diff --git a/README b/README
index 40a72d3..34cc51a 100644
--- a/README
+++ b/README
@@ -1,16 +1,21 @@
 Building the KVM kernel module is performed differently depending on whether
 you are working from a clone of the git repository or from a source release.
+Notice that two kernels are involved: One from which the KVM sources
+are taken (kernel A), and one for which the module is built (kernel B). 
+For out-of-tree module builds, it is well possible that kernel A is more
+recent than kernel B.
 
 - To build from a release, simply use ./configure (possibly with any
   arguments that are required for your setup, see ./configure --help)
-  and make.
+  and make. The kernel specified with --kerneldir refers to kernel B,
+  that is, the kernel for which the module is built.
 
 - Building from a cloned git repository requires a kernel tree with the main
-  kvm sources that is included as a submodule in the linux-2.6/ directory.  By
-  default, the KVM development tree on git.kernel.org is used, but you can
-  change this setting in .gitmodules
+  kvm sources (kernel A) that is included as a submodule in the linux-2.6/
+  directory.  By default, the KVM development tree on git.kernel.org is used,
+  but you can change this setting in .gitmodules
 
-  Before the kvm module can be built, the linux submodule must be initialised 
+  Before the kvm module can be built, the linux submodule must be initialised
   and populated. The required sequence of commands is
 
   git submodule init
@@ -24,3 +29,5 @@ you are working from a clone of the git repository or from a source release.
 
   make sync LINUX=/path/to/tree
 
+  The synchronisation stage refers to kernel A, that is, the kernel
+  from which the KVM sources are taken.