-----Original Message----- From: Lorenzo Pieralisi [mailto:lorenzo.pieralisi@arm.com] Sent: 13 April 2021 11:35 To: Shameerali Kolothum Thodi shameerali.kolothum.thodi@huawei.com Cc: Jonathan Cameron jonathan.cameron@huawei.com; wanghuiqiang wanghuiqiang@huawei.com; linaro-open-discussions@op-lists.linaro.org Subject: Re: RMR spec //(was)RE: [Linaro-open-discussions] Suggested Agenda / timings for Monday 7 Dec call
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I am trying to respin the RMR series now and after re-reading the RMR part of the IORT spec, a bit confused now.
In section 3.1.1.5, it says "The association of reserved memory ranges to stream IDs is always expressed as M:1 for each RMR node....". Does that mean the "Number of ID Mappings" for each RMR node should be set to 1?
Also to confirm, that means if there are multiple stream IDs that requires
same
memory regions to be unity mapped, then we need multiple RMR nodes for
each
stream IDs, right?
You mean an RMR node per streamID and answer is yes to both questions.
Ok. Thanks for confirming.
Out of curiosity: do you have a use case for multiple streamids requiring the *same* unity mappings ?
Not that I am aware of. But my current RMR implementation supports M:N. So thought of double checking before I change it to M:1.
Further down, it also says, "Each Memory Range descriptor must describe a unique range of memory that does not overlap with memory ranges
described
by other descriptors.". So if above is true(ie, M:1), then the statement about the unique range is only applicable to the descriptors in a particular RMR
node
and not across the nodes.
It refers to descriptors within one RMR node, I asked to add a clarification to the specs.
Ok. That will help.
Could you please take a look and clarify
Have I managed to clarify ? Please let me know.
Yes absolutely.
Thanks, Shameer