Re: [RFC PATCH 08/16] hw/arm/smmuv3: Support S2AFFD

[Mostafa Saleh <smostafa@google.com>]

Hi Eric,

On Wed, Feb 15, 2023 at 07:37:52PM +0100, Eric Auger wrote:
> > Parse S2AFFD from STE and use it in stage-2 translation.
> >
> > This is described in the SMMUv3 manual "5.2. Stream Table Entry" in
> > "[181] S2AFFD".
> 
> from a patch structure pov, to me it would make more sense to add the
> STE field decoding in
> [RFC PATCH 06/16] hw/arm/smmuv3: Parse STE config for stage-2 and use it
> in hw/arm/smmuv3: Add page table walk for stage-2
Yes, as all STE parsing will be in the same patch, it make sense to
remove this one and AFFD in stage-2 PTW.

> > +         * An Access fault takes priority over a Permission fault.
> > +         */
> > +        if (!PTE_AF(pte) && !cfg->s2cfg.affd) {
> > +            info->type = SMMU_PTW_ERR_ACCESS;
> Wondering how you are going to differentiate page faults at S1 versus
> page faults at S2.
> Event number #10 differentiates both and recorded fields are different.
> 
> Do you handle that somewhere?
Yes, this is missing, similar to F_TRANSLATION, we can set
info->u.f_walk_eabt.s2 which would set S2[103] bit in the fault event.


Thanks,
Mostafa