[virtio-dev] Re: [virtio-comment] [RFC PATCH] admin-queue: bind the group member to the device

["Zhu, Lingshan" <lingshan.zhu@intel.com>]

On 6/26/2023 3:08 PM, Xuan Zhuo wrote:
> On Mon, 26 Jun 2023 14:43:17 +0800, "Zhu, Lingshan" <lingshan.zhu@intel.com> wrote:
>>
>> On 6/26/2023 2:22 PM, Xuan Zhuo wrote:
>>> The VFs of the SR-IOV are created by the user inside the guest OS, so the virtio
>>> devices don't know about these VFs. Because each VF may be assigned a different role
>>> by the user, the virtio device can not choose one VF to bind random.
>>> So only the user knows how to bind the virtio devices to the VFs.
>>> On the other hand, generally the virtio devices are not created by the user
>>> inside the guest OS. This requires some management platform to participate.
>>>
>>> So the usage of this command:
>>> 1. The user purchases a virtio network card on the management platform,
>>>      and sets the ip, queue number, etc. The user obtains the identity of
>>>      the network card.
>>> 2. The user creates a VF with echo 8 > sriov_numvfs
>>> 3. The user binds the net crad to a VF with identity through the command
>>>      of the patch
>>>
>>> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
>>> ---
>>>    admin.tex | 41 ++++++++++++++++++++++++++++++++++++++++-
>>>    1 file changed, 40 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/admin.tex b/admin.tex
>>> index 2efd4d7..64d0667 100644
>>> --- a/admin.tex
>>> +++ b/admin.tex
>>> @@ -115,7 +115,8 @@ \subsection{Group administration commands}\label{sec:Basic Facilities of a Virti
>>>    \hline \hline
>>>    0x0000 & VIRTIO_ADMIN_CMD_LIST_QUERY & Provides to driver list of commands supported for this group type    \\
>>>    0x0001 & VIRTIO_ADMIN_CMD_LIST_USE & Provides to device list of commands used for this group type \\
>>> -0x0002 - 0x7FFF & - & Commands using \field{struct virtio_admin_cmd}    \\
>>> +0x0002 & VIRTIO_ADMIN_CMD_BIND_DEVICE & Bind the device to one group member \\
>>> +0x0003 - 0x7FFF & - & Commands using \field{struct virtio_admin_cmd}    \\
>>>    \hline
>>>    0x8000 - 0xFFFF & - & Reserved for future commands (possibly using a different structure)    \\
>>>    \hline
>>> @@ -429,6 +430,44 @@ \subsection{Group administration commands}\label{sec:Basic Facilities of a Virti
>>>    \field{VF Enable} refer to registers within the SR-IOV Extended
>>>    Capability as specified by \hyperref[intro:PCIe]{[PCIe]}.
>>>
>>> +\subsubsection{Bind the device for member}
>>> +
>>> +The VFs of the SR-IOV are created by the user inside the guest OS, so the virtio
>> If the VFs are create in a guest OS, I assume that means the user has
>> passthrough-ed the
>> PF to the guest. For nested, I am not sure whether this is a security
>> issue(affects host pci).
>
> No care about the passthrough, we always created VFs by the PF.
>
> I should not say "inside the guest OS". I just want to say that the VF is create
> by the user in the OS. The devices does not know about it.
OK, perhaps just say create VFs from a PF in the OS?
>
>
>>> +devices don't know about these VFs. Because each VF may be assigned a different role
>>> +by the user, the virtio device can not choose one VF to bind random.
>> I failed to understand this, once a VF is created, it has a personality,
>> e.g.,
>> create a virtio-net VF from a virtio-net PF, and PF knows that.
>>
>> I am not familiar with the background, What do you mean by virtio device
>> choose
>> one VF to bind?
>
> On the cloud, the nic is created by the management platform, the
> user can not create a new nic inside the OS.
>
> So after echo sriov_numvfs, the user just got some VFs,
> there is not backend virtio-net devices.
I think it is not a "user" mange the VFs, the VFs usually provisioned by
the orchestration software and it assign properly selected a VF to a 
guest on demands.

So I am confused what the intention of this patch.
>
> Thanks.
>
>
>>> +So only the user knows how to bind the virtio devices to the VFs.
>>> +On the other hand, generally the virtio devices are not created by the user
>>> +inside the guest OS. This requires some management platform to participate.
>>> +
>>> +So we introduce a new admin queue command to bind the VFs and the virtio
>>> +devices.
>> Sorry, failed to process this. Maybe an orchestration sw layer can help?
>> Provision a device on demands and assign it to a guest?
>>
>> Thanks
>>> +
>>> +\begin{lstlisting}
>>> +struct virtio_admin_cmd_bind {
>>> +    u64 identity;
>>> +};
>>> +\end{lstlisting}
>>> +
>>> +The user got the \field{identity} from the management platform, that is not
>>> +included by this spec.
>>> +
>>> +\drivernormative{\paragraph}{Group administration commands}{Basic Facilities of a Virtio Device / Device groups / Group administration commands / Bind the device for member}
>>> +
>>> +VIRTIO_ADMIN_CMD_BIND_DEVICE requires that the \field{group_member_id} MUST be set.
>>> +
>>> +The \field{identity} is passed by the user. It is the identity of the virtio
>>> +device.
>>> +
>>> +\devicenormative{\paragraph}{Group administration commands}{Basic Facilities of a Virtio Device / Device groups / Group administration commands / Bind the device for member}
>>> +
>>> +Every device MUST have one unique \field{identity} in the host.
>>> +
>>> +If the PF device can not find the device by the \field{identity},
>>> +the \field{status} MUST be set to VIRTIO_ADMIN_STATUS_EINVAL.
>>> +
>>> +If the device is found by the \field{identity}, the device MUST work as the
>>> +device of this group member specified by the \field{group_member_id}.
>>> +
>>>    \section{Administration Virtqueues}\label{sec:Basic Facilities of a Virtio Device / Administration Virtqueues}
>>>
>>>    An administration virtqueue of an owner device is used to submit
> This publicly archived list offers a means to provide input to the
> OASIS Virtual I/O Device (VIRTIO) TC.
>
> In order to verify user consent to the Feedback License terms and
> to minimize spam in the list archive, subscription is required
> before posting.
>
> Subscribe: virtio-comment-subscribe@lists.oasis-open.org
> Unsubscribe: virtio-comment-unsubscribe@lists.oasis-open.org
> List help: virtio-comment-help@lists.oasis-open.org
> List archive: https://lists.oasis-open.org/archives/virtio-comment/
> Feedback License: https://www.oasis-open.org/who/ipr/feedback_license.pdf
> List Guidelines: https://www.oasis-open.org/policies-guidelines/mailing-lists
> Committee: https://www.oasis-open.org/committees/virtio/
> Join OASIS: https://www.oasis-open.org/join/
>


---------------------------------------------------------------------
To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org
For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org