| 1 |
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| 2 | #ifndef _LINUX_VIRTIO_FEATURES_H
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| 3 | #define _LINUX_VIRTIO_FEATURES_H
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| 4 |
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| 5 | #include <linux/bits.h>
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| 6 | #include <linux/bug.h>
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| 7 | #include <linux/string.h>
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| 8 |
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| 9 | #define VIRTIO_FEATURES_U64S 2
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| 10 | #define VIRTIO_FEATURES_BITS (VIRTIO_FEATURES_U64S * 64)
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| 11 |
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| 12 | #define VIRTIO_BIT(b) BIT_ULL((b) & 0x3f)
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| 13 | #define VIRTIO_U64(b) ((b) >> 6)
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| 14 |
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| 15 | #define VIRTIO_DECLARE_FEATURES(name) \
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| 16 | union { \
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| 17 | u64 name; \
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| 18 | u64 name##_array[VIRTIO_FEATURES_U64S];\
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| 19 | }
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| 20 |
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| 21 | static inline bool virtio_features_chk_bit(unsigned int bit)
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| 22 | {
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| 23 | if (__builtin_constant_p(bit)) {
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| 24 | |
| 25 | * Don't care returning the correct value: the build
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| 26 | * will fail before any bad features access
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| 27 |
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| 28 | BUILD_BUG_ON(bit >= VIRTIO_FEATURES_BITS);
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| 29 | } else {
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| 30 | if (WARN_ON_ONCE(bit >= VIRTIO_FEATURES_BITS))
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| 31 | return false;
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| 32 | }
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| 33 | return true;
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| 34 | }
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| 35 |
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| 36 | static inline bool virtio_features_test_bit(const u64 *features,
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| 37 | unsigned int bit)
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| 38 | {
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| 39 | return virtio_features_chk_bit(bit) &&
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| 40 | !!(features[VIRTIO_U64(bit)] & VIRTIO_BIT(bit));
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| 41 | }
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| 42 |
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| 43 | static inline void virtio_features_set_bit(u64 *features,
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| 44 | unsigned int bit)
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| 45 | {
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| 46 | if (virtio_features_chk_bit(bit))
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| 47 | features[VIRTIO_U64(bit)] |= VIRTIO_BIT(bit);
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| 48 | }
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| 49 |
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| 50 | static inline void virtio_features_clear_bit(u64 *features,
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| 51 | unsigned int bit)
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| 52 | {
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| 53 | if (virtio_features_chk_bit(bit))
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| 54 | features[VIRTIO_U64(bit)] &= ~VIRTIO_BIT(bit);
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| 55 | }
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| 56 |
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| 57 | static inline void virtio_features_zero(u64 *features)
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| 58 | {
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| 59 | memset(features, 0, sizeof(features[0]) * VIRTIO_FEATURES_U64S);
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| 60 | }
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| 61 |
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| 62 | static inline void virtio_features_from_u64(u64 *features, u64 from)
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| 63 | {
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| 64 | virtio_features_zero(features);
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| 65 | features[0] = from;
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| 66 | }
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| 67 |
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| 68 | static inline bool virtio_features_equal(const u64 *f1, const u64 *f2)
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| 69 | {
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| 70 | int i;
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| 71 |
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| 72 | for (i = 0; i < VIRTIO_FEATURES_U64S; ++i)
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| 73 | if (f1[i] != f2[i])
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| 74 | return false;
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| 75 | return true;
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| 76 | }
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| 77 |
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| 78 | static inline void virtio_features_copy(u64 *to, const u64 *from)
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| 79 | {
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| 80 | memcpy(to, from, sizeof(to[0]) * VIRTIO_FEATURES_U64S);
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| 81 | }
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| 82 |
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| 83 | static inline void virtio_features_andnot(u64 *to, const u64 *f1, const u64 *f2)
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| 84 | {
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| 85 | int i;
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| 86 |
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| 87 | for (i = 0; i < VIRTIO_FEATURES_U64S; i++)
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| 88 | to[i] = f1[i] & ~f2[i];
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| 89 | }
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| 90 |
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| 91 | #endif
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