hold_page.c revision 6eaf49db7995729511d1d890a498b9ae1150e9c5
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#include <sys/hold_page.h>
#if defined(__xpv)
#include <sys/hypervisor.h>
#endif
int
plat_hold_page(pfn_t pfn, int lock, page_t **pp_ret)
{
page_t *pp = page_numtopp_nolock(pfn);
if (pp == NULL)
return (PLAT_HOLD_FAIL);
#if !defined(__xpv)
/*
* Pages are locked SE_SHARED because some hypervisors
* like xVM ESX reclaim Guest OS memory by locking
* it SE_EXCL so we want to leave these pages alone.
*/
if (lock == PLAT_HOLD_LOCK) {
ASSERT(pp_ret != NULL);
if (page_trylock(pp, SE_SHARED) == 0)
return (PLAT_HOLD_FAIL);
}
#else /* __xpv */
if (lock == PLAT_HOLD_LOCK) {
ASSERT(pp_ret != NULL);
if (page_trylock(pp, SE_EXCL) == 0)
return (PLAT_HOLD_FAIL);
}
if (mfn_list[pfn] == MFN_INVALID) {
/* We failed - release the lock if we grabbed it earlier */
if (lock == PLAT_HOLD_LOCK) {
page_unlock(pp);
}
return (PLAT_HOLD_FAIL);
}
#endif /* __xpv */
if (lock == PLAT_HOLD_LOCK)
*pp_ret = pp;
return (PLAT_HOLD_OK);
}
void
plat_release_page(page_t *pp)
{
ASSERT((pp != NULL) && PAGE_LOCKED(pp));
page_unlock(pp);
}