KVM: Move architecture capability Kconfigs to header defines

With s390 hosting multiple independent KVM implementations within the
same kernel build (native s390 KVM and arm64 on s390), global Kconfig
selections force both implementations to inherit options that only apply
to one of them.

Replace global Kconfig options which only apply to one KVM
implementation with architecture-specific opt-in defines in the
respective <asm/kvm_host.h>. Only remove Kconfig symbols that would be
different on both s390 KVM implementations

  - __KVM_HAVE_INVALID_WAKEUPS		(formerly HAVE_KVM_INVALID_WAKEUPS)
  - __KVM_HAVE_MSI			(formerly HAVE_KVM_MSI)
  - __KVM_HAVE_NO_POLL			(formerly HAVE_KVM_NO_POLL)
  - __KVM_HAVE_READONLY_MEM		(formerly HAVE_KVM_READONLY_MEM)
  - __KVM_HAVE_VCPU_RUN_PID_CHANGE	(formerly HAVE_KVM_VCPU_RUN_PID_CHANGE)

This allows each architecture and guest implementation to configure its
supported capabilities independently in its kvm_host header and eliminates
adding unnecessary fallback stubs across different KVM targets.

Acked-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Link: https://patch.msgid.link/20261013121343.1997112-1-seiden@linux.ibm.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

17 files changed, 30 insertions, 38 deletions

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 27fe0cd5b2d7..41e75b8fbc3b 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -30,6 +30,9 @@
 #include <asm/vncr_mapping.h>
 
 #define __KVM_HAVE_ARCH_INTC_INITIALIZED
+#define __KVM_HAVE_MSI
+#define __KVM_HAVE_READONLY_MEM
+#define __KVM_HAVE_VCPU_RUN_PID_CHANGE
 
 #define KVM_HALT_POLL_NS_DEFAULT 500000
 
diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index 449154f9a485..7329124deb2f 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -28,12 +28,9 @@ menuconfig KVM
 	select KVM_VFIO
 	select HAVE_KVM_DIRTY_RING_ACQ_REL
 	select NEED_KVM_DIRTY_RING_WITH_BITMAP
-	select HAVE_KVM_MSI
 	select HAVE_KVM_IRQCHIP
 	select HAVE_KVM_IRQ_ROUTING
 	select HAVE_KVM_IRQ_BYPASS
-	select HAVE_KVM_READONLY_MEM
-	select HAVE_KVM_VCPU_RUN_PID_CHANGE
 	select SCHED_INFO
 	select GUEST_PERF_EVENTS if PERF_EVENTS
 	select KVM_GUEST_MEMFD
diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include/asm/kvm_host.h
index 65d91c3ce313..79d3ce7ad029 100644
--- a/arch/loongarch/include/asm/kvm_host.h
+++ b/arch/loongarch/include/asm/kvm_host.h
@@ -26,6 +26,8 @@
 #include <asm/loongarch.h>
 
 #define __KVM_HAVE_ARCH_INTC_INITIALIZED
+#define __KVM_HAVE_MSI
+#define __KVM_HAVE_READONLY_MEM
 
 /* Loongarch KVM register ids */
 #define KVM_GET_IOC_CSR_IDX(id)		((id & KVM_CSR_IDX_MASK) >> LOONGARCH_REG_SHIFT)
diff --git a/arch/loongarch/kvm/Kconfig b/arch/loongarch/kvm/Kconfig
index 15da2d88c0c1..a427429a2b05 100644
--- a/arch/loongarch/kvm/Kconfig
+++ b/arch/loongarch/kvm/Kconfig
@@ -23,8 +23,6 @@ config KVM
 	select HAVE_KVM_DIRTY_RING_ACQ_REL
 	select HAVE_KVM_IRQ_ROUTING
 	select HAVE_KVM_IRQCHIP
-	select HAVE_KVM_MSI
-	select HAVE_KVM_READONLY_MEM
 	select KVM_COMMON
 	select KVM_GENERIC_DIRTYLOG_READ_PROTECT
 	select KVM_GENERIC_HARDWARE_ENABLING
diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index c14b10821817..d481275f38eb 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -893,5 +893,6 @@ static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {}
 static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {}
 
 #define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS
+#define __KVM_HAVE_READONLY_MEM
 
 #endif /* __MIPS_KVM_HOST_H__ */
diff --git a/arch/mips/kvm/Kconfig b/arch/mips/kvm/Kconfig
index b1b9a1d67758..c24b872afbcb 100644
--- a/arch/mips/kvm/Kconfig
+++ b/arch/mips/kvm/Kconfig
@@ -24,7 +24,6 @@ config KVM
 	select KVM_GENERIC_DIRTYLOG_READ_PROTECT
 	select KVM_MMIO
 	select KVM_GENERIC_HARDWARE_ENABLING
-	select HAVE_KVM_READONLY_MEM
 	help
 	  Support for hosting Guest kernels.
 
