On Wed, 30 Nov 2016 17:52:03 +1100
Alexey Kardashevskiy <a...@ozlabs.ru> wrote:
> We are going to allow the userspace to configure container in
> one memory context and pass container fd to another so
> we are postponing memory allocations accounted against
> the locked memory limit. One of previous patches took care of
> it_userspace.
>
> At the moment we create the default DMA window when the first group is
> attached to a container; this is done for the userspace which is not
> DDW-aware but familiar with the SPAPR TCE IOMMU v2 in the part of memory
> pre-registration - such client expects the default DMA window to exist.
>
> This postpones the default DMA window allocation till one of
> the folliwing happens:
> 1. first map/unmap request arrives;
> 2. new window is requested;
> This adds noop for the case when the userspace requested removal
> of the default window which has not been created yet.
>
> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
> Reviewed-by: David Gibson <da...@gibson.dropbear.id.au>
> ---
> Changes:
> v6:
> * new helper tce_iommu_create_default_window() moved to a separate patch;
> * creates a default window when new window is requested; it used to
> reset the def_window_pending flag instead;
> * def_window_pending handling (mostly) localized in
> tce_iommu_create_default_window() now, the only exception is removal
> of not yet created default window.
> ---
> drivers/vfio/vfio_iommu_spapr_tce.c | 40
> +++++++++++++++++++++++--------------
> 1 file changed, 25 insertions(+), 15 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 a67bbfd..88622be 100644
> --- a/drivers/vfio/vfio_iommu_spapr_tce.c
> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
> @@ -97,6 +97,7 @@ struct tce_container {
> struct mutex lock;
> bool enabled;
> bool v2;
> + bool def_window_pending;
> unsigned long locked_pages;
> struct iommu_table *tables[IOMMU_TABLE_GROUP_MAX_TABLES];
> struct list_head group_list;
> @@ -717,6 +718,9 @@ static long tce_iommu_create_default_window(struct
> tce_container *container)
> struct tce_iommu_group *tcegrp;
> struct iommu_table_group *table_group;
>
> + if (!container->def_window_pending)
> + return 0;
> +
> if (!tce_groups_attached(container))
> return -ENODEV;
>
> @@ -730,6 +734,9 @@ static long tce_iommu_create_default_window(struct
> tce_container *container)
> table_group->tce32_size, 1, &start_addr);
> WARN_ON_ONCE(!ret && start_addr);
>
> + if (!ret)
> + container->def_window_pending = false;
> +
> return ret;
> }
>
> @@ -823,6 +830,10 @@ static long tce_iommu_ioctl(void *iommu_data,
> VFIO_DMA_MAP_FLAG_WRITE))
> return -EINVAL;
>
> + ret = tce_iommu_create_default_window(container);
> + if (ret)
> + return ret;
> +
> num = tce_iommu_find_table(container, param.iova, &tbl);
> if (num < 0)
> return -ENXIO;
> @@ -886,6 +897,10 @@ static long tce_iommu_ioctl(void *iommu_data,
> if (param.flags)
> return -EINVAL;
>
> + ret = tce_iommu_create_default_window(container);
> + if (ret)
> + return ret;
> +
> num = tce_iommu_find_table(container, param.iova, &tbl);
> if (num < 0)
> return -ENXIO;
> @@ -1012,6 +1027,10 @@ static long tce_iommu_ioctl(void *iommu_data,
>
> mutex_lock(&container->lock);
>
> + ret = tce_iommu_create_default_window(container);
> + if (ret)
> + return ret;
> +
> ret = tce_iommu_create_window(container, create.page_shift,
> create.window_size, create.levels,
> &create.start_addr);
> @@ -1044,6 +1063,11 @@ static long tce_iommu_ioctl(void *iommu_data,
> if (remove.flags)
> return -EINVAL;
>
> + if (container->def_window_pending && !remove.start_addr) {
> + container->def_window_pending = false;
> + return 0;
> + }
> +
> mutex_lock(&container->lock);
>
> ret = tce_iommu_remove_window(container, remove.start_addr);
> @@ -1141,7 +1165,6 @@ static int tce_iommu_attach_group(void *iommu_data,
> struct tce_container *container = iommu_data;
> struct iommu_table_group *table_group;
> struct tce_iommu_group *tcegrp = NULL;
> - bool create_default_window = false;
>
> mutex_lock(&container->lock);
>
> @@ -1189,25 +1212,12 @@ static int tce_iommu_attach_group(void *iommu_data,
> } else {
> ret = tce_iommu_take_ownership_ddw(container, table_group);
> if (!tce_groups_attached(container) && !container->tables[0])
> - create_default_window = true;
> + container->def_window_pending = true;
> }
>
> if (!ret) {
> tcegrp->grp = iommu_group;
> list_add(&tcegrp->next, &container->group_list);
> - /*
> - * If it the first group attached, check if there is
> - * a default DMA window and create one if none as
> - * the userspace expects it to exist.
> - */
> - if (create_default_window) {
> - ret = tce_iommu_create_default_window(container);
> - if (ret) {
> - list_del(&tcegrp->next);
> - tce_iommu_release_ownership_ddw(container,
> - table_group);
> - }
> - }
> }
>
> unlock_exit:
