[Xen-devel] [PATCH 00/45] initial arm v8 (64-bit) support

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

First off, Apologies for the massive patch series...

This series boots a 32-bit dom0 kernel to a command prompt on an ARMv8
(AArch64) model. The kernel is the same one as I am currently using with
the 32 bit hypervisor

I haven't yet tried starting a guest or anything super advanced like
that ;-). Also there is not real support for 64-bit domains at all,
although in one or two places I have laid some groundwork.

Sadly the 32- and 64-bit assembly is very different, which makes sharing
the ASM bits pretty much impossible. (Other than register names, the big
change is lack of general conditional instructions).

AArch64 has removed the concept of co-processor registers and replaced
it with system registers which are accessed by name (i.e. the assembler
understands the names). There is most often a 1-1 mapping between an
AArch64 system register and a AArch32 cp register. To try and reduce
ifdeferry in common code I've introduced some macros which take the
AArch64 name but which translate to the appropriate AArch32 cpreg access
in the 32-bit hypervisor. A little bit of ifdeferry remains.

Other uses of the coprocessors (e.g. cache/TLB flushing etc) are
replaced with explicit instructions (again there's mostly a 1-1
mapping). We had already wrapped most of these in a suitable inline
function so it was easy enough to abstract away.

Lastly, rather than switch internally from explicitly sized types to
unsigned long I have instead introduced some semantic types (register_t
and vaddr_t, which complement the existing paddr_t). I'm not really too
sure of this approach though.

Ian.



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