kvm.ko is nothing but library code shared by kvm-intel.ko and kvm-amd.ko.
It provides no functionality on its own and it is unnecessary unless one
of the vendor-specific module is compiled. In particular, /dev/kvm is
not created until one of kvm-intel.ko or kvm-amd.ko is loaded.
Use CONFIG_KVM to decide if it is built-in or a module, but use the
vendor-specific modules for the actual decision on whether to build it.
This also fixes a build failure when CONFIG_KVM_INTEL and CONFIG_KVM_AMD
are both disabled. The cpu_emergency_register_virt_callback() function
is called from kvm.ko, but it is only defined if at least one of
CONFIG_KVM_INTEL and CONFIG_KVM_AMD is provided.
Fixes: 590b09b1d88e ("KVM: x86: Register "emergency disable" callbacks when virt is enabled")
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/kvm/Kconfig | 7 +++++--
arch/x86/kvm/Makefile | 2 +-
2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index 730c2f34d347..81bce9dd9331 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -17,8 +17,8 @@ menuconfig VIRTUALIZATION
if VIRTUALIZATION
-config KVM
- tristate "Kernel-based Virtual Machine (KVM) support"
+config KVM_X86_COMMON
+ def_tristate KVM if KVM_INTEL || KVM_AMD
depends on X86_LOCAL_APIC
select KVM_COMMON
select KVM_GENERIC_MMU_NOTIFIER
@@ -45,6 +45,9 @@ config KVM
select KVM_GENERIC_HARDWARE_ENABLING
select KVM_GENERIC_PRE_FAULT_MEMORY
select KVM_WERROR if WERROR
+
+config KVM
+ tristate "Kernel-based Virtual Machine (KVM) support"
help
Support hosting fully virtualized guest machines using hardware
virtualization extensions. You will need a fairly recent
diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
index 5494669a055a..0d050cfaffb2 100644
--- a/arch/x86/kvm/Makefile
+++ b/arch/x86/kvm/Makefile
@@ -32,7 +32,7 @@ kvm-intel-y += vmx/vmx_onhyperv.o vmx/hyperv_evmcs.o
kvm-amd-y += svm/svm_onhyperv.o
endif
-obj-$(CONFIG_KVM) += kvm.o
+obj-$(CONFIG_KVM_X86_COMMON) += kvm.o
obj-$(CONFIG_KVM_INTEL) += kvm-intel.o
obj-$(CONFIG_KVM_AMD) += kvm-amd.o
--
2.43.5
