Re: [PATCH v6 0/6] hmp, qmp: Add some commands to introspect virtio devices

[Jason Wang <jasowang@redhat.com>]

在 2021/7/21 下午4:53, Jonah Palmer 写道:
>
> Hi Jason. My apologies for the delayed response, several work-related 
> things came up recently, but they're slowing down now so I'm turning 
> my attention these patches to get taken care of.
>
> A few questions and comments below (and in other following patches):
>
>
> On 7/13/21 10:42 PM, Jason Wang wrote:
>>
>> 在 2021/7/12 下午6:35, Jonah Palmer 写道:
>>>          Dump the information of the head element of the third queue 
>>> of virtio-scsi:
>>>
>>>          (qemu) virtio queue-element 
>>> /machine/peripheral-anon/device[3]/virtio-backend 3
>>>          index: 122
>>>          ndescs: 3
>>>          descs: addr 0x7302d000 len 4096 (write), addr 0x3c951763 
>>> len 108 (write, next),
>>>                 addr 0x3c951728 len 51 (next)
>>
>>
>> I think it would be nice if we can show driver area and device area 
>> as well here.
> Sure thing. And I apologize if it's obvious (I'm relatively new to virtio), but how can I expose the driver area?


So the spec defines three parts: the device area, the driver area, and 
the descriptor area. And they are all located in the guest memory.


> I understand that virtio devices are part of the Qemu process, but I also thought that virtio drivers are in the
> guest's kernel, which I don't believe I can see into from Qemu (or, at least, it's not obvious to me).


It works like how you access the descriptor ring (descriptor area).

Thanks


>
> Jonah
>>
>> Thanks
>>