From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753702AbcLFSXe (ORCPT ); Tue, 6 Dec 2016 13:23:34 -0500 Received: from foss.arm.com ([217.140.101.70]:50052 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752294AbcLFSXc (ORCPT ); Tue, 6 Dec 2016 13:23:32 -0500 Subject: Re: [RFC v3 06/10] iommu: iommu_get_group_resv_regions To: Eric Auger , eric.auger.pro@gmail.com, christoffer.dall@linaro.org, marc.zyngier@arm.com, alex.williamson@redhat.com, will.deacon@arm.com, joro@8bytes.org, tglx@linutronix.de, jason@lakedaemon.net, linux-arm-kernel@lists.infradead.org References: <1479215363-2898-1-git-send-email-eric.auger@redhat.com> <1479215363-2898-7-git-send-email-eric.auger@redhat.com> Cc: kvm@vger.kernel.org, drjones@redhat.com, linux-kernel@vger.kernel.org, pranav.sawargaonkar@gmail.com, iommu@lists.linux-foundation.org, punit.agrawal@arm.com, diana.craciun@nxp.com From: Robin Murphy Message-ID: <8eb9662b-d677-546c-feb8-32fe5bd624f2@arm.com> Date: Tue, 6 Dec 2016 18:13:01 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <1479215363-2898-7-git-send-email-eric.auger@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 15/11/16 13:09, Eric Auger wrote: > Introduce iommu_get_group_resv_regions whose role consists in > enumerating all devices from the group and collecting their > reserved regions. It checks duplicates. > > Signed-off-by: Eric Auger > > --- > > - we do not move list elements from device to group list since > the iommu_put_resv_regions() could not be called. > - at the moment I did not introduce any iommu_put_group_resv_regions > since it simply consists in voiding/freeing the list > --- > drivers/iommu/iommu.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/iommu.h | 8 ++++++++ > 2 files changed, 61 insertions(+) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index a4530ad..e0fbcc5 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -133,6 +133,59 @@ static ssize_t iommu_group_show_name(struct iommu_group *group, char *buf) > return sprintf(buf, "%s\n", group->name); > } > > +static bool iommu_resv_region_present(struct iommu_resv_region *region, > + struct list_head *head) > +{ > + struct iommu_resv_region *entry; > + > + list_for_each_entry(entry, head, list) { > + if ((region->start == entry->start) && > + (region->length == entry->length) && > + (region->prot == entry->prot)) > + return true; > + } > + return false; > +} > + > +static int > +iommu_insert_device_resv_regions(struct list_head *dev_resv_regions, > + struct list_head *group_resv_regions) > +{ > + struct iommu_resv_region *entry, *region; > + > + list_for_each_entry(entry, dev_resv_regions, list) { > + if (iommu_resv_region_present(entry, group_resv_regions)) > + continue; In the case of overlapping regions which _aren't_ an exact match, would it be better to expand the existing one rather than leave the caller to sort it out? It seems a bit inconsistent to handle only the one case here. > + region = iommu_alloc_resv_region(entry->start, entry->length, > + entry->prot); > + if (!region) > + return -ENOMEM; > + > + list_add_tail(®ion->list, group_resv_regions); > + } > + return 0; > +} > + > +int iommu_get_group_resv_regions(struct iommu_group *group, > + struct list_head *head) > +{ > + struct iommu_device *device; > + int ret = 0; > + > + list_for_each_entry(device, &group->devices, list) { Should we not be taking the group mutex around this? Robin. > + struct list_head dev_resv_regions; > + > + INIT_LIST_HEAD(&dev_resv_regions); > + iommu_get_resv_regions(device->dev, &dev_resv_regions); > + ret = iommu_insert_device_resv_regions(&dev_resv_regions, head); > + iommu_put_resv_regions(device->dev, &dev_resv_regions); > + if (ret) > + break; > + } > + return ret; > +} > +EXPORT_SYMBOL_GPL(iommu_get_group_resv_regions); > + > static IOMMU_GROUP_ATTR(name, S_IRUGO, iommu_group_show_name, NULL); > > static void iommu_group_release(struct kobject *kobj) > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index 0aea877..0f7ae2c 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -243,6 +243,8 @@ extern void iommu_set_fault_handler(struct iommu_domain *domain, > extern int iommu_request_dm_for_dev(struct device *dev); > extern struct iommu_resv_region * > iommu_alloc_resv_region(phys_addr_t start, size_t length, unsigned int prot); > +extern int iommu_get_group_resv_regions(struct iommu_group *group, > + struct list_head *head); > > extern int iommu_attach_group(struct iommu_domain *domain, > struct iommu_group *group); > @@ -462,6 +464,12 @@ static inline void iommu_put_resv_regions(struct device *dev, > return NULL; > } > > +static inline int iommu_get_group_resv_regions(struct iommu_group *group, > + struct list_head *head) > +{ > + return -ENODEV; > +} > + > static inline int iommu_request_dm_for_dev(struct device *dev) > { > return -ENODEV; >