xref: /openbmc/qemu/page-vary-common.c (revision d0bf492f)
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 }
54