[PATCH v3 02/10] iommu/vt-d: Extend dmar_domain to support nested domain

[Yi Liu <yi.l.liu@intel.com>]

From: Lu Baolu <baolu.lu@linux.intel.com>

The nested domain fields are exclusive to those that used for a DMA
remapping domain. Use union to avoid memory waste.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
 drivers/iommu/intel/iommu.h | 35 +++++++++++++++++++++++++++++------
 1 file changed, 29 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index 1c5e1d88862b..e818520f4068 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -596,15 +596,38 @@ struct dmar_domain {
 	spinlock_t lock;		/* Protect device tracking lists */
 	struct list_head devices;	/* all devices' list */
 
-	struct dma_pte	*pgd;		/* virtual address */
-	int		gaw;		/* max guest address width */
-
-	/* adjusted guest address width, 0 is level 2 30-bit */
-	int		agaw;
 	int		iommu_superpage;/* Level of superpages supported:
 					   0 == 4KiB (no superpages), 1 == 2MiB,
 					   2 == 1GiB, 3 == 512GiB, 4 == 1TiB */
-	u64		max_addr;	/* maximum mapped address */
+	union {
+		/* DMA remapping domain */
+		struct {
+			/* virtual address */
+			struct dma_pte	*pgd;
+			/* max guest address width */
+			int		gaw;
+			/*
+			 * adjusted guest address width:
+			 *   0: level 2 30-bit
+			 *   1: level 3 39-bit
+			 *   2: level 4 48-bit
+			 *   3: level 5 57-bit
+			 */
+			int		agaw;
+			/* maximum mapped address */
+			u64		max_addr;
+		};
+
+		/* Nested user domain */
+		struct {
+			/* 2-level page table the user domain nested */
+			struct dmar_domain *s2_domain;
+			/* user page table pointer (in GPA) */
+			unsigned long s1_pgtbl;
+			/* page table attributes */
+			struct iommu_hwpt_intel_vtd s1_cfg;
+		};
+	};
 
 	struct iommu_domain domain;	/* generic domain data structure for
 					   iommu core */
-- 
2.34.1