On Mon, 13 Sep 2021 09:16:05 +0200
Christoph Hellwig <hch@xxxxxx> wrote:
> The external_domain concept rather misleading and not actually needed.
> Replace it with a list of emulated groups in struct vfio_iommu.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
> ---
> drivers/vfio/vfio_iommu_type1.c | 121 ++++++++++++++------------------
> 1 file changed, 54 insertions(+), 67 deletions(-)
>
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index a48e9f597cb213..d2db62cb2aaa39 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
...
> @@ -2163,62 +2163,52 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
> struct vfio_iommu_group *group;
> struct vfio_domain *domain, *d;
> struct bus_type *bus = NULL;
> - int ret;
> bool resv_msi, msi_remap;
> phys_addr_t resv_msi_base = 0;
> struct iommu_domain_geometry *geo;
> LIST_HEAD(iova_copy);
> LIST_HEAD(group_resv_regions);
> + int ret = -EINVAL;
>
> mutex_lock(&iommu->lock);
>
> /* Check for duplicates */
> - if (vfio_iommu_find_iommu_group(iommu, iommu_group)) {
> - mutex_unlock(&iommu->lock);
> - return -EINVAL;
> - }
> + if (vfio_iommu_find_iommu_group(iommu, iommu_group))
> + goto out_unlock;
>
> + ret = -ENOMEM;
> group = kzalloc(sizeof(*group), GFP_KERNEL);
> - domain = kzalloc(sizeof(*domain), GFP_KERNEL);
> - if (!group || !domain) {
> - ret = -ENOMEM;
> - goto out_free;
> - }
> -
> + if (!group)
> + goto out_unlock;
> group->iommu_group = iommu_group;
>
> - /* Determine bus_type in order to allocate a domain */
> - ret = iommu_group_for_each_dev(iommu_group, &bus, vfio_bus_type);
> - if (ret)
> - goto out_free;
> -
> if (type == VFIO_EMULATED_IOMMU) {
> - if (!iommu->external_domain) {
> - INIT_LIST_HEAD(&domain->group_list);
> - iommu->external_domain = domain;
> - vfio_update_pgsize_bitmap(iommu);
> - } else {
> - kfree(domain);
> - }
> -
> - list_add(&group->next, &iommu->external_domain->group_list);
> + list_add(&group->next, &iommu->emulated_iommu_groups);
> /*
> - * Non-iommu backed group cannot dirty memory directly, it can
> + * An emulated IOMMU group cannot dirty memory directly, it can
> * only use interfaces that provide dirty tracking.
> * The iommu scope can only be promoted with the addition of a
> * dirty tracking group.
> */
> group->pinned_page_dirty_scope = true;
> - mutex_unlock(&iommu->lock);
> -
> - return 0;
> + ret = 0;
> + goto out_unlock;
> }
I think this dropped the call to vfio_update_pgsize_bitmap(), which
would leave iommu->pgsize_bitmap = 0 for a container hosting only mdev
devices, which leads us to undefined behavior when we're using ffs on
it to validate maps, unmaps, dirty bitmap support, etc. Did I miss
this getting moved elsewhere? Thanks,
Alex
