[PATCH v2 05/13] gpu: host1x: Restrict IOVA space to DMA mask

Thierry Reding
2019-01-24T18:03:06Z

On Tegra186 and later, the ARM SMMU provides an input address space that
is 48 bits wide. However, memory clients can only address up to 40 bits.
If the geometry is used as-is, allocations of IOVA space can end up in a
region that is not addressable by the memory clients.

To fix this, restrict the IOVA space to the DMA mask of the host1x
device.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
drivers/gpu/host1x/dev.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c
index 4c044ee54fe6..544b67f2b3ff 100644
--- a/drivers/gpu/host1x/dev.c
+++ b/drivers/gpu/host1x/dev.c
@@ -283,6 +283,8 @@ static int host1x_probe(struct platform_device *pdev)
host->group = iommu_group_get(&pdev->dev);
if (host->group) {
struct iommu_domain_geometry *geometry;
+ u64 mask = dma_get_mask(host->dev);
+ dma_addr_t start, end;
unsigned long order;

err = iova_cache_get();
@@ -310,11 +312,12 @@ static int host1x_probe(struct platform_device *pdev)
}

geometry = &host->domain->geometry;
+ start = geometry->aperture_start & mask;
+ end = geometry->aperture_end & mask;

order = __ffs(host->domain->pgsize_bitmap);
- init_iova_domain(&host->iova, 1UL << order,
- geometry->aperture_start >> order);
- host->iova_end = geometry->aperture_end;
+ init_iova_domain(&host->iova, 1UL << order, start >> order);
+ host->iova_end = end;
}