[PATCH v9 24/24] KVM: s390: arm64: Integrate arm on s390
Steffen Eiden
seiden at linux.ibm.com
Wed Sep 30 10:34:39 PDT 2026
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 at linux.ibm.com>
Signed-off-by: Andreas Grapentin <gra at linux.ibm.com>
Co-developed-by: Nina Schoetterl-Glausch <nsg at linux.ibm.com>
Signed-off-by: Nina Schoetterl-Glausch <nsg at linux.ibm.com>
Co-developed-by: Gautam Gala <ggala at linux.ibm.com>
Signed-off-by: Gautam Gala <ggala at linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden at linux.ibm.com>
---
arch/s390/kvm/Kconfig | 25 +++++---
arch/s390/kvm/Makefile | 1 +
arch/s390/kvm/arm64/Makefile | 110 +++++++++++++++++++++++++++++++++++
3 files changed, 127 insertions(+), 9 deletions(-)
create mode 100644 arch/s390/kvm/arm64/Makefile
diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig
index 9045ae20fd89..e7b525d04c6d 100644
--- a/arch/s390/kvm/Kconfig
+++ b/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.
-
- This module provides access to the hardware capabilities through
- a character device node named /dev/kvm.
-
- To compile this as a module, choose M here: the module
- will be called kvm.
+ Enable support for hosting virtualized, hardware-accelerated
+ virtual machines via two modules: kvm and kvm_arm64.
+
+ 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).
+
+ 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.
diff --git a/arch/s390/kvm/Makefile b/arch/s390/kvm/Makefile
index a4e3875b5bdd..380db443a0e9 100644
--- a/arch/s390/kvm/Makefile
+++ b/arch/s390/kvm/Makefile
@@ -4,3 +4,4 @@
# Copyright IBM Corp. 2008
obj-$(CONFIG_KVM) += s390/
+obj-$(CONFIG_KVM) += arm64/
diff --git a/arch/s390/kvm/arm64/Makefile b/arch/s390/kvm/arm64/Makefile
new file mode 100644
index 000000000000..3f0fe5c9f0a1
--- /dev/null
+++ b/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
+
--
2.53.0
More information about the linux-arm-kernel
mailing list