From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:55582 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726072AbgLVXPm (ORCPT ); Tue, 22 Dec 2020 18:15:42 -0500 Subject: Re: [PATCH v4] s390/vfio-ap: clean up vfio_ap resources when KVM pointer invalidated References: <20201221185625.24914-1-akrowiak@linux.ibm.com> <20201222050521.46af2bf1.pasic@linux.ibm.com> <853da84f-092b-6b94-62d5-628f440abc40@linux.ibm.com> <20201222165706.66e0120d.cohuck@redhat.com> <20201222204335.1b456342.pasic@linux.ibm.com> From: Tony Krowiak Message-ID: <5b10c838-bdc6-1923-bae7-ede1a0efe933@linux.ibm.com> Date: Tue, 22 Dec 2020 18:14:58 -0500 MIME-Version: 1.0 In-Reply-To: <20201222204335.1b456342.pasic@linux.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US List-ID: To: Halil Pasic , Cornelia Huck Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, stable@vger.kernel.org, borntraeger@de.ibm.com, kwankhede@nvidia.com, pbonzini@redhat.com, alex.williamson@redhat.com, pasic@linux.vnet.ibm.com On 12/22/20 2:43 PM, Halil Pasic wrote: > On Tue, 22 Dec 2020 16:57:06 +0100 > Cornelia Huck wrote: > >> On Tue, 22 Dec 2020 10:37:01 -0500 >> Tony Krowiak wrote: >> >>> On 12/21/20 11:05 PM, Halil Pasic wrote: >>>> On Mon, 21 Dec 2020 13:56:25 -0500 >>>> Tony Krowiak wrote: >>>>> static int vfio_ap_mdev_group_notifier(struct notifier_block *nb, >>>>> unsigned long action, void *data) >>>>> { >>>>> - int ret; >>>>> + int ret, notify_rc = NOTIFY_DONE; >>>>> struct ap_matrix_mdev *matrix_mdev; >>>>> >>>>> if (action != VFIO_GROUP_NOTIFY_SET_KVM) >>>>> return NOTIFY_OK; >>>>> >>>>> matrix_mdev = container_of(nb, struct ap_matrix_mdev, group_notifier); >>>>> + mutex_lock(&matrix_dev->lock); >>>>> >>>>> if (!data) { >>>>> - matrix_mdev->kvm = NULL; >>>>> - return NOTIFY_OK; >>>>> + if (matrix_mdev->kvm) >>>>> + vfio_ap_mdev_unset_kvm(matrix_mdev); >>>>> + notify_rc = NOTIFY_OK; >>>>> + goto notify_done; >>>>> } >>>>> >>>>> ret = vfio_ap_mdev_set_kvm(matrix_mdev, data); >>>>> if (ret) >>>>> - return NOTIFY_DONE; >>>>> + goto notify_done; >>>>> >>>>> /* If there is no CRYCB pointer, then we can't copy the masks */ >>>>> if (!matrix_mdev->kvm->arch.crypto.crycbd) >>>>> - return NOTIFY_DONE; >>>>> + goto notify_done; >>>>> >>>>> kvm_arch_crypto_set_masks(matrix_mdev->kvm, matrix_mdev->matrix.apm, >>>>> matrix_mdev->matrix.aqm, >>>>> matrix_mdev->matrix.adm); >>>>> >>>>> - return NOTIFY_OK; >>>> Shouldn't there be an >>>> + notify_rc = NOTIFY_OK; >>>> here? I mean you initialize notify_rc to NOTIFY_DONE, in the !data branch >>>> on success you set notify_rc to NOTIFY_OK, but in the !!data branch it >>>> just stays NOTIFY_DONE. Or am I missing something? >>> I don't think it matters much since NOTIFY_OK and NOTIFY_DONE have >>> no further effect on processing of the notification queue, but I believe >>> you are correct, this is a change from what we originally had. I can >>> restore the original return values if you'd prefer. >> Even if they have the same semantics now, that might change in the >> future; restoring the original behaviour looks like the right thing to >> do. > I agree. Especially since we do care to preserve the behavior in > the !data branch. If there is no difference between the two, then it > would probably make sense to clean that up globally. Got it. I'm going to do a quick turnaround on the next version so we can get this merged if need be. I will be taking off for Christmas vacation and will be gone until sometime the first week in January. > > Regards, > Halil