Re: [RFC PATCH v4 00/19] Core scheduling v4

[Dario Faggioli]

On Tue, 2020-01-14 at 10:40 -0500, Vineeth Remanan Pillai wrote:
> On Mon, Jan 13, 2020 at 8:12 PM Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
> 
> > As a side effect of the fix, each core can now operate in core-
> > scheduling
> > mode or non core-scheduling mode, depending on how many online SMT
> > threads it has.
> > 
> > Vineet, are you guys planning to refresh v4 and update it to
> > v5?  Aubrey posted
> > a port to the latest kernel earlier.
> > 
> We are investigating a performance issue
> with
> high overcommit io intensive workload and also we are trying to see
> if
> we can add synchronization during VMEXITs so that a guest vm cannot
> run
> run alongside with host kernel. 
>
So, about this VMEXIT sync thing. I do agree that we should at least
try and do it (and assess performance).

I was wondering, however, what we think about core-scheduling + address
space isolation (or whatever it is/will be called). More specifically,
whether such a solution wouldn't be considered an equally safe setup
(at least for the virt use-cases, of course).

Basically, core-scheduling would prevent VM-to-VM attacks while ASI
would mitigate VM-to-hypervisor attacks.

Of course, such a solution would need to be fully implemented and
evaluated too... I just wanted to toss it around, mostly to know what
you think about it and whether or not it is already on your radar.

Thanks and Regards
-- 
Dario Faggioli, Ph.D
http://about.me/dario.faggioli
Virtualization Software Engineer
SUSE Labs, SUSE https://www.suse.com/
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