> On 6 Oct 2016, at 17:43, Dr. David Alan Gilbert <dgilb...@redhat.com> wrote:
>
> * Dmitry Fleytman (dmi...@daynix.com) wrote:
>>
>>> On 30 Sep 2016, at 15:08 PM, Markus Armbruster <arm...@redhat.com> wrote:
>>>
>>> Cao jin <caoj.f...@cn.fujitsu.com> writes:
>>>
>>>>> On 09/29/2016 10:42 PM, Markus Armbruster wrote:
>>>>> Cao jin <caoj.f...@cn.fujitsu.com> writes:
>>>>>
>>>>
>>>>>> static int vmxnet3_post_load(void *opaque, int version_id)
>>>>>> {
>>>>>> VMXNET3State *s = opaque;
>>>>>> - PCIDevice *d = PCI_DEVICE(s);
>>>>>>
>>>>>> net_tx_pkt_init(&s->tx_pkt, PCI_DEVICE(s),
>>>>>> s->max_tx_frags, s->peer_has_vhdr);
>>>>>> net_rx_pkt_init(&s->rx_pkt, s->peer_has_vhdr);
>>>>>>
>>>>>> - if (s->msix_used) {
>>>>>> - if (!vmxnet3_use_msix_vectors(s, VMXNET3_MAX_INTRS)) {
>>>>>> - VMW_WRPRN("Failed to re-use MSI-X vectors");
>>>>>> - msix_uninit(d, &s->msix_bar, &s->msix_bar);
>>>>>> - s->msix_used = false;
>>>>>> - return -1;
>>>>>> - }
>>>>>> - }
>>>>>> -
>>>>>> vmxnet3_validate_queues(s);
>>>>>> vmxnet3_validate_interrupts(s);
>>>>>
>>>>> This hunk isn't obvious. Can you explain the change?
>>>>>
>>>>
>>>> flag msix_used is used in VMStateDescription.post_Load().
>>>>
>>>> 1st, I think msix's code here is not necessary, because in
>>>> destination, device has been realized before incoming migration, So I
>>>> don't know why re-use MSI-X vectors here. Dmitry, could help to
>>>> explain?
>>>>
>>>> 2nd, this patch is going to remove this flag, so I removed the hunk.
>>>
>>> We need to find out whether the call of vmxnet3_use_msix_vectors() is
>>> necessary. I suspect it's not only not necessary, but actively wrong.
>>>
>>> If that's true, removing becomes a bug fix that should be a separate
>>> patch.
>>>
>>> If it's only unnecessary, the removal may stay in this patch, but it
>>> needs to be explained. Separate patch might be easier to explain. Your
>>> choice.
>>>
>>> If it correct and necessary, then this patch needs to be changed not to
>>> drop it. Instead, replace s->msix_used by msix_enabled(d) like you do
>>> elsewhere.
>>>
>>> Dmitry, can you help us find out?
>>
>> Hello,
>>
>> Yes, from what I see, this call is wrong and leads to
>> reference leaks on device unload at migration target.
>> It should be removed.
>
> Talking of oddities in vmxnet3's msix load/save,
> vmxnet3 has the honour of being the only device that
> has both a register_savevm (which registers vmxnet3-msix)
> and also has a ->vmsd entry (dc->vmsd = &vmstate_vmxnet3)
>
> What's the history behind that? Is there some ordering requirement
> etc about the order the two get loaded/saved?
>
> Dave
Hi Dave,
There is no specific history behind that. Vmxnet3 code was written long time
ago and this part is just a legacy code that was not cleaned up as QEMU code
base evolved.
~Dmitry
>
>> Best regards,
>> Dmitry
>>
>>
>>
> --
> Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
