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<TITLE>RE: [openib-general] [ANNOUNCE] GSI Implementation Candidate</TITLE>
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<P><FONT SIZE=2>> -----Original Message-----</FONT>
<BR><FONT SIZE=2>> From: Roland Dreier [<A HREF="mailto:roland@topspin.com">mailto:roland@topspin.com</A>]</FONT>
<BR><FONT SIZE=2>> Sent: Wednesday, August 04, 2004 7:23 AM</FONT>
<BR><FONT SIZE=2>> To: Dror Goldenberg</FONT>
<BR><FONT SIZE=2>> Cc: Grant Grundler; openib-general@openib.org</FONT>
<BR><FONT SIZE=2>> Subject: Re: [openib-general] [ANNOUNCE] GSI Implementation Candidate</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> Dror> It is not possible to turn off PD check on a MR in</FONT>
<BR><FONT SIZE=2>> Dror> Tavor. You will have to create an MR for each PD that you</FONT>
<BR><FONT SIZE=2>> Dror> need. One way to go is to map all kernel apps to the same</FONT>
<BR><FONT SIZE=2>> Dror> PD, but you probably don't want to do such a thing.</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> It's no big deal to create one more MR with translation off for each</FONT>
<BR><FONT SIZE=2>> kernel PD (in fact mthca does it already for access to address</FONT>
<BR><FONT SIZE=2>> vectors). So this is a perfectly reasonable solution, it just means</FONT>
<BR><FONT SIZE=2>> our API can't perfectly match the verbs extensions.</FONT>
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<P><FONT SIZE=2>If you want to follow the VE API, then here is an idea. The consumer gets</FONT>
<BR><FONT SIZE=2>the reserved LKey value through query HCA. If you allocate an MR with translation</FONT>
<BR><FONT SIZE=2>off for each different PD you allocate, then you can provide the consumer with this</FONT>
<BR><FONT SIZE=2>MR. Obviously you need to do that only for kernel consumers only, and you have a hidden </FONT>
<BR><FONT SIZE=2>assumption that a consumer doesn't create more than one PD. If you can not assume </FONT>
<BR><FONT SIZE=2>that , then it won't work... Obviously, you'd need to create the PD (if it hasn't</FONT>
<BR><FONT SIZE=2>been created yet) when the CA is queried, which is also a bit ugly.</FONT>
<BR><FONT SIZE=2>Bottom line, is that I am not so sure that it is so important to match the </FONT>
<BR><FONT SIZE=2>exact verbs in this case.</FONT>
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<P><FONT SIZE=2>-Dror</FONT>
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