[Xen-devel] [v4][PATCH 03/19] xen/vtd: create RMRR mapping

[Tiejun Chen <tiejun.chen@xxxxxxxxx>]

RMRR reserved regions must be setup in the pfn space with an identity
mapping to reported mfn. However existing code has problem to setup
correct mapping when VT-d shares EPT page table, so lead to problem
when assigning devices (e.g GPU) with RMRR reported. So instead, this
patch aims to setup identity mapping in p2m layer, regardless of
whether EPT is shared or not. And we still keep creating VT-d table.

CC: Yang Zhang <yang.z.zhang@xxxxxxxxx>
CC: Kevin Tian <kevin.tian@xxxxxxxxx>
Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxx>
---
v4:

* Instead of intel_iommu_unmap_page(), we should use
  guest_physmap_remove_page() to unmap rmrr mapping correctly. 

* Drop iommu_map_page() since actually ept_set_entry() can do this
  internally.

 xen/drivers/passthrough/vtd/iommu.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/xen/drivers/passthrough/vtd/iommu.c 
b/xen/drivers/passthrough/vtd/iommu.c
index 44ed23d..202b2d0 100644
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -1839,7 +1839,7 @@ static int rmrr_identity_mapping(struct domain *d, bool_t 
map,
 
             while ( base_pfn < end_pfn )
             {
-                if ( intel_iommu_unmap_page(d, base_pfn) )
+                if ( guest_physmap_remove_page(d, base_pfn, base_pfn, 0) )
                     ret = -ENXIO;
                 base_pfn++;
             }
@@ -1855,8 +1855,7 @@ static int rmrr_identity_mapping(struct domain *d, bool_t 
map,
 
     while ( base_pfn < end_pfn )
     {
-        int err = intel_iommu_map_page(d, base_pfn, base_pfn,
-                                       IOMMUF_readable|IOMMUF_writable);
+        int err = set_identity_p2m_entry(d, base_pfn, p2m_access_rw);
 
         if ( err )
             return err;
-- 
1.9.1


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