> -----Original Message----- > From: Tian, Kevin [mailto:kevin.tian@xxxxxxxxx] > Sent: Monday, March 19, 2018 7:52 AM > To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@xxxxxxxxxx>; > alex.williamson@xxxxxxxxxx; eric.auger@xxxxxxxxxx; > pmorel@xxxxxxxxxxxxxxxxxx > Cc: kvm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; xuwei (O) > <xuwei5@xxxxxxxxxx>; Linuxarm <linuxarm@xxxxxxxxxx>; > iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx > 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 > > <shameerali.kolothum.thodi@xxxxxxxxxx> > > --- > > 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. Thanks, Shameer > > + > > + return 0; > > +} > > + > > +static void vfio_iommu_resv_free(struct list_head *resv_regions) > > +{ > > + struct iommu_resv_region *n, *next; > > + > > + list_for_each_entry_safe(n, next, resv_regions, list) { > > + list_del(&n->list); > > + kfree(n); > > + } > > +} > > + > > static void vfio_iommu_iova_free(struct list_head *iova) > > { > > struct vfio_iova *n, *next; > > @@ -1366,6 +1442,7 @@ static int vfio_iommu_type1_attach_group(void > > *iommu_data, > > phys_addr_t resv_msi_base; > > struct iommu_domain_geometry geo; > > LIST_HEAD(iova_copy); > > + LIST_HEAD(group_resv_regions); > > > > mutex_lock(&iommu->lock); > > > > @@ -1444,6 +1521,13 @@ static int vfio_iommu_type1_attach_group(void > > *iommu_data, > > goto out_detach; > > } > > > > + iommu_get_group_resv_regions(iommu_group, > > &group_resv_regions); > > + > > + if (vfio_iommu_resv_conflict(iommu, &group_resv_regions)) { > > + ret = -EINVAL; > > + goto out_detach; > > + } > > + > > /* Get a copy of the current iova list and work on it */ > > ret = vfio_iommu_iova_get_copy(iommu, &iova_copy); > > if (ret) > > @@ -1454,6 +1538,10 @@ static int vfio_iommu_type1_attach_group(void > > *iommu_data, > > if (ret) > > goto out_detach; > > > > + ret = vfio_iommu_resv_exclude(&iova_copy, &group_resv_regions); > > + if (ret) > > + goto out_detach; > > + > > resv_msi = vfio_iommu_has_sw_msi(iommu_group, > > &resv_msi_base); > > > > INIT_LIST_HEAD(&domain->group_list); > > @@ -1514,6 +1602,7 @@ static int vfio_iommu_type1_attach_group(void > > *iommu_data, > > /* Delete the old one and insert new iova list */ > > vfio_iommu_iova_insert_copy(iommu, &iova_copy); > > mutex_unlock(&iommu->lock); > > + vfio_iommu_resv_free(&group_resv_regions); > > > > return 0; > > > > @@ -1522,6 +1611,7 @@ static int vfio_iommu_type1_attach_group(void > > *iommu_data, > > out_domain: > > iommu_domain_free(domain->domain); > > vfio_iommu_iova_free(&iova_copy); > > + vfio_iommu_resv_free(&group_resv_regions); > > out_free: > > kfree(domain); > > kfree(group); > > -- > > 2.7.4 > > > > > > _______________________________________________ > > iommu mailing list > > iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx > > https://lists.linuxfoundation.org/mailman/listinfo/iommu
