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From: Paolo Bonzini <pbonzini@redhat.com>
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Date: Fri, 23 Sep 2016 10:18:04 +0200
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Subject: Re: [Qemu-devel] [PATCH v11 0/8] Add a generic loader
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To: Markus Armbruster <armbru@redhat.com>, Peter Maydell <peter.maydell@linaro.org>
Cc: Peter Crosthwaite <crosthwaitepeter@gmail.com>, Alistair Francis <alistair.francis@xilinx.com>, Christopher Covington <cov@codeaurora.org>, "qemu-devel@nongnu.org Developers" <qemu-devel@nongnu.org>



On 23/09/2016 10:10, Markus Armbruster wrote:
> For me, the similarity (at the conceptual level) to the persistent
> memory case is striking: in both cases, we need a backend to manage
> memory contents.  The difference is that for persistent memory, changes
> persist, while for the loader, they get reverted at reset.

Not just that.  For persistent memory, there is a MemoryRegion
corresponding to the memory _and_ an interface to manage it.

For the loader the contents are copied every time from an out-of-band
storage.

> An argument for using -device could go as follows: this is a device to
> monkey patch memory.  It needs a backend to manage the bits, just like
> other memory-related devices do.  Since its backend is trivial, we
> folded it in rather than make it a separate backend.

The backend is not just trivial, it is _literally_ a 64-bit value...  I
think "-object long,value=3D0x123456789abcdef0 is taking things a bit too=
 far.

Paolo

> If we decide to use this argument for the present interface design, I
> want it recorded in the code and commit messages.