[Xen-devel] [PATCH for 4.6] VT-d: Create IOMMU mappings for RMRR regions if shared EPT is not being used

[Malcolm Crossley <malcolm.crossley@xxxxxxxxxx>]

Add RMRR 1:1 IOMMU mappings to IOMMU page tables if EPT page table are not being
shared with the IOMMU.

This is a regression in behaviour versus Xen 4.5.

Signed-off-by: Malcolm Crossley <malcolm.crossley@xxxxxxxxxx>
---
 xen/drivers/passthrough/vtd/iommu.c | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/xen/drivers/passthrough/vtd/iommu.c 
b/xen/drivers/passthrough/vtd/iommu.c
index 836aed5..89de741 100644
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -1839,8 +1839,16 @@ static int rmrr_identity_mapping(struct domain *d, 
bool_t map,
 
             while ( base_pfn < end_pfn )
             {
-                if ( clear_identity_p2m_entry(d, base_pfn) )
-                    ret = -ENXIO;
+                if ( iommu_use_hap_pt(d) )
+                {
+                    if ( clear_identity_p2m_entry(d, base_pfn) )
+                            ret = -ENXIO;
+                }
+                else
+                {
+                    if ( intel_iommu_unmap_page(d, base_pfn) )
+                        ret = -ENXIO;
+                }
                 base_pfn++;
             }
 
@@ -1855,7 +1863,16 @@ static int rmrr_identity_mapping(struct domain *d, 
bool_t map,
 
     while ( base_pfn < end_pfn )
     {
-        int err = set_identity_p2m_entry(d, base_pfn, p2m_access_rw, flag);
+        int err;
+        if ( iommu_use_hap_pt(d) )
+        {
+            err = set_identity_p2m_entry(d, base_pfn, p2m_access_rw, flag);
+        }
+        else
+        {
+            err = intel_iommu_map_page(d, base_pfn, base_pfn,
+                                       IOMMUF_readable|IOMMUF_writable);
+        }
 
         if ( err )
             return err;
-- 
1.7.12.4


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