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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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e7d4c1c5a5
The virtio specifications allows for up to 128 bits for the device features. Soon we are going to use some of the 'extended' bits features (above 64) for the virtio_net driver. Introduce extended features as a fixed size array of u64. To minimize the diffstat allows legacy driver to access the low 64 bits via a transparent union. Introduce an extended get_extended_features configuration callback that devices supporting the extended features range must implement in place of the traditional one. Note that legacy and transport features don't need any change, as they are always in the low 64 bit range. Acked-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
89 lines
2.1 KiB
C
89 lines
2.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_VIRTIO_FEATURES_H
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#define _LINUX_VIRTIO_FEATURES_H
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#include <linux/bits.h>
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#define VIRTIO_FEATURES_DWORDS 2
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#define VIRTIO_FEATURES_MAX (VIRTIO_FEATURES_DWORDS * 64)
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#define VIRTIO_FEATURES_WORDS (VIRTIO_FEATURES_DWORDS * 2)
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#define VIRTIO_BIT(b) BIT_ULL((b) & 0x3f)
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#define VIRTIO_DWORD(b) ((b) >> 6)
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#define VIRTIO_DECLARE_FEATURES(name) \
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union { \
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u64 name; \
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u64 name##_array[VIRTIO_FEATURES_DWORDS];\
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}
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static inline bool virtio_features_chk_bit(unsigned int bit)
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{
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if (__builtin_constant_p(bit)) {
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/*
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* Don't care returning the correct value: the build
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* will fail before any bad features access
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*/
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BUILD_BUG_ON(bit >= VIRTIO_FEATURES_MAX);
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} else {
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if (WARN_ON_ONCE(bit >= VIRTIO_FEATURES_MAX))
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return false;
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}
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return true;
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}
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static inline bool virtio_features_test_bit(const u64 *features,
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unsigned int bit)
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{
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return virtio_features_chk_bit(bit) &&
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!!(features[VIRTIO_DWORD(bit)] & VIRTIO_BIT(bit));
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}
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static inline void virtio_features_set_bit(u64 *features,
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unsigned int bit)
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{
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if (virtio_features_chk_bit(bit))
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features[VIRTIO_DWORD(bit)] |= VIRTIO_BIT(bit);
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}
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static inline void virtio_features_clear_bit(u64 *features,
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unsigned int bit)
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{
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if (virtio_features_chk_bit(bit))
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features[VIRTIO_DWORD(bit)] &= ~VIRTIO_BIT(bit);
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}
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static inline void virtio_features_zero(u64 *features)
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{
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memset(features, 0, sizeof(features[0]) * VIRTIO_FEATURES_DWORDS);
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}
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static inline void virtio_features_from_u64(u64 *features, u64 from)
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{
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virtio_features_zero(features);
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features[0] = from;
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}
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static inline bool virtio_features_equal(const u64 *f1, const u64 *f2)
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{
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int i;
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for (i = 0; i < VIRTIO_FEATURES_DWORDS; ++i)
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if (f1[i] != f2[i])
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return false;
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return true;
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}
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static inline void virtio_features_copy(u64 *to, const u64 *from)
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{
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memcpy(to, from, sizeof(to[0]) * VIRTIO_FEATURES_DWORDS);
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}
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static inline void virtio_features_andnot(u64 *to, const u64 *f1, const u64 *f2)
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{
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int i;
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for (i = 0; i < VIRTIO_FEATURES_DWORDS; i++)
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to[i] = f1[i] & ~f2[i];
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}
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#endif
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