[Qemu-devel] Patch: ptable calculation broken for 32bit code under x86_64

[Bernhard Kauer]

The calculation of pdpe and pde addresses is broken, when running 32bit
code under x86_64-qemu. The code assumes that the addr parameter is 32bit
wide. This assumption does not hold for x86_64 as target.

        Bernhard Kauer


Index: target-i386/helper2.c
===================================================================
RCS file: /sources/qemu/qemu/target-i386/helper2.c,v
retrieving revision 1.46
diff -u -r1.46 helper2.c
--- target-i386/helper2.c	7 Apr 2007 11:21:28 -0000	1.46
+++ target-i386/helper2.c	10 Apr 2007 13:28:02 -0000
@@ -670,7 +670,7 @@
 #endif
         {
             /* XXX: load them when cr3 is loaded ? */
-            pdpe_addr = ((env->cr[3] & ~0x1f) + ((addr >> 30) << 3)) & 
+            pdpe_addr = ((env->cr[3] & ~0x1f) + ((addr >> 27) & 0x18)) & 
                 env->a20_mask;
             pdpe = ldq_phys(pdpe_addr);
             if (!(pdpe & PG_PRESENT_MASK)) {
@@ -765,7 +765,7 @@
         uint32_t pde;
 
         /* page directory entry */
-        pde_addr = ((env->cr[3] & ~0xfff) + ((addr >> 20) & ~3)) & 
+        pde_addr = ((env->cr[3] & ~0xfff) + ((addr >> 20) & 0xffc)) & 
             env->a20_mask;
         pde = ldl_phys(pde_addr);
         if (!(pde & PG_PRESENT_MASK)) {
@@ -910,7 +910,7 @@
         } else 
 #endif
         {
-            pdpe_addr = ((env->cr[3] & ~0x1f) + ((addr >> 30) << 3)) & 
+            pdpe_addr = ((env->cr[3] & ~0x1f) + ((addr >> 27) & 0x18)) & 
                 env->a20_mask;
             pdpe = ldl_phys(pdpe_addr);
             if (!(pdpe & PG_PRESENT_MASK))
@@ -940,7 +940,7 @@
             page_size = 4096;
         } else {
             /* page directory entry */
-            pde_addr = ((env->cr[3] & ~0xfff) + ((addr >> 20) & ~3)) & env->a20_mask;
+            pde_addr = ((env->cr[3] & ~0xfff) + ((addr >> 20) & 0xffc)) & env->a20_mask;
             pde = ldl_phys(pde_addr);
             if (!(pde & PG_PRESENT_MASK)) 
                 return -1;