On Wednesday 02 Jun 2021 at 11:19:49 (+0100), Marc Zyngier wrote:
> On Thu, 15 Apr 2021 12:50:28 +0100,
> > @@ -583,6 +589,7 @@ static int stage2_map_walker_try_leaf(u64 addr, u64 end, u32 level,
> > {
> > kvm_pte_t new, old = *ptep;
> > u64 granule = kvm_granule_size(level), phys = data->phys;
> > + struct kvm_pgtable *pgt = data->mmu->pgt;
> > struct kvm_pgtable_mm_ops *mm_ops = data->mm_ops;
> >
> > if (!kvm_block_mapping_supported(addr, end, phys, level))
> > @@ -606,6 +613,13 @@ static int stage2_map_walker_try_leaf(u64 addr, u64 end, u32 level,
> > stage2_put_pte(ptep, data->mmu, addr, level, mm_ops);
> > }
> >
> > + /* Perform CMOs before installation of the guest stage-2 PTE */
> > + if (pgt->flags & KVM_PGTABLE_S2_GUEST) {
> > + if (stage2_pte_cacheable(pgt, new) && !stage2_has_fwb(pgt))
> > + __flush_dcache_area(mm_ops->phys_to_virt(phys),
> > + granule);
> > + }
>
> Rather than this, why not provide new callbacks in mm_ops, even if we
> have to provide one that is specific to guests (and let the protected
> stuff do its own thing)?
Ack, an optional callback in the mm_ops sounds much nicer.
> One thing I really dislike though is that the page-table code is
> starting to be littered with things that are not directly related to
> page tables. We are re-creating the user_mem_abort() mess in a
> different place.
+1, we should probably keep the page-table code as close as possible
to a standalone and architecturally-compliant library as opposed to a
mess of unrelated logic, simply because that will lead to a cleaner and
more maintainable design in the long run, and because that will ease the
interoperability with EL2 in protected mode.
Thanks,
Quentin
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