Re: [Xen-devel] [PATCH RFC v2 2/4] x86/mem_access: mem_access and mem_event changes to support PV domains

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 25.07.14 at 23:47, <aravindp@xxxxxxxxx> wrote:
>>you need to restrict the memory size of guests that can be subject
>>to mem-access handling.
> 
> If I was to stick to using the shadow_flags, what should the memory size 
> restriction be so as to not have a hypercall continuation? 

That's very hard to tell: What we care about is maximum processing
time for an individual hypercall (or non-preemptible portion thereof).
Hence you could either take a low enough guessed value that all of
us are convince won't cause any problems, or come up with a more
or less sophisticated formula that _you_ would need to prove is
never going to cause any problems. I can only repeat what I
(perhaps indirectly) stated before: You want the new feature, so
it's going to be primarily you to solve the problems associated with
it. We're there to help where possible, but as far as I'm concerned
if I don't offer an alternative suggestion right away then this usually
is because I can't think of one. Beyond that our primary role here
is to avoid new code causing damage or introducing (security or
other) risks.

Jan


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