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

[Oleksandr Tyshchenko <olekstysh@xxxxxxxxx>]

On Thu, May 11, 2017 at 2:24 PM, Julien Grall <julien.grall@xxxxxxx> wrote:
> Hi Oleksandr,
Hi Julien

>
> 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>
Great. Thank you.

>
>
>>
>> ---
>>    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



-- 
Regards,

Oleksandr Tyshchenko

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