Re: [dpdk-dev] [PATCH 7/7] vhost: simplify features set/get

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

On 08/25/2016 10:36 AM, Xu, Qian Q wrote:
>
>
> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Maxime Coquelin
> Sent: Thursday, August 25, 2016 3:19 PM
> To: Yuanhan Liu <yuanhan.liu@linux.intel.com>
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH 7/7] vhost: simplify features set/get
>
>
>
> On 08/25/2016 05:03 AM, Yuanhan Liu wrote:
>> On Wed, Aug 24, 2016 at 10:11:57AM +0200, Maxime Coquelin wrote:
>>>
>>>
>>> On 08/18/2016 10:48 AM, Yuanhan Liu wrote:
>>>> No need to use a pointer to store/retrieve features.
>>>>
>>>> Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
>>>> ---
>>>> lib/librte_vhost/vhost_user.c | 20 ++++++++------------
>>>> 1 file changed, 8 insertions(+), 12 deletions(-)
>>>>
>>>> diff --git a/lib/librte_vhost/vhost_user.c
>>>> b/lib/librte_vhost/vhost_user.c index ef4a0c1..eee99e9 100644
>>>> --- a/lib/librte_vhost/vhost_user.c
>>>> +++ b/lib/librte_vhost/vhost_user.c
>>>> @@ -155,23 +155,22 @@ vhost_user_reset_owner(struct virtio_net *dev)
>>>> /*
>>>>  * The features that we support are requested.
>>>>  */
>>>> -static int
>>>> -vhost_user_get_features(uint64_t *pu)
>>>> +static uint64_t
>>>> +vhost_user_get_features(void)
>>>> {
>>>> -	*pu = VHOST_FEATURES;
>>>> -	return 0;
>>>> +	return VHOST_FEATURES;
>>>> }
>>>
>>> This is not the topic of this series, but I wonder if it could make
>>> sense to be able to override supported features at device init time.
>>
>> Not quite sure I understood it correctly: is
>> rte_vhost_feature_disable() the answer you are looking for?
> Not really.
>
> I meant a per-device supported features, and something you could set also via the vhost PMD options, without needing to recompile.
>
> But maybe it would make more sense to do it a guest level?
>
> Maxime
>
> -------Agreed, as you know we have the vhost PMD port and virtio-user PMD port and we can launch both vhost/virtio on the host, but we
> Can't set the mergeable in the command line, we may need add some feature settings for virtio-user interface. It will be much easier to
> Run tests or application.

I never tried virtio-user PMD on host, but my proposal should be
applicable there too.

Regards,
Maxime