RE: [RFC PATCH v6 1/5] iommu: add an exported function to get minimum page size for a domain

[Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>]

Hi Robin,

> From: Robin Murphy, Sent: Friday, June 14, 2019 6:41 PM
> 
> On 13/06/2019 11:20, Yoshihiro Shimoda wrote:
> > This patch adds an exported function to get minimum page size for
> > a domain. This patch also modifies similar codes on the iommu.c.
> 
> Heh, seeing this gave me a genuine déjà vu moment...
> 
> ...but it turns out I actually *have* reviewed this patch before :)
> 
> https://lore.kernel.org/lkml/05eca601-0264-8141-ceeb-7ef7ad5d5650@arm.com/

Thank you for the information :)
I realized my patch should have taken care of the CONFIG_IPMMU_API=n case.

However, the latest patch series doesn't have such a patch. So, I'll keep this
my patch on next patch version.
https://lore.kernel.org/lkml/20190603011620.31999-1-baolu.lu@linux.intel.com/

Best regards,
Yoshihiro Shimoda

> Robin.
> 
> > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> > ---
> >   drivers/iommu/iommu.c | 18 +++++++++++++++---
> >   include/linux/iommu.h |  1 +
> >   2 files changed, 16 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> > index 2a90638..7ed16af 100644
> > --- a/drivers/iommu/iommu.c
> > +++ b/drivers/iommu/iommu.c
> > @@ -280,6 +280,18 @@ iommu_insert_device_resv_regions(struct list_head *dev_resv_regions,
> >   	return ret;
> >   }
> >
> > +/**
> > + * iommu_get_minimum_page_size - get minimum page size for a domain
> > + * @domain: the domain
> > + *
> > + * Allow iommu driver to get a minimum page size for a domain.
> > + */
> > +unsigned long iommu_get_minimum_page_size(struct iommu_domain *domain)
> > +{
> > +	return 1UL << __ffs(domain->pgsize_bitmap);
> > +}
> > +EXPORT_SYMBOL_GPL(iommu_get_minimum_page_size);
> > +
> >   int iommu_get_group_resv_regions(struct iommu_group *group,
> >   				 struct list_head *head)
> >   {
> > @@ -558,7 +570,7 @@ static int iommu_group_create_direct_mappings(struct iommu_group *group,
> >
> >   	BUG_ON(!domain->pgsize_bitmap);
> >
> > -	pg_size = 1UL << __ffs(domain->pgsize_bitmap);
> > +	pg_size = iommu_get_minimum_page_size(domain);
> >   	INIT_LIST_HEAD(&mappings);
> >
> >   	iommu_get_resv_regions(dev, &mappings);
> > @@ -1595,7 +1607,7 @@ int iommu_map(struct iommu_domain *domain, unsigned long iova,
> >   		return -EINVAL;
> >
> >   	/* find out the minimum page size supported */
> > -	min_pagesz = 1 << __ffs(domain->pgsize_bitmap);
> > +	min_pagesz = iommu_get_minimum_page_size(domain);
> >
> >   	/*
> >   	 * both the virtual address and the physical one, as well as
> > @@ -1655,7 +1667,7 @@ static size_t __iommu_unmap(struct iommu_domain *domain,
> >   		return 0;
> >
> >   	/* find out the minimum page size supported */
> > -	min_pagesz = 1 << __ffs(domain->pgsize_bitmap);
> > +	min_pagesz = iommu_get_minimum_page_size(domain);
> >
> >   	/*
> >   	 * The virtual address, as well as the size of the mapping, must be
> > diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> > index 91af22a..7e53b43 100644
> > --- a/include/linux/iommu.h
> > +++ b/include/linux/iommu.h
> > @@ -366,6 +366,7 @@ extern int iommu_request_dma_domain_for_dev(struct device *dev);
> >   extern struct iommu_resv_region *
> >   iommu_alloc_resv_region(phys_addr_t start, size_t length, int prot,
> >   			enum iommu_resv_type type);
> > +extern unsigned long iommu_get_minimum_page_size(struct iommu_domain *domain);
> >   extern int iommu_get_group_resv_regions(struct iommu_group *group,
> >   					struct list_head *head);
> >
> >
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