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, 134 insertions, 0 deletions

diff --git a/arch/m68k/Makefile b/arch/m68k/Makefile
new file mode 100644
index 000000000..0abcf994c
--- /dev/null
+++ b/arch/m68k/Makefile
@@ -0,0 +1,134 @@
+#
+# m68k/Makefile
+#
+# This file is included by the global makefile so that you can add your own
+# architecture-specific flags and dependencies.
+#
+# This file is subject to the terms and conditions of the GNU General Public
+# License.  See the file "COPYING" in the main directory of this archive
+# for more details.
+#
+# Copyright (C) 1994 by Hamish Macdonald
+# Copyright (C) 2002,2011 Greg Ungerer <gerg@snapgear.com>
+#
+
+KBUILD_DEFCONFIG := multi_defconfig
+
+ifdef cross_compiling
+    ifeq ($(CROSS_COMPILE),)
+		CROSS_COMPILE := $(call cc-cross-prefix, \
+			m68k-linux-gnu- m68k-linux- m68k-unknown-linux-gnu-)
+    endif
+endif
+
+#
+#	Enable processor type. Ordering of these is important - we want to
+#	use the minimum processor type of the range we support. The logic
+#	for 680x0 will only allow use of the -m68060 or -m68040 if no other
+#	680x0 type is specified - and no option is specified for 68030 or
+#	68020. The other m68k/ColdFire types always specify some type of
+#	compiler cpu type flag.
+#
+ifndef CONFIG_M68040
+cpuflags-$(CONFIG_M68060)	= -m68060
+endif
+ifndef CONFIG_M68060
+cpuflags-$(CONFIG_M68040)	= -m68040
+endif
+cpuflags-$(CONFIG_M68030)	=
+cpuflags-$(CONFIG_M68020)	=
+cpuflags-$(CONFIG_M68000)	= -m68000
+cpuflags-$(CONFIG_M5441x)	= $(call cc-option,-mcpu=54455,-mcfv4e)
+cpuflags-$(CONFIG_M54xx)	= $(call cc-option,-mcpu=5475,-m5200)
+cpuflags-$(CONFIG_M5407)	= $(call cc-option,-mcpu=5407,-m5200)
+cpuflags-$(CONFIG_M532x)	= $(call cc-option,-mcpu=532x,-m5307)
+cpuflags-$(CONFIG_M537x)	= $(call cc-option,-mcpu=537x,-m5307)
+cpuflags-$(CONFIG_M5307)	= $(call cc-option,-mcpu=5307,-m5200)
+cpuflags-$(CONFIG_M528x)	= $(call cc-option,-mcpu=528x,-m5307)
+cpuflags-$(CONFIG_M5275)	= $(call cc-option,-mcpu=5275,-m5307)
+cpuflags-$(CONFIG_M5272)	= $(call cc-option,-mcpu=5272,-m5307)
+cpuflags-$(CONFIG_M5271)	= $(call cc-option,-mcpu=5271,-m5307)
+cpuflags-$(CONFIG_M523x)	= $(call cc-option,-mcpu=523x,-m5307)
+cpuflags-$(CONFIG_M525x)	= $(call cc-option,-mcpu=5253,-m5200)
+cpuflags-$(CONFIG_M5249)	= $(call cc-option,-mcpu=5249,-m5200)
+cpuflags-$(CONFIG_M520x)	= $(call cc-option,-mcpu=5208,-m5200)
+cpuflags-$(CONFIG_M5206e)	= $(call cc-option,-mcpu=5206e,-m5200)
+cpuflags-$(CONFIG_M5206)	= $(call cc-option,-mcpu=5206,-m5200)
+
+# Evaluate tune cc-option calls now
+cpuflags-y := $(cpuflags-y)
+
+KBUILD_AFLAGS += $(cpuflags-y)
+KBUILD_CFLAGS += $(cpuflags-y)
+
+KBUILD_CFLAGS += -pipe -ffreestanding
+
+ifdef CONFIG_MMU
+KBUILD_CFLAGS += -ffixed-a2
+else
+# we can use a m68k-linux-gcc toolchain with these in place
+KBUILD_CPPFLAGS += -DUTS_SYSNAME=\"uClinux\"
+KBUILD_CPPFLAGS += -D__uClinux__
+endif
+
+KBUILD_LDFLAGS := -m m68kelf
+
+ifdef CONFIG_SUN3
+LDFLAGS_vmlinux = -N
+endif
+
+CHECKFLAGS += -D__mc68000__
+
+
+ifdef CONFIG_KGDB
+# If configured for kgdb support, include debugging infos and keep the
+# frame pointer
+KBUILD_CFLAGS := $(subst -fomit-frame-pointer,,$(KBUILD_CFLAGS)) -g
+endif
+
+libs-y				+= arch/m68k/lib/
+
+
+all:	zImage
+
+lilo:	vmlinux
+	if [ -f $(INSTALL_PATH)/vmlinux ]; then mv -f $(INSTALL_PATH)/vmlinux $(INSTALL_PATH)/vmlinux.old; fi
+	if [ -f $(INSTALL_PATH)/System.map ]; then mv -f $(INSTALL_PATH)/System.map $(INSTALL_PATH)/System.old; fi
+	cat vmlinux > $(INSTALL_PATH)/vmlinux
+	cp System.map $(INSTALL_PATH)/System.map
+	if [ -x /sbin/lilo ]; then /sbin/lilo; else /etc/lilo/install; fi
+
+zImage compressed: vmlinux.gz
+
+vmlinux.gz: vmlinux
+
+ifndef CONFIG_KGDB
+	cp vmlinux vmlinux.tmp
+	$(STRIP) vmlinux.tmp
+	$(KGZIP) -9c vmlinux.tmp >vmlinux.gz
+	rm vmlinux.tmp
+else
+	$(KGZIP) -9c vmlinux >vmlinux.gz
+endif
+
+bzImage: vmlinux.bz2
+
+vmlinux.bz2: vmlinux
+
+ifndef CONFIG_KGDB
+	cp vmlinux vmlinux.tmp
+	$(STRIP) vmlinux.tmp
+	$(KBZIP2) -1c vmlinux.tmp >vmlinux.bz2
+	rm vmlinux.tmp
+else
+	$(KBZIP2) -1c vmlinux >vmlinux.bz2
+endif
+
+CLEAN_FILES += vmlinux.gz vmlinux.bz2
+
+archheaders:
+	$(Q)$(MAKE) $(build)=arch/m68k/kernel/syscalls all
+
+install: KBUILD_IMAGE := vmlinux.gz
+install:
+	$(call cmd,install)