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

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

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).
> +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?
> +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