[PATCH v6 05/12] iommu/vt-d: Reserve a domain id for FL and PT modes

Lu Baolu
2018-12-10T01:58:59Z

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-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Cc: Jacob Pan <jacob.jun.pan-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Cc: Kevin Tian <kevin.tian-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Cc: Liu Yi L <yi.l.liu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Cc: Sanjay Kumar <sanjay.k.kumar-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Lu Baolu <baolu.lu-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
---
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 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;
};
--
2.17.1