[PATCH v2] iommu: map reserved memory as cacheable if device is coherent

[PATCH v2] iommu: map reserved memory as cacheable if device is coherent

[Laurentiu Tudor]

Check if the device is marked as DMA coherent in the DT and if so,
map its reserved memory as cacheable in the IOMMU.
This fixes the recently added IOMMU reserved memory support which
uses IOMMU_RESV_DIRECT without properly building the PROT for the
mapping.

Fixes: a5bf3cfce8cb ("iommu: Implement of_iommu_get_resv_regions()")
Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
---
Changes in v2:
 - added Reviewed-by tag

 drivers/iommu/of_iommu.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 157b286e36bf..5b3631ba5a45 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -254,6 +254,9 @@ void of_iommu_get_resv_regions(struct device *dev, struct list_head *list)
 				phys_addr_t iova;
 				size_t length;
 
+				if (of_dma_is_coherent(dev->of_node))
+					prot |= IOMMU_CACHE;
+
 				maps = of_translate_dma_region(np, maps, &iova, &length);
 				type = iommu_resv_region_get_type(dev, &phys, iova, length);
 
-- 
2.17.1

Re: [PATCH v2] iommu: map reserved memory as cacheable if device is coherent

[Thierry Reding]

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On Thu, Sep 14, 2023 at 03:52:58PM +0300, Laurentiu Tudor wrote:
> Check if the device is marked as DMA coherent in the DT and if so,
> map its reserved memory as cacheable in the IOMMU.
> This fixes the recently added IOMMU reserved memory support which
> uses IOMMU_RESV_DIRECT without properly building the PROT for the
> mapping.
> 
> Fixes: a5bf3cfce8cb ("iommu: Implement of_iommu_get_resv_regions()")
> Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
> Changes in v2:
>  - added Reviewed-by tag
> 
>  drivers/iommu/of_iommu.c | 3 +++
>  1 file changed, 3 insertions(+)

Acked-by: Thierry Reding <treding@nvidia.com>

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