[libvirt] [PATCH v3 19/18] [RFC] qemu: assure there are always at least 4 open pcie-root-ports for hotplug

[Ján Tomko]

On Fri, Oct 14, 2016 at 03:13:16PM +0200, Andrea Bolognani wrote:
>On Thu, 2016-09-29 at 15:20 -0400, Laine Stump wrote:
>> In the absense of anything configurable, we will need to pick a number
>> though. I've done that here, and now we can argue about it (or not :-)
>
>Ján raised an interesting point:

[in person, there is no mailing list link]

> whatever number we choose,
>no matter how wrong doing so is, some user or application
>will end up relying on us providing at least that many
>hotpluggable ports, so there's no going back.
>
>For that reason, I would recommend leaving just a single
>empty hotpluggable port for now, and raise the number in
>the future if we find out that one's definitely not enough.
>

Also, would it be possible to make this feature of leaving
free hot-pluggable slots opt-in?

E.g. a <controller model='pcie-root-port'> without an index
would be considered a port where we should not put devices
with auto-assigned addresses.

(This might actually be more ugly than the proposed solution,
or the 'freeHotplugSlots' attribute, but I dislike implicit
device additions after having model='none' memballoon and usb
controller)

Jan
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 801 bytes
Desc: Digital signature
URL: <http://listman.redhat.com/archives/libvir-list/attachments/20161014/d4d9a94a/attachment-0001.sig>