Hi Eric, > -----Original Message----- > From: Auger Eric [mailto:eric.auger@xxxxxxxxxx] > Sent: 07 July 2019 16:03 > To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@xxxxxxxxxx>; > alex.williamson@xxxxxxxxxx; pmorel@xxxxxxxxxxxxxxxxxx > Cc: 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 > > Hi Shameer, > > On 6/26/19 5:12 PM, Shameer Kolothum 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) > Maybe you could just remove iova_copy for the args and return start, > size. See comment below. > > +{ > > + 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); > > + } > > + > > + if (list_empty(&resv_regions)) > > + return 0; > vfio_iommu_aper_expand() just extended the start/end of first & last > node respectively. In case the iova_copy() featured excluded resv > regions before and now you don't have any anymore, the previous holes > will stay if I don't miss anything? Good catch!. Yes, I think there is a problem here. > > You may unconditionally recompute start/end, free the copy, > aper_resize() with new start/end and exclude resv regions again? Ok. I will fix this in next revision. Cheers, Shameer
