KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted

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>

1 files changed, 167 insertions, 0 deletions

diff --git a/scripts/Makefile.modinst b/scripts/Makefile.modinst
new file mode 100644
index 000000000..9ba45e5b3
--- /dev/null
+++ b/scripts/Makefile.modinst
@@ -0,0 +1,167 @@
+# SPDX-License-Identifier: GPL-2.0
+# ==========================================================================
+# Installing modules
+# ==========================================================================
+
+PHONY := __modinst
+__modinst:
+
+include $(objtree)/include/config/auto.conf
+include $(srctree)/scripts/Kbuild.include
+
+install-y :=
+
+ifeq ($(KBUILD_EXTMOD)$(sign-only),)
+
+# remove the old directory and symlink
+$(shell rm -fr $(MODLIB)/kernel $(MODLIB)/build)
+
+install-$(CONFIG_MODULES) += $(addprefix $(MODLIB)/, build modules.order)
+
+$(MODLIB)/build: FORCE
+	$(call cmd,symlink)
+
+quiet_cmd_symlink = SYMLINK $@
+      cmd_symlink = ln -s $(CURDIR) $@
+
+$(MODLIB)/modules.order: modules.order FORCE
+	$(call cmd,install_modorder)
+
+quiet_cmd_install_modorder = INSTALL $@
+      cmd_install_modorder = sed 's:^\(.*\)\.o$$:kernel/\1.ko:' $< > $@
+
+# Install modules.builtin(.modinfo,.ranges) even when CONFIG_MODULES is disabled.
+install-y += $(addprefix $(MODLIB)/, modules.builtin modules.builtin.modinfo)
+
+install-$(CONFIG_BUILTIN_MODULE_RANGES) += $(MODLIB)/modules.builtin.ranges
+
+$(addprefix $(MODLIB)/, modules.builtin modules.builtin.modinfo modules.builtin.ranges): $(MODLIB)/%: % FORCE
+	$(call cmd,install)
+
+endif
+
+modules := $(call read-file, modules.order)
+
+ifeq ($(KBUILD_EXTMOD),)
+dst := $(MODLIB)/kernel
+else
+INSTALL_MOD_DIR ?= updates
+dst := $(MODLIB)/$(INSTALL_MOD_DIR)
+endif
+
+$(foreach x, % :, $(if $(findstring $x, $(dst)), \
+	$(error module installation path cannot contain '$x')))
+
+suffix-y				:=
+ifdef CONFIG_MODULE_COMPRESS_ALL
+suffix-$(CONFIG_MODULE_COMPRESS_GZIP)	:= .gz
+suffix-$(CONFIG_MODULE_COMPRESS_XZ)	:= .xz
+suffix-$(CONFIG_MODULE_COMPRESS_ZSTD)	:= .zst
+endif
+
+modules := $(patsubst %.o, $(dst)/%.ko$(suffix-y), $(modules))
+install-$(CONFIG_MODULES) += $(modules)
+
+__modinst: $(install-y)
+	@:
+
+#
+# Installation
+#
+quiet_cmd_install = INSTALL $@
+      cmd_install = cp $< $@
+
+# Strip
+#
+# INSTALL_MOD_STRIP, if defined, will cause modules to be stripped after they
+# are installed. If INSTALL_MOD_STRIP is '1', then the default option
+# --strip-debug will be used. Otherwise, INSTALL_MOD_STRIP value will be used
+# as the options to the strip command.
+ifdef INSTALL_MOD_STRIP
+
+ifeq ($(INSTALL_MOD_STRIP),1)
+strip-option := --strip-debug
+else
+strip-option := $(INSTALL_MOD_STRIP)
+endif
+
+quiet_cmd_strip = STRIP   $@
+      cmd_strip = $(STRIP) $(strip-option) $@
+
+else
+
+quiet_cmd_strip =
+      cmd_strip = :
+
+endif
+
+#
+# Signing
+# Don't stop modules_install even if we can't sign external modules.
+#
+ifeq ($(filter pkcs11:%, $(CONFIG_MODULE_SIG_KEY)),)
+sig-key := $(if $(wildcard $(CONFIG_MODULE_SIG_KEY)),,$(objtree)/)$(CONFIG_MODULE_SIG_KEY)
+else
+sig-key := $(CONFIG_MODULE_SIG_KEY)
+endif
+quiet_cmd_sign = SIGN    $@
+      cmd_sign = $(objtree)/scripts/sign-file $(CONFIG_MODULE_SIG_HASH) "$(sig-key)" $(objtree)/certs/signing_key.x509 $@ \
+                 $(if $(KBUILD_EXTMOD),|| true)
+
+ifeq ($(sign-only),)
+
+# During modules_install, modules are signed only when CONFIG_MODULE_SIG_ALL=y.
+ifndef CONFIG_MODULE_SIG_ALL
+quiet_cmd_sign :=
+      cmd_sign := :
+endif
+
+# Create necessary directories
+$(foreach dir, $(sort $(dir $(install-y))), $(shell mkdir -p $(dir)))
+
+$(dst)/%.ko: %.ko FORCE
+	$(call cmd,install)
+	$(call cmd,strip)
+	$(call cmd,sign)
+
+ifdef CONFIG_MODULES
+__modinst: depmod
+
+PHONY += depmod
+depmod: $(install-y)
+	$(call cmd,depmod)
+
+quiet_cmd_depmod = DEPMOD  $(MODLIB)
+      cmd_depmod = $(srctree)/scripts/depmod.sh $(KERNELRELEASE)
+endif
+
+else
+
+$(dst)/%.ko: FORCE
+	$(call cmd,sign)
+
+endif
+
+#
+# Compression
+#
+quiet_cmd_gzip = GZIP    $@
+      cmd_gzip = $(KGZIP) -n -f $<
+quiet_cmd_xz = XZ      $@
+      cmd_xz = $(XZ) --check=crc32 --lzma2=dict=1MiB -f $<
+quiet_cmd_zstd = ZSTD    $@
+      cmd_zstd = $(ZSTD) --rm -f -q $<
+
+$(dst)/%.ko.gz: $(dst)/%.ko FORCE
+	$(call cmd,gzip)
+
+$(dst)/%.ko.xz: $(dst)/%.ko FORCE
+	$(call cmd,xz)
+
+$(dst)/%.ko.zst: $(dst)/%.ko FORCE
+	$(call cmd,zstd)
+
+PHONY += FORCE
+FORCE:
+
+.PHONY: $(PHONY)