[PATCH v5 3/7] vfio/type1: Update iova list on detach

Shameer Kolothum
2018-03-15T16:35:05Z

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-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
---
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 cfe2bb2..25e6920 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -1667,12 +1667,88 @@ 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);
+ }
+
+ 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);

@@ -1695,6 +1771,12 @@ 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)
@@ -1720,10 +1802,19 @@ 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);
+ }
+
detach_group_done:
mutex_unlock(&iommu->lock);
}
--
2.7.4