KVM: x86/mmu: Move KVM-only page-track declarations to internal header

Bury the declaration of the page-track helpers that are intended only for
internal KVM use in a "private" header.  In addition to guarding against
unwanted usage of the internal-only helpers, dropping their definitions
avoids exposing other structures that should be KVM-internal, e.g. for
memslots.  This is a baby step toward making kvm_host.h a KVM-internal
header in the very distant future.

Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-22-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Author: sean-jc

arch/x86/include/asm/kvm_page_track.h

@@ -2,6 +2,8 @@
 #ifndef _ASM_X86_KVM_PAGE_TRACK_H
 #define _ASM_X86_KVM_PAGE_TRACK_H
 
+#include <linux/kvm_types.h>
+
 enum kvm_page_track_mode {
 	KVM_PAGE_TRACK_WRITE,
 	KVM_PAGE_TRACK_MAX,
@@ -46,37 +48,18 @@ struct kvm_page_track_notifier_node {
 				    struct kvm_page_track_notifier_node *node);
 };
 
-int kvm_page_track_init(struct kvm *kvm);
-void kvm_page_track_cleanup(struct kvm *kvm);
-
-bool kvm_page_track_write_tracking_enabled(struct kvm *kvm);
-int kvm_page_track_write_tracking_alloc(struct kvm_memory_slot *slot);
-
-void kvm_page_track_free_memslot(struct kvm_memory_slot *slot);
-int kvm_page_track_create_memslot(struct kvm *kvm,
-				  struct kvm_memory_slot *slot,
-				  unsigned long npages);
-
 void kvm_slot_page_track_add_page(struct kvm *kvm,
 				  struct kvm_memory_slot *slot, gfn_t gfn,
 				  enum kvm_page_track_mode mode);
 void kvm_slot_page_track_remove_page(struct kvm *kvm,
 				     struct kvm_memory_slot *slot, gfn_t gfn,
 				     enum kvm_page_track_mode mode);
-bool kvm_slot_page_track_is_active(struct kvm *kvm,
-				   const struct kvm_memory_slot *slot,
-				   gfn_t gfn, enum kvm_page_track_mode mode);
 
 void
 kvm_page_track_register_notifier(struct kvm *kvm,
 				 struct kvm_page_track_notifier_node *n);
 void
 kvm_page_track_unregister_notifier(struct kvm *kvm,
 				   struct kvm_page_track_notifier_node *n);
-void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
-			  int bytes);
-void kvm_page_track_delete_slot(struct kvm *kvm, struct kvm_memory_slot *slot);
-
-bool kvm_page_track_has_external_user(struct kvm *kvm);
 
 #endif

arch/x86/kvm/mmu/mmu.c

@@ -25,6 +25,7 @@
 #include "kvm_cache_regs.h"
 #include "smm.h"
 #include "kvm_emulate.h"
+#include "page_track.h"
 #include "cpuid.h"
 #include "spte.h"
 
@@ -53,7 +54,7 @@
 #include <asm/io.h>
 #include <asm/set_memory.h>
 #include <asm/vmx.h>
-#include <asm/kvm_page_track.h>
+
 #include "trace.h"
 
 extern bool itlb_multihit_kvm_mitigation;

arch/x86/kvm/mmu/page_track.c

@@ -15,10 +15,9 @@
 #include <linux/kvm_host.h>
 #include <linux/rculist.h>
 
-#include <asm/kvm_page_track.h>
-
 #include "mmu.h"
 #include "mmu_internal.h"
+#include "page_track.h"
 
 bool kvm_page_track_write_tracking_enabled(struct kvm *kvm)
 {
@@ -300,8 +299,3 @@ void kvm_page_track_delete_slot(struct kvm *kvm, struct kvm_memory_slot *slot)
 			n->track_remove_region(slot->base_gfn, slot->npages, n);
 	srcu_read_unlock(&head->track_srcu, idx);
 }
-
-bool kvm_page_track_has_external_user(struct kvm *kvm)
-{
-	return !hlist_empty(&kvm->arch.track_notifier_head.track_notifier_list);
-}

arch/x86/kvm/mmu/page_track.h

@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __KVM_X86_PAGE_TRACK_H
+#define __KVM_X86_PAGE_TRACK_H
+
+#include <linux/kvm_host.h>
+
+#include <asm/kvm_page_track.h>
+
+int kvm_page_track_init(struct kvm *kvm);
+void kvm_page_track_cleanup(struct kvm *kvm);
+
+bool kvm_page_track_write_tracking_enabled(struct kvm *kvm);
+int kvm_page_track_write_tracking_alloc(struct kvm_memory_slot *slot);
+
+void kvm_page_track_free_memslot(struct kvm_memory_slot *slot);
+int kvm_page_track_create_memslot(struct kvm *kvm,
+				  struct kvm_memory_slot *slot,
+				  unsigned long npages);
+
+bool kvm_slot_page_track_is_active(struct kvm *kvm,
+				   const struct kvm_memory_slot *slot,
+				   gfn_t gfn, enum kvm_page_track_mode mode);
+
+void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
+			  int bytes);
+void kvm_page_track_delete_slot(struct kvm *kvm, struct kvm_memory_slot *slot);
+
+static inline bool kvm_page_track_has_external_user(struct kvm *kvm)
+{
+	return !hlist_empty(&kvm->arch.track_notifier_head.track_notifier_list);
+}
+
+#endif /* __KVM_X86_PAGE_TRACK_H */

arch/x86/kvm/x86.c

@@ -25,6 +25,7 @@
 #include "tss.h"
 #include "kvm_cache_regs.h"
 #include "kvm_emulate.h"
+#include "mmu/page_track.h"
 #include "x86.h"
 #include "cpuid.h"
 #include "pmu.h"