From patchwork Fri Dec 8 16:22:48 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anthony Krowiak X-Patchwork-Id: 13485640 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="QBxTVyba" Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2D2D2173F; Fri, 8 Dec 2023 08:23:08 -0800 (PST) Received: from pps.filterd (m0353724.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 3B8GID0j020666; Fri, 8 Dec 2023 16:23:06 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=BrL9cLcoos8OUrrFviFcgpkOZczpwLcNVeseNGIUVoI=; b=QBxTVybaw8Csng1wsQyksoK7MAoNvGaZ181iAvZHRYdVGe7hXa1fGx6QkZ8ZzjrZc3mQ lnp8AU/FiOVF0f+8lWA1BZqo/mq0ejhmtbiaJ4drPgaA+mrcqYXV1rqJLiA+Yc1EQ1mU tSPe7SP4Euu436YWklO8W+nvY+Q7d0PspU23iM7MPdztOcHUN0fcdfJhSEsjTYSZ1CUL 18Exen6SNaacDexAiQYxN7IlKDwo+zqezoLrIjQ7DVk/b9us8F+Q3zklMZZJhVJk+7ck kr3rZnamRd5BL3J2Ew2w7l2OZ4xpiIF6O36h3tQUrvS/W61PT1PAtvV5eMB7lLMbZuCe BA== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3uv6htr6bd-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 08 Dec 2023 16:23:06 +0000 Received: from m0353724.ppops.net (m0353724.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 3B8GIgJQ022621; Fri, 8 Dec 2023 16:23:05 GMT Received: from ppma22.wdc07v.mail.ibm.com (5c.69.3da9.ip4.static.sl-reverse.com [169.61.105.92]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3uv6htr6b1-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 08 Dec 2023 16:23:05 +0000 Received: from pps.filterd (ppma22.wdc07v.mail.ibm.com [127.0.0.1]) by ppma22.wdc07v.mail.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 3B8GLjU1001561; Fri, 8 Dec 2023 16:23:04 GMT Received: from smtprelay05.wdc07v.mail.ibm.com ([172.16.1.72]) by ppma22.wdc07v.mail.ibm.com (PPS) with ESMTPS id 3utav2tjf7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 08 Dec 2023 16:23:04 +0000 Received: from smtpav06.wdc07v.mail.ibm.com (smtpav06.wdc07v.mail.ibm.com [10.39.53.233]) by smtprelay05.wdc07v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 3B8GN3RI60686616 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 8 Dec 2023 16:23:03 GMT Received: from smtpav06.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 90F7058054; Fri, 8 Dec 2023 16:23:03 +0000 (GMT) Received: from smtpav06.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6AB7C5803F; Fri, 8 Dec 2023 16:23:02 +0000 (GMT) Received: from li-2c1e724c-2c76-11b2-a85c-ae42eaf3cb3d.ibm.com.com (unknown [9.61.47.9]) by smtpav06.wdc07v.mail.ibm.com (Postfix) with ESMTP; Fri, 8 Dec 2023 16:23:02 +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 v1 3/6] s390/vfio-ap: let 'on_scan_complete' callback filter matrix and update guest's APCB Date: Fri, 8 Dec 2023 11:22:48 -0500 Message-ID: <20231208162256.10633-4-akrowiak@linux.ibm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231208162256.10633-1-akrowiak@linux.ibm.com> References: <20231208162256.10633-1-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: SfTKicTGCbIMKwWGabBkNUbRK9MIUwcR X-Proofpoint-ORIG-GUID: qMPkzXcrSBIXq6dqE6c5cwqjdHUQark_ 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=2023-12-08_11,2023-12-07_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 mlxlogscore=999 bulkscore=0 phishscore=0 suspectscore=0 malwarescore=0 adultscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 priorityscore=1501 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2311290000 definitions=main-2312080135 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 --- 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);