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From:   Yi Liu <yi.l.liu@intel.com>
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Subject: [PATCH v6 01/10] iommu: Add IOMMU_DOMAIN_NESTED
Date:   Tue, 24 Oct 2023 08:06:00 -0700
Message-Id: <20231024150609.46884-2-yi.l.liu@intel.com>
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From: Lu Baolu <baolu.lu@linux.intel.com>

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@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
 include/linux/iommu.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 1d42bdb37cbc..becfc8b725de 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -67,6 +67,9 @@ 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
@@ -93,6 +96,7 @@ 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