Re: [Xen-devel] [PATCH v1 04/10] xen/arm: p2m: Update IOMMU mapping whenever possible if page table is not shared

[Julien Grall <julien.grall@xxxxxxx>]

Hi Oleksandr,

On 10/05/17 15:03, Oleksandr Tyshchenko wrote:
> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
>
> Update IOMMU mapping if the IOMMU doesn't share page table with the CPU.
> The best place to do so on ARM is __p2m_set_entry(). Use mfn as an indicator
> of the required action. If mfn is valid call iommu_map_pages(),
> otherwise - iommu_unmap_pages().
>
> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
> CC: Julien Grall <julien.grall@xxxxxxx>
Acked-by: Julien Grall <julien.grall@xxxxxxx>

> ---
>    Changes in v1:
>       - Update IOMMU mapping in __p2m_set_entry() instead of p2m_set_entry().
>       - Pass order argument to IOMMU APIs instead of page_count.
> ---
>  xen/arch/arm/p2m.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> index 34d5776..9ca491b 100644
> --- a/xen/arch/arm/p2m.c
> +++ b/xen/arch/arm/p2m.c
> @@ -984,7 +984,15 @@ static int __p2m_set_entry(struct p2m_domain *p2m,
>          p2m_free_entry(p2m, orig_pte, level);
>
>      if ( need_iommu(p2m->domain) && (p2m_valid(orig_pte) || p2m_valid(*entry)) 
> )
> -        rc = iommu_iotlb_flush(p2m->domain, gfn_x(sgfn), 1UL << page_order);
> +    {
> +        if ( iommu_use_hap_pt(p2m->domain) )
> +            rc = iommu_iotlb_flush(p2m->domain, gfn_x(sgfn), 1UL << 
> page_order);
> +        else if ( !mfn_eq(smfn, INVALID_MFN) )
> +            rc = iommu_map_pages(p2m->domain, gfn_x(sgfn), mfn_x(smfn),
> +                                 page_order, p2m_get_iommu_flags(t));
> +        else
> +            rc = iommu_unmap_pages(p2m->domain, gfn_x(sgfn), page_order);
> +    }
>      else
>          rc = 0;
Cheers,

--
Julien Grall

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