The existing SPAPR TCE driver advertises both VFIO_SPAPR_TCE_IOMMU and
VFIO_SPAPR_TCE_v2_IOMMU types to the userspace and the userspace usually
picks the v2.
Normally the userspace would create a container, attach an IOMMU group
to it and only then set the IOMMU type (which would normally be v2).
However a specific IOMMU group may not support v2, in other words
it may not implement set_window/unset_window/take_ownership/
release_ownership and such a group should not be attached to
a v2 container.
This adds extra checks that a new group can do what the selected IOMMU
type suggests. The userspace can then test the return value from
ioctl(VFIO_SET_IOMMU, VFIO_SPAPR_TCE_v2_IOMMU) and try
VFIO_SPAPR_TCE_IOMMU.
Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx>
---
This is one of the patches needed to do nested VFIO - for either
second level guest or DPDK running in a guest.
---
drivers/vfio/vfio_iommu_spapr_tce.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index cf3de91fbfe7..a7d811524092 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -1335,8 +1335,16 @@ static int tce_iommu_attach_group(void *iommu_data,
if (!table_group->ops || !table_group->ops->take_ownership ||
!table_group->ops->release_ownership) {
+ if (container->v2) {
+ ret = -EPERM;
+ goto unlock_exit;
+ }
ret = tce_iommu_take_ownership(container, table_group);
} else {
+ if (!container->v2) {
+ ret = -EPERM;
+ goto unlock_exit;
+ }
ret = tce_iommu_take_ownership_ddw(container, table_group);
if (!tce_groups_attached(container) && !container->tables[0])
container->def_window_pending = true;
--
2.11.0
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