RE: [PATCH v7 4/4] transport-pci: Introduce group legacy group member config region access

[Parav Pandit <parav@nvidia.com>]

> From: Michael S. Tsirkin <mst@redhat.com>
> Sent: Thursday, June 29, 2023 3:54 PM

> > +In \field{struct virtio_virtio_admin_cmd_legacy_notify_query_entry},
> > +\field{region} is defined as following:
> > +
> > +\begin{lstlisting}
> > +struct virtio_pci_notify_region {
> > +        u8 owner;    /* When set to 1, notification region of the owner device */
> > +        u8 bar;    /* BAR of the member or owner device */
> > +        u8 padding[2];
> > +        le32 offset; /* Offset within bar. */ }; \end{lstlisting}
> 
> Is this just a legacy thing or somehow generic? If the former please stick
> _legacy_ in the struct name.
>
Yes, let me prefix legacy to it. 
 
> 
> > +
> > +The group owner device hardwire VF BAR0 in the SR-IOV Extended capability.
> > +
> > +The group member device does not use PCI BAR0 in various PCI capabilities.
> 
> what does this mean? what various capabilities? VFs don't have PCI BAR0 at all
> ...
> 
The PCI capabilities listed in "section 4.1.4 Virtio Structure PCI Capabilities"

> > +
> > +\devicenormative{\subsubsection}{Legacy Interface: Group Member
> > +Device Legacy Configuration Region Access}{Virtio Transport Options /
> > +Virtio Over PCI Bus / Legacy Interface: Group Member Device
> > +Configuration Region Access}
> > +
> > +When a PCI SR-IOV group owner device supports
> > +VIRTIO_ADMIN_CMD_LEGACY_COMMON_CFG_READ,
> > +VIRTIO_ADMIN_CMD_LEGACY_COMMON_CFG_WRITE,
> > +VIRTIO_ADMIN_CMD_LEGACY_DEV_CFG_READ,
> > +VIRTIO_ADMIN_CMD_LEGACY_DEV_CFG_WRITE commands, the group
> owner
> > +device MUST hardwire VF BAR0 in the SR-IOV Extended capability and
> > +the group member device MUST NOT use BAR0 in any of the Virtio Structure
> PCI Capabilities.
> > +
> > +The group member driver SHOULD use the notification region supplied
> > +by the group owner driver.
> > +
> > +The group owner device or the group member device or both MAY support
> > +driver notifications region.
> 
> why is this text here as opposed to the other file?
> But really I think for now it's easier to just have everything in admin-cmds-
> legacy-interface.tex
>
Because the owner/member flag is in this structure.
It was too much to split a byte out of a structure for the spirit of keeping it generic.
 
Most things are in the admin-cmds-legacy-interface.tex.
Here only PCI specific structs are located.

Do you propose to move above