From patchwork Tue Dec 12 21:25:14 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anthony Krowiak X-Patchwork-Id: 13490000 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="AyUH59aG" Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A68FBCE; Tue, 12 Dec 2023 13:25:31 -0800 (PST) Received: from pps.filterd (m0353728.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 3BCLHcko023633; Tue, 12 Dec 2023 21:25:30 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=41kSqjRA8LZoRNq2Fpx4NoqSL80yGNnpkuhMiftcsxI=; b=AyUH59aGgwVacHbZ7iTQmwLgS6acafXSaN7c6pop97VAl8oXC+HhLRZDPMreS5K8kKd0 EdfwCUwvXL/eIJq0ecQhUx0OaRwWI3Jj/ClepHfHxz3wE5pOJx6WQJ0BVtp4uRn1dJif KMDyGwOh5by7HP3dOVi1BRe9/OkhJbbdzDHIKGeEE9Wmh/xoN60XBQrhKPPBacXQGE1t WyH4IvdAaxo+mluoVCxYSsQFgxKbwIpS8XQUM2kFKyTpxNfZFWZjQUwpsu/UPg5O5aS6 671gK32oEOpsFExZBgUVfcIQc8YEu6Cfmkmhmv2hZ2ichS90wjSbwoUsiE+pMh7mYU+v +Q== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3uxya3r34j-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 12 Dec 2023 21:25:30 +0000 Received: from m0353728.ppops.net (m0353728.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 3BCLPTIL007375; Tue, 12 Dec 2023 21:25:29 GMT Received: from ppma12.dal12v.mail.ibm.com (dc.9e.1632.ip4.static.sl-reverse.com [50.22.158.220]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3uxya3r33w-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 12 Dec 2023 21:25:29 +0000 Received: from pps.filterd (ppma12.dal12v.mail.ibm.com [127.0.0.1]) by ppma12.dal12v.mail.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 3BCKv76g008491; Tue, 12 Dec 2023 21:25:29 GMT Received: from smtprelay04.dal12v.mail.ibm.com ([172.16.1.6]) by ppma12.dal12v.mail.ibm.com (PPS) with ESMTPS id 3uw2jtcd3s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 12 Dec 2023 21:25:29 +0000 Received: from smtpav05.dal12v.mail.ibm.com (smtpav05.dal12v.mail.ibm.com [10.241.53.104]) by smtprelay04.dal12v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 3BCLPRR712321314 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 12 Dec 2023 21:25:27 GMT Received: from smtpav05.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 818F85805D; Tue, 12 Dec 2023 21:25:27 +0000 (GMT) Received: from smtpav05.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AB0C058068; Tue, 12 Dec 2023 21:25:26 +0000 (GMT) Received: from li-2c1e724c-2c76-11b2-a85c-ae42eaf3cb3d.ibm.com.com (unknown [9.61.187.43]) by smtpav05.dal12v.mail.ibm.com (Postfix) with ESMTP; Tue, 12 Dec 2023 21:25:26 +0000 (GMT) From: Tony Krowiak To: 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, pbonzini@redhat.com, frankja@linux.ibm.com, imbrenda@linux.ibm.com, alex.williamson@redhat.com, kwankhede@nvidia.com Subject: [PATCH v2 3/6] s390/vfio-ap: let 'on_scan_complete' callback filter matrix and update guest's APCB Date: Tue, 12 Dec 2023 16:25:14 -0500 Message-ID: <20231212212522.307893-4-akrowiak@linux.ibm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231212212522.307893-1-akrowiak@linux.ibm.com> References: <20231212212522.307893-1-akrowiak@linux.ibm.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: mQAsMO85gFsEZzAuii-DRbLZNatJ__Ko X-Proofpoint-ORIG-GUID: JX8-vT4gTtWf8uU0RlhjoeBps26z1NZ6 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.997,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-12-12_12,2023-12-12_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 bulkscore=0 adultscore=0 lowpriorityscore=0 clxscore=1015 priorityscore=1501 malwarescore=0 mlxscore=0 spamscore=0 impostorscore=0 mlxlogscore=999 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2311290000 definitions=main-2312120165 When adapters and/or domains are added to the host's AP configuration, this may result in multiple queue devices getting created and probed by the vfio_ap device driver. For each queue device probed, the matrix of adapters and domains assigned to a matrix mdev will be filtered to update the guest's APCB. If any adapters or domains get added to or removed from the APCB, the guest's AP configuration will be dynamically updated (i.e., hot plug/unplug). To dynamically update the guest's configuration, its VCPUs must be taken out of SIE for the period of time it takes to make the update. This is disruptive to the guest's operation and if there are many queues probed due to a change in the host's AP configuration, this could be troublesome. The problem is exacerbated by the fact that the 'on_scan_complete' callback also filters the mdev's matrix and updates the guest's AP configuration. In order to reduce the potential amount of disruption to the guest that may result from a change to the host's AP configuration, let's bypass the filtering of the matrix and updating of the guest's AP configuration in the probe callback - if due to a host config change - and defer it until the 'on_scan_complete' callback is invoked after the AP bus finishes its device scan operation. This way the filtering and updating will be performed only once regardless of the number of queues added. Signed-off-by: Tony Krowiak Reviewed-by: Halil Pasic --- drivers/s390/crypto/vfio_ap_ops.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c index 47232e19a50e..26bd4aca497a 100644 --- a/drivers/s390/crypto/vfio_ap_ops.c +++ b/drivers/s390/crypto/vfio_ap_ops.c @@ -2083,9 +2083,22 @@ int vfio_ap_mdev_probe_queue(struct ap_device *apdev) if (matrix_mdev) { vfio_ap_mdev_link_queue(matrix_mdev, q); + /* + * If we're in the process of handling the adding of adapters or + * domains to the host's AP configuration, then let the + * vfio_ap device driver's on_scan_complete callback filter the + * matrix and update the guest's AP configuration after all of + * the new queue devices are probed. + */ + if (!bitmap_empty(matrix_mdev->apm_add, AP_DEVICES) || + !bitmap_empty(matrix_mdev->aqm_add, AP_DOMAINS)) + goto done; + if (vfio_ap_mdev_filter_matrix(matrix_mdev)) vfio_ap_mdev_update_guest_apcb(matrix_mdev); } + +done: dev_set_drvdata(&apdev->device, q); release_update_locks_for_mdev(matrix_mdev);