Re: [dpdk-dev] [PATCH 2/4] vdpa/mlx5: support direct HW notifications

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 4/26/20 9:06 AM, Matan Azrad wrote:
> 
> 
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
>> On 4/15/20 11:47 AM, Maxime Coquelin wrote:
>>>
>>>
>>> On 3/24/20 3:24 PM, Asaf Penso wrote:
>>>> From: Matan Azrad <matan@mellanox.com>
>>>>
>>>> Add support for the next 2 callbacks:
>>>> get_vfio_device_fd and get_notify_area.
>>>>
>>>> This will allow direct HW doorbell ringing from guest and will save
>>>> CPU usage in host.
>>>>
>>>> By this patch, the QEMU will map the physical address of the virtio
>>>> device in guest directly to the physical address of the HW device
>>>> doorbell.
>>>>
>>>> The guest doorbell write is 2 bytes transaction while some Mellanox
>>>> nics support only 4 bytes transactions.
>>>>
>>>> Remove ConnectX-5 and BF1 devices support which don't support 2B
>>>> doorbell writes for HW triggering.
>>>
>>> Couldn't we have different rte_vdpa_dev_ops depending on whether
>>> doorbell write support?
>>
>> I'll take the patch so that it lands into -rc1.
>> But I would like to discuss the opportunity to have different dev_ops based
>> on the device IDs, so that BF can still be supported. Maybe that could be
>> done in -rc2?
> 
> Mellanox decided to remove BF1 from GA and from upstream support.
> GA devices are CX6dx + BF2.

Thanks for the clarification.

Maxime

>>
>> Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>>
>> Thanks,
>> Maxime
>>
>