Re: [PATCH] iommu/arm-smmu-v3: Align size in __arm_smmu_tlb_inv_range

Robin Murphy
2022-04-13T13:41:51Z

On 2022-04-13 05:17, Nicolin Chen wrote:
> To calculate num_pages, the size should be aligned with
> "page size", determined by the tg value. Otherwise, its
> following "while (iova < end)" might become an infinite
> loop if unaligned size is slightly greater than 1 << tg.

Hmm, how does a non-page-aligned invalidation request get generated in
the first place?

Robin.

> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> index 627a3ed5ee8f..8249dad5ae44 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -1879,7 +1879,7 @@ static void __arm_smmu_tlb_inv_range(struct arm_smmu_cmdq_ent *cmd,
> /* Determine what level the granule is at */
> cmd->tlbi.ttl = 4 - ((ilog2(granule) - 3) / (tg - 3));
>
> - num_pages = size >> tg;
> + num_pages = ALIGN(size, 1 << tg) >> tg;
> }
>
> cmds.num = 0;