Messages in this thread | | | Subject | Re: [Xen-devel] [PATCH 0/2] block/xen-blkfront: Support non-indirect with 64KB page granularity | From | Julien Grall <> | Date | Sun, 13 Sep 2015 18:47:41 +0100 |
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On 13/09/2015 13:44, Bob Liu wrote: > I may misunderstood here. > But I think same changes are also required even if backend supports indirect grant when frontend is using 64KB page granularity. > Else > 1) How to set up the grant map for requests in domU? > The minimum segment buffer size in a request is PAGE_SIZE(64KB) while grant is 4KB based. > > 2) Codes like below in blkback.c may not work correctly? > if ((req->u.rw.seg[i].last_sect >= (PAGE_SIZE >> 9)) || > > Because PAGE_SIZE in backend is 4KB, while the written value by domU is 64KB based.
As mention in my cover letter, this patch is not self-sufficient to support 64KB guest. It's a follow-up of the 64KB page granularity support I sent on the ML (the new version was sent earlier this week [1]).
One of the patch [2] is taking care of breaking down the I/O request in multiple 4KB segment that will be used in the ring request. You may want to give a look to this patch before looking to this series.
Regards,
[1] https://lwn.net/Articles/656797/ [2] http://www.spinics.net/lists/arm-kernel/msg430468.html
-- Julien Grall
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