page-vary-common.c

/*
 * Variable page size handling -- target independent part.
 *
 *  Copyright (c) 2003 Fabrice Bellard
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
 */

#define IN_PAGE_VARY 1

#include "qemu/osdep.h"
#include "qemu/target-info-def.h"
#include "exec/page-vary.h"

/* WARNING: This file must *not* be complied with -flto. */

TargetPageBits target_page;

bool set_preferred_target_page_bits(int bits)
{
    const TargetInfo *ti = target_info();

    assert(bits >= TARGET_PAGE_BITS_MIN);
    if (ti->page_bits_vary) {

        /*
         * The target page size is the lowest common denominator for all
         * the CPUs in the system, so we can only make it smaller, never
         * larger. And we can't make it smaller once we've committed to
         * a particular size.
         */
        if (target_page.bits == 0 || target_page.bits > bits) {
            if (target_page.decided) {
                return false;
            }
            target_page.bits = bits;
        }
    }
    return true;
}

void finalize_target_page_bits(void)
{
    int bits = target_page.bits;

    if (bits == 0) {
        const TargetInfo *ti = target_info();

        bits = ti->page_bits_init;
        assert(bits != 0);
        target_page.bits = bits;
    }

    target_page.mask = -1ull << bits;
    target_page.decided = true;
}