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, 120 insertions, 0 deletions

diff --git a/arch/alpha/boot/Makefile b/arch/alpha/boot/Makefile
new file mode 100644
index 000000000..d8dba85e6
--- /dev/null
+++ b/arch/alpha/boot/Makefile
@@ -0,0 +1,120 @@
+#
+# arch/alpha/boot/Makefile
+#
+# 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 Linus Torvalds
+#
+
+hostprogs	:= tools/mkbb tools/objstrip
+targets		:= vmlinux.gz vmlinux \
+		   vmlinux.nh tools/lxboot tools/bootlx tools/bootph \
+		   tools/bootpzh bootloader bootpheader bootpzheader 
+OBJSTRIP	:= $(obj)/tools/objstrip
+
+KBUILD_HOSTCFLAGS := -Wall -I$(objtree)/usr/include
+BOOTCFLAGS	+= -I$(objtree)/$(obj) -I$(srctree)/$(obj)
+
+# SRM bootable image.  Copy to offset 512 of a partition.
+$(obj)/bootimage: $(addprefix $(obj)/tools/,mkbb lxboot bootlx) $(obj)/vmlinux.nh
+	( cat $(obj)/tools/lxboot $(obj)/tools/bootlx $(obj)/vmlinux.nh ) > $@ 
+	$(obj)/tools/mkbb $@ $(obj)/tools/lxboot
+	@echo '  Bootimage $@ is ready'
+
+# BOOTP bootable image.  Define INITRD during make to append initrd image.
+$(obj)/bootpfile: $(obj)/tools/bootph $(obj)/vmlinux.nh
+	cat $(obj)/tools/bootph $(obj)/vmlinux.nh > $@
+ifdef INITRD
+	cat $(INITRD) >> $@
+endif
+
+# Compressed kernel BOOTP bootable image.
+# Define INITRD during make to append initrd image.
+$(obj)/bootpzfile: $(obj)/tools/bootpzh $(obj)/vmlinux.nh.gz
+	cat $(obj)/tools/bootpzh $(obj)/vmlinux.nh.gz > $@
+ifdef INITRD
+	cat $(INITRD) >> $@
+endif
+
+# Compressed kernel image
+$(obj)/vmlinux.gz: $(obj)/vmlinux FORCE
+	$(call if_changed,gzip)
+	@echo '  Kernel $@ is ready'
+
+$(obj)/main.o: $(obj)/ksize.h
+$(obj)/bootp.o: $(obj)/ksize.h
+$(obj)/bootpz.o: $(obj)/kzsize.h
+
+$(obj)/ksize.h: $(obj)/vmlinux.nh FORCE
+	echo "#define KERNEL_SIZE `ls -l $(obj)/vmlinux.nh | awk '{print $$5}'`" > $@T
+ifdef INITRD
+	[ -f $(INITRD) ] || exit 1
+	echo "#define INITRD_IMAGE_SIZE `ls -l $(INITRD) | awk '{print $$5}'`" >> $@T
+endif
+	cmp -s $@T $@ || mv -f $@T $@
+	rm -f $@T
+
+$(obj)/kzsize.h: $(obj)/vmlinux.nh.gz FORCE
+	echo "#define KERNEL_SIZE `ls -l $(obj)/vmlinux.nh | awk '{print $$5}'`" > $@T
+	echo "#define KERNEL_Z_SIZE `ls -l $(obj)/vmlinux.nh.gz | awk '{print $$5}'`" >> $@T
+ifdef INITRD
+	[ -f $(INITRD) ] || exit 1
+	echo "#define INITRD_IMAGE_SIZE `ls -l $(INITRD) | awk '{print $$5}'`" >> $@T
+endif
+	cmp -s $@T $@ || mv -f $@T $@
+	rm -f $@T
+
+quiet_cmd_strip = STRIP  $@
+      cmd_strip = $(STRIP) -o $@ $<
+
+$(obj)/vmlinux: vmlinux FORCE
+	$(call if_changed,strip)
+
+quiet_cmd_objstrip = OBJSTRIP $@
+      cmd_objstrip = $(OBJSTRIP) $(OSFLAGS_$(@F)) $< $@
+
+OSFLAGS_vmlinux.nh	:= -v
+OSFLAGS_lxboot		:= -p
+OSFLAGS_bootlx		:= -vb
+OSFLAGS_bootph		:= -vb
+OSFLAGS_bootpzh		:= -vb
+
+$(obj)/vmlinux.nh: vmlinux $(OBJSTRIP) FORCE
+	$(call if_changed,objstrip)
+
+$(obj)/vmlinux.nh.gz: $(obj)/vmlinux.nh FORCE
+	$(call if_changed,gzip)
+
+$(obj)/tools/lxboot: $(obj)/bootloader $(OBJSTRIP) FORCE
+	$(call if_changed,objstrip)
+
+$(obj)/tools/bootlx: $(obj)/bootloader $(OBJSTRIP) FORCE
+	$(call if_changed,objstrip)
+
+$(obj)/tools/bootph: $(obj)/bootpheader $(OBJSTRIP) FORCE
+	$(call if_changed,objstrip)
+
+$(obj)/tools/bootpzh: $(obj)/bootpzheader $(OBJSTRIP) FORCE
+	$(call if_changed,objstrip)
+
+LDFLAGS_bootloader   := -static -T # -N -relax
+LDFLAGS_bootloader   := -static -T # -N -relax
+LDFLAGS_bootpheader  := -static -T # -N -relax
+LDFLAGS_bootpzheader := -static -T # -N -relax
+
+OBJ_bootlx   := $(obj)/head.o $(obj)/stdio.o $(obj)/main.o
+OBJ_bootph   := $(obj)/head.o $(obj)/stdio.o $(obj)/bootp.o
+OBJ_bootpzh  := $(obj)/head.o $(obj)/stdio.o $(obj)/bootpz.o $(obj)/misc.o
+
+$(obj)/bootloader: $(obj)/bootloader.lds $(OBJ_bootlx) $(LIBS_Y) FORCE
+	$(call if_changed,ld)
+
+$(obj)/bootpheader: $(obj)/bootloader.lds $(OBJ_bootph) $(LIBS_Y) FORCE
+	$(call if_changed,ld)
+
+$(obj)/bootpzheader: $(obj)/bootloader.lds $(OBJ_bootpzh) $(LIBS_Y) FORCE
+	$(call if_changed,ld)
+
+$(obj)/misc.o: lib/inflate.c