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 --- scripts/Makefile.kcsan | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) create mode 100644 scripts/Makefile.kcsan (limited to 'scripts/Makefile.kcsan') diff --git a/scripts/Makefile.kcsan b/scripts/Makefile.kcsan new file mode 100644 index 000000000..19f693b68 --- /dev/null +++ b/scripts/Makefile.kcsan @@ -0,0 +1,26 @@ +# SPDX-License-Identifier: GPL-2.0 +# GCC and Clang accept backend options differently. Do not wrap in cc-option, +# because Clang accepts "--param" even if it is unused. +ifdef CONFIG_CC_IS_CLANG +cc-param = -mllvm -$(1) +else +cc-param = --param $(1) +endif + +# Keep most options here optional, to allow enabling more compilers if absence +# of some options does not break KCSAN nor causes false positive reports. +kcsan-cflags := -fsanitize=thread -fno-optimize-sibling-calls \ + $(call cc-option,$(call cc-param,tsan-compound-read-before-write=1),$(call cc-option,$(call cc-param,tsan-instrument-read-before-write=1))) \ + $(call cc-param,tsan-distinguish-volatile=1) + +ifdef CONFIG_CC_IS_GCC +# GCC started warning about operations unsupported by the TSan runtime. But +# KCSAN != TSan, so just ignore these warnings. +kcsan-cflags += -Wno-tsan +endif + +ifndef CONFIG_KCSAN_WEAK_MEMORY +kcsan-cflags += $(call cc-option,$(call cc-param,tsan-instrument-func-entry-exit=0)) +endif + +export CFLAGS_KCSAN := $(kcsan-cflags) -- cgit v1.3.1