KVM: s390: arm64: Integrate arm on s390

Add all Kbuild/Makefile configurations to build a second KVM module on
s390 implementing the arm64 KVM API. The new module is named kvm_arm64.

Symbol conflicts with kvm_s390 are prevented by localising all internal
symbols in kvm_arm64 when compiled as built-in (=y): kvm-unnamespaced.o
holds all constituent objects. objcopy --localize-symbols then produces
kvm-namespaced.o which is what kvm-arm64.o resolves to. For =m the
normal module symbol scoping applies and no localisation step is needed.

Because the %-arm64.o pattern targets do not match any kvm-arm64-y entry,
kbuild would derive a wrong KBUILD_MODNAME (e.g. "kvm_main_arm64") and
a wrong KBUILD_MODFILE for the virt/kvm and gmap copies.

Co-developed-by: Andreas Grapentin <gra@linux.ibm.com>
Signed-off-by: Andreas Grapentin <gra@linux.ibm.com>
Co-developed-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Signed-off-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Co-developed-by: Gautam Gala <ggala@linux.ibm.com>
Signed-off-by: Gautam Gala <ggala@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>

arch/s390/kvm/Kconfig

@@ -30,15 +30,22 @@ config KVM
 	select KVM_MMU_LOCKLESS_AGING
 	select KVM_GENERIC_PRE_FAULT_MEMORY
 	help
-	  Support hosting paravirtualized guest machines using the SIE
-	  virtualization capability on the mainframe. This should work
-	  on any 64bit machine.
+	  Enable support for hosting virtualized, hardware-accelerated
+	  virtual machines via two modules: kvm and kvm_arm64.
 
-	  This module provides access to the hardware capabilities through
-	  a character device node named /dev/kvm.
+	  The kvm module provides access to host hardware-accelerated s390
+	  guests using the Start Interpretive Execution (SIE) instruction via a
+	  character device node named /dev/kvm. This requires a 64-bit machine
+	  (hardware model).
 
-	  To compile this as a module, choose M here: the module
-	  will be called kvm.
+	  The kvm_arm64 module provides access to host hardware-accelerated
+	  arm64 guests using the Start ARM Execution (SAE) instruction via a
+	  character device node named /dev/kvm_arm64. This requires hardware
+	  models that support the Arm execution facility (AEF).
+
+	  To compile this driver as a module, choose M here. The module will be
+	  called kvm for the SIE acceleration and kvm_arm64 for the SAE
+	  acceleration.
 
 	  If unsure, say N.
 

