Re: [libvirt] question about PCI new_id sysfs interface

On Wed, 29 Jun 2016 09:47:55 +0100 "Daniel P. Berrange" <berrange(a)redhat.com&gt; wrote: > On Tue, Jun 28, 2016 at 02:30:47PM -0400, Bandan Das wrote: > > "Daniel P. Berrange" <berrange(a)redhat.com&gt; writes: > > > > > Adding Alex & Bandan, since they signed off the kernel patch which > > > I'm thinking either pci-back should be made to work more like > > > vfio, or the kernel patch should be reverted or fixed to take > > > account of the way pci-back works. > > > > > > Whichever way, I don't consider this a libvirt problem to solve. As > > > Linus' always says - the kernel must never break existing userspace > > > > Agreed, but in this specific case, the usage is unsafe since unknown indexes > > are potentially being passed to the driver operations. It should always have been > > 3. to begin with. > > Whether the userspace usage is good or not is irrelevant - this kernel change > has broken existing userspace apps and that is not acceptable and must be fixed. > > I'm fine with suggestions to change future libvirt to work in a better way, > but we need to fix the regressions seen by *current* libvirt releases I don't think this is a reasonable demand. For one, the change was made 2yrs ago and nobody noticed until now, I don't think there are stable kernel releases to cover all those kernels. There must be some sort of statute of limitations.