From: Robin Murphy <robin.mur...@arm.com>
[ Upstream commit 1be08f458d1602275b02f5357ef069957058f3fd ]
In principle, Midgard GPUs supporting smaller VA sizes should only
require 3-level pagetables, since level 0 only resolves bits 48:40 of
the address. However, the kbase driver does not appear to have any
notion of a variable start level, and empirically T720 and T820 rapidly
blow up with translation faults unless given a full 4-level table,
despite only supporting a 33-bit VA size.
The 'real' IAS value is still valuable in terms of validating addresses
on map/unmap, so tweak the allocator to allow smaller values while still
forcing the resultant tables to the full 4 levels. As far as I can test,
this should make all known Midgard variants happy.
Fixes: d08d42de6432 ("iommu: io-pgtable: Add ARM Mali midgard MMU page table
format")
Tested-by: Neil Armstrong <narmstr...@baylibre.com>
Reviewed-by: Steven Price <steven.pr...@arm.com>
Reviewed-by: Rob Herring <r...@kernel.org>
Signed-off-by: Robin Murphy <robin.mur...@arm.com>
Signed-off-by: Will Deacon <w...@kernel.org>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
drivers/iommu/io-pgtable-arm.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 9e35cd991f065..77f41c9dd9be7 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -1022,7 +1022,7 @@ arm_mali_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg,
void *cookie)
if (cfg->quirks)
return NULL;
- if (cfg->ias != 48 || cfg->oas > 40)
+ if (cfg->ias > 48 || cfg->oas > 40)
return NULL;
cfg->pgsize_bitmap &= (SZ_4K | SZ_2M | SZ_1G);
@@ -1031,6 +1031,11 @@ arm_mali_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg,
void *cookie)
if (!data)
return NULL;
+ /* Mali seems to need a full 4-level table regardless of IAS */
+ if (data->levels < ARM_LPAE_MAX_LEVELS) {
+ data->levels = ARM_LPAE_MAX_LEVELS;
+ data->pgd_size = sizeof(arm_lpae_iopte);
+ }
/*
* MEMATTR: Mali has no actual notion of a non-cacheable type, so the
* best we can do is mimic the out-of-tree driver and hope that the
--
2.20.1
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