KVM: Drop "const" attribute from old memslot in commit_memory_region()

Drop the "const" attribute from @old in kvm_arch_commit_memory_region()
to allow arch specific code to free arch specific resources in the old
memslot without having to cast away the attribute.  Freeing resources in
kvm_arch_commit_memory_region() paves the way for simplifying
kvm_free_memslot() by eliminating the last usage of its @dont param.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/mips/kvm/mips.c

@@ -224,7 +224,7 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 
 void kvm_arch_commit_memory_region(struct kvm *kvm,
 				   const struct kvm_userspace_memory_region *mem,
-				   const struct kvm_memory_slot *old,
+				   struct kvm_memory_slot *old,
 				   const struct kvm_memory_slot *new,
 				   enum kvm_mr_change change)
 {

arch/powerpc/kvm/powerpc.c

@@ -701,7 +701,7 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 
 void kvm_arch_commit_memory_region(struct kvm *kvm,
 				   const struct kvm_userspace_memory_region *mem,
-				   const struct kvm_memory_slot *old,
+				   struct kvm_memory_slot *old,
 				   const struct kvm_memory_slot *new,
 				   enum kvm_mr_change change)
 {

arch/s390/kvm/kvm-s390.c

@@ -4532,7 +4532,7 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 
 void kvm_arch_commit_memory_region(struct kvm *kvm,
 				const struct kvm_userspace_memory_region *mem,
-				const struct kvm_memory_slot *old,
+				struct kvm_memory_slot *old,
 				const struct kvm_memory_slot *new,
 				enum kvm_mr_change change)
 {

arch/x86/kvm/x86.c

@@ -10024,7 +10024,7 @@ static void kvm_mmu_slot_apply_flags(struct kvm *kvm,
 
 void kvm_arch_commit_memory_region(struct kvm *kvm,
 				const struct kvm_userspace_memory_region *mem,
-				const struct kvm_memory_slot *old,
+				struct kvm_memory_slot *old,
 				const struct kvm_memory_slot *new,
 				enum kvm_mr_change change)
 {

include/linux/kvm_host.h

@@ -678,7 +678,7 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 				enum kvm_mr_change change);
 void kvm_arch_commit_memory_region(struct kvm *kvm,
 				const struct kvm_userspace_memory_region *mem,
-				const struct kvm_memory_slot *old,
+				struct kvm_memory_slot *old,
 				const struct kvm_memory_slot *new,
 				enum kvm_mr_change change);
 bool kvm_largepages_enabled(void);

virt/kvm/arm/mmu.c

@@ -2251,7 +2251,7 @@ int kvm_mmu_init(void)
 
 void kvm_arch_commit_memory_region(struct kvm *kvm,
 				   const struct kvm_userspace_memory_region *mem,
-				   const struct kvm_memory_slot *old,
+				   struct kvm_memory_slot *old,
 				   const struct kvm_memory_slot *new,
 				   enum kvm_mr_change change)
 {

virt/kvm/kvm_main.c

@@ -985,7 +985,7 @@ static struct kvm_memslots *install_new_memslots(struct kvm *kvm,
 
 static int kvm_set_memslot(struct kvm *kvm,
 			   const struct kvm_userspace_memory_region *mem,
-			   const struct kvm_memory_slot *old,
+			   struct kvm_memory_slot *old,
 			   struct kvm_memory_slot *new, int as_id,
 			   enum kvm_mr_change change)
 {