• Luis R. Rodriguez's avatar
    kconfig: add xenconfig defconfig helper · 6c668505
    Luis R. Rodriguez authored
    This lets you build a kernel which can support xen dom0
    or xen guests on i386, x86-64 and arm64 by just using:
       make xenconfig
    You can start from an allnoconfig and then switch to xenconfig.
    This also splits out the options which are available currently
    to be built with x86 and 'make ARCH=arm64' under a shared config.
    Technically xen supports a dom0 kernel and also a guest
    kernel configuration but upon review with the xen team
    since we don't have many dom0 options its best to just
    combine these two into one.
    A few generic notes: we enable both of these:
    although technically not required given you likely will
    end up with a pretty useless system otherwise.
    A few architectural differences worth noting:
    $ make allnoconfig; make xenconfig > /dev/null ; \
    	grep XEN .config > 64-bit-config
    $ make ARCH=i386 allnoconfig; make ARCH=i386 xenconfig > /dev/null; \
    	grep XEN .config > 32-bit-config
    $ make ARCH=arm64 allnoconfig; make ARCH=arm64 xenconfig > /dev/null; \
    	grep XEN .config > arm64-config
    Since the options are already split up with a generic config and
    architecture specific configs you anything on the x86 configs
    are known to only work right now on x86. For instance arm64 doesn't
    support MEMORY_HOTPLUG yet as such although we try to enabe it
    generically arm64 doesn't have it yet, so we leave the xen
    specific kconfig option XEN_BALLOON_MEMORY_HOTPLUG on x86's config
    file to set expecations correctly.
    Then on x86 we have differences between i386 and x86-64. The difference
    between 64-bit-config and 32-bit-config is you don't get XEN_MCE_LOG as
    this is only supported on 64-bit. You also do not get on i386
    XEN_BALLOON_MEMORY_HOTPLUG, there does not seem to be any technical
    reasons to not allow this but I gave up after a few attempts.
    Cc: Josh Triplett <josh@joshtriplett.org>
    Cc: Borislav Petkov <bp@suse.de>
    Cc: Pekka Enberg <penberg@kernel.org>
    Cc: David Rientjes <rientjes@google.com>
    Cc: Michal Marek <mmarek@suse.cz>
    Cc: Randy Dunlap <rdunlap@infradead.org>
    Cc: penberg@kernel.org
    Cc: levinsasha928@gmail.com
    Cc: mtosatti@redhat.com
    Cc: fengguang.wu@intel.com
    Cc: David Vrabel <david.vrabel@citrix.com>
    Cc: Ian Campbell <Ian.Campbell@citrix.com>
    Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
    Cc: xen-devel@lists.xenproject.org
    Acked-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
    Acked-by: default avatarJulien Grall <julien.grall@linaro.org>
    Acked-by: default avatarMichal Marek <mmarek@suse.cz>
    Acked-by: default avatarDavid Rientjes <rientjes@google.com>
    Reviewed-by: default avatarJosh Triplett <josh@joshtriplett.org>
    Signed-off-by: default avatarLuis R. Rodriguez <mcgrof@suse.com>
    Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>