From b380e3e0c30fb68dbbfb1397f3c374adfff77ac4 Mon Sep 17 00:00:00 2001
From: Eric Auger <eric.auger@redhat.com>
Date: Mon, 1 Jul 2019 11:30:30 +0200
Subject: [PATCH] memory: Add IOMMU_ATTR_VFIO_NESTED IOMMU memory region
 attribute

We introduce a new IOMMU Memory Region attribute,
IOMMU_ATTR_VFIO_NESTED that tells whether the virtual IOMMU
requires HW nested paging for VFIO integration.

Current Intel virtual IOMMU device supports "Caching
Mode" and does not require 2 stages at physical level to be
integrated with VFIO. However SMMUv3 does not implement such
"caching mode" and requires to use HW nested paging.

As such SMMUv3 is the first IOMMU device to advertise this
attribute.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com>
---
 hw/arm/smmuv3.c       | 12 ++++++++++++
 include/exec/memory.h |  3 ++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/hw/arm/smmuv3.c b/hw/arm/smmuv3.c
index da5dac1ba5..9b87d16217 100644
--- a/hw/arm/smmuv3.c
+++ b/hw/arm/smmuv3.c
@@ -1589,6 +1589,17 @@ static int smmuv3_notify_flag_changed(IOMMUMemoryRegion *iommu,
     return 0;
 }
 
+static int smmuv3_get_attr(IOMMUMemoryRegion *iommu,
+                           enum IOMMUMemoryRegionAttr attr,
+                           void *data)
+{
+    if (attr == IOMMU_ATTR_VFIO_NESTED) {
+        *(bool *) data = true;
+        return 0;
+    }
+    return -EINVAL;
+}
+
 static void smmuv3_iommu_memory_region_class_init(ObjectClass *klass,
                                                   void *data)
 {
@@ -1596,6 +1607,7 @@ static void smmuv3_iommu_memory_region_class_init(ObjectClass *klass,
 
     imrc->translate = smmuv3_translate;
     imrc->notify_flag_changed = smmuv3_notify_flag_changed;
+    imrc->get_attr = smmuv3_get_attr;
 }
 
 static const TypeInfo smmuv3_type_info = {
diff --git a/include/exec/memory.h b/include/exec/memory.h
index c3180075e1..864bcaeb01 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -321,7 +321,8 @@ typedef struct MemoryRegionClass {
 
 
 enum IOMMUMemoryRegionAttr {
-    IOMMU_ATTR_SPAPR_TCE_FD
+    IOMMU_ATTR_SPAPR_TCE_FD,
+    IOMMU_ATTR_VFIO_NESTED,
 };
 
 /*
-- 
2.27.0