• Keir Fraser's avatar
    Disable kernel build in Xen build system. · 25ea3857
    Keir Fraser authored
    Cloning and building a kernel as part of the Xen distribution
    implicitly advises that this kernel is the best kernel for all users
    and many users appear to be under this impression, even though there
    is no fundamental coupling between the Xen distribution and a
    particular domain 0 kernel.
    
    There are several choices available for domain 0 kernel, as well as
    other user specific variations in requirements e.g. for kernel
    configurations. It's not clear that whatever the xen build system
    happens to produce (which is really tailored to the needs of the
    automated build system) is best for anybody.
    
    Coupling the kernel build with the Xen build has proved problematic
    for stable Xen releases as it implicitly blesses the particular kernel
    (at a particular point in time) as a constituent part of the Xen
    release, while in reality the OS kernels are separate entities with
    their own release cycles which may or may not coincide with the
    maintenance of Xen stable branches.
    
    Therefore disable the building of a kernel as part of the Xen
    distribution by default and instead direct users to use an OS
    distribution provided kernel (properly packaged with security updates
    via the normal distribution mechanisms etc) where possible and give
    pointers to suitable resources providing guidance for cases where it
    is not.
    
    This decouples the implicit advice as to the best kernel at any moment
    from Xen's own release cycle and removes the implicit suggestion that
    only particular domain 0 kernel will do.
    
    The actual infrastructure is left in place since the automated test
    system (currently) relies on it (but always asks for the specific
    kernel variant it wants for a particular test).
    
    (I also tried to remove Linux-isms from the README's Quick start
    guide. In particular I'm not sure what was supposedly Linux specific
    about steps 3 and 4 therefore I have removed the suggestion that they
    are.)
    Signed-off-by: 's avatarIan Campbell <ian.campbell@citrix.com>
    Acked-by: 's avatarIan Jackson <ian.jackson@eu.citrix.com>
    25ea3857