Re: [Qemu-devel] [PATCH 0/7] merge some xen bits into qemu

[Gerd Hoffmann <kraxel@redhat.com>]

Anthony Liguori wrote:
> However, I'd like to see agreement within the Xen community that this
>  is the right approach first.  In particular, I would like to see 
> these patches either merged with upstream Xen or for upstream Xen to 
> plan to rebase against QEMU to pick them up and use them for PV 
> support.

Ian Jackson has a qemu git tree at
  http://www.chiark.greenend.org.uk/~ijackson/qemu-xen.git

As far I know it is rebased now and then and the long-term plan is to
get the delta to upstream qemu at least smaller.  Dunno whenever it ever
will be zero due to stuff like mapcache.

There are a few compatibility issues to be solved somehow before
upstream qemu is able to completely replace xen's qemu-dm:

(1) my patches use -domid to specify the domain id.  xen uses (used?) -d
instead.  Which isn't going to work because upstream qemu uses that
switch for something else.  Ian's tree supports both -d and -domid, with
a comment saying -d is deprecated.  So I think we have an agreement to
use -domid here ;)

(2) xen added a -domain-name switch.  upstream qemu has a -name switch.
my patches do not implement -domain-name, I use the name set via -name
instead.  IMHO xen should pick up the upstream way to do things here,
i.e. switch over to -name.

(3) vnc configuration is different.  This one is not so easy due to
xenstore being involved.  So the way things work are pretty xen specific
and don't make that much sense for upstream qemu.  The differences are:

Setting the vnc password:  qemu uses a monitor command.  xen reads it
from xenstore (set by xend).  I think we can just support both ways here.

xen has a -vncunused switch which makes qemu scan for a free vnc
display.  The tcp port actually used is written to xenstore.  Dunno how
to handle that one best.  First, I think should be a -vnc switch option
instead of a separate command line switch.  Second, propagating the used
port via xenstore doesn't make sense at all for upstream qemu ...

cheers,
  Gerd

-- 
http://kraxel.fedorapeople.org/xenner/