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

[Kunkun Jiang]

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(+)
> .