Re: [Qemu-devel] [PATCH] exec: limit system memory size

[Paolo Bonzini]

Il 04/11/2013 13:04, Michael S. Tsirkin ha scritto:
> > > > Also, I'm not sure what will this test tell
> > > > us: inl reads io space, not memory, right?
> > 
> > The number of levels in the dispatch radix tree is independent of the
> > size of the AddressSpace; it is P_L2_LEVELS for both the 64K io space
> > and the 2^TARGET_PHYS_ADDRESS_SPACE_BITS memory space.
> 
> Hmm I think it's *at most* that deep but can be more shallow, no?

Yes, but it gets more shallow only if you have very large regions (which
is obviously not the case for io space).  The levels always cover the
same bit range (e.g. bits 42-51 for the first level on x86).

Paolo