* [PATCH] iommu/io-pgtable-arm: Fix iova_to_phys for block entries
@ 2016-06-16 17:44 ` Will Deacon
0 siblings, 0 replies; 4+ messages in thread
From: Will Deacon @ 2016-06-16 17:44 UTC (permalink / raw)
To: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r
Cc: Will Deacon, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA
The implementation of iova_to_phys for the long-descriptor ARM
io-pgtable code always masks with the granule size when inserting the
low virtual address bits into the physical address determined from the
page tables. In cases where the leaf entry is found before the final
level of table (i.e. due to a block mapping), this results in rounding
down to the bottom page of the block mapping. Consequently, the physical
address range batching in the vfio_unmap_unpin is defeated and we end
up taking the long way home.
This patch fixes the problem by masking the virtual address with the
appropriate mask for the level at which the leaf descriptor is located.
The short-descriptor code already gets this right, so no change is
needed there.
Reported-by: Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>
Signed-off-by: Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>
---
drivers/iommu/io-pgtable-arm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index a1ed1b73fed4..f5c90e1366ce 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -576,7 +576,7 @@ static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
return 0;
found_translation:
- iova &= (ARM_LPAE_GRANULE(data) - 1);
+ iova &= (ARM_LPAE_BLOCK_SIZE(lvl, data) - 1);
return ((phys_addr_t)iopte_to_pfn(pte,data) << data->pg_shift) | iova;
}
--
2.1.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH] iommu/io-pgtable-arm: Fix iova_to_phys for block entries
@ 2016-06-16 17:44 ` Will Deacon
0 siblings, 0 replies; 4+ messages in thread
From: Will Deacon @ 2016-06-16 17:44 UTC (permalink / raw)
To: linux-arm-kernel
The implementation of iova_to_phys for the long-descriptor ARM
io-pgtable code always masks with the granule size when inserting the
low virtual address bits into the physical address determined from the
page tables. In cases where the leaf entry is found before the final
level of table (i.e. due to a block mapping), this results in rounding
down to the bottom page of the block mapping. Consequently, the physical
address range batching in the vfio_unmap_unpin is defeated and we end
up taking the long way home.
This patch fixes the problem by masking the virtual address with the
appropriate mask for the level at which the leaf descriptor is located.
The short-descriptor code already gets this right, so no change is
needed there.
Reported-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
---
drivers/iommu/io-pgtable-arm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index a1ed1b73fed4..f5c90e1366ce 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -576,7 +576,7 @@ static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
return 0;
found_translation:
- iova &= (ARM_LPAE_GRANULE(data) - 1);
+ iova &= (ARM_LPAE_BLOCK_SIZE(lvl, data) - 1);
return ((phys_addr_t)iopte_to_pfn(pte,data) << data->pg_shift) | iova;
}
--
2.1.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
[parent not found: <1466099078-3919-1-git-send-email-will.deacon-5wv7dgnIgG8@public.gmane.org>]
* Re: [PATCH] iommu/io-pgtable-arm: Fix iova_to_phys for block entries
2016-06-16 17:44 ` Will Deacon
@ 2016-06-17 14:07 ` Robin Murphy
-1 siblings, 0 replies; 4+ messages in thread
From: Robin Murphy @ 2016-06-17 14:07 UTC (permalink / raw)
To: Will Deacon, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r
Cc: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA
On 16/06/16 18:44, Will Deacon wrote:
> The implementation of iova_to_phys for the long-descriptor ARM
> io-pgtable code always masks with the granule size when inserting the
> low virtual address bits into the physical address determined from the
> page tables. In cases where the leaf entry is found before the final
> level of table (i.e. due to a block mapping), this results in rounding
> down to the bottom page of the block mapping. Consequently, the physical
> address range batching in the vfio_unmap_unpin is defeated and we end
> up taking the long way home.
>
> This patch fixes the problem by masking the virtual address with the
> appropriate mask for the level at which the leaf descriptor is located.
> The short-descriptor code already gets this right, so no change is
> needed there.
With this, I now see VFIO unmapping at the same granularity as the
initial mapping. To think of all the cumulative hours we've spent
watching it split the blocks and go 4K at a time... *sigh*
Tested-by: Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>
> Reported-by: Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>
> Signed-off-by: Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>
> ---
> drivers/iommu/io-pgtable-arm.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
> index a1ed1b73fed4..f5c90e1366ce 100644
> --- a/drivers/iommu/io-pgtable-arm.c
> +++ b/drivers/iommu/io-pgtable-arm.c
> @@ -576,7 +576,7 @@ static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
> return 0;
>
> found_translation:
> - iova &= (ARM_LPAE_GRANULE(data) - 1);
> + iova &= (ARM_LPAE_BLOCK_SIZE(lvl, data) - 1);
> return ((phys_addr_t)iopte_to_pfn(pte,data) << data->pg_shift) | iova;
> }
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] iommu/io-pgtable-arm: Fix iova_to_phys for block entries
@ 2016-06-17 14:07 ` Robin Murphy
0 siblings, 0 replies; 4+ messages in thread
From: Robin Murphy @ 2016-06-17 14:07 UTC (permalink / raw)
To: linux-arm-kernel
On 16/06/16 18:44, Will Deacon wrote:
> The implementation of iova_to_phys for the long-descriptor ARM
> io-pgtable code always masks with the granule size when inserting the
> low virtual address bits into the physical address determined from the
> page tables. In cases where the leaf entry is found before the final
> level of table (i.e. due to a block mapping), this results in rounding
> down to the bottom page of the block mapping. Consequently, the physical
> address range batching in the vfio_unmap_unpin is defeated and we end
> up taking the long way home.
>
> This patch fixes the problem by masking the virtual address with the
> appropriate mask for the level at which the leaf descriptor is located.
> The short-descriptor code already gets this right, so no change is
> needed there.
With this, I now see VFIO unmapping at the same granularity as the
initial mapping. To think of all the cumulative hours we've spent
watching it split the blocks and go 4K at a time... *sigh*
Tested-by: Robin Murphy <robin.murphy@arm.com>
> Reported-by: Robin Murphy <robin.murphy@arm.com>
> Signed-off-by: Will Deacon <will.deacon@arm.com>
> ---
> drivers/iommu/io-pgtable-arm.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
> index a1ed1b73fed4..f5c90e1366ce 100644
> --- a/drivers/iommu/io-pgtable-arm.c
> +++ b/drivers/iommu/io-pgtable-arm.c
> @@ -576,7 +576,7 @@ static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
> return 0;
>
> found_translation:
> - iova &= (ARM_LPAE_GRANULE(data) - 1);
> + iova &= (ARM_LPAE_BLOCK_SIZE(lvl, data) - 1);
> return ((phys_addr_t)iopte_to_pfn(pte,data) << data->pg_shift) | iova;
> }
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2016-06-16 17:44 [PATCH] iommu/io-pgtable-arm: Fix iova_to_phys for block entries Will Deacon
2016-06-16 17:44 ` Will Deacon
[not found] ` <1466099078-3919-1-git-send-email-will.deacon-5wv7dgnIgG8@public.gmane.org>
2016-06-17 14:07 ` Robin Murphy
2016-06-17 14:07 ` Robin Murphy
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