Re: [Qemu-devel] [PATCH 2/5] Add SCM_RIGHTS support to unix socket character devices

[Jamie Lokier]

Avi Kivity wrote:
> Why impose unnecessary restrictions?  I agree that the guest shouldn't 
> use qemu as an fd store.  But putting such limits in the code is laying 
> a trap for the client, which will show up in rare cases, for example two 
> client threads issuing unrelated getfd commands with the client author 
> not knowing it should serialize them.

If there is an fd queue, then it clearly must be limited on the QEMU
side to avoid becoming an fd store.

A client issuing unrelated commands must be aware of that limitation.
The queue length could be 1, or it could be 10 per monitor to allow
some command overlap, but the client will need to be aware of it and
limit overlap.

That means the limit must be documented in any (future :-) monitor
protocol documentation.

-- Jamie