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 2d139c807577..d8ef70c14aad 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -49,6 +49,9 @@
 #endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */
 
 #define __KVM_HAVE_ARCH_INTC_INITIALIZED
+#ifdef CONFIG_KVM_MPIC
+#define __KVM_HAVE_MSI
+#endif
 
 #define KVM_HALT_POLL_NS_DEFAULT 10000	/* 10 us */
 
diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
index b6bc2fc86dca..1fae2de8fa68 100644
--- a/arch/powerpc/kvm/Kconfig
+++ b/arch/powerpc/kvm/Kconfig
@@ -232,7 +232,6 @@ config KVM_MPIC
 	depends on KVM && PPC_E500
 	select HAVE_KVM_IRQCHIP
 	select HAVE_KVM_IRQ_ROUTING
-	select HAVE_KVM_MSI
 	help
 	  Enable support for emulating MPIC devices inside the
 	  host kernel, rather than relying on userspace to emulate.
diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index a30600579231..e28f058a94d7 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -47,6 +47,8 @@
 #define KVM_REQ_STEAL_UPDATE		KVM_ARCH_REQ(6)
 
 #define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS_RANGE
+#define __KVM_HAVE_MSI
+#define __KVM_HAVE_READONLY_MEM
 
 #define KVM_HAVE_MMU_RWLOCK
 
diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig
index ec2cee0a39e0..3cb4f8037300 100644
--- a/arch/riscv/kvm/Kconfig
+++ b/arch/riscv/kvm/Kconfig
@@ -22,8 +22,6 @@ config KVM
 	depends on RISCV_SBI && MMU
 	select HAVE_KVM_IRQCHIP
 	select HAVE_KVM_IRQ_ROUTING
-	select HAVE_KVM_MSI
-	select HAVE_KVM_READONLY_MEM
 	select HAVE_KVM_DIRTY_RING_ACQ_REL
 	select KVM_COMMON
 	select KVM_GENERIC_DIRTYLOG_READ_PROTECT
diff --git a/arch/s390/include/asm/kvm_host_s390.h b/arch/s390/include/asm/kvm_host_s390.h
index 9519b8028b10..a00353ba0343 100644
--- a/arch/s390/include/asm/kvm_host_s390.h
+++ b/arch/s390/include/asm/kvm_host_s390.h
@@ -34,6 +34,9 @@
 
 #define KVM_INTERNAL_MEM_SLOTS 1
 
+#define __KVM_HAVE_INVALID_WAKEUPS
+#define __KVM_HAVE_NO_POLL
+
 #define KVM_S390_MANAGES_S390_GUEST 1
 
 /*
diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig
index 8d3ee17a1bcb..9045ae20fd89 100644
--- a/arch/s390/kvm/Kconfig
+++ b/arch/s390/kvm/Kconfig
@@ -25,8 +25,6 @@ config KVM
 	select KVM_COMMON
 	select HAVE_KVM_IRQCHIP
 	select HAVE_KVM_IRQ_ROUTING
-	select HAVE_KVM_INVALID_WAKEUPS
-	select HAVE_KVM_NO_POLL
 	select KVM_VFIO
 	select VIRT_XFER_TO_GUEST_WORK
 	select KVM_MMU_LOCKLESS_AGING
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 0e827dcd0b88..a902b055c7f2 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -48,6 +48,9 @@
 #define kvm_file_to_kvm_arch x86
 
 #define __KVM_HAVE_ARCH_VCPU_DEBUGFS
+#define __KVM_HAVE_MSI
+#define __KVM_HAVE_NO_POLL
+#define __KVM_HAVE_READONLY_MEM
 
 /*
  * CONFIG_KVM_MAX_NR_VCPUS is defined iff CONFIG_KVM!=n, provide a dummy max if
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index 538ed1e80332..294684b217bb 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -28,7 +28,6 @@ config KVM_X86
 	select HAVE_KVM_DIRTY_RING_ACQ_REL
 	select HAVE_KVM_IRQ_BYPASS
 	select HAVE_KVM_IRQ_ROUTING
-	select HAVE_KVM_READONLY_MEM
 	select VHOST_TASK
 	select KVM_ASYNC_PF
 	select USER_RETURN_NOTIFIER
@@ -37,9 +36,7 @@ config KVM_X86
 	select PERF_EVENTS
 	select GUEST_PERF_EVENTS
 	select PERF_GUEST_MEDIATED_PMU
-	select HAVE_KVM_MSI
 	select HAVE_KVM_CPU_RELAX_INTERCEPT
-	select HAVE_KVM_NO_POLL
 	select VIRT_XFER_TO_GUEST_WORK
 	select KVM_GENERIC_DIRTYLOG_READ_PROTECT
 	select KVM_VFIO
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 5624b572cb85..e4ae201a1707 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -750,7 +750,11 @@ static inline u64 kvm_gmem_get_supported_flags(struct kvm *kvm)
 #ifndef kvm_arch_has_readonly_mem
 static inline bool kvm_arch_has_readonly_mem(struct kvm *kvm)
 {
-	return IS_ENABLED(CONFIG_HAVE_KVM_READONLY_MEM);
+#ifdef __KVM_HAVE_READONLY_MEM
+	return true;
+#else
+	return false;
+#endif
 }
 #endif
 
