xref: /titanic_41/usr/src/uts/i86pc/os/hold_page.c (revision 71269a2275bf5a143dad6461eee2710a344e7261)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include <sys/hold_page.h>
30 
31 #if defined(__xpv)
32 #include <sys/hypervisor.h>
33 #endif
34 
35 /*ARGSUSED*/
36 int
37 plat_hold_page(pfn_t pfn, int lock, page_t **pp_ret)
38 {
39 #if defined(__xpv)
40 	page_t *pp = page_numtopp_nolock(pfn);
41 
42 	if (pp == NULL)
43 		return (PLAT_HOLD_FAIL);
44 
45 	if (lock == PLAT_HOLD_LOCK) {
46 		ASSERT(pp_ret != NULL);
47 		if (page_trylock(pp, SE_EXCL) == 0)
48 			return (PLAT_HOLD_FAIL);
49 	}
50 
51 	if (mfn_list[pfn] == MFN_INVALID) {
52 		/* We failed - release the lock if we grabbed it earlier */
53 		if (lock == PLAT_HOLD_LOCK) {
54 			page_unlock(pp);
55 		}
56 		return (PLAT_HOLD_FAIL);
57 	}
58 	if (lock == PLAT_HOLD_LOCK)
59 		*pp_ret = pp;
60 #endif	/* __xpv */
61 
62 	return (PLAT_HOLD_OK);
63 }
64 
65 /*ARGSUSED*/
66 void
67 plat_release_page(page_t *pp)
68 {
69 #if defined(__xpv)
70 	ASSERT((pp != NULL) && PAGE_LOCKED(pp));
71 	page_unlock(pp);
72 #endif
73 }
74