[v9,07/13] efi: use new page table APIs in copy_mapping

Commit Message

Hongyan Xia April 6, 2021, 11:05 a.m. UTC

From: Wei Liu <[e-mail]>

Signed-off-by: Wei Liu <[e-mail]>
Signed-off-by: Hongyan Xia <[e-mail]>
Reviewed-by: Jan Beulich <[e-mail]>

---
Changed in v8:
- remove redundant commit message.
- unmap l3src based on va instead of mfn.
- re-structure if condition around l3dst.

Changed in v7:
- hoist l3 variables out of the loop to avoid repetitive mappings.
---
 xen/common/efi/boot.c | 28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

Patch

diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c
index 63e289ab8506..64b319d0013b 100644
--- a/xen/common/efi/boot.c
+++ b/xen/common/efi/boot.c
@@ -6,6 +6,7 @@ 
 #include <xen/compile.h>
 #include <xen/ctype.h>
 #include <xen/dmi.h>
+#include <xen/domain_page.h>
 #include <xen/init.h>
 #include <xen/keyhandler.h>
 #include <xen/lib.h>
@@ -1439,29 +1440,42 @@  static __init void copy_mapping(unsigned long mfn, unsigned long end,
                                                  unsigned long emfn))
 {
     unsigned long next;
+    l3_pgentry_t *l3src = NULL, *l3dst = NULL;
 
     for ( ; mfn < end; mfn = next )
     {
         l4_pgentry_t l4e = efi_l4_pgtable[l4_table_offset(mfn << PAGE_SHIFT)];
-        l3_pgentry_t *l3src, *l3dst;
         unsigned long va = (unsigned long)mfn_to_virt(mfn);
 
+        if ( !(mfn & ((1UL << (L4_PAGETABLE_SHIFT - PAGE_SHIFT)) - 1)) )
+            UNMAP_DOMAIN_PAGE(l3dst);
+        if ( !(va & ((1UL << L4_PAGETABLE_SHIFT) - 1)) )
+            UNMAP_DOMAIN_PAGE(l3src);
         next = mfn + (1UL << (L3_PAGETABLE_SHIFT - PAGE_SHIFT));
         if ( !is_valid(mfn, min(next, end)) )
             continue;
-        if ( !(l4e_get_flags(l4e) & _PAGE_PRESENT) )
+
+        if ( l3dst )
+            /* nothing */;
+        else if ( !(l4e_get_flags(l4e) & _PAGE_PRESENT) )
         {
-            l3dst = alloc_xen_pagetable();
+            mfn_t l3mfn;
+
+            l3dst = alloc_map_clear_xen_pt(&l3mfn);
             BUG_ON(!l3dst);
-            clear_page(l3dst);
             efi_l4_pgtable[l4_table_offset(mfn << PAGE_SHIFT)] =
-                l4e_from_paddr(virt_to_maddr(l3dst), __PAGE_HYPERVISOR);
+                l4e_from_mfn(l3mfn, __PAGE_HYPERVISOR);
         }
         else
-            l3dst = l4e_to_l3e(l4e);
-        l3src = l4e_to_l3e(idle_pg_table[l4_table_offset(va)]);
+            l3dst = map_l3t_from_l4e(l4e);
+
+        if ( !l3src )
+            l3src = map_l3t_from_l4e(idle_pg_table[l4_table_offset(va)]);
         l3dst[l3_table_offset(mfn << PAGE_SHIFT)] = l3src[l3_table_offset(va)];
     }
+
+    unmap_domain_page(l3src);
+    unmap_domain_page(l3dst);
 }
 
 static bool __init ram_range_valid(unsigned long smfn, unsigned long emfn)