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From: Peter Maydell <peter.maydell@linaro.org>
Date: Fri, 10 Oct 2014 12:23:21 +0100
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Subject: Re: [Qemu-devel] [PATCH v2 1/1] virtio: serial: expose a
 'guest_writable' callback for users
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To: Amit Shah <amit.shah@redhat.com>
Cc: marcandre.lureau@redhat.com, Amos Kong <akong@redhat.com>, Markus Armbruster <armbru@redhat.com>, qemu list <qemu-devel@nongnu.org>

On 10 October 2014 12:19, Amit Shah <amit.shah@redhat.com> wrote:
> On (Thu) 09 Oct 2014 [14:04:53], Peter Maydell wrote:
>> What I would like to see in this patch is a comment giving
>> much clearer definition of the semantics of the guest_writable
>> call: for instance, is it always called when the guest is
>> writable, or is it only guaranteed to be called if the
>> QEMU backend has previously tried to do virtio_serial_write
>> and got back a return code indicating an incomplete write?
>
> Right now it's called always; if it's necessary to only call after an
> incomplete / failed write, we just need to implement that (and also
> add that state to the migration data).
>
> I have no preference; just depends on the users of the API.

Called-always makes sense; I'd just like to see the semantics
documented so you don't have to read the whole implementation
of virtio to figure out what they are :-)

-- PMM