Re: [RFC PATCH v1 0/2] iommu/arm-smmu-v3: Add some parameter check in __arm_smmu_tlb_inv_range()

[Kunkun Jiang <jiangkunkun@huawei.com>]

Hi Robin,

On 2021/5/19 18:01, Robin Murphy wrote:
> On 2021-05-19 10:43, Kunkun Jiang wrote:
>> Hi all,
>>
>> This set of patches solves some errors when I tested the SMMU nested 
>> mode.
>>
>> Test scenario description:
>> guest kernel: 4KB translation granule
>> host kernel: 16KB translation granule
>>
>> errors:
>> 1. encountered an endless loop in __arm_smmu_tlb_inv_range because
>> num_pages is 0
>> 2. encountered CERROR_ILL because the fields of TLB invalidation
>> command are as follow: TG = 2, NUM = 0, SCALE = 0, TTL = 0. The
>> combination is exactly the kind of reserved combination pointed
>> out in the SMMUv3 spec(page 143-144, version D.a)
>>
>> In my opinion, it is more appropriate to add parameter check in
>> __arm_smmu_tlb_inv_range(), although these problems only appeared
>> when I tested the SMMU nested mode. What do you think?
>
> FWIW I think it would be better to fix the caller to not issue broken 
> commands in the first place. The kernel shouldn't do so for itself 
> (and definitely needs fixing if it ever does), so it sounds like the 
> nesting implementation needs to do a bit more validation of what it's 
> passing through.
Thanks for your reply.
I will report these errors to Eric and discuss how to fix them.

Thanks,
Kunkun Jiang
>
> Robin.
>
>> This series include patches as below:
>> Patch 1:
>> - align the invalid range with leaf page size upwards when smmu
>> supports RIL
>>
>> Patch 2:
>> - add a check to standardize granule size when smmu supports RIL
>>
>> Kunkun Jiang (2):
>>    iommu/arm-smmu-v3: Align invalid range with leaf page size upwards
>>      when support RIL
>>    iommu/arm-smmu-v3: Standardize granule size when support RIL
>>
>>   drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 9 +++++++++
>>   1 file changed, 9 insertions(+)
>>
> .



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