xref: /freebsd/sys/dev/virtio/virtio_endian.h (revision 734e82fe33aa764367791a7d603b383996c6b40b)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2017, Bryan Venteicher <bryanv@FreeBSD.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice unmodified, this list of conditions, and the following
12  *    disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #ifndef _VIRTIO_ENDIAN_H_
30 #define _VIRTIO_ENDIAN_H_
31 
32 #include <sys/endian.h>
33 #ifndef _KERNEL
34 #include <stdbool.h>
35 #endif /* _KERNEL */
36 
37 /*
38  * VirtIO V1 (modern) uses little endian, while legacy VirtIO uses the guest's
39  * native endian. These functions convert to and from the Guest's (driver's)
40  * and the Host's (device's) endianness when needed.
41  */
42 
43 static inline uint16_t
44 virtio_htog16(bool modern, uint16_t val)
45 {
46 	if (modern)
47 		return (le16toh(val));
48 	else
49 		return (val);
50 }
51 
52 static inline uint16_t
53 virtio_gtoh16(bool modern, uint16_t val)
54 {
55 	if (modern)
56 		return (htole16(val));
57 	else
58 		return (val);
59 }
60 
61 static inline uint32_t
62 virtio_htog32(bool modern, uint32_t val)
63 {
64 	if (modern)
65 		return (le32toh(val));
66 	else
67 		return (val);
68 }
69 
70 static inline uint32_t
71 virtio_gtoh32(bool modern, uint32_t val)
72 {
73 	if (modern)
74 		return (htole32(val));
75 	else
76 		return (val);
77 }
78 
79 static inline uint64_t
80 virtio_htog64(bool modern, uint64_t val)
81 {
82 	if (modern)
83 		return (le64toh(val));
84 	else
85 		return (val);
86 }
87 
88 static inline uint64_t
89 virtio_gtoh64(bool modern, uint64_t val)
90 {
91 	if (modern)
92 		return (htole64(val));
93 	else
94 		return (val);
95 }
96 
97 #endif /* _VIRTIO_ENDIAN_H_ */
98