[Xen-devel] [PATCH v2 3/3] x86/mm: subsume set_gpfn_from_mfn() into guest_physmap_add_page()

["Jan Beulich" <JBeulich@xxxxxxxx>]

The two callers in common/memory.c currently call set_gpfn_from_mfn()
themselves, so moving the call into guest_physmap_add_page() helps
tidy their code.

The two callers in common/grant_table.c fail to make that call alongside
the one to guest_physmap_add_page(), so will actually get fixed by the
change.

Other (x86) callers are HVM only and are hence unaffected by a change
to the function's !paging_mode_translate() part.

Sadly this isn't enough yet to drop Arm's dummy macro, as there's one
more use in page_alloc.c.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Acked-by: Julien Grall <julien.grall@xxxxxxx>
---
v2: Re-base over added earlier patch. Re-write description.

--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -833,15 +833,16 @@ guest_physmap_add_page(struct domain *d,
          * any guest-requested type changes succeed and remove the IOMMU
          * entry).
          */
-        if ( !need_iommu_pt_sync(d) )
-            return 0;
-
         for ( i = 0; i < (1UL << page_order); ++i, ++page )
         {
-            if ( get_page_and_type(page, d, PGT_writable_page) )
+            if ( !need_iommu_pt_sync(d) )
+                /* nothing */;
+            else if ( get_page_and_type(page, d, PGT_writable_page) )
                 put_page_and_type(page);
             else
                 return -EINVAL;
+
+            set_gpfn_from_mfn(mfn_x(mfn) + i, gfn_x(gfn) + i);
         }
 
         return 0;
--- a/xen/common/memory.c
+++ b/xen/common/memory.c
@@ -270,16 +270,10 @@ static void populate_physmap(struct memo
 
             guest_physmap_add_page(d, _gfn(gpfn), mfn, a->extent_order);
 
-            if ( !paging_mode_translate(d) )
-            {
-                for ( j = 0; j < (1U << a->extent_order); j++ )
-                    set_gpfn_from_mfn(mfn_x(mfn_add(mfn, j)), gpfn + j);
-
-                /* Inform the domain of the new page's machine address. */ 
-                if ( unlikely(__copy_mfn_to_guest_offset(a->extent_list, i,
-                                                         mfn)) )
-                    goto out;
-            }
+            if ( !paging_mode_translate(d) &&
+                 /* Inform the domain of the new page's machine address. */
+                 unlikely(__copy_mfn_to_guest_offset(a->extent_list, i, mfn)) )
+                goto out;
         }
     }
 
@@ -755,15 +749,11 @@ static long memory_exchange(XEN_GUEST_HA
             guest_physmap_add_page(d, _gfn(gpfn), mfn,
                                    exch.out.extent_order);
 
-            if ( !paging_mode_translate(d) )
-            {
-                for ( k = 0; k < (1UL << exch.out.extent_order); k++ )
-                    set_gpfn_from_mfn(mfn_x(mfn_add(mfn, k)), gpfn + k);
-                if ( __copy_mfn_to_guest_offset(exch.out.extent_start,
-                                                (i << out_chunk_order) + j,
-                                                mfn) )
-                    rc = -EFAULT;
-            }
+            if ( !paging_mode_translate(d) &&
+                 __copy_mfn_to_guest_offset(exch.out.extent_start,
+                                            (i << out_chunk_order) + j,
+                                            mfn) )
+                rc = -EFAULT;
         }
         BUG_ON( !(d->is_dying) && (j != (1UL << out_chunk_order)) );
 





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