[PATCH v7 09/15] efi: use new page table APIs in copy_mapping

From: Hongyan Xia <hx242@xen.org>
To: xen-devel@lists.xenproject.org
Cc: julien@xen.org, Jan Beulich <jbeulich@suse.com>
Subject: [PATCH v7 09/15] efi: use new page table APIs in copy_mapping
Date: Fri, 29 May 2020 12:11:53 +0100	[thread overview]
Message-ID: <0259b645c81ecc3879240e30760b0e7641a2b602.1590750232.git.hongyxia@amazon.com> (raw)
In-Reply-To: <cover.1590750232.git.hongyxia@amazon.com>
In-Reply-To: <cover.1590750232.git.hongyxia@amazon.com>

From: Wei Liu <wei.liu2@citrix.com>

After inspection ARM doesn't have alloc_xen_pagetable so this function
is x86 only, which means it is safe for us to change.

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

---
Changed in v7:
- hoist l3 variables out of the loop to avoid repetitive mappings.
---
 xen/common/efi/boot.c | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c
index a6f84c945a..2599ae50d2 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>
@@ -1442,29 +1443,42 @@ 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 << PAGE_SHIFT) & ((1UL << L4_PAGETABLE_SHIFT) - 1)) )
+        {
+            UNMAP_DOMAIN_PAGE(l3src);
+            UNMAP_DOMAIN_PAGE(l3dst);
+        }
         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 )
         {
-            l3dst = alloc_xen_pagetable();
-            BUG_ON(!l3dst);
-            clear_page(l3dst);
-            efi_l4_pgtable[l4_table_offset(mfn << PAGE_SHIFT)] =
-                l4e_from_paddr(virt_to_maddr(l3dst), __PAGE_HYPERVISOR);
+            if ( !(l4e_get_flags(l4e) & _PAGE_PRESENT) )
+            {
+                mfn_t l3mfn;
+
+                l3dst = alloc_map_clear_xen_pt(&l3mfn);
+                BUG_ON(!l3dst);
+                efi_l4_pgtable[l4_table_offset(mfn << PAGE_SHIFT)] =
+                    l4e_from_mfn(l3mfn, __PAGE_HYPERVISOR);
+            }
+            else
+                l3dst = map_l3t_from_l4e(l4e);
         }
-        else
-            l3dst = l4e_to_l3e(l4e);
-        l3src = l4e_to_l3e(idle_pg_table[l4_table_offset(va)]);
+        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)
-- 
2.24.1.AMZN


