Re: [PATCH v2] Use EfiACPIReclaimMemory for ESRT

[Demi Marie Obenour <demi@xxxxxxxxxxxxxxxxxxxxxx>]

On Tue, Oct 11, 2022 at 11:59:01AM +0200, Jan Beulich wrote:
> On 11.10.2022 05:42, Demi Marie Obenour wrote:
> > A previous patch tried to get Linux to use the ESRT under Xen if it is
> > in memory of type EfiRuntimeServicesData.  However, this turns out to be
> > a bad idea.  Ard Biesheuvel pointed out that EfiRuntimeServices* memory
> > winds up fragmenting both the EFI page tables and the direct map,
> 
> Can this statement please be made describe Xen, not Linux? Aiui at least
> the directmap aspect doesn't apply to Xen.

Should it apply to Xen?  My understanding is that Ard’s statements
regarding mismatched attributes refer to any kernel, not just Linux.
You would be in a better position to judge that, though.

> > and
> > that EfiACPIReclaimMemory is a much better choice for this purpose.
> 
> I think the "better" wants explaining here, without requiring people to
> follow ...

Something like, “EfiACPIReclaimMemory is the correct type for
configuration tables that are only used by the OS.”?

> > Link: 
> > https://lists.xenproject.org/archives/html/xen-devel/2022-09/msg01365.html
> 
> ... this link. Since the code change looks okay to me, I'd be okay to
> replace the description with an adjusted one while committing.

That is fine with me.

> However,
> if you expect the change to go into 4.17, you will want to resubmit
> with Henry on Cc:, so he can consider giving the now necessary release-
> ack.

Will do, with your updated commit message.
-- 
Sincerely,
Demi Marie Obenour (she/her/hers)
Invisible Things Lab

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