[PATCH 3/3] KVM: always make in-place conversion a compile-time constant when possible

[Paolo Bonzini]

Remove the unnecessary static call indirection and make
gmem_in_place_conversion a constant if CONFIG_KVM_PRIVATE_MEMATTR_VM
is false.

Require that CONFIG_KVM_PRIVATE_MEMATTR_VM is y only if
kvm_arch_has_private_mem is also defined.  This way, the three
possible cases can be expressed without nested #ifs.

Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
 include/linux/kvm_host.h | 13 +++++--------
 virt/kvm/kvm_main.c      | 13 +++++++------
 2 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 09c57d31d153..e7fc94e2910a 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2585,15 +2585,7 @@ bool kvm_arch_post_set_vm_memory_attributes(struct kvm *kvm,
 #endif  /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
 
 #ifdef CONFIG_KVM_PRIVATE_MEMATTR_VM
-static inline bool kvm_vm_is_private_gfn(struct kvm *kvm, gfn_t gfn)
-{
-	return kvm_get_vm_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE;
-}
-#endif  /* CONFIG_KVM_PRIVATE_MEMATTR_VM */
-
-#ifdef kvm_arch_has_private_mem
 extern bool gmem_in_place_conversion;
-
 typedef bool (kvm_is_private_gfn_t)(struct kvm *kvm, gfn_t gfn);
 DECLARE_STATIC_CALL(__kvm_is_private_gfn, kvm_is_private_gfn_t);
 
@@ -2601,6 +2593,11 @@ static inline bool kvm_is_private_gfn(struct kvm *kvm, gfn_t gfn)
 {
 	return static_call(__kvm_is_private_gfn)(kvm, gfn);
 }
+
+#elif defined kvm_arch_has_private_mem
+#define gmem_in_place_conversion true
+#define kvm_is_private_gfn kvm_gmem_is_private_gfn
+
 #else
 #define gmem_in_place_conversion false
 
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 3e35766f5c7e..a356a29be985 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -104,11 +104,9 @@ EXPORT_SYMBOL_FOR_KVM_INTERNAL(halt_poll_ns_shrink);
 static bool __ro_after_init allow_unsafe_mappings;
 module_param(allow_unsafe_mappings, bool, 0444);
 
-#ifdef kvm_arch_has_private_mem
-bool __ro_after_init gmem_in_place_conversion = !IS_ENABLED(CONFIG_KVM_PRIVATE_MEMATTR_VM);
 #ifdef CONFIG_KVM_PRIVATE_MEMATTR_VM
+bool __ro_after_init gmem_in_place_conversion = false;
 module_param(gmem_in_place_conversion, bool, 0444);
-#endif
 EXPORT_SYMBOL_FOR_KVM_INTERNAL(gmem_in_place_conversion);
 #endif
 
@@ -2705,18 +2703,21 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
 }
 #endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
 
-#ifdef kvm_arch_has_private_mem
+#ifdef CONFIG_KVM_PRIVATE_MEMATTR_VM
 DEFINE_STATIC_CALL_RET0(__kvm_is_private_gfn, kvm_is_private_gfn_t);
 EXPORT_STATIC_CALL_GPL(__kvm_is_private_gfn);
 
+static bool kvm_vm_is_private_gfn(struct kvm *kvm, gfn_t gfn)
+{
+	return kvm_get_vm_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE;
+}
+
 static void kvm_init_memory_attributes(void)
 {
 	if (gmem_in_place_conversion)
 		static_call_update(__kvm_is_private_gfn, kvm_gmem_is_private_gfn);
-#ifdef CONFIG_KVM_PRIVATE_MEMATTR_VM
 	else
 		static_call_update(__kvm_is_private_gfn, kvm_vm_is_private_gfn);
-#endif
 }
 #else
 static void kvm_init_memory_attributes(void) { }
-- 
2.52.0