netdev - Re: [PATCH V2 4/6] vDPA: !FEATURES_OK should not block querying device config space

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Message-ID: <25b0b924-14ec-496d-b986-65b3b4e224d5@intel.com>
Date:   Tue, 14 Jun 2022 10:53:55 +0800
From:   "Zhu, Lingshan" <lingshan.zhu@...el.com>
To:     Parav Pandit <parav@...dia.com>,
        "jasowang@...hat.com" <jasowang@...hat.com>,
        "mst@...hat.com" <mst@...hat.com>
Cc:     "virtualization@...ts.linux-foundation.org" 
        <virtualization@...ts.linux-foundation.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "xieyongji@...edance.com" <xieyongji@...edance.com>,
        "gautam.dawar@....com" <gautam.dawar@....com>
Subject: Re: [PATCH V2 4/6] vDPA: !FEATURES_OK should not block querying
 device config space



On 6/14/2022 4:31 AM, Parav Pandit wrote:
>
>> From: Zhu Lingshan <lingshan.zhu@...el.com>
>> Sent: Monday, June 13, 2022 6:17 AM
>>
>> Users may want to query the config space of a vDPA device, to choose a
>> appropriate one for a certain guest. This means the users need to read the
>> config space before FEATURES_OK, and the existence of config space
>> contents does not depend on FEATURES_OK.
>>
>> The spec says:
>> The device MUST allow reading of any device-specific configuration field
>> before FEATURES_OK is set by the driver. This includes fields which are
>> conditional on feature bits, as long as those feature bits are offered by the
>> device.
>>
>> Signed-off-by: Zhu Lingshan <lingshan.zhu@...el.com>
>> ---
>>   drivers/vdpa/vdpa.c | 8 --------
>>   1 file changed, 8 deletions(-)
>>
>> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c index
>> 9b0e39b2f022..d76b22b2f7ae 100644
>> --- a/drivers/vdpa/vdpa.c
>> +++ b/drivers/vdpa/vdpa.c
>> @@ -851,17 +851,9 @@ vdpa_dev_config_fill(struct vdpa_device *vdev,
>> struct sk_buff *msg, u32 portid,  {
>>   	u32 device_id;
>>   	void *hdr;
>> -	u8 status;
>>   	int err;
>>
>>   	down_read(&vdev->cf_lock);
>> -	status = vdev->config->get_status(vdev);
>> -	if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
>> -		NL_SET_ERR_MSG_MOD(extack, "Features negotiation not
>> completed");
>> -		err = -EAGAIN;
>> -		goto out;
>> -	}
>> -
>>   	hdr = genlmsg_put(msg, portid, seq, &vdpa_nl_family, flags,
>>   			  VDPA_CMD_DEV_CONFIG_GET);
>>   	if (!hdr) {
>> --
>> 2.31.1
> Management interface should not mix up the device state machine checks like above.
> Hence above code removal is better choice.
> Please add fixes tag to this patch.
will do, thanks for your review

Thanks,
Zhu Lingshan
>
> Reviewed-by: Parav Pandit <parav@...dia.com>