@@ -2483,7 +2487,7 @@ void kvm_arch_update_irqfd_routing(struct kvm_kernel_irqfd *irqfd,
 				   struct kvm_kernel_irq_routing_entry *new);
 #endif /* CONFIG_HAVE_KVM_IRQ_BYPASS */
 
-#ifdef CONFIG_HAVE_KVM_INVALID_WAKEUPS
+#ifdef __KVM_HAVE_INVALID_WAKEUPS
 /* If we wakeup during the poll time, was it a sucessful poll? */
 static inline bool vcpu_valid_wakeup(struct kvm_vcpu *vcpu)
 {
@@ -2495,9 +2499,9 @@ static inline bool vcpu_valid_wakeup(struct kvm_vcpu *vcpu)
 {
 	return true;
 }
-#endif /* CONFIG_HAVE_KVM_INVALID_WAKEUPS */
+#endif /* __KVM_HAVE_INVALID_WAKEUPS */
 
-#ifdef CONFIG_HAVE_KVM_NO_POLL
+#ifdef __KVM_HAVE_NO_POLL
 /* Callback that tells if we must not poll */
 bool kvm_arch_no_poll(struct kvm_vcpu *vcpu);
 #else
@@ -2505,18 +2509,18 @@ static inline bool kvm_arch_no_poll(struct kvm_vcpu *vcpu)
 {
 	return false;
 }
-#endif /* CONFIG_HAVE_KVM_NO_POLL */
+#endif /* __KVM_HAVE_NO_POLL */
 
 void kvm_arch_guest_memory_reclaimed(struct kvm *kvm);
 
-#ifdef CONFIG_HAVE_KVM_VCPU_RUN_PID_CHANGE
+#ifdef __KVM_HAVE_VCPU_RUN_PID_CHANGE
 int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu);
 #else
 static inline int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu)
 {
 	return 0;
 }
-#endif /* CONFIG_HAVE_KVM_VCPU_RUN_PID_CHANGE */
+#endif /* __KVM_HAVE_VCPU_RUN_PID_CHANGE */
 
 #ifdef CONFIG_VIRT_XFER_TO_GUEST_WORK
 static inline void kvm_handle_signal_exit(struct kvm_vcpu *vcpu)
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index c3c0ee253fc7..f3d7f66746c8 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -50,21 +50,12 @@ config KVM_ASYNC_PF
 config KVM_ASYNC_PF_SYNC
        bool
 
-config HAVE_KVM_MSI
-       bool
-
-config HAVE_KVM_READONLY_MEM
-       bool
-
 config HAVE_KVM_CPU_RELAX_INTERCEPT
        bool
 
 config KVM_VFIO
        bool
 
-config HAVE_KVM_INVALID_WAKEUPS
-       bool
-
 config KVM_GENERIC_DIRTYLOG_READ_PROTECT
        bool
 
@@ -79,12 +70,6 @@ config HAVE_KVM_IRQ_BYPASS
        tristate
        select IRQ_BYPASS_MANAGER
 
-config HAVE_KVM_VCPU_RUN_PID_CHANGE
-       bool
-
-config HAVE_KVM_NO_POLL
-       bool
-
 config VIRT_XFER_TO_GUEST_WORK
        bool
 
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 09ee08092ced..fe6dc0bf3bde 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4903,7 +4903,7 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
 	case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
 	case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS:
 	case KVM_CAP_INTERNAL_ERROR_DATA:
-#ifdef CONFIG_HAVE_KVM_MSI
+#ifdef __KVM_HAVE_MSI
 	case KVM_CAP_SIGNAL_MSI:
 #endif
 #ifdef CONFIG_HAVE_KVM_IRQCHIP
@@ -5293,7 +5293,7 @@ static long kvm_vm_ioctl(struct file *filp,
 		r = kvm_ioeventfd(kvm, &data);
 		break;
 	}
-#ifdef CONFIG_HAVE_KVM_MSI
+#ifdef __KVM_HAVE_MSI
 	case KVM_SIGNAL_MSI: {
 		struct kvm_msi msi;