Re: [Qemu-devel] [PATCH 16/17] spapr_vio: take care of creating our own AddressSpace/DMAContext

[Paolo Bonzini]

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Il 01/05/2013 07:16, David Gibson ha scritto:
> Lack of atomicity makes me a little nervous there, although I
> guess its ok since qemu is single-threaded.

Yes.  The original plan was to add a boolean return value to
address_space_rw, but I left this for later since I wasn't sure of the
semantics for multipage writes.  What happens if the second half of
the destination buffer has an invalid translation?  Right now it's
atomic, but it sounds weird for real hardware.

Paolo

> It does mean we do the translations twice, effectively, which isn't
> ideal, although emulated devices are already so slow it probably
> doesn't matter.
> 


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