Hi,
On 19/10/17 16:11, Jan Beulich wrote:
On 19.10.17 at 16:49, <paul.durr...@citrix.com> wrote:
I'd prefer to make the whole thing x86-only since that's the only platform
on which I can test it, and indeed the code used to be x86-only. Jan objected
to this so all I'm trying to achieve is that it builds for ARM. Please can you
and
Jan reach agreement on where the code should live and how, if at all, it
should be #ifdef-ed?
I am quite surprised of "it is tools-only" so it is fine to not protect
it even if it is x86 only. That's probably going to bite us in the future.
So, this appears to have reached an impasse. I don't know how to proceed
without having to also fix priv mapping for x86, which is a yak far too large
for me to shave at the moment.
Julien,
why is it that you are making refcounting on p2m insertion / removal
a requirement for this series? We all know it's not there right now
(and similarly also not for the IOMMU, which might affect ARM as well
unless you always use shared page tables), and it's - as Paul validly
says - unrelated to his series.
Well, we do at least have refcounting for foreign mapping on Arm. So if
a foreign domain remove the mapping, the page will stay allocated until
the last mapping is removed. For IOMMU, page tables are for the moment
always shared.
If you don't want to fix x86 now, then it is fine. But I would
appreciate if you don't spread that on Arm.
To give you a bit more context, I was ready to implement the Arm version
of set_foreign_p2m_entry (it is quite trivial) to append at the end of
this series. But given that refcounting is not done, I am more reluctant
to do that.
Anyway, I don't plan to block common code. But I will block any
implementation of set_foreign_p2m_entry (other than returning not
implemented) on Arm until someone step up and fix the refcounting.
Cheers,
--
Julien Grall
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