On Wed, 30 Nov 2016 17:52:01 +1100
Alexey Kardashevskiy <a...@ozlabs.ru> wrote:
> The iommu_table struct manages a hardware TCE table and a vmalloc'd
> table with corresponding userspace addresses. Both are allocated when
> the default DMA window is created and this happens when the very first
> group is attached to a container.
>
> As we are going to allow the userspace to configure container in one
> memory context and pas container fd to another, we have to postpones
> such allocations till a container fd is passed to the destination
> user process so we would account locked memory limit against the actual
> container user constrainsts.
>
> This postpones the it_userspace array allocation till it is used first
> time for mapping. The unmapping patch already checks if the array is
> allocated.
>
> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
> Reviewed-by: David Gibson <da...@gibson.dropbear.id.au>
> ---
> Changes:
> v6:
> * moved missing hunk from the next patch: tce_iommu_create_table()
> would decrement locked_vm while new caller - tce_iommu_build_v2() -
> will not; this adds a new return code to the DMA mapping path but
> this seems to be a minor change.
> ---
> drivers/vfio/vfio_iommu_spapr_tce.c | 20 +++++++-------------
> 1 file changed, 7 insertions(+), 13 deletions(-)
Acked-by: Alex Williamson <alex.william...@redhat.com>
> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c
> b/drivers/vfio/vfio_iommu_spapr_tce.c
> index d0c38b2..4efd2b2 100644
> --- a/drivers/vfio/vfio_iommu_spapr_tce.c
> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
> @@ -515,6 +515,12 @@ static long tce_iommu_build_v2(struct tce_container
> *container,
> unsigned long hpa;
> enum dma_data_direction dirtmp;
>
> + if (!tbl->it_userspace) {
> + ret = tce_iommu_userspace_view_alloc(tbl);
> + if (ret)
> + return ret;
> + }
> +
> for (i = 0; i < pages; ++i) {
> struct mm_iommu_table_group_mem_t *mem = NULL;
> unsigned long *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl,
> @@ -588,15 +594,6 @@ static long tce_iommu_create_table(struct tce_container
> *container,
> WARN_ON(!ret && !(*ptbl)->it_ops->free);
> WARN_ON(!ret && ((*ptbl)->it_allocated_size != table_size));
>
> - if (!ret && container->v2) {
> - ret = tce_iommu_userspace_view_alloc(*ptbl);
> - if (ret)
> - (*ptbl)->it_ops->free(*ptbl);
> - }
> -
> - if (ret)
> - decrement_locked_vm(table_size >> PAGE_SHIFT);
> -
> return ret;
> }
>
> @@ -1068,10 +1065,7 @@ static int tce_iommu_take_ownership(struct
> tce_container *container,
> if (!tbl || !tbl->it_map)
> continue;
>
> - rc = tce_iommu_userspace_view_alloc(tbl);
> - if (!rc)
> - rc = iommu_take_ownership(tbl);
> -
> + rc = iommu_take_ownership(tbl);
> if (rc) {
> for (j = 0; j < i; ++j)
> iommu_release_ownership(
