Re: [PATCH v5 29/30] ARM: vITS: create ITS subnodes for Dom0 DT

[Andre Przywara <andre.przywara@arm.com>]

Hi,

On 07/04/17 14:47, Julien Grall wrote:
> 
> 
> On 07/04/17 14:45, Julien Grall wrote:
>>
>>
>> On 07/04/17 14:46, Andre Przywara wrote:
>>> Hi,
>>>
>>> On 07/04/17 14:41, Julien Grall wrote:
>>>> Hi Andre,
>>>>
>>>> On 06/04/17 00:19, Andre Przywara wrote:
>>>>> Dom0 expects all ITSes in the system to be propagated to be able to
>>>>> use MSIs.
>>>>> Create Dom0 DT nodes for each hardware ITS, keeping the register frame
>>>>> address the same, as the doorbell address that the Dom0 drivers
>>>>> program
>>>>> into the BARs has to match the hardware.
>>>>>
>>>>> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
>>>>> ---
>>>>>  xen/arch/arm/gic-v3-its.c        | 78
>>>>> ++++++++++++++++++++++++++++++++++++++++
>>>>>  xen/arch/arm/gic-v3.c            |  4 ++-
>>>>>  xen/include/asm-arm/gic_v3_its.h | 13 +++++++
>>>>>  3 files changed, 94 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/xen/arch/arm/gic-v3-its.c b/xen/arch/arm/gic-v3-its.c
>>>>> index a57e63a..a167471 100644
>>>>> --- a/xen/arch/arm/gic-v3-its.c
>>>>> +++ b/xen/arch/arm/gic-v3-its.c
>>>>> @@ -20,6 +20,7 @@
>>>>>
>>>>>  #include <xen/lib.h>
>>>>>  #include <xen/delay.h>
>>>>> +#include <xen/libfdt/libfdt.h>
>>>>>  #include <xen/mm.h>
>>>>>  #include <xen/rbtree.h>
>>>>>  #include <xen/sched.h>
>>>>> @@ -875,6 +876,83 @@ int gicv3_lpi_change_vcpu(struct domain *d,
>>>>> paddr_t vdoorbell,
>>>>>      return 0;
>>>>>  }
>>>>>
>>>>> +/*
>>>>> + * Create the respective guest DT nodes for a list of host ITSes.
>>>>> + * This copies the reg property, so the guest sees the ITS at the
>>>>> same address
>>>>> + * as the host.
>>>>> + * Giving NULL for the its_list will make it use the list of host
>>>>> ITSes.
>>>>> + */
>>>>> +int gicv3_its_make_dt_nodes(struct list_head *its_list,
>>>>
>>>> Why do you have this parameter its_list that you always set to NULL?
>>>
>>> The idea is to later allow only a subset of ITSes to be mapped into a
>>> guest. In this case this function would be called with a specific
>>> version of the list.
>>> So this feature is basically just in for future DomU support.
>>
>> DomU DTS are created by the toolstack and not Xen. So please drop this
>> pointless variable.
> 
> To complete what I just said, DOM0 will always have a virtual ITS per
> host ITS not matter whether they will be used. So there is really no
> point of that.

OK, fair enough.

Thanks!
Andre.

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