[PATCH v5 15/31] KVM: s390: Guard KVM/s390 behind CONFIG_KVM_S390

From: Steffen Eiden

Date: Fri Jul 31 2026 - 09:22:12 EST

To allow for a second KVM Module guard KVM/s390 behind CONIG_KVM_S390
instead of CONFIG_KVM and turn CONFIG_KVM on if selected.

Signed-off-by: Steffen Eiden <seiden@xxxxxxxxxxxxx>
---
arch/s390/Kconfig | 2 +-
arch/s390/boot/ipl_parm.c | 2 +-
arch/s390/boot/uv.c | 2 +-
arch/s390/configs/debug_defconfig | 2 +-
arch/s390/configs/defconfig | 2 +-
arch/s390/kernel/early.c | 2 +-
arch/s390/kernel/entry.S | 10 +++++-----
arch/s390/kernel/perf_event.c | 2 +-
arch/s390/kvm/Kconfig | 3 +++
arch/s390/kvm/Makefile | 2 +-
arch/s390/kvm/s390/Kconfig | 5 +++--
arch/s390/kvm/s390/Makefile | 2 +-
include/linux/kvm_host.h | 2 +-
13 files changed, 21 insertions(+), 17 deletions(-)

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 84404e6778d5..b2eaa2000b10 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -834,7 +834,7 @@ config VFIO_CCW
config VFIO_AP
def_tristate n
prompt "VFIO support for AP devices"
- depends on KVM
+ depends on KVM_S390
depends on VFIO
depends on AP
select VFIO_MDEV
diff --git a/arch/s390/boot/ipl_parm.c b/arch/s390/boot/ipl_parm.c
index 6bc950b92be7..b8906ba7e5e8 100644
--- a/arch/s390/boot/ipl_parm.c
+++ b/arch/s390/boot/ipl_parm.c
@@ -300,7 +300,7 @@ void parse_boot_command_line(void)
stack_protector_debug = 1;
#endif

-#if IS_ENABLED(CONFIG_KVM)
+#if IS_ENABLED(CONFIG_KVM_S390)
if (!strcmp(param, "prot_virt")) {
rc = kstrtobool(val, &enabled);
if (!rc && enabled)
diff --git a/arch/s390/boot/uv.c b/arch/s390/boot/uv.c
index 4568e8f81dac..f7b68bdcedc1 100644
--- a/arch/s390/boot/uv.c
+++ b/arch/s390/boot/uv.c
@@ -26,7 +26,7 @@ void uv_query_info(void)
if (uv_call(0, (uint64_t)&uvcb) && uvcb.header.rc != UVC_RC_MORE_DATA)
return;

- if (IS_ENABLED(CONFIG_KVM)) {
+ if (IS_ENABLED(CONFIG_KVM_S390)) {
memcpy(uv_info.inst_calls_list, uvcb.inst_calls_list, sizeof(uv_info.inst_calls_list));
uv_info.uv_base_stor_len = uvcb.uv_base_stor_len;
uv_info.guest_base_stor_len = uvcb.conf_base_phys_stor_len;
diff --git a/arch/s390/configs/debug_defconfig b/arch/s390/configs/debug_defconfig
index 54637be87fb7..e9ad718a9408 100644
--- a/arch/s390/configs/debug_defconfig
+++ b/arch/s390/configs/debug_defconfig
@@ -63,7 +63,7 @@ CONFIG_IOMMUFD=y
CONFIG_CMM=m
CONFIG_APPLDATA_BASE=y
CONFIG_S390_HYPFS_FS=y
-CONFIG_KVM=m
+CONFIG_KVM_S390=m
CONFIG_KVM_S390_UCONTROL=y
CONFIG_S390_UNWIND_SELFTEST=m
CONFIG_S390_KPROBES_SANITY_TEST=m
diff --git a/arch/s390/configs/defconfig b/arch/s390/configs/defconfig
index 5f5114a253cf..327ab4a3933c 100644
--- a/arch/s390/configs/defconfig
+++ b/arch/s390/configs/defconfig
@@ -61,7 +61,7 @@ CONFIG_IOMMUFD=y
CONFIG_CMM=m
CONFIG_APPLDATA_BASE=y
CONFIG_S390_HYPFS_FS=y
-CONFIG_KVM=m
+CONFIG_KVM_S390=m
CONFIG_S390_UNWIND_SELFTEST=m
CONFIG_S390_KPROBES_SANITY_TEST=m
CONFIG_S390_MODULES_SANITY_TEST=m
diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index b27239c03d79..464f8918d447 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -57,7 +57,7 @@ decompressor_handled_param(cmma);
decompressor_handled_param(relocate_lowcore);
decompressor_handled_param(bootdebug);
__decompressor_handled_param(debug_alternative, debug-alternative);
-#if IS_ENABLED(CONFIG_KVM)
+#if IS_ENABLED(CONFIG_KVM_S390)
decompressor_handled_param(prot_virt);
#endif

diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 79a45efae23d..9572620fcaa6 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -113,7 +113,7 @@ _LPP_OFFSET = __LC_LPP
"jnz .+8; .insn rrf,0xb2e80000,0,0,13,0", ALT_SPEC(82)
.endm

-#if IS_ENABLED(CONFIG_KVM)
+#if IS_ENABLED(CONFIG_KVM_S390)
.macro SIEEXIT sie_control,lowcore
lg %r9,\sie_control # get control block pointer
ni __SIE_PROG0C+3(%r9),0xfe # no longer in SIE
@@ -184,7 +184,7 @@ EXPORT_SYMBOL(__WARN_trap)

