Re: [Qemu-devel] [PATCH v3 3/3] pc-dimm: factor out address space logic into MemoryDevice code

[David Hildenbrand]

On 24.04.2018 15:31, Igor Mammedov wrote:
> On Mon, 23 Apr 2018 14:52:37 +0200
> David Hildenbrand <address@hidden> wrote:
> 
>>>   
>>>> +    /* we will need a new memory slot for kvm and vhost */
>>>> +    if (kvm_enabled() && !kvm_has_free_slot(machine)) {
>>>> +        error_setg(errp, "hypervisor has no free memory slots left");
>>>> +        return;
>>>> +    }
>>>> +    if (!vhost_has_free_slot()) {
>>>> +        error_setg(errp, "a used vhost backend has no free memory slots 
>>>> left");
>>>> +        return;
>>>> +    }  
>>> move these checks to pre_plug time
>>>   
>>>> +
>>>> +    memory_region_add_subregion(&hpms->mr, addr - hpms->base, mr);  
>>> missing vmstate registration?  
>>
>> Missed this one: To be called by the caller. Important because e.g. for
>> virtio-pmem we don't want this (I assume :) ).
> if pmem isn't on shared storage, then We'd probably want to migrate
> it as well, otherwise target would experience data loss.
> Anyways, I'd just reat it as normal RAM in migration case

Yes, if we realize that all MemoryDevices need this call, we can move it
to that place, too.

Wonder if we might want to make this configurable for virtio-pmem later
on (via a flag or sth like that).

-- 

Thanks,

David / dhildenb