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Mon, 24 Aug 2026 16:57:20 +0000 (GMT) Received: from [9.61.21.147] (unknown [9.61.21.147]) by smtpav04.dal12v.mail.ibm.com (Postfix) with ESMTP; Mon, 24 Aug 2026 16:57:20 +0000 (GMT) Message-ID: Date: Mon, 24 Aug 2026 12:57:19 -0400 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/4] s390/vfio-ap: Fix leak of pinned NIB and registered NISC in vfio_ap_irq_enable() To: Anthony Krowiak , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: jjherne@linux.ibm.com, borntraeger@de.ibm.com, pasic@linux.ibm.com, alex@shazbot.org, kwankhede@nvidia.com, fiuczy@linux.ibm.com, pbonzini@redhat.com, frankja@linux.ibm.com, imbrenda@linux.ibm.com, agordeev@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, stable@vger.kernel.org References: <20260824135850.503728-1-akrowiak@linux.ibm.com> <20260824135850.503728-2-akrowiak@linux.ibm.com> Content-Language: en-US From: Matthew Rosato In-Reply-To: <20260824135850.503728-2-akrowiak@linux.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 9ppxfdOiWxo71pX4HhdvMFK4alxv2A-j X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODI0MDEzOSBTYWx0ZWRfX7m3NyDw4ks5t BJX0bqy5/HuF8eIfpPhypu2brL3QkMwkFUYTvqSbXCiOPh/oJ2QSxwnekXnmIwnRxAGN/W+pkhP a0oGpV8V4UoWB0hF5ieBRpYHZhwtGbev8UpnLHIce++D5rGLcM1v8+SKMyQBc3jupFKCpUe9V05 yKFAGDxOKl3yGI3XBTeVXDy3UxlIu2fxY2HlKygXeh/pguPUAR1Wv2/k/x5J7dcoCU2EefyrSh4 ZIV87QxEUSvBpTIpW5OxuQWTa8FD0sCTjbrZ4CXzdx+DvYjEp9v1ZS73H7TSXoSSBmpF9kgQt9t guBrUo/XSodrzb/SAsYZzjEs540LcAmA4jVaSlYIytUymdv3IgPldN4GLqqZbpbLSVcwjNCgEj5 MzWwNeY/LkYqOMOduIA3GN4TkKtKqZ52ZU+FyKp4jJlhIXJbbMvsSp1E0dU5eZYKrefsvWIH9rH 2jUUBm1Z+vMwJml8RZA== X-Authority-Analysis: v=2.4 cv=Y/nIdBeN c=1 sm=1 tr=0 ts=6a8c77f3 cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=Mqm6PHJeAsOntypqS9kA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Info: AW1haW4tMjYwODI0MDEzOSBTYWx0ZWRfXzr+d7DlFzWwe yPkTMAQWLaaJMIgpfomcj/yOnG/SVouB6GJ5BcxRQ4ibsa2trodqSPQP4a+k5et0Gkww9XAEjBd KTZ8pwBO5WmleFu7eKJ2u+M4ZELsxxI= X-Proofpoint-ORIG-GUID: 9ppxfdOiWxo71pX4HhdvMFK4alxv2A-j X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-24_05,2026-08-24_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 impostorscore=0 priorityscore=1501 adultscore=0 bulkscore=0 suspectscore=0 malwarescore=0 clxscore=1015 lowpriorityscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608240139 On 8/24/26 9:58 AM, Anthony Krowiak wrote: > The vfio_ap_irq_enable() function executes the PQAP(AQIC) instruction to > enable interrupts for an AP queue. A switch statement is used to examine > the status response code returned from the instruction to determine > whether it succeeded or failed and react accordingly. For the default case, > the vfio_ap_irq_disable function is invoked to disable interrupts for the > queue and clean up the AQIC resources (i.e., unpin the NIB and unregister > the NISC). There are a number of problems with this: > > 1. Neither the q->saved_iova nor q->saved_isc has been set, so the > AQIC resources - assuming those values have been previously set - will > be the NIB and NISC resources from a prior call; the NIB and NISC from > the current call are therefore leaked. > > 2. Interrupts may never have been enabled. Sending a disable instruction to > a queue that the hardware just told you is in a bad state (CHECKSTOPPED, > DECONFIGURED, Q_NOT_AVAIL) is at best wasted work and at worst generates > a further WARN_ONCE from inside vfio_ap_irq_disable's own default. > > 3. The hardware just rejected the new ap_aqic() enable attempt with an > unexpected status. Disabling a previously-working IRQ config - assuming > that is even possible - as a reaction to a failed enable attempt does > not make sense; it is actively destructive, tearing down something that > was working for no valid reason. > > The fix is to unregister the NISC and an unpin the NIB in the default case > of the switch statement. > > Fixes: ec89b55e3bce7 ("s390: ap: implement PAPQ AQIC interception in kernel") > Cc: stable@vger.kernel.org > Signed-off-by: Anthony Krowiak > --- > drivers/s390/crypto/vfio_ap_ops.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c > index 940c0ff668be..a46bf381ab72 100644 > --- a/drivers/s390/crypto/vfio_ap_ops.c > +++ b/drivers/s390/crypto/vfio_ap_ops.c > @@ -503,9 +503,14 @@ static struct ap_queue_status vfio_ap_irq_enable(struct vfio_ap_queue *q, > vfio_unpin_pages(&q->matrix_mdev->vdev, nib, 1); > break; > default: > - pr_warn("%s: apqn %04x: response: %02x\n", __func__, q->apqn, > - status.response_code); > - vfio_ap_irq_disable(q); > + pr_warn("%s: PQAP(AQIC) failed with response code %02x for apqn %04x\n", > + __func__, status.response_code, q->apqn); LGTM, except Sashiko mentions the pr_warn here that you are updating has a pre-existing issue. Since you're touching it already, do you think it makes sense to switch to pr_warn_ratelimited with this patch? > + /* We could not modify IRQ settings: clear new configuration */ > + ret = kvm_s390_gisc_unregister(kvm, isc); > + if (ret) > + VFIO_AP_DBF_WARN("%s: kvm_s390_gisc_unregister: rc=%d isc=%d, apqn=%#04x\n", > + __func__, ret, isc, q->apqn); > + vfio_unpin_pages(&q->matrix_mdev->vdev, nib, 1); > break; > } >