Re: [PATCH v7 9/9] iommu/dma: Reserve any RMR regions associated with a dev

Robin Murphy
2021-10-08T13:10:13Z

On 2021-08-05 09:07, Shameer Kolothum wrote:
> Get ACPI IORT RMR regions associated with a dev reserved
> so that there is a unity mapping for them in SMMU.

This feels like most of it belongs in the IORT code rather than
iommu-dma (which should save the temporary list copy as well).

Robin.

> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> ---
> drivers/iommu/dma-iommu.c | 56 +++++++++++++++++++++++++++++++++++----
> 1 file changed, 51 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index 1b6e27475279..c1ae0c3d4b33 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -207,22 +207,68 @@ void iommu_dma_put_rmrs(struct fwnode_handle *iommu_fwnode,
> }
> EXPORT_SYMBOL(iommu_dma_put_rmrs);
>
> +static bool iommu_dma_dev_has_rmr(struct iommu_fwspec *fwspec,
> + struct iommu_resv_region *e)
> +{
> + int i;
> +
> + for (i = 0; i < fwspec->num_ids; i++) {
> + if (e->fw_data.rmr.sid == fwspec->ids[i])
> + return true;
> + }
> +
> + return false;
> +}
> +
> +static void iommu_dma_get_rmr_resv_regions(struct device *dev,
> + struct list_head *list)
> +{
> + struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> + struct list_head rmr_list;
> + struct iommu_resv_region *rmr, *tmp;
> +
> + INIT_LIST_HEAD(&rmr_list);
> + if (iommu_dma_get_rmrs(fwspec->iommu_fwnode, &rmr_list))
> + return;
> +
> + if (dev_is_pci(dev)) {
> + struct pci_dev *pdev = to_pci_dev(dev);
> + struct pci_host_bridge *host = pci_find_host_bridge(pdev->bus);
> +
> + if (!host->preserve_config)
> + return;
> + }
> +
> + list_for_each_entry_safe(rmr, tmp, &rmr_list, list) {
> + if (!iommu_dma_dev_has_rmr(fwspec, rmr))
> + continue;
> +
> + /* Remove from iommu RMR list and add to dev resv_regions */
> + list_del_init(&rmr->list);
> + list_add_tail(&rmr->list, list);
> + }
> +
> + iommu_dma_put_rmrs(fwspec->iommu_fwnode, &rmr_list);
> +}
> +
> /**
> * iommu_dma_get_resv_regions - Reserved region driver helper
> * @dev: Device from iommu_get_resv_regions()
> * @list: Reserved region list from iommu_get_resv_regions()
> *
> * IOMMU drivers can use this to implement their .get_resv_regions callback
> - * for general non-IOMMU-specific reservations. Currently, this covers GICv3
> - * ITS region reservation on ACPI based ARM platforms that may require HW MSI
> - * reservation.
> + * for general non-IOMMU-specific reservations. Currently this covers,
> + * -GICv3 ITS region reservation on ACPI based ARM platforms that may
> + * require HW MSI reservation.
> + * -Any ACPI IORT RMR memory range reservations (IORT spec rev E.b)
> */
> void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list)
> {
>
> - if (!is_of_node(dev_iommu_fwspec_get(dev)->iommu_fwnode))
> + if (!is_of_node(dev_iommu_fwspec_get(dev)->iommu_fwnode)) {
> iort_iommu_msi_get_resv_regions(dev, list);
> -
> + iommu_dma_get_rmr_resv_regions(dev, list);
> + }
> }
> EXPORT_SYMBOL(iommu_dma_get_resv_regions);