arch/s390/kvm/Makefile

@@ -4,3 +4,4 @@
 # Copyright IBM Corp. 2008
 
 obj-$(CONFIG_KVM) += s390/
+obj-$(CONFIG_KVM) += arm64/

arch/s390/kvm/arm64/Makefile

@@ -0,0 +1,110 @@
+# SPDX-License-Identifier: GPL-2.0
+
+KVM := ../../../../virt/kvm
+KVM_DEV_NAME = kvm_arm64
+KVM_DEV_MINOR = MISC_DYNAMIC_MINOR
+include $(srctree)/virt/kvm/Makefile.kvm
+include $(srctree)/arch/$(SRCARCH)/kvm/gmap/Makefile
+include $(src)/Makefile.gen
+
+ccflags-y += -I $(src) -I $(objtree)/$(obj) -I$(srctree)/arch/$(SRCARCH)/kvm/gmap -DKVM_S390_ARM64
+
+kvm-arm64-local := \
+	arm.o \
+	guest.o \
+	handle_exit.o \
+	inject_fault.o \
+	mmio.o \
+	mmu.o \
+	reset.o
+
+kvm-arm64-obj := $(kvm-arm64-local)
+kvm-arm64-obj += $(patsubst %.o,%-arm64.o,$(kvm-y))
+kvm-arm64-obj += $(patsubst %.o,%-arm64.o,$(gmap-y))
+
+targets += $(kvm-arm64-obj)
+
+$(obj)/%-arm64.o: $(src)/%.c FORCE
+	@mkdir -p $(dir $@)
+	$(call if_changed_rule,cc_o_c)
+	$(call cmd,force_checksrc)
+
+# %-arm64.o stems don't match any kvm-arm64-y entry so Kbuild derives wrong
+# KBUILD_MODNAME/KBUILD_MODFILE. Force include a generated header to override.
+KVM_ARM64_MODNAME_H := $(obj)/generated/kvm_arm64_modname.h
+ccflags-y += -include $(KVM_ARM64_MODNAME_H)
+
+$(addprefix $(obj)/,$(kvm-arm64-obj)): $(KVM_ARM64_MODNAME_H)
+$(foreach sfx, i s ll lst, \
+	$(eval $(patsubst %.o,%.$(sfx),$(addprefix $(obj)/,$(kvm-arm64-local))): $(KVM_ARM64_MODNAME_H)))
+
+targets += generated/kvm_arm64_modname.h
+
+define filechk_kvm_arm64_modname
+	echo '#ifndef __KVM_ARM64_MODNAME_H';			\
+	echo '#define __KVM_ARM64_MODNAME_H';			\
+	echo '#undef KBUILD_MODNAME';				\
+	echo '#define KBUILD_MODNAME "$(KVM_DEV_NAME)"';	\
+	echo '#undef __KBUILD_MODNAME';				\
+	echo '#define __KBUILD_MODNAME $(KVM_DEV_NAME)';	\
+	echo '#undef KBUILD_MODFILE';				\
+	echo '#define KBUILD_MODFILE "$(obj)/kvm-arm64"';	\
+	echo '#endif /* __KVM_ARM64_MODNAME_H */'
+endef
+
+$(KVM_ARM64_MODNAME_H): FORCE
+	$(call filechk,kvm_arm64_modname)
+
+# Members are not in real-obj-y. Set part-of-builtin to enable instrumentation.
+$(addprefix $(obj)/,$(kvm-arm64-obj)): private part-of-builtin := y
+
+ifeq ($(CONFIG_KVM),m)
+
+kvm-arm64-y = $(kvm-arm64-obj)
+
+else ifeq ($(CONFIG_KVM),y)
+
+prereq-o-cmd = $(foreach o, $(filter %.o, $^), $(dir $(o)).$(notdir $(o)).cmd)
+cmd_gen_symversions_o = \
+	grep --no-filename "^\#SYMVER" $(prereq-o-cmd) >> $(dot-target).cmd || true
+
+cmd_ld_o_o = $(cmd_ld)
+define rule_ld_o_o
+	$(call cmd_and_savecmd,ld)
+	$(call cmd,gen_symversions_o)
+endef
+
+LDFLAGS_kvm-unnamespaced.o := -r
+$(obj)/kvm-unnamespaced.o: $(addprefix $(obj)/,$(kvm-arm64-obj)) FORCE
+	$(call if_changed_rule,ld_o_o)
+
+quiet_cmd_nm_filter = NMFLTR  $@
+	cmd_nm_filter = $(NM) --defined-only --format=just-symbols $< | sort -u > $@
+
+$(obj)/kvm_symbol_list: $(obj)/kvm-unnamespaced.o FORCE
+	$(call if_changed,nm_filter)
+
+# cmd_oc_o_o carries -DKBUILD_MODFILE so generate_builtin_ranges.awk
+# can attribute kvm-namespaced.o to kvm_arm64 via its .cmd file.
+cmd_oc_o_o = $(cmd_objcopy) -DKBUILD_MODFILE='"$(obj)/kvm-arm64"'
+define rule_oc_o_o
+	$(call cmd,objcopy)
+	@printf '%s\n' 'savedcmd_$@ := $(call make-cmd,oc_o_o)' > $(dot-target).cmd
+	$(call cmd,gen_objtooldep)
+	$(call cmd,gen_symversions_o)
+endef
+
+OBJCOPYFLAGS_kvm-namespaced.o := -O $(LD_BFD) --localize-symbols=$(obj)/kvm_symbol_list
+$(obj)/kvm-namespaced.o: $(obj)/kvm-unnamespaced.o $(obj)/kvm_symbol_list FORCE
+	$(call if_changed_rule,oc_o_o)
+
+kvm-arm64-y = kvm-namespaced.o
+
+targets += kvm-unnamespaced.o kvm_symbol_list kvm-namespaced.o
+
+endif
+
+clean-files += kvm-unnamespaced.o kvm_symbol_list kvm-namespaced.o
+
+obj-$(CONFIG_KVM) += kvm-arm64.o
+