#endif /* CONFIG_BUG && CONFIG_CC_HAS_ASM_IMMEDIATE_STRINGS */

-#if IS_ENABLED(CONFIG_KVM)
+#if IS_ENABLED(CONFIG_KVM_S390)
/*
* __sie64a calling convention:
* %r2 pointer to sie control block phys
@@ -315,7 +315,7 @@ SYM_CODE_START(pgm_check_handler)
xgr %r10,%r10
tmhh %r8,0x0001 # coming from user space?
jo 3f # -> fault in user space
-#if IS_ENABLED(CONFIG_KVM)
+#if IS_ENABLED(CONFIG_KVM_S390)
lg %r11,__LC_CURRENT(%r13)
tm __TI_sie(%r11),0xff
jz 1f
@@ -397,7 +397,7 @@ SYM_CODE_START(\name)
lmg %r8,%r9,\lc_old_psw(%r13)
tmhh %r8,0x0001 # interrupting from user ?
jnz 1f
-#if IS_ENABLED(CONFIG_KVM)
+#if IS_ENABLED(CONFIG_KVM_S390)
lg %r10,__LC_CURRENT(%r13)
tm __TI_sie(%r10),0xff
jz 0f
@@ -475,7 +475,7 @@ SYM_CODE_START(mcck_int_handler)
jnz .Lmcck_user
TSTMSK __LC_MCCK_CODE(%r13),MCCK_CODE_PSW_IA_VALID
jno .Lmcck_panic
-#if IS_ENABLED(CONFIG_KVM)
+#if IS_ENABLED(CONFIG_KVM_S390)
lg %r10,__LC_CURRENT(%r13)
tm __TI_sie(%r10),0xff
jz .Lmcck_user
diff --git a/arch/s390/kernel/perf_event.c b/arch/s390/kernel/perf_event.c
index 606750bae508..6441746b8e72 100644
--- a/arch/s390/kernel/perf_event.c
+++ b/arch/s390/kernel/perf_event.c
@@ -37,7 +37,7 @@ static bool is_in_guest(struct pt_regs *regs)
{
if (user_mode(regs))
return false;
-#if IS_ENABLED(CONFIG_KVM)
+#if IS_ENABLED(CONFIG_KVM_S390)
return instruction_pointer(regs) == (unsigned long) &sie_exit;
#else
return false;
diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig
index 51646b067935..f8d4a9a38dae 100644
--- a/arch/s390/kvm/Kconfig
+++ b/arch/s390/kvm/Kconfig
@@ -16,6 +16,9 @@ menuconfig VIRTUALIZATION

if VIRTUALIZATION

+config KVM
+ tristate
+
source "arch/s390/kvm/s390/Kconfig"

endif # VIRTUALIZATION
diff --git a/arch/s390/kvm/Makefile b/arch/s390/kvm/Makefile
index a4e3875b5bdd..c43d7dffca13 100644
--- a/arch/s390/kvm/Makefile
+++ b/arch/s390/kvm/Makefile
@@ -3,4 +3,4 @@
#
# Copyright IBM Corp. 2008

-obj-$(CONFIG_KVM) += s390/
+obj-$(CONFIG_KVM_S390) += s390/
diff --git a/arch/s390/kvm/s390/Kconfig b/arch/s390/kvm/s390/Kconfig
index 62d65de3878d..bacfa1a48446 100644
--- a/arch/s390/kvm/s390/Kconfig
+++ b/arch/s390/kvm/s390/Kconfig
@@ -1,12 +1,13 @@
# SPDX-License-Identifier: GPL-2.0

-config KVM
+config KVM_S390
def_tristate y
prompt "Kernel-based Virtual Machine (KVM) support (s390)"
select HAVE_KVM_CPU_RELAX_INTERCEPT
select KVM_ASYNC_PF
select KVM_ASYNC_PF_SYNC
select KVM_COMMON
+ select KVM
select HAVE_KVM_IRQCHIP
select HAVE_KVM_IRQ_ROUTING
select HAVE_KVM_INVALID_WAKEUPS
@@ -30,7 +31,7 @@ config KVM

config KVM_S390_UCONTROL
bool "Userspace controlled virtual machines"
- depends on KVM
+ depends on KVM_S390
help
Allow CAP_SYS_ADMIN users to create KVM virtual machines that are
controlled by userspace.
diff --git a/arch/s390/kvm/s390/Makefile b/arch/s390/kvm/s390/Makefile
index de7deb81e655..354cb4c52635 100644
--- a/arch/s390/kvm/s390/Makefile
+++ b/arch/s390/kvm/s390/Makefile
@@ -11,4 +11,4 @@ kvm-y += diag.o gaccess.o guestdbg.o vsie.o pv.o

kvm-$(CONFIG_VFIO_PCI_ZDEV_KVM) += pci.o

-obj-$(CONFIG_KVM) += kvm.o
+obj-$(CONFIG_KVM_S390) += kvm.o
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 7a5e2797db7f..050aca8a8ff4 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1541,7 +1541,7 @@ void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu);
void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu);
bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu);

-#ifndef CONFIG_S390
+#ifndef CONFIG_KVM_S390
void __kvm_vcpu_kick(struct kvm_vcpu *vcpu, bool wait);

static inline void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
--
2.53.0