On Tue, 2022-11-08 at 15:34 -0400, Jason Gunthorpe wrote: > On Tue, Nov 08, 2022 at 10:29:33AM -0500, Eric Farman wrote: > > On Tue, 2022-11-08 at 10:37 -0400, Jason Gunthorpe wrote: > > > On Tue, Nov 08, 2022 at 09:19:17AM -0500, Eric Farman wrote: > > > > On Tue, 2022-11-08 at 09:54 -0400, Jason Gunthorpe wrote: > > > > > On Tue, Nov 08, 2022 at 08:50:53AM -0500, Matthew Rosato > > > > > wrote: > > > > > > > > > > > FWIW, vfio-pci via s390 is working fine so far, though I'll > > > > > > put > > > > > > it > > > > > > through more paces over the next few weeks and report if I > > > > > > find > > > > > > anything. > > > > > > > > > > OK great > > > > > > > > > > > As far as mdev drivers... > > > > > > > > > > > > -ccw: Sounds like Eric is already aware there is an issue > > > > > > and > > > > > > is > > > > > > investigating (I see errors as well). > > > > > > > > I -think- the problem for -ccw is that the new vfio_pin_pages > > > > requires > > > > the input addresses to be page-aligned, and while most of ours > > > > are, > > > > the > > > > first one in any given transaction may not be. We never > > > > bothered to > > > > mask off the addresses since it was handled for us, and we > > > > needed > > > > to > > > > keep the offsets anyway. > > > > > > > > By happenstance, I had some code that would do the masking > > > > ourselves > > > > (for an unrelated reason); I'll see if I can get that fit on > > > > top > > > > and if > > > > it helps matters. After coffee. > > > > > > Oh, yes, that makes alot of sense. > > > > > > Ah, if that is how VFIO worked we could match it like below: > > > > That's a start. The pin appears to have worked, but the unpin fails > > at > > the bottom of iommufd_access_unpin_pages: > > > > WARN_ON(!iopt_area_contig_done(&iter)); > > This seems like a different bug, probably a ccw driver bug. The > WARN_ON is designed to detect cases where the driver is unpinning an > IOVA range that is not exactly what it pinned. The pin side already > does this validation, so if it fails it means pin/unpin did not have > identical iova ranges. Some debugging prints should confirm this. > > I looked at CCW and came up with the following two things, can you > look at them and finish them off? It will probably help. I happen to already have patch 1 in a series I've been working on in parallel with the private/parent split. I haven't forgotten it. :) Patch 2 doesn't address the above symptoms, but a lot of that code is getting reworked by the aforementioned series so I didn't spend a lot of time studying your suggestion. And as I type this I see you just sent a new patch, let me go try that...
