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Message-ID: <27b04293-2225-c78d-f6e3-ffe8a7472ea1@intel.com>
Date: Wed, 21 Sep 2022 13:59:46 +0800
From: "Zhu, Lingshan" <lingshan.zhu@...el.com>
To: Jason Wang <jasowang@...hat.com>
Cc: mst <mst@...hat.com>,
virtualization <virtualization@...ts.linux-foundation.org>,
netdev <netdev@...r.kernel.org>, kvm <kvm@...r.kernel.org>
Subject: Re: [PATCH 1/4] vDPA: allow userspace to query features of a vDPA
device
On 9/21/2022 10:17 AM, Jason Wang wrote:
> On Tue, Sep 20, 2022 at 5:58 PM Zhu, Lingshan <lingshan.zhu@...el.com> wrote:
>>
>>
>> On 9/20/2022 10:02 AM, Jason Wang wrote:
>>> On Fri, Sep 9, 2022 at 5:05 PM Zhu Lingshan <lingshan.zhu@...el.com> wrote:
>>>> This commit adds a new vDPA netlink attribution
>>>> VDPA_ATTR_VDPA_DEV_SUPPORTED_FEATURES. Userspace can query
>>>> features of vDPA devices through this new attr.
>>>>
>>>> This commit invokes vdpa_config_ops.get_config() than
>>>> vdpa_get_config_unlocked() to read the device config
>>>> spcae, so no raeces in vdpa_set_features_unlocked()
>>>>
>>>> Signed-off-by: Zhu Lingshan <lingshan.zhu@...el.com>
>>> It's better to share the userspace code as well.
>> OK, will share it in V2.
>>>> ---
>>>> drivers/vdpa/vdpa.c | 19 ++++++++++++++-----
>>>> include/uapi/linux/vdpa.h | 4 ++++
>>>> 2 files changed, 18 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
>>>> index c06c02704461..798a02c7aa94 100644
>>>> --- a/drivers/vdpa/vdpa.c
>>>> +++ b/drivers/vdpa/vdpa.c
>>>> @@ -491,6 +491,8 @@ static int vdpa_mgmtdev_fill(const struct vdpa_mgmt_dev *mdev, struct sk_buff *m
>>>> err = -EMSGSIZE;
>>>> goto msg_err;
>>>> }
>>>> +
>>>> + /* report features of a vDPA management device through VDPA_ATTR_DEV_SUPPORTED_FEATURES */
>>> The code explains itself, there's no need for the comment.
>> these comments are required in other discussions
> I think it's more than sufficient to clarify the semantic where it is defined.
OK, then only comments in the header file
>
>>>> if (nla_put_u64_64bit(msg, VDPA_ATTR_DEV_SUPPORTED_FEATURES,
>>>> mdev->supported_features, VDPA_ATTR_PAD)) {
>>>> err = -EMSGSIZE;
>>>> @@ -815,10 +817,10 @@ static int vdpa_dev_net_mq_config_fill(struct vdpa_device *vdev,
>>>> static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *msg)
>>>> {
>>>> struct virtio_net_config config = {};
>>>> - u64 features;
>>>> + u64 features_device, features_driver;
>>>> u16 val_u16;
>>>>
>>>> - vdpa_get_config_unlocked(vdev, 0, &config, sizeof(config));
>>>> + vdev->config->get_config(vdev, 0, &config, sizeof(config));
>>>>
>>>> if (nla_put(msg, VDPA_ATTR_DEV_NET_CFG_MACADDR, sizeof(config.mac),
>>>> config.mac))
>>>> @@ -832,12 +834,19 @@ static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *ms
>>>> if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MTU, val_u16))
>>>> return -EMSGSIZE;
>>>>
>>>> - features = vdev->config->get_driver_features(vdev);
>>>> - if (nla_put_u64_64bit(msg, VDPA_ATTR_DEV_NEGOTIATED_FEATURES, features,
>>>> + features_driver = vdev->config->get_driver_features(vdev);
>>>> + if (nla_put_u64_64bit(msg, VDPA_ATTR_DEV_NEGOTIATED_FEATURES, features_driver,
>>>> + VDPA_ATTR_PAD))
>>>> + return -EMSGSIZE;
>>>> +
>>>> + features_device = vdev->config->get_device_features(vdev);
>>>> +
>>>> + /* report features of a vDPA device through VDPA_ATTR_VDPA_DEV_SUPPORTED_FEATURES */
>>>> + if (nla_put_u64_64bit(msg, VDPA_ATTR_VDPA_DEV_SUPPORTED_FEATURES, features_device,
>>>> VDPA_ATTR_PAD))
>>>> return -EMSGSIZE;
>>>>
>>>> - return vdpa_dev_net_mq_config_fill(vdev, msg, features, &config);
>>>> + return vdpa_dev_net_mq_config_fill(vdev, msg, features_driver, &config);
>>>> }
>>>>
>>>> static int
>>>> diff --git a/include/uapi/linux/vdpa.h b/include/uapi/linux/vdpa.h
>>>> index 25c55cab3d7c..97531b52dcbe 100644
>>>> --- a/include/uapi/linux/vdpa.h
>>>> +++ b/include/uapi/linux/vdpa.h
>>>> @@ -46,12 +46,16 @@ enum vdpa_attr {
>>>>
>>>> VDPA_ATTR_DEV_NEGOTIATED_FEATURES, /* u64 */
>>>> VDPA_ATTR_DEV_MGMTDEV_MAX_VQS, /* u32 */
>>>> + /* features of a vDPA management device */
>>>> VDPA_ATTR_DEV_SUPPORTED_FEATURES, /* u64 */
>>>>
>>>> VDPA_ATTR_DEV_QUEUE_INDEX, /* u32 */
>>>> VDPA_ATTR_DEV_VENDOR_ATTR_NAME, /* string */
>>>> VDPA_ATTR_DEV_VENDOR_ATTR_VALUE, /* u64 */
>>>>
>>>> + /* features of a vDPA device, e.g., /dev/vhost-vdpa0 */
>>>> + VDPA_ATTR_VDPA_DEV_SUPPORTED_FEATURES, /* u64 */
>>> What's the difference between this and VDPA_ATTR_DEV_SUPPORTED_FEATURES?
>> This is to report a vDPA device features, and
>> VDPA_ATTR_DEV_SUPPORTED_FEATURES
>> is used for reporting the management device features, we have a long
>> discussion
>> on this before.
> Yes, but the comment is not clear in many ways:
>
> " features of a vDPA management device" sounds like features that is
> out of the scope of the virtio.
I think the term "vDPA device" implies that it is a virtio device.
So how about: "virtio features of a vDPA management device"
>
> And
>
> "/dev/vhost-vdpa0" is not a vDPA device but a vhost-vDPA device.
will remove this example here.
Thanks
>
> Thanks
>
>>> Thanks
>>>
>>>> +
>>>> /* new attributes must be added above here */
>>>> VDPA_ATTR_MAX,
>>>> };
>>>> --
>>>> 2.31.1
>>>>
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