From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001
From: Zeng Chi <zengchi@kylinos.cn>
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 <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 scripts/Kconfig.include | 78 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 scripts/Kconfig.include

(limited to 'scripts/Kconfig.include')

diff --git a/scripts/Kconfig.include b/scripts/Kconfig.include
new file mode 100644
index 000000000..fc10671c2
--- /dev/null
+++ b/scripts/Kconfig.include
@@ -0,0 +1,78 @@
+# SPDX-License-Identifier: GPL-2.0-only
+# Kconfig helper macros
+
+# Convenient variables
+comma       := ,
+quote       := "
+squote      := '
+empty       :=
+space       := $(empty) $(empty)
+dollar      := $
+right_paren := )
+left_paren  := (
+
+# $(if-success,<command>,<then>,<else>)
+# Return <then> if <command> exits with 0, <else> otherwise.
+if-success = $(shell,{ $(1); } >/dev/null 2>&1 && echo "$(2)" || echo "$(3)")
+
+# $(success,<command>)
+# Return y if <command> exits with 0, n otherwise
+success = $(if-success,$(1),y,n)
+
+# $(failure,<command>)
+# Return n if <command> exits with 0, y otherwise
+failure = $(if-success,$(1),n,y)
+
+# $(cc-option,<flag>)
+# Return y if the compiler supports <flag>, n otherwise
+cc-option = $(success,trap "rm -rf .tmp_$$" EXIT; mkdir .tmp_$$; $(CC) -Werror $(CLANG_FLAGS) $(1) -c -x c /dev/null -o .tmp_$$/tmp.o)
+
+# $(ld-option,<flag>)
+# Return y if the linker supports <flag>, n otherwise
+ld-option = $(success,$(LD) -v $(1))
+
+# $(as-instr,<instr>)
+# Return y if the assembler supports <instr>, n otherwise
+as-instr = $(success,printf "%b\n" "$(1)" | $(CC) $(CLANG_FLAGS) $(2) -Wa$(comma)--fatal-warnings -c -x assembler-with-cpp -o /dev/null -)
+as-instr64 = $(as-instr,$(1),$(m64-flag))
+
+# check if $(CC) and $(LD) exist
+$(error-if,$(failure,command -v $(CC)),C compiler '$(CC)' not found)
+$(error-if,$(failure,command -v $(LD)),linker '$(LD)' not found)
+
+# Get the C compiler name, version, and error out if it is not supported.
+cc-info := $(shell,$(srctree)/scripts/cc-version.sh $(CC))
+$(error-if,$(success,test -z "$(cc-info)"),Sorry$(comma) this C compiler is not supported.)
+cc-name := $(shell,set -- $(cc-info) && echo $1)
+cc-version := $(shell,set -- $(cc-info) && echo $2)
+
+# Get the assembler name, version, and error out if it is not supported.
+as-info := $(shell,$(srctree)/scripts/as-version.sh $(CC) $(CLANG_FLAGS))
+$(error-if,$(success,test -z "$(as-info)"),Sorry$(comma) this assembler is not supported.)
+as-name := $(shell,set -- $(as-info) && echo $1)
+as-version := $(shell,set -- $(as-info) && echo $2)
+
+# Get the linker name, version, and error out if it is not supported.
+ld-info := $(shell,$(srctree)/scripts/ld-version.sh $(LD))
+$(error-if,$(success,test -z "$(ld-info)"),Sorry$(comma) this linker is not supported.)
+ld-name := $(shell,set -- $(ld-info) && echo $1)
+ld-version := $(shell,set -- $(ld-info) && echo $2)
+
+# machine bit flags
+#  $(m32-flag): -m32 if the compiler supports it, or an empty string otherwise.
+#  $(m64-flag): -m64 if the compiler supports it, or an empty string otherwise.
+cc-option-bit = $(if-success,$(CC) -Werror $(1) -E -x c /dev/null -o /dev/null,$(1))
+m32-flag := $(cc-option-bit,-m32)
+m64-flag := $(cc-option-bit,-m64)
+
+# Test whether the compiler can link userspace applications
+cc_can_link_user = $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(1))
+
+rustc-version := $(shell,$(srctree)/scripts/rustc-version.sh $(RUSTC))
+rustc-llvm-version := $(shell,$(srctree)/scripts/rustc-llvm-version.sh $(RUSTC))
+
+# $(rustc-option,<flag>)
+# Return y if the Rust compiler supports <flag>, n otherwise
+# If you are testing for unstable features, consider testing RUSTC_VERSION
+# instead, as features may have different completeness while available.
+rustc-option = $(success,trap "rm -rf .tmp_$$" EXIT; mkdir .tmp_$$; $(RUSTC) $(1) --crate-type=rlib /dev/null --out-dir=.tmp_$$ -o .tmp_$$/tmp.rlib)
-- 
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