On Wed, 15 May 2019 01:42:41 +0200 Eric Farman <farman@xxxxxxxxxxxxx> wrote: > The attached are a few fixes to the vfio-ccw kernel code for potential > errors or architecture anomalies. Under normal usage, and even most > abnormal usage, they don't expose any problems to a well-behaved guest > and its devices. But, they are deficiencies just the same and could > cause some weird behavior if they ever popped up in real life. > > I have tried to arrange these patches in a "solves a noticeable problem > with existing workloads" to "solves a theoretical problem with > hypothetical workloads" order. This way, the bigger ones at the end > can be discussed without impeding the smaller and more impactful ones > at the start. > > Per the conversations on patch 7, the last several patches remain > unchanged. They continue to buid an IDAL for each CCW, and only pin > guest pages and assign the resulting addresses to IDAWs if they are > expected to cause a data transfer. This will avoid sending an > unmodified guest address, which may be invalid but anyway is not mapped > to the same host address, in the IDAL sent to the channel subsystem and > any unexpected behavior that may result. > > They are based on 5.1.0, not Conny's vfio-ccw tree even though there are > some good fixes pending for 5.2 there. I've run this series both with > and without that code, but couldn't decide which base would provide an > easier time applying patches. "I think" they should apply fine to both, > but I apologize in advance if I guessed wrong! :) They also should apply on current master, no? My 5.2 branch should be all merged by now :) Nothing really jumped out at me; I'm happy to queue the patches if I get some more feedback. > > > Changelog: > v1 -> v2: > - Patch 1: > - [Cornelia] Added a code comment about why we update the SCSW when > we've gone past the end of the chain for normal, successful, I/O > - Patch 2: > - [Cornelia] Cleaned up the cc info in the commit message > - [Pierre] Added r-b > - Patch 3: > - [Cornelia] Update the return code information in prologue of > pfn_array_pin(), and then only call vfio_unpin_pages() if we > pinned anything, rather than silently creating an error > (this last bit was mentioned on patch 6, but applied here) > - [Eric] Clean up the error exit in pfn_array_pin() > - Patch 4-7 unchanged > > Eric Farman (7): > s390/cio: Update SCSW if it points to the end of the chain > s390/cio: Set vfio-ccw FSM state before ioeventfd > s390/cio: Split pfn_array_alloc_pin into pieces > s390/cio: Initialize the host addresses in pfn_array > s390/cio: Allow zero-length CCWs in vfio-ccw > s390/cio: Don't pin vfio pages for empty transfers > s390/cio: Remove vfio-ccw checks of command codes > > drivers/s390/cio/vfio_ccw_cp.c | 159 +++++++++++++++++++++++--------- > drivers/s390/cio/vfio_ccw_drv.c | 6 +- > 2 files changed, 119 insertions(+), 46 deletions(-) >
