Re: [Xen-devel] [PATCH v1 10/10] xen/arm: domain_build: Don't expose the "iommus" property to the guest

[Oleksandr Tyshchenko <olekstysh@xxxxxxxxx>]

On Thu, May 11, 2017 at 9:07 PM, Julien Grall <julien.grall@xxxxxxx> wrote:
>
>
> On 11/05/17 15:15, Oleksandr Tyshchenko wrote:
>>
>> On Thu, May 11, 2017 at 2:58 PM, Julien Grall <julien.grall@xxxxxxx>
>> wrote:
>>>
>>> Hi Oleksandr,
>>
>> Hi Julien
>
>
> Hi,
>
>
>>>
>>> On 10/05/17 15:03, Oleksandr Tyshchenko wrote:
>>>>
>>>>
>>>> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
>>>>
>>>> We don't passthrough IOMMU device to DOM0 even if it is not used by
>>>> Xen. Therefore exposing the property that describes the IOMMU
>>>> master interfaces of the device does not make any sense.
>>>>
>>>> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
>>>> ---
>>>>  xen/arch/arm/domain_build.c | 4 ++++
>>>>  1 file changed, 4 insertions(+)
>>>>
>>>> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
>>>> index 3abacc0..2defb60 100644
>>>> --- a/xen/arch/arm/domain_build.c
>>>> +++ b/xen/arch/arm/domain_build.c
>>>> @@ -432,6 +432,10 @@ static int write_properties(struct domain *d,
>>>> struct
>>>> kernel_info *kinfo,
>>>>              continue;
>>>>          }
>>>>
>>>> +        /* Don't expose the property "iommus" to the guest */
>>>> +        if ( dt_property_name_is_equal(prop, "iommus") )
>>>> +            continue;
>>>
>>>
>>>
>>> It would be useful to have a link to the bindings associated
>>> (Documentation/devicetree/bindings/iommu/iommu.txt).
>>
>> Agree. I will mention it in commit description.
>>
>>>
>>> Also, whilst you are at it, you likely want to remove all the other iommu
>>> properties such as iommu-map.
>>
>> Excuse me, I have never heard about it. Is it a required property?
>
>
> This property is used to translate an RID into a Master ID (see the
> documentation in bindings/pci/pci-iommu.txt).
So, these two should be skipped too:
- iommu-map
- iommu-map-mask

Right?

>
> Cheers,
>
> --
> Julien Grall



-- 
Regards,

Oleksandr Tyshchenko

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