Re: [PATCH v3 4/4] vfio/type1: Use iommu_aux_at(de)tach_group() APIs

Alex Williamson
2020-07-29T20:33:13Z

On Tue, 14 Jul 2020 13:57:03 +0800
Lu Baolu <baolu.lu@linux.intel.com> wrote:

> Replace iommu_aux_at(de)tach_device() with iommu_aux_at(de)tach_group().
> It also saves the IOMMU_DEV_FEAT_AUX-capable physcail device in the
> vfio_group data structure so that it could be reused in other places.
>
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> ---
> drivers/vfio/vfio_iommu_type1.c | 44 ++++++---------------------------
> 1 file changed, 7 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 5e556ac9102a..f8812e68de77 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -100,6 +100,7 @@ struct vfio_dma {
> struct vfio_group {
> struct iommu_group *iommu_group;
> struct list_head next;
> + struct device *iommu_device;
> bool mdev_group; /* An mdev group */
> bool pinned_page_dirty_scope;
> };
> @@ -1627,45 +1628,13 @@ static struct device *vfio_mdev_get_iommu_device(struct device *dev)
> return NULL;
> }
>
> -static int vfio_mdev_attach_domain(struct device *dev, void *data)
> -{
> - struct iommu_domain *domain = data;
> - struct device *iommu_device;
> -
> - iommu_device = vfio_mdev_get_iommu_device(dev);
> - if (iommu_device) {
> - if (iommu_dev_feature_enabled(iommu_device, IOMMU_DEV_FEAT_AUX))
> - return iommu_aux_attach_device(domain, iommu_device);
> - else
> - return iommu_attach_device(domain, iommu_device);
> - }
> -
> - return -EINVAL;
> -}
> -
> -static int vfio_mdev_detach_domain(struct device *dev, void *data)
> -{
> - struct iommu_domain *domain = data;
> - struct device *iommu_device;
> -
> - iommu_device = vfio_mdev_get_iommu_device(dev);
> - if (iommu_device) {
> - if (iommu_dev_feature_enabled(iommu_device, IOMMU_DEV_FEAT_AUX))
> - iommu_aux_detach_device(domain, iommu_device);
> - else
> - iommu_detach_device(domain, iommu_device);
> - }
> -
> - return 0;
> -}
> -
> static int vfio_iommu_attach_group(struct vfio_domain *domain,
> struct vfio_group *group)
> {
> if (group->mdev_group)
> - return iommu_group_for_each_dev(group->iommu_group,
> - domain->domain,
> - vfio_mdev_attach_domain);
> + return iommu_aux_attach_group(domain->domain,
> + group->iommu_group,
> + group->iommu_device);

No, we previously iterated all devices in the group and used the aux
interface only when we have an iommu_device supporting aux. If we
simply assume an mdev group only uses an aux domain we break existing
users, ex. SR-IOV VF backed mdevs. Thanks,

Alex

> else
> return iommu_attach_group(domain->domain, group->iommu_group);
> }
> @@ -1674,8 +1643,8 @@ static void vfio_iommu_detach_group(struct vfio_domain *domain,
> struct vfio_group *group)
> {
> if (group->mdev_group)
> - iommu_group_for_each_dev(group->iommu_group, domain->domain,
> - vfio_mdev_detach_domain);
> + iommu_aux_detach_group(domain->domain, group->iommu_group,
> + group->iommu_device);
> else
> iommu_detach_group(domain->domain, group->iommu_group);
> }
> @@ -2007,6 +1976,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
> return 0;
> }
>
> + group->iommu_device = iommu_device;
> bus = iommu_device->bus;
> }