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 2009 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 #include <sys/hold_page.h>
28
29 #if defined(__xpv)
30 #include <sys/hypervisor.h>
31 #endif
32
33 int
plat_hold_page(pfn_t pfn,int lock,page_t ** pp_ret)34 plat_hold_page(pfn_t pfn, int lock, page_t **pp_ret)
35 {
36 page_t *pp = page_numtopp_nolock(pfn);
37
38 if (pp == NULL)
39 return (PLAT_HOLD_FAIL);
40
41 #if !defined(__xpv)
42 /*
43 * Pages are locked SE_SHARED because some hypervisors
44 * like xVM ESX reclaim Guest OS memory by locking
45 * it SE_EXCL so we want to leave these pages alone.
46 */
47 if (lock == PLAT_HOLD_LOCK) {
48 ASSERT(pp_ret != NULL);
49 if (page_trylock(pp, SE_SHARED) == 0)
50 return (PLAT_HOLD_FAIL);
51 }
52 #else /* __xpv */
53 if (lock == PLAT_HOLD_LOCK) {
54 ASSERT(pp_ret != NULL);
55 if (page_trylock(pp, SE_EXCL) == 0)
56 return (PLAT_HOLD_FAIL);
57 }
58
59 if (mfn_list[pfn] == MFN_INVALID) {
60 /* We failed - release the lock if we grabbed it earlier */
61 if (lock == PLAT_HOLD_LOCK) {
62 page_unlock(pp);
63 }
64 return (PLAT_HOLD_FAIL);
65 }
66 #endif /* __xpv */
67
68 if (lock == PLAT_HOLD_LOCK)
69 *pp_ret = pp;
70
71 return (PLAT_HOLD_OK);
72 }
73
74 void
plat_release_page(page_t * pp)75 plat_release_page(page_t *pp)
76 {
77 ASSERT((pp != NULL) && PAGE_LOCKED(pp));
78 page_unlock(pp);
79 }
80