Re: [Qemu-devel] [PATCH 3/6] rdma: core logic

[Michael R. Hines]

On 06/28/2013 09:28 AM, Peter Maydell wrote:
> On 28 June 2013 14:23, Michael R. Hines <address@hidden> wrote:
> > > I assume from the PACKED annotations (do we really need both,
> > > incidentally) that this is shared with either the guest or
> > > with another instance of QEMU. Are there definitely no
> > > endianness issues to deal with here?
> >
> > I have ntohl()/htonl() on the protocol headers, but I did not
> > add them for the data portions of the protocol.
> >
> >
> > Is endianess for the data a big issue when you are assume the migration
> > is happening across identical CPU architectures?
> Well:
>   * is that a reasonable assumption? (why?)

I would yes, because we're dealing raw guest RAM.
Migration of memory would not work across a different architecture
(particularly page tables - which would need to be canonicalized
and de-canonicalized).

>   * if you try this on some setup where it's not true, do we
>     fail helpfully or obscurely?

Shouldn't a check like that occur before the migration actually begins?
Is this specific to RDMA?