1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_VIRTIO_FEATURES_H
3 #define _LINUX_VIRTIO_FEATURES_H
4
5 #include <linux/bits.h>
6
7 #define VIRTIO_FEATURES_U64S 2
8 #define VIRTIO_FEATURES_BITS (VIRTIO_FEATURES_U64S * 64)
9
10 #define VIRTIO_BIT(b) BIT_ULL((b) & 0x3f)
11 #define VIRTIO_U64(b) ((b) >> 6)
12
13 #define VIRTIO_DECLARE_FEATURES(name) \
14 union { \
15 u64 name; \
16 u64 name##_array[VIRTIO_FEATURES_U64S];\
17 }
18
virtio_features_chk_bit(unsigned int bit)19 static inline bool virtio_features_chk_bit(unsigned int bit)
20 {
21 if (__builtin_constant_p(bit)) {
22 /*
23 * Don't care returning the correct value: the build
24 * will fail before any bad features access
25 */
26 BUILD_BUG_ON(bit >= VIRTIO_FEATURES_BITS);
27 } else {
28 if (WARN_ON_ONCE(bit >= VIRTIO_FEATURES_BITS))
29 return false;
30 }
31 return true;
32 }
33
virtio_features_test_bit(const u64 * features,unsigned int bit)34 static inline bool virtio_features_test_bit(const u64 *features,
35 unsigned int bit)
36 {
37 return virtio_features_chk_bit(bit) &&
38 !!(features[VIRTIO_U64(bit)] & VIRTIO_BIT(bit));
39 }
40
virtio_features_set_bit(u64 * features,unsigned int bit)41 static inline void virtio_features_set_bit(u64 *features,
42 unsigned int bit)
43 {
44 if (virtio_features_chk_bit(bit))
45 features[VIRTIO_U64(bit)] |= VIRTIO_BIT(bit);
46 }
47
virtio_features_clear_bit(u64 * features,unsigned int bit)48 static inline void virtio_features_clear_bit(u64 *features,
49 unsigned int bit)
50 {
51 if (virtio_features_chk_bit(bit))
52 features[VIRTIO_U64(bit)] &= ~VIRTIO_BIT(bit);
53 }
54
virtio_features_zero(u64 * features)55 static inline void virtio_features_zero(u64 *features)
56 {
57 memset(features, 0, sizeof(features[0]) * VIRTIO_FEATURES_U64S);
58 }
59
virtio_features_from_u64(u64 * features,u64 from)60 static inline void virtio_features_from_u64(u64 *features, u64 from)
61 {
62 virtio_features_zero(features);
63 features[0] = from;
64 }
65
virtio_features_equal(const u64 * f1,const u64 * f2)66 static inline bool virtio_features_equal(const u64 *f1, const u64 *f2)
67 {
68 int i;
69
70 for (i = 0; i < VIRTIO_FEATURES_U64S; ++i)
71 if (f1[i] != f2[i])
72 return false;
73 return true;
74 }
75
virtio_features_copy(u64 * to,const u64 * from)76 static inline void virtio_features_copy(u64 *to, const u64 *from)
77 {
78 memcpy(to, from, sizeof(to[0]) * VIRTIO_FEATURES_U64S);
79 }
80
virtio_features_andnot(u64 * to,const u64 * f1,const u64 * f2)81 static inline void virtio_features_andnot(u64 *to, const u64 *f1, const u64 *f2)
82 {
83 int i;
84
85 for (i = 0; i < VIRTIO_FEATURES_U64S; i++)
86 to[i] = f1[i] & ~f2[i];
87 }
88
89 #endif
90