[Qemu-devel] Re: [PATCH] introduce kvm64 CPU

[Jamie Lokier <jamie@shareable.org>]

Andre Przywara wrote:
> If you happen to stuck with 32bit 
> (pity you!) then I agree that a kvm32 would be nice to have.
> Will think about it...

I know that 32-bit is a bit slower for some things due to register
pressure (but it's a bit faster for some things due to less memory
needed for pointers), and it's RAM is limited to about 3GB in
practice, which affects some things but is plenty for others.

I know it's a pain for KVM developers to support 32-bit hosts.

And yes, it would be nice to run a 64-bit guest from time to time.

But apart from being a bit slower, is there anything wrong with 32-bit
x86s compared with 64-bit that justifies pity?

The 32-bitness doesn't seem to be a handicap, only perhaps the
expected amount of slowness for a laptop that's 2-3 years old, or a
current netbook, compared with current desktops and servers.

So I'm having a hard time understanding why 32-bitness is considered
bad for KVM - why "pity"?  Does it have any other real problems than
not being able to emulate 64-bit guests that I should know about, or
is it just a matter of distaste?

-- Jamie