Xen (PV and HVM) multiple PV consoles

Hi all,
this small patch series (sent before a few times) achieves two goals:

- make PV consoles work for PV on HVM guests;

- implement support for multiple PV consoles for PV and PV on HVM guests.



Changes in v2:

- nicer safety check in patch #1;

- kzalloc instead of kmalloc;

- removed the spin_lock in vtermno_to_xencons, use
list_for_each_entry_safe.


It has been tested with pv and hvm guests, with console=ttyS0,
console=hvc0, and earlyprintk=xen, with and without serial='pty' in the
VM config file.


Stefano Stabellini (2):
      hvc_xen: support PV on HVM consoles
      hvc_xen: implement multiconsole support

 drivers/tty/hvc/hvc_xen.c          |  455 ++++++++++++++++++++++++++++++++----
 include/xen/interface/hvm/params.h |    6 +-
 2 files changed, 420 insertions(+), 41 deletions(-)


A branch with these patches based on 3.2 is available here:

git://xenbits.xen.org/people/sstabellini/linux-pvhvm.git 3.2-multiconsole-2

Cheers,

Stefano