1 files changed, 126 insertions, 0 deletions
diff --git a/include/hw/virtio/virtio-features.h b/include/hw/virtio/virtio-features.h
new file mode 100644
index 0000000..e29b7fe
--- /dev/null
+++ b/include/hw/virtio/virtio-features.h
@@ -0,0 +1,126 @@
+/*
+ * Virtio features helpers
+ *
+ * Copyright 2025 Red Hat, Inc.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef QEMU_VIRTIO_FEATURES_H
+#define QEMU_VIRTIO_FEATURES_H
+
+#include "qemu/bitops.h"
+
+#define VIRTIO_FEATURES_FMT        "%016"PRIx64"%016"PRIx64
+#define VIRTIO_FEATURES_PR(f)      (f)[1], (f)[0]
+
+#define VIRTIO_FEATURES_MAX        128
+#define VIRTIO_FEATURES_BIT(b)     BIT_ULL((b) % 64)
+#define VIRTIO_FEATURES_U64(b)     ((b) / 64)
+#define VIRTIO_FEATURES_NU32S      (VIRTIO_FEATURES_MAX / 32)
+#define VIRTIO_FEATURES_NU64S      (VIRTIO_FEATURES_MAX / 64)
+
+#define VIRTIO_DECLARE_FEATURES(name)                        \
+    union {                                                  \
+        uint64_t name;                                       \
+        uint64_t name##_ex[VIRTIO_FEATURES_NU64S];           \
+    }
+
+#define VIRTIO_DEFINE_PROP_FEATURE(_name, _state, _field, _bit, _defval)   \
+    DEFINE_PROP_BIT64(_name, _state, _field[VIRTIO_FEATURES_U64(_bit)],    \
+                      (_bit) % 64, _defval)
+
+static inline void virtio_features_clear(uint64_t *features)
+{
+    memset(features, 0, sizeof(features[0]) * VIRTIO_FEATURES_NU64S);
+}
+
+static inline void virtio_features_from_u64(uint64_t *features, uint64_t from)
+{
+    virtio_features_clear(features);
+    features[0] = from;
+}
+
+static inline bool virtio_has_feature_ex(const uint64_t *features,
+                                         unsigned int fbit)
+{
+    assert(fbit < VIRTIO_FEATURES_MAX);
+    return features[VIRTIO_FEATURES_U64(fbit)] & VIRTIO_FEATURES_BIT(fbit);
+}
+
+static inline void virtio_add_feature_ex(uint64_t *features,
+                                         unsigned int fbit)
+{
+    assert(fbit < VIRTIO_FEATURES_MAX);
+    features[VIRTIO_FEATURES_U64(fbit)] |= VIRTIO_FEATURES_BIT(fbit);
+}
+
+static inline void virtio_clear_feature_ex(uint64_t *features,
+                                           unsigned int fbit)
+{
+    assert(fbit < VIRTIO_FEATURES_MAX);
+    features[VIRTIO_FEATURES_U64(fbit)] &= ~VIRTIO_FEATURES_BIT(fbit);
+}
+
+static inline bool virtio_features_equal(const uint64_t *f1,
+                                         const uint64_t *f2)
+{
+    return !memcmp(f1, f2, sizeof(uint64_t) * VIRTIO_FEATURES_NU64S);
+}
+
+static inline bool virtio_features_use_ex(const uint64_t *features)
+{
+    int i;
+
+    for (i = 1; i < VIRTIO_FEATURES_NU64S; ++i) {
+        if (features[i]) {
+            return true;
+        }
+    }
+    return false;
+}
+
+static inline bool virtio_features_empty(const uint64_t *features)
+{
+    return !virtio_features_use_ex(features) && !features[0];
+}
+
+static inline void virtio_features_copy(uint64_t *to, const uint64_t *from)
+{
+    memcpy(to, from, sizeof(to[0]) * VIRTIO_FEATURES_NU64S);
+}
+
+static inline bool virtio_features_andnot(uint64_t *to, const uint64_t *f1,
+                                           const uint64_t *f2)
+{
+    uint64_t diff = 0;
+    int i;
+
+    for (i = 0; i < VIRTIO_FEATURES_NU64S; i++) {
+        to[i] = f1[i] & ~f2[i];
+        diff |= to[i];
+    }
+    return diff;
+}
+
+static inline void virtio_features_and(uint64_t *to, const uint64_t *f1,
+                                       const uint64_t *f2)
+{
+    int i;
+
+    for (i = 0; i < VIRTIO_FEATURES_NU64S; i++) {
+        to[i] = f1[i] & f2[i];
+    }
+}
+
+static inline void virtio_features_or(uint64_t *to, const uint64_t *f1,
+                                       const uint64_t *f2)
+{
+    int i;
+
+    for (i = 0; i < VIRTIO_FEATURES_NU64S; i++) {
+        to[i] = f1[i] | f2[i];
+    }
+}
+
+#endif