RE: [virtio] [PATCH REQUIREMENTS v2 1/7] net-features: Add requirements document for release 1.4

[Parav Pandit <parav@nvidia.com>]

> From: virtio@lists.oasis-open.org <virtio@lists.oasis-open.org> On Behalf Of
> Xuan Zhuo
> Sent: Wednesday, July 19, 2023 10:11 PM
> 
> On Mon, 3 Jul 2023 02:44:04 +0300, Parav Pandit <parav@nvidia.com> wrote:
> > Add requirements document template for the virtio net features.
> >
> > Add virtio net device counters visible to driver.
> >
> > Signed-off-by: Parav Pandit <parav@nvidia.com>
> > ---
> > changelog:
> > v0->v1:
> > - removed tx dropped counter
> > - updated requirements to mention about virtqueue interface for counters
> >   query
> > ---
> >  net-workstream/features-1.4.md | 35
> > ++++++++++++++++++++++++++++++++++
> >  1 file changed, 35 insertions(+)
> >  create mode 100644 net-workstream/features-1.4.md
> >
> > diff --git a/net-workstream/features-1.4.md
> > b/net-workstream/features-1.4.md new file mode 100644 index
> > 0000000..4c3797b
> > --- /dev/null
> > +++ b/net-workstream/features-1.4.md
> > @@ -0,0 +1,35 @@
> > +# 1. Introduction
> > +
> > +This document describes the overall requirements for virtio net
> > +device improvements for upcoming release 1.4. Some of these
> > +requirements are interrelated and influence the interface design,
> > +hence reviewing them together is desired while updating the virtio net
> interface.
> > +
> > +# 2. Summary
> > +1. Device counters visible to the driver
> > +
> > +# 3. Requirements
> > +## 3.1 Device counters
> > +1. The driver should be able to query the device and/or per vq counters for
> > +   debugging purpose using a virtqueue directly from driver to device for
> > +   example using a control vq.
> > +2. The driver should be able to query which counters are supported using a
> > +   virtqueue command, for example using an existing control vq.
> > +3. If this device is migrated between two hosts, the driver should be able
> > +   get the counter values in the destination host from where it was left
> > +   off in the source host.
> > +4. If a virtio device is group member device, a group owner should be able
> > +   to query all the counter attributes using the administration command
> which
> > +   a virtio member device will expose via a virtqueue to the driver.
> > +
> > +### 3.1.1 Per receive queue counters
> > +1. le64 rx_oversize_pkt_errors: Packet dropped due to receive packet being
> > +    oversize than the buffer size
> > +2. le64 rx_no_buffer_pkt_errors: Packet dropped due to unavailability of the
> > +    buffer in the receive queue
> > +3. le64 rx_gro_pkts: Packets treated as receive GSO sequence by the
> > +device 4. le64 rx_pkts: Total packets received by the device
> > +
> > +### 3.1.2 Per transmit queue counters 1. le64 tx_gso_pkts: Packets
> > +send as transmit GSO sequence 2. le64 tx_pkts: Total packets send by
> > +the device
> 
> 
> Hi
> 
> About the device counter, I will continue to push this patch, can you review it.
> 
> http://lore.kernel.org/all/20220315032402.6088-1-
> xuanzhuo@linux.alibaba.com
Yes. I had trouble working this week.
But want to review later in the week.

A quick glance at patch,
we need a bitmap to indicate which counters are supported by device or not.
Seeing zero from driver for unsupported is misleading to user.
So we want to avoid showing those counters in ethtool which are not supported by the device.