Hi,
On 11/7/18 2:55 PM, Liu, Yi L wrote:
Hi Baolu,
From: Lu Baolu [mailto:baolu...@linux.intel.com]
Sent: Monday, November 5, 2018 1:32 PM
Subject: [PATCH v4 05/12] iommu/vt-d: Reserve a domain id for FL and PT modes
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....@intel.com>
Cc: Jacob Pan <jacob.jun....@linux.intel.com>
Cc: Kevin Tian <kevin.t...@intel.com>
Cc: Liu Yi L <yi.l....@intel.com>
Cc: Sanjay Kumar <sanjay.k.ku...@intel.com>
Signed-off-by: Lu Baolu <baolu...@linux.intel.com>
---
drivers/iommu/intel-iommu.c | 10 ++++++++++
drivers/iommu/intel-pasid.h | 6 ++++++
2 files changed, 16 insertions(+)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 9331240c70b8..2f7455ee4e7a 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1618,6 +1618,16 @@ 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);
"FLPT_DEFAULT_DID" looks very likely for first level translation. How about
"PT_FL_DEFAULT_DID"?
We have comments above it, so people won't be confused.
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
Would be helpful to elaborate why DID 1 is selected in the patch
description.
Yeah. DID 0 has been caved out for caching mode and we start from 1 for
this.
Best regards,
Lu Baolu
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