From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E72FCC468BC for ; Fri, 7 Jun 2019 12:48:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C8C0D208C3 for ; Fri, 7 Jun 2019 12:48:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728665AbfFGMse (ORCPT ); Fri, 7 Jun 2019 08:48:34 -0400 Received: from foss.arm.com ([217.140.110.172]:39564 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727102AbfFGMse (ORCPT ); Fri, 7 Jun 2019 08:48:34 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 77A82499; Fri, 7 Jun 2019 05:48:33 -0700 (PDT) Received: from [10.1.196.129] (ostrya.cambridge.arm.com [10.1.196.129]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 734AA40151; Fri, 7 Jun 2019 05:48:31 -0700 (PDT) Subject: Re: [PATCH v8 26/29] vfio-pci: Register an iommu fault handler To: Eric Auger , "eric.auger.pro@gmail.com" , "iommu@lists.linux-foundation.org" , "linux-kernel@vger.kernel.org" , "kvm@vger.kernel.org" , "kvmarm@lists.cs.columbia.edu" , "joro@8bytes.org" , "alex.williamson@redhat.com" , "jacob.jun.pan@linux.intel.com" , "yi.l.liu@intel.com" , Will Deacon , Robin Murphy Cc: "kevin.tian@intel.com" , "ashok.raj@intel.com" , Marc Zyngier , "peter.maydell@linaro.org" , Vincent Stehle References: <20190526161004.25232-1-eric.auger@redhat.com> <20190526161004.25232-27-eric.auger@redhat.com> From: Jean-Philippe Brucker Message-ID: <63b37149-1f74-bca1-35ea-5e849c0c2bbb@arm.com> Date: Fri, 7 Jun 2019 13:48:07 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20190526161004.25232-27-eric.auger@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 26/05/2019 17:10, Eric Auger wrote: > +int vfio_pci_iommu_dev_fault_handler(struct iommu_fault_event *evt, void *data) > +{ > + struct vfio_pci_device *vdev = (struct vfio_pci_device *) data; > + struct vfio_region_fault_prod *prod_region = > + (struct vfio_region_fault_prod *)vdev->fault_pages; > + struct vfio_region_fault_cons *cons_region = > + (struct vfio_region_fault_cons *)(vdev->fault_pages + 2 * PAGE_SIZE); > + struct iommu_fault *new = > + (struct iommu_fault *)(vdev->fault_pages + prod_region->offset + > + prod_region->prod * prod_region->entry_size); > + int prod, cons, size; > + > + mutex_lock(&vdev->fault_queue_lock); > + > + if (!vdev->fault_abi) > + goto unlock; > + > + prod = prod_region->prod; > + cons = cons_region->cons; > + size = prod_region->nb_entries; > + > + if (CIRC_SPACE(prod, cons, size) < 1) > + goto unlock; > + > + *new = evt->fault; Could you check fault.type and return an error if it's not UNRECOV here? If the fault is recoverable (very unlikely since the PRI capability is disabled, but allowed) and we return an error here, then the caller takes care of completing the fault. If we forward it to the guest instead, the producer will wait indefinitely for a response. Thanks, Jean > + prod = (prod + 1) % size; > + prod_region->prod = prod; > + mutex_unlock(&vdev->fault_queue_lock); > + > + mutex_lock(&vdev->igate); > + if (vdev->dma_fault_trigger) > + eventfd_signal(vdev->dma_fault_trigger, 1); > + mutex_unlock(&vdev->igate); > + return 0; > + > +unlock: > + mutex_unlock(&vdev->fault_queue_lock); > + return -EINVAL; > +}