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Date: Wed, 25 Jun 2014 20:00:59 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] vhost-user: broken mem regions
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To: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>
Cc: qemu-devel <qemu-devel@nongnu.org>, VirtualOpenSystems Technical Team <tech@virtualopensystems.com>, "Damjan Marion (damarion)" <damarion@cisco.com>, "Michael S. Tsirkin" <mst@redhat.com>

Il 25/06/2014 19:06, Nikolay Nikolaev ha scritto:
>> > I understand now what you mean.  Yeah, the format should be changed
>> > to include the offset (why does vhost-user need the ua at all?
>> > perhaps the offset can replace the ua).
> I am trying to do the math here. So if this file is mapped by QEMU
> into a single file then probably
> (region[4].ua - region[3].ua) should give you the offset. And also
> (region[4].ua - region[1].ua) shoudl give the above 3G offset. Or I am
> missing something?

This is correct, but in principle it's not required to map all the 
areas.  The lowest region could correspond to a offset=65536, or 
something like that.  It's better to change the vring values to use 
offsets instead of absolute addresses.

Paolo