Re: [PATCH v5 23/26] KVM: arm/arm64: GICv4: Prevent a VM using GICv4 from being saved

Auger Eric
2017-11-07T16:12:12Z

Hi Marc,

On 07/11/2017 16:38, Marc Zyngier wrote:
> On 07/11/17 15:24, Auger Eric wrote:
>> Hi Marc,
>>
>> Hi Marc,
>> On 27/10/2017 16:28, Marc Zyngier wrote:
>>> The GICv4 architecture doesn't make it easy for save/restore to
>>> work, as it doesn't give any guarantee that the pending state
>>> is written into the pending table.
>>
>> I don't understand where does the limitation exactly come from. Can't we
>> use the GICR_VPENDBASER table data?
> You can't. None of the tables that are written by either the ITS or the
> redistributors are architected. All you know is that there is one bit
> per vLPI, but that's it (you don't even know which one is which).
Oh I thought the redistributor config and pending tables were fully
specified (6.1.2 and 6.1.3 of the spec), except the 1kB of the pending
table.
>
> But that's not a big deal. I don't think you can realistically migrate a
> VM that has a directly assigned device anyway. Or can we?
No we can't except for mediated devices for which migration can be
supported.

Thanks

Eric
>
> Thanks,
>
> M.
>