.2.3.1) requires that each pasid
+	 * entry for first-level or pass-through translation modes should
+	 * be programmed with a domain id different from those used for
+	 * second-level or nested translation. We reserve a domain id for
+	 * this purpose.
+	 */
+	if (sm_supported(iommu))
+		set_bit(FLPT_DEFAULT_DID, iommu->domain_ids);
+
 	return 0;
 }
 
diff --git a/drivers/iommu/intel-pasid.h b/drivers/iommu/intel-pasid.h
index 12f480c2bb8b..03c1612d173c 100644
--- a/drivers/iommu/intel-pasid.h
+++ b/drivers/iommu/intel-pasid.h
@@ -17,6 +17,12 @@ 
 #define PDE_PFN_MASK			PAGE_MASK
 #define PASID_PDE_SHIFT			6
 
+/*
+ * Domain ID reserved for pasid entries programmed for first-level
+ * only and pass-through transfer modes.
+ */
+#define FLPT_DEFAULT_DID		1
+
 struct pasid_dir_entry {
 	u64 val;
 };