[RFC PATCH v4 12/15] iommu/io-pgtable-arm-v7s: Implement arm_v7s_unmap_pages()

[Will Deacon]

On Thu, Apr 08, 2021 at 07:19:29AM -0700, isaacm at codeaurora.org wrote:
> On 2021-04-08 06:58, Will Deacon wrote:
> > On Wed, Apr 07, 2021 at 09:52:38PM -0700, Isaac J. Manjarres wrote:
> > > Implement the unmap_pages() callback for the ARM v7s io-pgtable
> > > format.
> > > 
> > > Signed-off-by: Isaac J. Manjarres <isaacm at codeaurora.org>
> > > ---
> > >  drivers/iommu/io-pgtable-arm-v7s.c | 23 ++++++++++++++++++++---
> > >  1 file changed, 20 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/drivers/iommu/io-pgtable-arm-v7s.c
> > > b/drivers/iommu/io-pgtable-arm-v7s.c
> > > index d4004bcf333a..5e203e03c352 100644
> > > --- a/drivers/iommu/io-pgtable-arm-v7s.c
> > > +++ b/drivers/iommu/io-pgtable-arm-v7s.c
> > > @@ -710,15 +710,32 @@ static size_t __arm_v7s_unmap(struct
> > > arm_v7s_io_pgtable *data,
> > >  	return __arm_v7s_unmap(data, gather, iova, size, lvl + 1, ptep);
> > >  }
> > > 
> > > -static size_t arm_v7s_unmap(struct io_pgtable_ops *ops, unsigned
> > > long iova,
> > > -			    size_t size, struct iommu_iotlb_gather *gather)
> > > +static size_t arm_v7s_unmap_pages(struct io_pgtable_ops *ops,
> > > unsigned long iova,
> > > +				  size_t pgsize, size_t pgcount,
> > > +				  struct iommu_iotlb_gather *gather)
> > >  {
> > >  	struct arm_v7s_io_pgtable *data = io_pgtable_ops_to_data(ops);
> > > +	size_t unmapped = 0, ret;
> > > 
> > >  	if (WARN_ON(iova >= (1ULL << data->iop.cfg.ias)))
> > >  		return 0;
> > > 
> > > -	return __arm_v7s_unmap(data, gather, iova, size, 1, data->pgd);
> > > +	while (pgcount--) {
> > > +		ret = __arm_v7s_unmap(data, gather, iova, pgsize, 1, data->pgd);
> > > +		if (!ret)
> > > +			break;
> > > +
> > > +		unmapped += pgsize;
> > > +		iova += pgsize;
> > > +	}
> > > +
> > > +	return unmapped;
> > > +}
> > 
> > Wait -- don't you need to hook this up somewhere (likewise for
> > ->map_pages)?
> Done. Likewise for map_pages(). I'm not sure how the compiler didn't catch
> this; I'm compile testing this, as I don't have hardware that uses the short
> descriptor format.

Damn, neither do I :/ My seattle has all the memory high up iirc.

Will