[Qemu-devel] [5227] Make page_find() return 0 for too-large addresses (Eduardo Habkost)

[Qemu-devel] [5227] Make page_find() return 0 for too-large addresses (Eduardo Habkost)

[Anthony Liguori]

Revision: 5227
          http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=5227
Author:   aliguori
Date:     2008-09-15 15:56:30 +0000 (Mon, 15 Sep 2008)

Log Message:
-----------
Make page_find() return 0 for too-large addresses (Eduardo Habkost)

On some cases, such as under KVM, tb_invalidate_phys_page_range()
may be called for large addresses, when qemu is configured to more than
4GB of RAM.

On these cases, qemu was crashing because it was using an index too
large for l1_map[], that supports only 32-bit addresses when compiling
without CONFIG_USER_ONLY.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

Modified Paths:
--------------
    trunk/exec.c

Modified: trunk/exec.c
===================================================================
--- trunk/exec.c	2008-09-15 15:51:35 UTC (rev 5226)
+++ trunk/exec.c	2008-09-15 15:56:30 UTC (rev 5227)
@@ -279,17 +279,24 @@
 #endif
 }
 
-static inline PageDesc *page_find_alloc(target_ulong index)
+static inline PageDesc **page_l1_map(target_ulong index)
 {
-    PageDesc **lp, *p;
-
 #if TARGET_LONG_BITS > 32
     /* Host memory outside guest VM.  For 32-bit targets we have already
        excluded high addresses.  */
     if (index > ((target_ulong)L2_SIZE * L1_SIZE))
         return NULL;
 #endif
-    lp = &l1_map[index >> L2_BITS];
+    return &l1_map[index >> L2_BITS];
+}
+
+static inline PageDesc *page_find_alloc(target_ulong index)
+{
+    PageDesc **lp, *p;
+    lp = page_l1_map(index);
+    if (!lp)
+        return NULL;
+
     p = *lp;
     if (!p) {
         /* allocate if not found */
@@ -316,9 +323,12 @@
 
 static inline PageDesc *page_find(target_ulong index)
 {
-    PageDesc *p;
+    PageDesc **lp, *p;
+    lp = page_l1_map(index);
+    if (!lp)
+        return NULL;
 
-    p = l1_map[index >> L2_BITS];
+    p = *lp;
     if (!p)
         return 0;
     return p + (index & (L2_SIZE - 1));