diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index db992e036bdf7ca512c76b5b901550f4d3141dc2..55867a2a460c76ef37845bbd06015f4023ca75f0 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -3905,7 +3905,7 @@ in userspace.
 	__u64 kvm_dirty_regs;
 	union {
 		struct kvm_sync_regs regs;
-		char padding[1024];
+		char padding[SYNC_REGS_SIZE_BYTES];
 	} s;
 
 If KVM_CAP_SYNC_REGS is defined, these fields allow userspace to access
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 2d2d926113bac06c10419fab643cb6b492436919..088c2c92db55782319bd5cfbbb44a74140a2e03b 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -396,6 +396,10 @@ struct kvm_run {
 		char padding[256];
 	};
 
+	/* 2048 is the size of the char array used to bound/pad the size
+	 * of the union that holds sync regs.
+	 */
+	#define SYNC_REGS_SIZE_BYTES 2048
 	/*
 	 * shared registers between kvm and userspace.
 	 * kvm_valid_regs specifies the register classes set by the host
@@ -407,7 +411,7 @@ struct kvm_run {
 	__u64 kvm_dirty_regs;
 	union {
 		struct kvm_sync_regs regs;
-		char padding[2048];
+		char padding[SYNC_REGS_SIZE_BYTES];
 	} s;
 };