On 07.07.2010 13:37, Thor Lancelot Simon wrote: > On Wed, Jul 07, 2010 at 01:57:30PM +0530, Cherry G. Mathew wrote: >>> >>> How would you stop the domU being able to increase its memory size (e.g. on >>> a hosted service, you wouldn't want the client taking more resources than >>> they've paid for)? >> >> There are no such limits by design at the moment. However at the >> moment a de-facto limit exists (ie; the amount specified in the domU >> config file), because we don't add more pages than we had to begin >> with. Fixing this will need looking at uvm(9).) > > This is pretty bogus -- it seems like it allows a single domU to > effectively take over the entire virtualization environment. I think > there really needs to be a hard cap enforced by the dom0 -- what's to > keep a misbehaving Linux domU, for instance, which starts up early, from > balooning away every last page on the machine and preventing later domUs > from starting? > > I believe this should be disabled on the dom0 side by default until > this problem is addressed.
The mem-max operation is part of the "domctl" hypercalls, like create, pause, resume, etc; they must be performed by a privileged domain (99,99% of the time, the dom0) or else, the hypervisor will return EPERM. -- Jean-Yves Migeon jeanyves.mig...@free.fr
