[PATCH v5 01/10] iommu: Add IOMMU_DOMAIN_NESTED

[Yi Liu]

From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>

Introduce a new domain type for a user I/O page table, which is nested on
top of another user space address represented by a PAGING domain. This
new domain can be allocated by the domain_alloc_user op, and attached to
a device through the existing iommu_attach_device/group() interfaces.

The mappings of a nested domain are managed by user space software, so it
is not necessary to have map/unmap callbacks.

Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
---
 include/linux/iommu.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 3861d66b65c1..ce08a3c41446 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -65,6 +65,9 @@ struct iommu_domain_geometry {
 
 #define __IOMMU_DOMAIN_SVA	(1U << 4)  /* Shared process address space */
 
+#define __IOMMU_DOMAIN_NESTED	(1U << 5)  /* User-managed address space nested
+					      on a stage-2 translation        */
+
 #define IOMMU_DOMAIN_ALLOC_FLAGS ~__IOMMU_DOMAIN_DMA_FQ
 /*
  * This are the possible domain-types
@@ -91,6 +94,7 @@ struct iommu_domain_geometry {
 				 __IOMMU_DOMAIN_DMA_API |	\
 				 __IOMMU_DOMAIN_DMA_FQ)
 #define IOMMU_DOMAIN_SVA	(__IOMMU_DOMAIN_SVA)
+#define IOMMU_DOMAIN_NESTED	(__IOMMU_DOMAIN_NESTED)
 
 struct iommu_domain {
 	unsigned type;
-- 
2.34.1