4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Alexey Kardashevskiy aik@ozlabs.ru
[ Upstream commit 1282ba7fc28dbc66c3f0e4aaafaaa228361d1ae5 ]
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@ozlabs.ru Signed-off-by: Alex Williamson alex.williamson@redhat.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/vfio/vfio_iommu_spapr_tce.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/drivers/vfio/vfio_iommu_spapr_tce.c +++ b/drivers/vfio/vfio_iommu_spapr_tce.c @@ -1332,8 +1332,16 @@ static int tce_iommu_attach_group(void *
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;