From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932841AbeCSMQa convert rfc822-to-8bit (ORCPT ); Mon, 19 Mar 2018 08:16:30 -0400 Received: from mga01.intel.com ([192.55.52.88]:30083 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755324AbeCSMQ1 (ORCPT ); Mon, 19 Mar 2018 08:16:27 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.48,330,1517904000"; d="scan'208";a="26906364" From: "Tian, Kevin" To: Shameerali Kolothum Thodi , "alex.williamson@redhat.com" , "eric.auger@redhat.com" , "pmorel@linux.vnet.ibm.com" CC: "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "xuwei (O)" , Linuxarm , "iommu@lists.linux-foundation.org" Subject: RE: [PATCH v5 2/7] vfio/type1: Check reserve region conflict and update iova list Thread-Topic: [PATCH v5 2/7] vfio/type1: Check reserve region conflict and update iova list Thread-Index: AQHTvHwgJKD0PzK49EKiN4zj+umOtKPXM8CA//+u0ICAAJv3oA== Date: Mon, 19 Mar 2018 12:16:22 +0000 Message-ID: References: <20180315163509.17740-1-shameerali.kolothum.thodi@huawei.com> <20180315163509.17740-3-shameerali.kolothum.thodi@huawei.com> <5FC3163CFD30C246ABAA99954A238FA838675F4F@FRAEML521-MBX.china.huawei.com> In-Reply-To: <5FC3163CFD30C246ABAA99954A238FA838675F4F@FRAEML521-MBX.china.huawei.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ctpclassification: CTP_NT x-titus-metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiZTE3Y2NiMjEtNjFlMS00ZmU3LWE1YTctMWM4MDU2NjY1YzE4IiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX05UIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE2LjUuOS4zIiwiVHJ1c3RlZExhYmVsSGFzaCI6ImlIZFwvaWVNUHFWbmJDRkhXRjk1WmFDRmN3UUpTU09hXC9JZENRTm9xMDlwMD0ifQ== dlp-product: dlpe-windows dlp-version: 11.0.0.116 dlp-reaction: no-action x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > From: Shameerali Kolothum Thodi > [mailto:shameerali.kolothum.thodi@huawei.com] > > > -----Original Message----- > > From: Tian, Kevin [mailto:kevin.tian@intel.com] > > Sent: Monday, March 19, 2018 7:52 AM > > To: Shameerali Kolothum Thodi > ; > > alex.williamson@redhat.com; eric.auger@redhat.com; > > pmorel@linux.vnet.ibm.com > > Cc: kvm@vger.kernel.org; linux-kernel@vger.kernel.org; xuwei (O) > > ; Linuxarm ; > > iommu@lists.linux-foundation.org > > Subject: RE: [PATCH v5 2/7] vfio/type1: Check reserve region conflict and > > update iova list > > > > > From: Shameer Kolothum > > > Sent: Friday, March 16, 2018 12:35 AM > > > > > > This retrieves the reserved regions associated with dev group and > > > checks for conflicts with any existing dma mappings. Also update > > > the iova list excluding the reserved regions. > > > > > > Signed-off-by: Shameer Kolothum > > > > > > --- > > > drivers/vfio/vfio_iommu_type1.c | 90 > > > +++++++++++++++++++++++++++++++++++++++++ > > > 1 file changed, 90 insertions(+) > > > > > > diff --git a/drivers/vfio/vfio_iommu_type1.c > > > b/drivers/vfio/vfio_iommu_type1.c > > > index 1123c74..cfe2bb2 100644 > > > --- a/drivers/vfio/vfio_iommu_type1.c > > > +++ b/drivers/vfio/vfio_iommu_type1.c > > > @@ -1313,6 +1313,82 @@ static int vfio_iommu_aper_resize(struct > > > list_head *iova, > > > return 0; > > > } > > > > > > +/* > > > + * Check reserved region conflicts with existing dma mappings > > > + */ > > > +static bool vfio_iommu_resv_conflict(struct vfio_iommu *iommu, > > > + struct list_head *resv_regions) > > > +{ > > > + struct iommu_resv_region *region; > > > + > > > + /* Check for conflict with existing dma mappings */ > > > + list_for_each_entry(region, resv_regions, list) { > > > + if (vfio_find_dma(iommu, region->start, region->length)) > > > + return true; > > > + } > > > + > > > + return false; > > > +} > > > + > > > +/* > > > + * Check iova region overlap with reserved regions and > > > + * exclude them from the iommu iova range > > > + */ > > > +static int vfio_iommu_resv_exclude(struct list_head *iova, > > > + struct list_head *resv_regions) > > > +{ > > > + struct iommu_resv_region *resv; > > > + struct vfio_iova *n, *next; > > > + > > > + list_for_each_entry(resv, resv_regions, list) { > > > + phys_addr_t start, end; > > > + > > > + start = resv->start; > > > + end = resv->start + resv->length - 1; > > > + > > > + list_for_each_entry_safe(n, next, iova, list) { > > > + int ret = 0; > > > + > > > + /* No overlap */ > > > + if ((start > n->end) || (end < n->start)) > > > + continue; > > > + /* > > > + * Insert a new node if current node overlaps with > > > the > > > + * reserve region to exlude that from valid iova > > > range. > > > + * Note that, new node is inserted before the > > > current > > > + * node and finally the current node is deleted > > > keeping > > > + * the list updated and sorted. > > > + */ > > > + if (start > n->start) > > > + ret = vfio_iommu_iova_insert(&n->list, > > > + n->start, start - 1); > > > + if (!ret && end < n->end) > > > + ret = vfio_iommu_iova_insert(&n->list, > > > + end + 1, n->end); > > > + if (ret) > > > + return ret; > > > > Is it safer to delete the 1st node here in case of failure of the 2nd node? > > There is no problem with current logic since upon error iova_copy will > > be released anyway. However this function alone doesn't assume the > > fact of a temporary list, thus it's better to keep the list clean w/o garbage > > left from any error handling. > > Agree. I will consider this. > > > > + > > > + list_del(&n->list); > > > + kfree(n); > > > + } > > > + } > > > + > > > + if (list_empty(iova)) > > > + return -EINVAL; > > > > if list_empty should BUG_ON here? or do we really need this check? > > I think we need the check here. This basically means there is no valid iova > region as the reserved regions overlaps it completely(very unlikely, a bad > configuration maybe). The __attach will fail if that happens and may be > WARN_ON is a good idea to notify the user. > you are right. I misread the code that deletion happens only after insertion... Thanks Kevin