From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 1 Feb 2019 15:35:22 +0100 From: Cornelia Huck Subject: Re: [PATCH] zcrypt: handle AP Info notification from CHSC SEI command Message-ID: <20190201153522.4f72cf00.cohuck@redhat.com> In-Reply-To: <2bb57977-bf03-f0c9-abd9-8baa74d31f8a@linux.ibm.com> References: <1548870526-30595-1-git-send-email-akrowiak@linux.ibm.com> <20190131105555.4af6d8ea.cohuck@redhat.com> <2bb57977-bf03-f0c9-abd9-8baa74d31f8a@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Tony Krowiak Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, sebott@linux.ibm.com, oberpar@linux.ibm.com, freude@linux.ibm.com, pmorel@linux.ibm.com, pasic@linux.ibm.com List-ID: On Thu, 31 Jan 2019 18:50:57 -0500 Tony Krowiak wrote: > On 1/31/19 4:55 AM, Cornelia Huck wrote: > > On Wed, 30 Jan 2019 12:48:46 -0500 > > Tony Krowiak 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(); > >> +} > >> +