From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- include/asm-generic/bitops/fls64.h | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 include/asm-generic/bitops/fls64.h (limited to 'include/asm-generic/bitops/fls64.h') diff --git a/include/asm-generic/bitops/fls64.h b/include/asm-generic/bitops/fls64.h new file mode 100644 index 000000000..b5f58dd26 --- /dev/null +++ b/include/asm-generic/bitops/fls64.h @@ -0,0 +1,37 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_GENERIC_BITOPS_FLS64_H_ +#define _ASM_GENERIC_BITOPS_FLS64_H_ + +#include + +/** + * fls64 - find last set bit in a 64-bit word + * @x: the word to search + * + * This is defined in a similar way as the libc and compiler builtin + * ffsll, but returns the position of the most significant set bit. + * + * fls64(value) returns 0 if value is 0 or the position of the last + * set bit if value is nonzero. The last (most significant) bit is + * at position 64. + */ +#if BITS_PER_LONG == 32 +static __always_inline __attribute_const__ int fls64(__u64 x) +{ + __u32 h = x >> 32; + if (h) + return fls(h) + 32; + return fls(x); +} +#elif BITS_PER_LONG == 64 +static __always_inline __attribute_const__ int fls64(__u64 x) +{ + if (x == 0) + return 0; + return __fls(x) + 1; +} +#else +#error BITS_PER_LONG not 32 or 64 +#endif + +#endif /* _ASM_GENERIC_BITOPS_FLS64_H_ */ -- cgit v1.3.1