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=ham 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 26510C2BCA1 for ; Fri, 7 Jun 2019 14:18:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 04DC6206E0 for ; Fri, 7 Jun 2019 14:18:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729509AbfFGOSq (ORCPT ); Fri, 7 Jun 2019 10:18:46 -0400 Received: from mx1.redhat.com ([209.132.183.28]:18503 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728442AbfFGOSp (ORCPT ); Fri, 7 Jun 2019 10:18:45 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 878C2308339B; Fri, 7 Jun 2019 14:18:35 +0000 (UTC) Received: from [10.36.116.67] (ovpn-116-67.ams2.redhat.com [10.36.116.67]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B60A57A4F5; Fri, 7 Jun 2019 14:18:23 +0000 (UTC) Subject: Re: [PATCH v8 26/29] vfio-pci: Register an iommu fault handler To: Jean-Philippe Brucker , "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> <63b37149-1f74-bca1-35ea-5e849c0c2bbb@arm.com> From: Auger Eric Message-ID: <76b9b3a8-28dc-8629-f3cc-23e42f869c3a@redhat.com> Date: Fri, 7 Jun 2019 16:18:22 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <63b37149-1f74-bca1-35ea-5e849c0c2bbb@arm.com> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.44]); Fri, 07 Jun 2019 14:18:45 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jean, On 6/7/19 2:48 PM, Jean-Philippe Brucker wrote: > 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. Sure I will add that check in the next version. Thanks Eric > > 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; >> +}