[Qemu-devel] [PATCH 0/3] target-arm: convert to VMState, fix bugs

[Peter Maydell]

This patch series converts target-arm to doing migration via
a VMState structure, and fixes some minor bugs in migration
of the CPU as well. The bulk of it is a patch Juan sent out
back in the middle of last year
 https://lists.gnu.org/archive/html/qemu-devel/2012-05/msg00550.html
which I have rebased and messed about with somewhat:
 * rebased and fixed conflicts
 * updated to use cpu_class_set_vmsd()
 * updated with new/removed fields since original patch
 * corrected subsection names so vmload doesn't fail
 * changed to use custom VMStateInfo for cpsr rather than
   presave/postload hooks

The last of these was the subject of some discussion when Juan
posted the patch (see URL above for the thread). The fundamental
problem that has to be solved is "how do you deal with cases
where the representation in the in memory struct is not the
same as the on the wire representation?":
(a) Juan's original patch does "write wire format to random dummy
    field in the struct and then clean things up in presave/postload
    hooks".
(b) My patch follows what Alpha, i386 and some devices do: define
    a custom VMStateInfo which reads/writes the wire format and
    does the conversion to/from the struct.
(c) There was a mooted third approach of defining new vmstate macros
    and functionality so you could specify conversion functions for
    a field but leave actual reading and writing of the wire format
    to the core savevm code.

The argument against (b) was that it makes introducing a new
migration wire format harder, but on the other hand it's a year
later and nobody has, and we already have examples of this in
tree so another user is no big deal. So it doesn't seem
to me to merit the effort of actually implementing (c). I've
gone for (b) because I think it's better than (a).

Overall I think the whole series is an improvement over the
separate save/load fields; I'd also like to get this changeover
done before we start having to worry about freezing the ARM
migration format.


Juan Quintela (1):
  target-arm: port ARM CPU save/load to use VMState

Peter Maydell (2):
  target-arm: Add some missing CPU state fields to VMState
  target-arm: Correctly restore FPSCR

 target-arm/cpu-qom.h |    4 +
 target-arm/cpu.c     |    1 +
 target-arm/cpu.h     |    2 -
 target-arm/machine.c |  430 +++++++++++++++++++++++++-------------------------
 4 files changed, 221 insertions(+), 216 deletions(-)

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1.7.9.5