> -----Original Message----- > From: kvm-owner@xxxxxxxxxxxxxxx [mailto:kvm-owner@xxxxxxxxxxxxxxx] On > Behalf Of Alex Williamson > Sent: 03 July 2019 21:35 > To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@xxxxxxxxxx> > Cc: eric.auger@xxxxxxxxxx; pmorel@xxxxxxxxxxxxxxxxxx; > kvm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; Linuxarm <linuxarm@xxxxxxxxxx>; John > Garry <john.garry@xxxxxxxxxx>; xuwei (O) <xuwei5@xxxxxxxxxx>; > kevin.tian@xxxxxxxxx > Subject: Re: [PATCH v7 3/6] vfio/type1: Update iova list on detach > > On Wed, 26 Jun 2019 16:12:45 +0100 > Shameer Kolothum <shameerali.kolothum.thodi@xxxxxxxxxx> wrote: > > > Get a copy of iova list on _group_detach and try to update the list. > > On success replace the current one with the copy. Leave the list as > > it is if update fails. > > > > Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@xxxxxxxxxx> > > --- > > drivers/vfio/vfio_iommu_type1.c | 91 > +++++++++++++++++++++++++++++++++ > > 1 file changed, 91 insertions(+) > > > > diff --git a/drivers/vfio/vfio_iommu_type1.c > b/drivers/vfio/vfio_iommu_type1.c > > index b6bfdfa16c33..e872fb3a0f39 100644 > > --- a/drivers/vfio/vfio_iommu_type1.c > > +++ b/drivers/vfio/vfio_iommu_type1.c > > @@ -1873,12 +1873,88 @@ static void vfio_sanity_check_pfn_list(struct > vfio_iommu *iommu) > > WARN_ON(iommu->notifier.head); > > } > > > > +/* > > + * Called when a domain is removed in detach. It is possible that > > + * the removed domain decided the iova aperture window. Modify the > > + * iova aperture with the smallest window among existing domains. > > + */ > > +static void vfio_iommu_aper_expand(struct vfio_iommu *iommu, > > + struct list_head *iova_copy) > > +{ > > + struct vfio_domain *domain; > > + struct iommu_domain_geometry geo; > > + struct vfio_iova *node; > > + dma_addr_t start = 0; > > + dma_addr_t end = (dma_addr_t)~0; > > + > > + list_for_each_entry(domain, &iommu->domain_list, next) { > > + iommu_domain_get_attr(domain->domain, > DOMAIN_ATTR_GEOMETRY, > > + &geo); > > + if (geo.aperture_start > start) > > + start = geo.aperture_start; > > + if (geo.aperture_end < end) > > + end = geo.aperture_end; > > + } > > + > > + /* Modify aperture limits. The new aper is either same or bigger */ > > + node = list_first_entry(iova_copy, struct vfio_iova, list); > > + node->start = start; > > + node = list_last_entry(iova_copy, struct vfio_iova, list); > > + node->end = end; > > +} > > + > > +/* > > + * Called when a group is detached. The reserved regions for that > > + * group can be part of valid iova now. But since reserved regions > > + * may be duplicated among groups, populate the iova valid regions > > + * list again. > > + */ > > +static int vfio_iommu_resv_refresh(struct vfio_iommu *iommu, > > + struct list_head *iova_copy) > > +{ > > + struct vfio_domain *d; > > + struct vfio_group *g; > > + struct vfio_iova *node; > > + dma_addr_t start, end; > > + LIST_HEAD(resv_regions); > > + int ret; > > + > > + list_for_each_entry(d, &iommu->domain_list, next) { > > + list_for_each_entry(g, &d->group_list, next) > > + iommu_get_group_resv_regions(g->iommu_group, > > + &resv_regions); > > Need to account for failure case here too. Ok. > > + } > > + > > + if (list_empty(&resv_regions)) > > + return 0; > > + > > + node = list_first_entry(iova_copy, struct vfio_iova, list); > > + start = node->start; > > + node = list_last_entry(iova_copy, struct vfio_iova, list); > > + end = node->end; > > + > > + /* purge the iova list and create new one */ > > + vfio_iommu_iova_free(iova_copy); > > + > > + ret = vfio_iommu_aper_resize(iova_copy, start, end); > > + if (ret) > > + goto done; > > + > > + /* Exclude current reserved regions from iova ranges */ > > + ret = vfio_iommu_resv_exclude(iova_copy, &resv_regions); > > +done: > > + vfio_iommu_resv_free(&resv_regions); > > + return ret; > > +} > > + > > static void vfio_iommu_type1_detach_group(void *iommu_data, > > struct iommu_group *iommu_group) > > { > > struct vfio_iommu *iommu = iommu_data; > > struct vfio_domain *domain; > > struct vfio_group *group; > > + bool iova_copy_fail; > > + LIST_HEAD(iova_copy); > > > > mutex_lock(&iommu->lock); > > > > @@ -1901,6 +1977,12 @@ static void vfio_iommu_type1_detach_group(void > *iommu_data, > > } > > } > > > > + /* > > + * Get a copy of iova list. If success, use copy to update the > > + * list and to replace the current one. > > + */ > > + iova_copy_fail = !!vfio_iommu_iova_get_copy(iommu, &iova_copy); > > + > > list_for_each_entry(domain, &iommu->domain_list, next) { > > group = find_iommu_group(domain, iommu_group); > > if (!group) > > @@ -1926,10 +2008,19 @@ static void > vfio_iommu_type1_detach_group(void *iommu_data, > > iommu_domain_free(domain->domain); > > list_del(&domain->next); > > kfree(domain); > > + if (!iova_copy_fail && !list_empty(&iommu->domain_list)) > > + vfio_iommu_aper_expand(iommu, &iova_copy); > > } > > break; > > } > > > > + if (!iova_copy_fail && !list_empty(&iommu->domain_list)) { > > + if (!vfio_iommu_resv_refresh(iommu, &iova_copy)) > > + vfio_iommu_iova_insert_copy(iommu, &iova_copy); > > + else > > + vfio_iommu_iova_free(&iova_copy); > > + } > > The iova_copy_fail and list_empty tests are rather ugly, could we avoid > them by pushing the tests to the expand and refresh functions? ie. it > looks like vfio_iommu_aper_expand() could test list_empty(iova_copy), > the list_for_each on domain_list doesn't need special handling. Same > for vfio_iommu_resv_refresh(). This would also fix the bug above that > I think we don't free iova_copy if domain_list becomes empty during > this operation. Thanks, Agree. I will change that in next revision. Thanks, Shameer
