On Fri, Sep 02, 2022 at 03:33:20PM +0000, Kalra, Ashish wrote:

Yes we want to map the faulting address to a RMP entry, but hugepage
entries in RMP table are basically subpage 4K entries. So it is a 4K
entry when the page is a 2M one and also a 4K entry when the page is a
1G one.

Wait, what?!

APM v2 section "15.36.11 Large Page Management" and PSMASH are then for
what exactly?

That's why the computation to get a 4K page index within a 2M/1G
hugepage mapping is required.

What if a guest RMP-faults on a 2M page and there's a corresponding 2M
RMP entry? What do you need the 4K entry then for?

Hell, __snp_lookup_rmpentry() even tries to return the proper page
level...

/me looks in disbelief in your direction...

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette