Re: [PATCH v3 2/7] x86/sgx: Add infrastructure to identify SGX EPC pages

[Jarkko Sakkinen]

On Fri, Jul 30, 2021 at 11:44:00AM -0700, Luck, Tony wrote:
> On Fri, Jul 30, 2021 at 09:50:59AM -0700, Dave Hansen wrote:
> > On 7/30/21 9:46 AM, Sean Christopherson wrote:
> > > Out of curiosity, on multi-socket systems, are EPC sections clustered in a single
> > > address range, or are they interleaved with regular RAM?  If they're clustered,
> > > you could track the min/max across all sections to optimize the common case that
> > > an address isn't in any EPC section.
> > 
> > They're interleaved on the systems that I've seen:
> > 
> > 	Socket 0 - RAM
> > 	Socket 0 - EPC
> > 	Socket 1 - RAM
> > 	Socket 1 - EPC
> > 
> > It would probably be pretty expensive in terms of the physical address
> > remapping resources to cluster them.
> 
> I thought xarray was overkill ... and it is ... but it makes the code
> considerably shorter/simpler!
> 
> I think I'm going to go with it. Thanks to Jarkko for the suggestion.

If it makes the code considerably simpler, that in my opinion justifies the
minor size increase.

/Jarkko