page-vary-common.c

   1 /*
   2  * Variable page size handling -- target independent part.
   3  *
   4  *  Copyright (c) 2003 Fabrice Bellard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #define IN_PAGE_VARY 1
  21
  22 #include "qemu/osdep.h"
  23 #include "exec/page-vary.h"
  24
  25 /* WARNING: This file must *not* be complied with -flto. */
  26
  27 TargetPageBits target_page;
  28
  29 bool set_preferred_target_page_bits_common(int bits)
  30 {
  31     /*
  32      * The target page size is the lowest common denominator for all
  33      * the CPUs in the system, so we can only make it smaller, never
  34      * larger. And we can't make it smaller once we've committed to
  35      * a particular size.
  36      */
  37     if (target_page.bits == 0 || target_page.bits > bits) {
  38         if (target_page.decided) {
  39             return false;
  40         }
  41         target_page.bits = bits;
  42     }
  43     return true;
  44 }
  45
  46 void finalize_target_page_bits_common(int min)
  47 {
  48     if (target_page.bits == 0) {
  49         target_page.bits = min;
  50     }
  51     target_page.mask = -1ull << target_page.bits;
  52     target_page.decided = true;
  53 }