Re: [Qemu-ppc] [PATCH v7 2/3] VFIO: Helper function to retrieve container fd

[Benjamin Herrenschmidt]

On Tue, 2014-05-27 at 12:27 -0600, Alex Williamson wrote:

> Ugh, the patches are flying too fast, I can't even keep track that this
> is a QEMU patch.  I'm not as concerned about the "get" in QEMU, but do
> we really want to create a future hotplug issue where we've handed out a
> file descriptor to another part of QEMU without a path to disable it
> when it gets closed?  I really have no idea what else you're relying on
> being exported here since we're building patches on top of out-of-tree
> patches.

Out-of-tree, you mean the powerpc VFIO bits ? The stuff that still
hasn't been merged almost a year after first submission ? :-)

In any case, if you look at Gavin's next patch which uses this exported
fd you'll see that it's never kept along. It's purely a sequence of
RTAS handlers that do:

        get fd
        do ioctl
        return to guest

Ie, they are short lived and this code is intimately linked to spapr
PCI so it will have to handle hotplug as well (hotplug for us goes
via RTAS calls too). I think there shouldn't be a problem.

Now, we can move those into a pile of additional wrappers and call them
vfio-eeh.c but it's a bit pointless isn't it ?

Cheers,
Ben.