Merge remote-tracking branch 'remotes/awilliam/tags/vfio-update-20210618.0' into...
[qemu.git] / 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 "qemu-common.h"
24 #include "exec/page-vary.h"
25
26 /* WARNING: This file must *not* be complied with -flto. */
27
28 TargetPageBits target_page;
29
30 bool set_preferred_target_page_bits_common(int bits)
31 {
32 /*
33 * The target page size is the lowest common denominator for all
34 * the CPUs in the system, so we can only make it smaller, never
35 * larger. And we can't make it smaller once we've committed to
36 * a particular size.
37 */
38 if (target_page.bits == 0 || target_page.bits > bits) {
39 if (target_page.decided) {
40 return false;
41 }
42 target_page.bits = bits;
43 }
44 return true;
45 }
46
47 void finalize_target_page_bits_common(int min)
48 {
49 if (target_page.bits == 0) {
50 target_page.bits = min;
51 }
52 target_page.mask = -1ull << target_page.bits;
53 target_page.decided = true;
54 }