Hi,

# xl vcpu-list
hangs on my big box. The issue is an endless loop, where the algorithm
for printing the CPU affinity in a condensed way looks for a set bit in
a zero-byte:
              for (i = 0; !(pcpumap & 1); ++i, pcpumap >>= 1)
Looking at the code I found that it is entirely broken if more than 8
CPUs are used. Beside that endless loop issue the output is totally
bogus except for the "any CPU" case, which is handled explicitly earlier.
I tried to fix it, but the whole approach does not work if the outer
loops actually iterates (executing more than once).
I could not copy the Linux version of that algorithm due to licensing
incompatibilities and the Python version is not easily converted to C,
so I coded my own version from scratch. It is a bit verbose since it
iterates over bits instead of bytes, but more cleaner and survived some
unit-testing. I didn't spend much time in optimizing it, though.
I put it in a separate function as I plan to use it later for printing
cpupool affinity in a similar way (a post 4.1.0 patch living in one of 
my branches).

If you have a better implementation available, I can push it through my 
automated unit test easily.

Please review and apply to Xen 4.1.0-rc.

Signed-off-by: Andre Przywara <andre.przywara@amd.com>

Regards,
Andre.

-- 
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany