[PATCH v8 28/29] KVM: s390: arm64: Integrate arm on s390
From: Steffen Eiden
Date: Fri Sep 18 2026 - 09:45:36 EST
Add all Kbuild/Makefile configurations to build a second KVM module on
s390 implementing the arm64-KVM API. To prevent symbol conflicts with
kvm-s390 all internal symbols in kvm-arm64 are mangled if compiled as
built-in. The new module ins named kvm-arm64.
As in this case the build does not go through the normal build process
the module parameter handling would be messed up. By forcing
KBUILD_MODNAME to kvm-arm64 all parameters are at the same location and
not at object/basename of the object file where the parameter is
introduced.
Co-developed-by: Andreas Grapentin <gra@xxxxxxxxxxxxx>
Signed-off-by: Andreas Grapentin <gra@xxxxxxxxxxxxx>
Co-developed-by: Nina Schoetterl-Glausch <nsg@xxxxxxxxxxxxx>
Signed-off-by: Nina Schoetterl-Glausch <nsg@xxxxxxxxxxxxx>
Co-developed-by: Gautam Gala <ggala@xxxxxxxxxxxxx>
Signed-off-by: Gautam Gala <ggala@xxxxxxxxxxxxx>
Signed-off-by: Steffen Eiden <seiden@xxxxxxxxxxxxx>
---
arch/s390/include/asm/Kbuild | 1 +
arch/s390/kvm/Kconfig | 28 +++++++----
arch/s390/kvm/Makefile | 1 +
arch/s390/kvm/arm64/Makefile | 93 ++++++++++++++++++++++++++++++++++++
arch/s390/kvm/arm64/arm.c | 2 +-
5 files changed, 115 insertions(+), 10 deletions(-)
create mode 100644 arch/s390/kvm/arm64/Makefile
diff --git a/arch/s390/include/asm/Kbuild b/arch/s390/include/asm/Kbuild
index 0c1fc47c3ba0..9409970a2123 100644
--- a/arch/s390/include/asm/Kbuild
+++ b/arch/s390/include/asm/Kbuild
@@ -8,3 +8,4 @@ generic-y += asm-offsets.h
generic-y += mcs_spinlock.h
generic-y += mmzone.h
generic-y += ring_buffer.h
+
diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig
index a6ff2e5aa19b..4e060185c2fb 100644
--- a/arch/s390/kvm/Kconfig
+++ b/arch/s390/kvm/Kconfig
@@ -19,6 +19,7 @@ if VIRTUALIZATION
config KVM
def_tristate y
prompt "Kernel-based Virtual Machine (KVM) support"
+ depends on HAS_IOMEM
select HAVE_KVM_CPU_RELAX_INTERCEPT
select KVM_ASYNC_PF
select KVM_ASYNC_PF_SYNC
@@ -28,16 +29,25 @@ config KVM
select KVM_VFIO
select VIRT_XFER_TO_GUEST_WORK
select KVM_MMU_LOCKLESS_AGING
+ select GUEST_PERF_EVENTS if PERF_EVENTS
+ select SCHED_INFO
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..bd78d64939d1
--- /dev/null
+++ b/arch/s390/kvm/arm64/Makefile
@@ -0,0 +1,93 @@
+# 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/s390/kvm/gmap/Makefile
+include $(src)/Makefile.gen
+
+ccflags-y += -I $(src) -I $(objtree)/$(obj) -I$(srctree)/arch/s390/kvm/gmap -DKVM_S390_ARM64
+
+kvm-arm64-obj := \
+ arm.o \
+ guest.o \
+ handle_exit.o \
+ inject_fault.o \
+ mmio.o \
+ mmu.o \
+ reset.o \
+
+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 $@)
+ $(call if_changed_rule,cc_o_c)
+
+ifeq ($(CONFIG_KVM),m)
+
+kvm-arm64-y = $(kvm-arm64-obj)
+
+else ifeq ($(CONFIG_KVM),y)
+
+KVM_ARM64_GEN_DIR := $(objtree)/arch/${SRCARCH}/include/generated/asm
+KVM_ARM64_MODNAME_H := $(KVM_ARM64_GEN_DIR)/kvm_arm64_modname.h
+ccflags-y += -include $(KVM_ARM64_MODNAME_H)
+
+targets += $(KVM_ARM64_MODNAME_H)
+
+quiet_cmd_kvm_arm64_modname_h = GEN $@
+ cmd_kvm_arm64_modname_h = { \
+ echo '/* Automatically generated; do not edit. */'; \
+ echo '\#ifndef _KVM_ARM64_MODNAME_H'; \
+ echo '\#define _KVM_ARM64_MODNAME_H'; \
+ echo '\#undef KBUILD_MODNAME'; \
+ echo '\#define KBUILD_MODNAME "kvm_arm64"'; \
+ echo '\#endif /* _KVM_ARM64_MODNAME_H */'; \
+ } > $@
+
+$(addprefix $(obj)/,$(kvm-arm64-obj)): $(KVM_ARM64_MODNAME_H)
+
+$(KVM_ARM64_MODNAME_H):
+ @mkdir -p $(KVM_ARM64_GEN_DIR)
+ $(call cmd,kvm_arm64_modname_h)
+
+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
+
+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)
+
+define rule_oc_o_o
+ $(call cmd_and_savecmd,objcopy)
+ $(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
+ $(call if_changed_rule,oc_o_o)
+
+kvm-arm64-y = kvm-namespaced.o
+
+targets += kvm-unnamespaced.o kvm_symbol_list kvm-namespaced.o
+
+endif
+
+obj-$(CONFIG_KVM) += kvm-arm64.o
diff --git a/arch/s390/kvm/arm64/arm.c b/arch/s390/kvm/arm64/arm.c
index bb3e7fa8cad5..43e40fc78501 100644
--- a/arch/s390/kvm/arm64/arm.c
+++ b/arch/s390/kvm/arm64/arm.c
@@ -1,6 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
-#define KMSG_COMPONENT "kvm-s390-arm64"
+#define KMSG_COMPONENT "kvm_arm64"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/miscdevice.h>
--
2.53.0