Re: [PATCH v7 4/9] ACPI/IORT: Add a helper to retrieve RMR memory regions

Lorenzo Pieralisi
2021-08-05T15:44:01Z

On Thu, Aug 05, 2021 at 09:07:19AM +0100, Shameer Kolothum wrote:
> Add a helper function (iort_iommu_get_rmrs()) that retrieves RMR
> memory descriptors associated with a given IOMMU. This will be used
> by IOMMU drivers to setup necessary mappings.
>
> Invoke it from the generic helper iommu_dma_get_rmrs().
>
> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> ---
> drivers/acpi/arm64/iort.c | 38 ++++++++++++++++++++++++++++++++++++++
> drivers/iommu/dma-iommu.c | 4 ++++
> include/linux/acpi_iort.h | 7 +++++++
> 3 files changed, 49 insertions(+)

Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> index d76ba46ebe67..3c32d62e63b6 100644
> --- a/drivers/acpi/arm64/iort.c
> +++ b/drivers/acpi/arm64/iort.c
> @@ -809,6 +809,42 @@ static struct acpi_iort_node *iort_get_msi_resv_iommu(struct device *dev)
> return NULL;
> }
>
> +/**
> + * iort_iommu_get_rmrs() - Helper to retrieve RMR info associated with IOMMU
> + * @iommu_fwnode: fwnode for the IOMMU
> + * @head: RMR list head to be populated
> + *
> + * Returns: 0 on success, <0 failure. Please note, we will keep the already
> + * allocated RMR reserve regions in case of a kmemdup()
> + * failure.
> + */
> +int iort_iommu_get_rmrs(struct fwnode_handle *iommu_fwnode,
> + struct list_head *head)
> +{
> + struct iommu_resv_region *e;
> + struct acpi_iort_node *iommu;
> + int rmrs = 0;
> +
> + iommu = iort_get_iort_node(iommu_fwnode);
> + if (!iommu || list_empty(&iort_rmr_list))
> + return -ENODEV;
> +
> + list_for_each_entry(e, &iort_rmr_list, list) {
> + struct iommu_resv_region *region;
> +
> + if (e->fw_data.rmr.smmu != iommu)
> + continue;
> +
> + region = kmemdup(e, sizeof(*region), GFP_KERNEL);
> + if (region) {
> + list_add_tail(&region->list, head);
> + rmrs++;
> + }
> + }
> +
> + return (rmrs == 0) ? -ENODEV : 0;
> +}
> +
> /**
> * iort_iommu_msi_get_resv_regions - Reserved region driver helper
> * @dev: Device from iommu_get_resv_regions()
> @@ -1041,6 +1077,8 @@ int iort_iommu_msi_get_resv_regions(struct device *dev, struct list_head *head)
> { return 0; }
> int iort_iommu_configure_id(struct device *dev, const u32 *input_id)
> { return -ENODEV; }
> +int iort_iommu_get_rmrs(struct fwnode_handle *fwnode, struct list_head *head)
> +{ return -ENODEV; }
> #endif
>
> static int nc_dma_get_range(struct device *dev, u64 *size)
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index 2fa2445e9070..1b6e27475279 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -185,6 +185,9 @@ EXPORT_SYMBOL(iommu_put_dma_cookie);
> int iommu_dma_get_rmrs(struct fwnode_handle *iommu_fwnode,
> struct list_head *list)
> {
> + if (!is_of_node(iommu_fwnode))
> + return iort_iommu_get_rmrs(iommu_fwnode, list);
> +
> return -EINVAL;
> }
> EXPORT_SYMBOL(iommu_dma_get_rmrs);
> @@ -200,6 +203,7 @@ EXPORT_SYMBOL(iommu_dma_get_rmrs);
> void iommu_dma_put_rmrs(struct fwnode_handle *iommu_fwnode,
> struct list_head *list)
> {
> + generic_iommu_put_resv_regions(iommu_fwnode->dev, list);
> }
> EXPORT_SYMBOL(iommu_dma_put_rmrs);
>
> diff --git a/include/linux/acpi_iort.h b/include/linux/acpi_iort.h
> index f1f0842a2cb2..d8c030c103f5 100644
> --- a/include/linux/acpi_iort.h
> +++ b/include/linux/acpi_iort.h
> @@ -38,6 +38,8 @@ int iort_dma_get_ranges(struct device *dev, u64 *size);
> int iort_iommu_configure_id(struct device *dev, const u32 *id_in);
> int iort_iommu_msi_get_resv_regions(struct device *dev, struct list_head *head);
> phys_addr_t acpi_iort_dma_get_max_cpu_address(void);
> +int iort_iommu_get_rmrs(struct fwnode_handle *iommu_fwnode,
> + struct list_head *list);
> #else
> static inline void acpi_iort_init(void) { }
> static inline u32 iort_msi_map_id(struct device *dev, u32 id)
> @@ -57,6 +59,11 @@ int iort_iommu_msi_get_resv_regions(struct device *dev, struct list_head *head)
>
> static inline phys_addr_t acpi_iort_dma_get_max_cpu_address(void)
> { return PHYS_ADDR_MAX; }
> +
> +static inline
> +int iort_iommu_get_rmrs(struct fwnode_handle *iommu_fwnode,
> + struct list_head *list)
> +{ return -ENODEV; }
> #endif
>
> #endif /* __ACPI_IORT_H__ */
> --
> 2.17.1