KVM: Explicitly free allocated-but-unused dirty bitmap

Sean Christopherson · bonzini · commit bd0e96fdc5a5 · 2020-03-16T17:57:18.000+01:00
Explicitly free an allocated-but-unused dirty bitmap instead of relying on kvm_free_memslot() if an error occurs in __kvm_set_memory_region(). There is no longer a need to abuse kvm_free_memslot() to free arch specific resources as arch specific code is now called only after the common flow is guaranteed to succeed. Arch code can still fail, but it's responsible for its own cleanup in that case. Eliminating the error path's abuse of kvm_free_memslot() paves the way for simplifying kvm_free_memslot(), i.e. dropping 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>
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
@@ -1093,7 +1093,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
 
 	slots = kvzalloc(sizeof(struct kvm_memslots), GFP_KERNEL_ACCOUNT);
 	if (!slots)
-		goto out_free;
+		goto out_bitmap;
 	memcpy(slots, __kvm_memslots(kvm, as_id), sizeof(struct kvm_memslots));
 
 	if ((change == KVM_MR_DELETE) || (change == KVM_MR_MOVE)) {
@@ -1141,8 +1141,9 @@ int __kvm_set_memory_region(struct kvm *kvm,
 	if (change == KVM_MR_DELETE || change == KVM_MR_MOVE)
 		slots = install_new_memslots(kvm, as_id, slots);
 	kvfree(slots);
-out_free:
-	kvm_free_memslot(kvm, &new, &old);
+out_bitmap:
+	if (new.dirty_bitmap && !old.dirty_bitmap)
+		kvm_destroy_dirty_bitmap(&new);
 out:
 	return r;
 }
