KVM: guest_memfd: Move gmem function declarations to dedicated guest_memfd.h

Extract the gmem function declarations out of kvm_mm.h and into a dedicated
header, guest_memfd.h.  This will allow creating a MAINTAINERS entry for
guest_memfd without having to rely on content pattern matching.

Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Link: https://patch.msgid.link/20260731173842.2649391-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

4 files changed, 36 insertions, 27 deletions

diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index 86690683b2fe..de2585539b25 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -9,6 +9,7 @@
 #include <linux/pagemap.h>
 
 #include "kvm_mm.h"
+#include "guest_memfd.h"
 
 static struct vfsmount *kvm_gmem_mnt;
 
diff --git a/virt/kvm/guest_memfd.h b/virt/kvm/guest_memfd.h
new file mode 100644
index 000000000000..0f9c6f840838
--- /dev/null
+++ b/virt/kvm/guest_memfd.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __KVM_GUEST_MEMFD_H__
+#define __KVM_GUEST_MEMFD_H__
+
+#include <linux/kvm_types.h>
+
+#ifdef CONFIG_KVM_GUEST_MEMFD
+int kvm_gmem_init(struct module *module);
+void kvm_gmem_exit(void);
+int kvm_gmem_create(struct kvm *kvm, struct kvm_create_guest_memfd *args);
+int kvm_gmem_bind(struct kvm *kvm, struct kvm_memory_slot *slot,
+		  unsigned int fd, uoff_t offset);
+void kvm_gmem_unbind(struct kvm_memory_slot *slot);
+#else
+static inline int kvm_gmem_init(struct module *module)
+{
+	return 0;
+}
+static inline void kvm_gmem_exit(void) {};
+static inline int kvm_gmem_bind(struct kvm *kvm,
+					 struct kvm_memory_slot *slot,
+					 unsigned int fd, uoff_t offset)
+{
+	WARN_ON_ONCE(1);
+	return -EIO;
+}
+
+static inline void kvm_gmem_unbind(struct kvm_memory_slot *slot)
+{
+	WARN_ON_ONCE(1);
+}
+#endif /* CONFIG_KVM_GUEST_MEMFD */
+
+#endif /* __KVM_GUEST_MEMFD_H__ */
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index e44c20c04961..a2f67623e60a 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -56,6 +56,7 @@
 
 #include "coalesced_mmio.h"
 #include "async_pf.h"
+#include "guest_memfd.h"
 #include "kvm_mm.h"
 #include "vfio.h"
 
diff --git a/virt/kvm/kvm_mm.h b/virt/kvm/kvm_mm.h
index 7510ca915dd1..c65cfdb14f1c 100644
--- a/virt/kvm/kvm_mm.h
+++ b/virt/kvm/kvm_mm.h
@@ -70,31 +70,4 @@ static inline void gfn_to_pfn_cache_invalidate_start(struct kvm *kvm,
 }
 #endif /* HAVE_KVM_PFNCACHE */
 
-#ifdef CONFIG_KVM_GUEST_MEMFD
-int kvm_gmem_init(struct module *module);
-void kvm_gmem_exit(void);
-int kvm_gmem_create(struct kvm *kvm, struct kvm_create_guest_memfd *args);
-int kvm_gmem_bind(struct kvm *kvm, struct kvm_memory_slot *slot,
-		  unsigned int fd, uoff_t offset);
-void kvm_gmem_unbind(struct kvm_memory_slot *slot);
-#else
-static inline int kvm_gmem_init(struct module *module)
-{
-	return 0;
-}
-static inline void kvm_gmem_exit(void) {};
-static inline int kvm_gmem_bind(struct kvm *kvm,
-					 struct kvm_memory_slot *slot,
-					 unsigned int fd, uoff_t offset)
-{
-	WARN_ON_ONCE(1);
-	return -EIO;
-}
-
-static inline void kvm_gmem_unbind(struct kvm_memory_slot *slot)
-{
-	WARN_ON_ONCE(1);
-}
-#endif /* CONFIG_KVM_GUEST_MEMFD */
-
 #endif /* __KVM_MM_H__ */