[Xen-devel] [v5][PATCH 2/2] xen:vtd: missing RMRR mapping while share EPT

[Tiejun Chen <tiejun.chen@xxxxxxxxx>]

intel_iommu_map_page() does nothing if VT-d shares EPT page table.
So rmrr_identity_mapping() never create RMRR mapping but in some
cases like some GFX drivers it still need to access RMRR.

Here we will create those RMRR mappings even in shared EPT case.

Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxx>
---
 xen/drivers/passthrough/vtd/iommu.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

v5:

* Don't pass mfn directly to set_identity_p2m_entry() since it can get that.

v4:

* After introduce set_rmrr_p2m_entry we can go there directly.

v3:

* Use set_mmio_p2m_entry() to replace p2m_set_entry()
* Use ASSERT to check

v2:

* Fix coding style.
* Still need to abide intel_iommu_map_page(), so we should do nothing
  if dom0 and iommu supports pass thru.

diff --git a/xen/drivers/passthrough/vtd/iommu.c 
b/xen/drivers/passthrough/vtd/iommu.c
index 042b882..bc50793 100644
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -1867,8 +1867,14 @@ static int rmrr_identity_mapping(struct domain *d,
 
     while ( base_pfn < end_pfn )
     {
-        if ( intel_iommu_map_page(d, base_pfn, base_pfn,
-                                  IOMMUF_readable|IOMMUF_writable) )
+        if ( iommu_use_hap_pt(d) )
+        {
+            ASSERT(!iommu_passthrough || !is_hardware_domain(d));
+            if ( set_identity_p2m_entry(d, base_pfn) )
+                return -1;
+        }
+        else if ( intel_iommu_map_page(d, base_pfn, base_pfn,
+                                       IOMMUF_readable|IOMMUF_writable) )
             return -1;
         base_pfn++;
     }
-- 
1.9.1


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