[Fedora-xen] Xen only showing 16GB of ram out of 28GB

[Gerd Hoffmann]

  Hi,

> than 16 GB of RAM. I believe you need 64-bit HV to see all. You may or
> may not also need a 64-bit Dom0 - I don't know for sure since I'm not
> lucky enough to have more than 16 GB of RAM :-(

Dom0 can be 32bit (and must be in fedora7 if you want run 32bit guests
and don't wait for the kernel update).

With a 32bit hypervisor everything must fit into the hypervisor address
space hole.  With a 64bit hypervisor only the m2p table must fit into
the address space hole.  Thus even 32bit guests can see much more memory
when running on a 64bit hypervisor.  The limit is far beyond 64GB (was
some odd number, 166GB IIRC), although I'd be prepared to run into bugs
when crossing the 64GB border ...

cheers,

  Gerd