On Thu, 31 Jan 2019 18:50:57 -0500 Tony Krowiak <[email protected]> wrote:
> On 1/31/19 4:55 AM, Cornelia Huck wrote: > > On Wed, 30 Jan 2019 12:48:46 -0500 > > Tony Krowiak <[email protected]> wrote: > > Two questions: > > - Does the event cover _any_ change to the AP configuration, or can the > > periodic scan detect changes that are not signaled? > > It can detect any change, such as a change to the CRYCB masks. Nice. I suppose we can not rely on those messages being generated, though, and therefore need to keep the periodic scan... > > > - Do we want to generate such an event in QEMU on plugging/unplugging > > the vfio-ap device? > > We've discussed this quite a bit internally and decided not to implement > that at this time. We will address it as a future enhancement. Ok, but I think it would be nice to have. > >> diff --git a/drivers/s390/cio/chsc.c b/drivers/s390/cio/chsc.c > >> index a0baee25134c..dccccc337078 100644 > >> --- a/drivers/s390/cio/chsc.c > >> +++ b/drivers/s390/cio/chsc.c > >> @@ -586,6 +586,15 @@ static void chsc_process_sei_scm_avail(struct > >> chsc_sei_nt0_area *sei_area) > >> " failed (rc=%d).\n", ret); > >> } > >> > >> +static void chsc_process_sei_ap_cfg_chg(struct chsc_sei_nt0_area > >> *sei_area) > >> +{ > >> + CIO_CRW_EVENT(3, "chsc: ap config changed\n"); > >> + if (sei_area->rs != 5) > >> + return; > > > > I'm guessing that a reporting source of 5 means ap, right? (The code is > > silent on all those magic rs values :/) > > The 5 indicates the accessibility of one or more adjunct processors has > changed. The reason this gets called is because the CC sent with the > instruction indicates the AP configuration has changed, so the reporting > belongs where it is. There is only one RS associated with it. So if we'd ever get there anything but rs == 5, it would be a hardware or hypervisor bug? Then the code makes sense, I guess. > > > > > If so, should the debug logging be moved after the check? > > covered in the response above. > > > > >> + > >> + ap_bus_cfg_chg(); > >> +} > >> +
