On Tue, Apr 19, 2022 at 02:01:58PM -0700, Nicolin Chen wrote:
> The arm_smmu_mm_invalidate_range function is designed to be called
> by mm core for Shared Virtual Addressing purpose between IOMMU and
> CPU MMU. However, the ways of two subsystems defining their "end"
> addresses are slightly different. IOMMU defines its "end" address
> using the last address of an address range, while mm core defines
> that using the following address of an address range:
>
> include/linux/mm_types.h:
> unsigned long vm_end;
> /* The first byte after our end address ...
>
> This mismatch resulted in an incorrect calculation for size so it
> failed to be page-size aligned. Further, it caused a dead loop at
> "while (iova < end)" check in __arm_smmu_tlb_inv_range function.
>
> This patch fixes the issue by doing the calculation correctly.
>
> Fixes: 2f7e8c553e98d ("iommu/arm-smmu-v3: Hook up ATC invalidation to mm ops")
> Cc: sta...@vger.kernel.org
> Signed-off-by: Nicolin Chen <nicol...@nvidia.com>
Thanks for the fix, I guess we didn't catch this earlier because our test
platforms didn't support range invalidation, so __arm_smmu_tlb_inv_range()
would always use PAGE_SIZE as increment.
Reviewed-by: Jean-Philippe Brucker <jean-phili...@linaro.org>
> ---
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
> b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
> index 22ddd05bbdcd..c623dae1e115 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
> @@ -183,7 +183,14 @@ static void arm_smmu_mm_invalidate_range(struct
> mmu_notifier *mn,
> {
> struct arm_smmu_mmu_notifier *smmu_mn = mn_to_smmu(mn);
> struct arm_smmu_domain *smmu_domain = smmu_mn->domain;
> - size_t size = end - start + 1;
> + size_t size;
> +
> + /*
> + * The mm_types defines vm_end as the first byte after the end address,
> + * different from IOMMU subsystem using the last address of an address
> + * range. So do a simple translation here by calculating size correctly.
> + */
> + size = end - start;
>
> if (!(smmu_domain->smmu->features & ARM_SMMU_FEAT_BTM))
> arm_smmu_tlb_inv_range_asid(start, size, smmu_mn->cd->asid,
> --
> 2.17.1
>
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