2020-12-07 12:01:51

by Keqian Zhu

Subject: [PATCH v2] iommu: Defer the early return in arm_(v7s/lpae)_map

Although handling a mapping request with no permissions is a
trivial no-op, defer the early return until after the size/range
checks so that we are consistent with other mapping requests.

Signed-off-by: Keqian Zhu <[email protected]>
---
drivers/iommu/io-pgtable-arm-v7s.c | 8 ++++----
drivers/iommu/io-pgtable-arm.c | 8 ++++----
2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c
index a688f22cbe3b..359b96b0fa3e 100644
--- a/drivers/iommu/io-pgtable-arm-v7s.c
+++ b/drivers/iommu/io-pgtable-arm-v7s.c
@@ -522,14 +522,14 @@ static int arm_v7s_map(struct io_pgtable_ops *ops, unsigned long iova,
struct io_pgtable *iop = &data->iop;
int ret;

- /* If no access, then nothing to do */
- if (!(prot & (IOMMU_READ | IOMMU_WRITE)))
- return 0;
-
if (WARN_ON(iova >= (1ULL << data->iop.cfg.ias) ||
paddr >= (1ULL << data->iop.cfg.oas)))
return -ERANGE;

+ /* If no access, then nothing to do */
+ if (!(prot & (IOMMU_READ | IOMMU_WRITE)))
+ return 0;
+
ret = __arm_v7s_map(data, iova, paddr, size, prot, 1, data->pgd, gfp);
/*
* Synchronise all PTE updates for the new mapping before there's
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index a7a9bc08dcd1..8ade72adab31 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -444,10 +444,6 @@ static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
arm_lpae_iopte prot;
long iaext = (s64)iova >> cfg->ias;

- /* If no access, then nothing to do */
- if (!(iommu_prot & (IOMMU_READ | IOMMU_WRITE)))
- return 0;
-
if (WARN_ON(!size || (size & cfg->pgsize_bitmap) != size))
return -EINVAL;

@@ -456,6 +452,10 @@ static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
if (WARN_ON(iaext || paddr >> cfg->oas))
return -ERANGE;

+ /* If no access, then nothing to do */
+ if (!(iommu_prot & (IOMMU_READ | IOMMU_WRITE)))
+ return 0;
+
prot = arm_lpae_prot_to_pte(data, iommu_prot);
ret = __arm_lpae_map(data, iova, paddr, size, prot, lvl, ptep, gfp);
/*
--
2.23.0

2020-12-08 14:25:42

by Robin Murphy

Subject: Re: [PATCH v2] iommu: Defer the early return in arm_(v7s/lpae)_map

On 2020-12-07 11:57, Keqian Zhu wrote:
> Although handling a mapping request with no permissions is a
> trivial no-op, defer the early return until after the size/range
> checks so that we are consistent with other mapping requests.

Reviewed-by: Robin Murphy <[email protected]>

> Signed-off-by: Keqian Zhu <[email protected]>
> ---
> drivers/iommu/io-pgtable-arm-v7s.c | 8 ++++----
> drivers/iommu/io-pgtable-arm.c | 8 ++++----
> 2 files changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c
> index a688f22cbe3b..359b96b0fa3e 100644
> --- a/drivers/iommu/io-pgtable-arm-v7s.c
> +++ b/drivers/iommu/io-pgtable-arm-v7s.c
> @@ -522,14 +522,14 @@ static int arm_v7s_map(struct io_pgtable_ops *ops, unsigned long iova,
> struct io_pgtable *iop = &data->iop;
> int ret;
>
> - /* If no access, then nothing to do */
> - if (!(prot & (IOMMU_READ | IOMMU_WRITE)))
> - return 0;
> -
> if (WARN_ON(iova >= (1ULL << data->iop.cfg.ias) ||
> paddr >= (1ULL << data->iop.cfg.oas)))
> return -ERANGE;
>
> + /* If no access, then nothing to do */
> + if (!(prot & (IOMMU_READ | IOMMU_WRITE)))
> + return 0;
> +
> ret = __arm_v7s_map(data, iova, paddr, size, prot, 1, data->pgd, gfp);
> /*
> * Synchronise all PTE updates for the new mapping before there's
> diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
> index a7a9bc08dcd1..8ade72adab31 100644
> --- a/drivers/iommu/io-pgtable-arm.c
> +++ b/drivers/iommu/io-pgtable-arm.c
> @@ -444,10 +444,6 @@ static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
> arm_lpae_iopte prot;
> long iaext = (s64)iova >> cfg->ias;
>
> - /* If no access, then nothing to do */
> - if (!(iommu_prot & (IOMMU_READ | IOMMU_WRITE)))
> - return 0;
> -
> if (WARN_ON(!size || (size & cfg->pgsize_bitmap) != size))
> return -EINVAL;
>
> @@ -456,6 +452,10 @@ static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
> if (WARN_ON(iaext || paddr >> cfg->oas))
> return -ERANGE;
>
> + /* If no access, then nothing to do */
> + if (!(iommu_prot & (IOMMU_READ | IOMMU_WRITE)))
> + return 0;
> +
> prot = arm_lpae_prot_to_pte(data, iommu_prot);
> ret = __arm_lpae_map(data, iova, paddr, size, prot, lvl, ptep, gfp);
> /*
>

2020-12-08 15:58:29

by Will Deacon

Subject: Re: [PATCH v2] iommu: Defer the early return in arm_(v7s/lpae)_map

On Mon, 7 Dec 2020 19:57:58 +0800, Keqian Zhu wrote:
> Although handling a mapping request with no permissions is a
> trivial no-op, defer the early return until after the size/range
> checks so that we are consistent with other mapping requests.

Applied to arm64 (for-next/iommu/misc), thanks!

[1/1] iommu: Defer the early return in arm_(v7s/lpae)_map
https://git.kernel.org/arm64/c/f12e0d22903e

Cheers,
--
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev