On Mon, Feb 26, 2018 at 10:05:31AM -0800, Alexander Duyck wrote: > On Mon, Feb 26, 2018 at 9:48 AM, Rustad, Mark D <mark.d.rustad@xxxxxxxxx> wrote: > > Alex, > > > >> On Feb 26, 2018, at 7:26 AM, Alexander Duyck <alexander.duyck@xxxxxxxxx> wrote: > >> > >> Mark, > >> > >> In the future please don't put my "Reviewed-by" on a patch that I > >> haven't reviewed. I believe I reviewed one of the earlier patches, but > >> I hadn't reviewed this version. > > > > I'm very sorry. I completely spaced doing something about that. I think yours was the first Reviewed-by I ever had in this way. In the future I will remove such things from my changelog right after sending. Thanks for alerting me to what I had failed to do. > > > >> Also, after thinking about it over the weekend we may want to look at > >> just coming up with a truly "generic" solution that is applied to > >> SR-IOV capable devices that don't have a SR-IOV capable driver loaded > >> on them. That would allow us to handle the uio, vfio, pci-stub, and > >> virtio cases all in one fell swoop. I think us going though and > >> modifying one patch at a time to do this kind of thing isn't going to > >> scale. > > > > The notion of that kind of troubles me - at least pci-stub does. Having worked on ixgbe a bit, I have to wonder what kind of havoc would ensue if an ixgbe device were assigned to a guest, and an attempt was made to allocate VFs by the pci-stub. The guest could be running any version of the ixgbe driver, possibly even an old one that didn't support SR-IOV. Even if it did support SR-IOV, I don't know how it would respond to mailbox messages when it doesn't think it has VFs. > > The assumption here is that the root user knows what they are doing. There are tools that let non-root users load the stub. People use that to e.g. prevent a native driver from loading while also assuming it won't break the kernel. > We have already had some discussion on this in regards to VFIO. My > thought is we look at adding a new PCI sysfs option called > "sriov_unmanaged_autoprobe" that would be similar to > "sriov_drivers_autoprobe" and is used to determine if we allow for > auto probing of the VFs into the host kernel when SR-IOV is enabled. I'm not sure how a global option can work for use-cases such as containers though. > I > would want to default the value to false so that by default an > unmanaged PF wouldn't have its VFs assigned to the host unless we > specifically enable it by updating the sysfs value. > > >> I'll try to do some digging and find the VFIO approach we had been > >> working on. I think with a couple tweaks we can probably make that > >> truly generic and ready for submission. > > > > I'd like to know more about you are thinking about. > > Basic idea is to take your generic SR-IOV enable/disable bits from > (http://patchwork.ozlabs.org/patch/877674/) and combine it with the > some of the autoprobe bits and feedback comments from > (http://patchwork.ozlabs.org/patch/846454/). The idea would be when > either no driver is loaded, or a driver without the sriov_configure > method we update the iov auto probe setting based on the value we set > via sriov_unamanaged_autoprobe, and then call your generic > configuration method to enable SR-IOV.
