diff mbox series

[v2,5/5] x86_64/mm: map and unmap page tables in destroy_m2p_mapping

Message ID 1f6bde6f67ef214a3d4ffa81f0c55c4416c8edd4.1586352238.git.hongyxia@amazon.com (mailing list archive)
State Superseded
Headers show
Series use new API for Xen page tables | expand

Commit Message

Hongyan Xia April 8, 2020, 1:36 p.m. UTC 
From: Wei Liu <wei.liu2@citrix.com>

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Hongyan Xia <hongyxia@amazon.com>

---
Changed in v2:
- no point in re-mapping l2t because it is exactly the same as
  l2_ro_mpt.
- point l2_ro_mpt to the entry instead of doing l2_table_offset() all
  the time.
---
 xen/arch/x86/x86_64/mm.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

Comments

Jan Beulich April 15, 2020, 8:32 a.m. UTC | #1 
On 08.04.2020 15:36, Hongyan Xia wrote:
> @@ -290,26 +291,30 @@ static void destroy_m2p_mapping(struct mem_hotadd_info *info)
>              continue;
>          }
>  
> -        l2_ro_mpt = l3e_to_l2e(l3_ro_mpt[l3_table_offset(va)]);
> -        if (!(l2e_get_flags(l2_ro_mpt[l2_table_offset(va)]) & _PAGE_PRESENT))
> +        l2_ro_mpt = map_l2t_from_l3e(l3_ro_mpt[l3_table_offset(va)]) +
> +                    l2_table_offset(va);

Either the name of the variable should be changed or you shouldn't
add in l2_table_offset(va) here. Personally I'd go with renaming
to just pl2e.

Jan
diff mbox series

Patch

diff --git a/xen/arch/x86/x86_64/mm.c b/xen/arch/x86/x86_64/mm.c
index ae8f4dd0b9..ec5269e7fc 100644
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -268,7 +268,8 @@  static void destroy_m2p_mapping(struct mem_hotadd_info *info)
     unsigned long i, va, rwva;
     unsigned long smap = info->spfn, emap = info->epfn;
 
-    l3_ro_mpt = l4e_to_l3e(idle_pg_table[l4_table_offset(RO_MPT_VIRT_START)]);
+    l3_ro_mpt = map_l3t_from_l4e(
+                    idle_pg_table[l4_table_offset(RO_MPT_VIRT_START)]);
 
     /*
      * No need to clean m2p structure existing before the hotplug
@@ -290,26 +291,30 @@  static void destroy_m2p_mapping(struct mem_hotadd_info *info)
             continue;
         }
 
-        l2_ro_mpt = l3e_to_l2e(l3_ro_mpt[l3_table_offset(va)]);
-        if (!(l2e_get_flags(l2_ro_mpt[l2_table_offset(va)]) & _PAGE_PRESENT))
+        l2_ro_mpt = map_l2t_from_l3e(l3_ro_mpt[l3_table_offset(va)]) +
+                    l2_table_offset(va);
+        if ( !(l2e_get_flags(*l2_ro_mpt) & _PAGE_PRESENT) )
         {
             i = ( i & ~((1UL << (L2_PAGETABLE_SHIFT - 3)) - 1)) +
                     (1UL << (L2_PAGETABLE_SHIFT - 3)) ;
+            UNMAP_DOMAIN_PAGE(l2_ro_mpt);
             continue;
         }
 
-        pt_pfn = l2e_get_pfn(l2_ro_mpt[l2_table_offset(va)]);
+        pt_pfn = l2e_get_pfn(*l2_ro_mpt);
         if ( hotadd_mem_valid(pt_pfn, info) )
         {
             destroy_xen_mappings(rwva, rwva + (1UL << L2_PAGETABLE_SHIFT));
 
-            l2_ro_mpt = l3e_to_l2e(l3_ro_mpt[l3_table_offset(va)]);
-            l2e_write(&l2_ro_mpt[l2_table_offset(va)], l2e_empty());
+            l2e_write(l2_ro_mpt, l2e_empty());
         }
         i = ( i & ~((1UL << (L2_PAGETABLE_SHIFT - 3)) - 1)) +
               (1UL << (L2_PAGETABLE_SHIFT - 3));
+        UNMAP_DOMAIN_PAGE(l2_ro_mpt);
     }
 
+    UNMAP_DOMAIN_PAGE(l3_ro_mpt);
+
     destroy_compat_m2p_mapping(info);
 
     /* Brute-Force flush all TLB */