Re: [Qemu-devel] [RFC/PATCH] migration: SMRAM dirty bitmap not fetched from kvm-kmod and not send to destination

["Herongguang (Stephen)" <herongguang.he@huawei.com>]

On 2016/9/23 16:59, Paolo Bonzini wrote:
>
>
> On 23/09/2016 10:51, Herongguang (Stephen) wrote:
>>
>>
>> On 2016/9/23 15:17, Paolo Bonzini wrote:
>>>
>>>
>>> On 22/09/2016 15:16, Herongguang (Stephen) wrote:
>>>> I have some concern:
>>>> 1. For example, vhost does not know about as_id, I wonder if guests in
>>>> SMM can operate disk or ether card, as in
>>>> that case vhost would not logging dirty pages correctly, without knowing
>>>> as_id.
>>>
>>> In the end memory is logged by ram_addr_t, not by address space.  So if
>>> vhost_sync_dirty_bitmap is called on the right region everything works.
>>>
>>> Guests in SMM can operate on storage devices, but storage devices cannot
>>> write to 0xA0000-0xBFFFF so that's safe.
>> You are right, as vhost does not have a smram address space listener. So
>> is this a qemu's flaw that virtual devices can not write to SMRAM?
>
> No, it's how it works in real hardware.  However, it is a (minor) bug
> that vhost doesn't have the equivalent of kvm_set_phys_mem's call to
> kvm_physical_sync_dirty_bitmap.
>
>> Fine, your patch is simpler than I thought and functions right.
>
> Great!
>
>> Reviewed-by: He Rongguang <herongguang.he@huawei.com>
>
> Also Tested-by?
Yes, I will test this patch in these days.

>
> Thanks,
>
> Paolo
>>
>>> .
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> .
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