Re: [PATCH v5 3/8] ACPI/IORT: Add a helper to retrieve RMR memory regions

[Laurentiu Tudor <laurentiu.tudor@nxp.com>]

Hi Shameer,

On 5/24/2021 2:02 PM, Shameer Kolothum wrote:
> Add a helper function that retrieves RMR memory descriptors
> associated with a given IOMMU. This will be used by IOMMU
> drivers to setup necessary mappings.
> 
> Now that we have this, invoke it from the generic helper
> interface.
> 
> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> ---
>  drivers/acpi/arm64/iort.c | 50 +++++++++++++++++++++++++++++++++++++++
>  drivers/iommu/dma-iommu.c |  4 ++++
>  include/linux/acpi_iort.h |  7 ++++++
>  3 files changed, 61 insertions(+)
> 
> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> index fea1ffaedf3b..01917caf58de 100644
> --- a/drivers/acpi/arm64/iort.c
> +++ b/drivers/acpi/arm64/iort.c
> @@ -12,6 +12,7 @@
>  
>  #include <linux/acpi_iort.h>
>  #include <linux/bitfield.h>
> +#include <linux/dma-iommu.h>
>  #include <linux/iommu.h>
>  #include <linux/kernel.h>
>  #include <linux/list.h>
> @@ -837,6 +838,53 @@ static inline int iort_add_device_replay(struct device *dev)
>  	return err;
>  }
>  
> +/**
> + * iort_iommu_get_rmrs - Helper to retrieve RMR info associated with IOMMU
> + * @iommu: fwnode for the IOMMU
> + * @head: RMR list head to be populated
> + *
> + * Returns: 0 on success, <0 failure
> + */
> +int iort_iommu_get_rmrs(struct fwnode_handle *iommu_fwnode,
> +			struct list_head *head)
> +{
> +	struct iort_rmr_entry *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) {
> +		int prot = IOMMU_READ | IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;

We have a case with an IP block that needs EXEC rights on its reserved
memory, so could you please drop the IOMMU_NOEXEC flag?

---
Thanks & Best Regards, Laurentiu