Re: [libvirt] [PATCH] docs: Add "PCI topology and hotplug" guidelines
On Wed, 2017-08-02 at 11:06 +0200, Marcin Juszkiewicz wrote:
Thanks a lot for that documentation.
Glad you found it useful :)
Hopefully I can get it merged soon.
At Linaro we use AArch64 servers to deploy VM machines (with
OpenStack
Newton or just libvirt) and issues with PCI hotplug came again and again.
https://bugs.linaro.org/show_bug.cgi?id=2819 is main one. It was created
when we used libvirt 2.2.0 but now we are at 3.4.0 version and problem
is finally debugged properly ;D
From my tests it looks like adding 9-10 pcie-root-port devices will
handle our use - just have to convince OpenStack guys about it (or find
a way around libvirt to get those by default).
The number of PCIe Root Ports provided by libvirt by default
is very unlikely to change: the current behavior, which is
consistent among aarch64/virt and x86_64/q35, has been
chosen specifically because it provides enough flexibility
for casual users without enforcing (too much of) a policy,
which is something that libvirt actively tries to avoid.
Adding extra PCIe Root Ports as appropriate for the specific
guest flavor is left as an exercise for the higher-level
management tool, in your case OpenStack.
--
Andrea Bolognani / Red Hat / Virtualization