From: "Michael S. Tsirkin" <mst@redhat.com>
To: Akihiko Odaki <akihiko.odaki@daynix.com>
Cc: Jason Wang <jasowang@redhat.com>,
Yuri Benditovich <yuri.benditovich@daynix.com>,
qemu-devel@nongnu.org, Andrew Melnychenko <andrew@daynix.com>
Subject: Re: [PATCH v6 11/21] virtio-net: Return an error when vhost cannot enable RSS
Date: Wed, 1 Nov 2023 05:09:41 -0400 [thread overview]
Message-ID: <20231101050838-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <39a02a4c-f8fa-437c-892f-caca84b8d85d@daynix.com>
On Wed, Nov 01, 2023 at 05:35:50PM +0900, Akihiko Odaki wrote:
> On 2023/11/01 15:38, Michael S. Tsirkin wrote:
> > On Wed, Nov 01, 2023 at 01:50:00PM +0900, Akihiko Odaki wrote:
> > > We had another discussion regarding migration for patch "virtio-net: Do not
> > > clear VIRTIO_NET_F_HASH_REPORT". It does change the runtime behavior so we
> > > need to take migration into account. I still think the patch does not
> > > require a compatibility flag since it only exposes a new feature and does
> > > not prevent migrating from old QEMU that exposes less features. It instead
> > > fixes the case where migrating between hosts with different tap feature
> > > sets.
> >
> > When in doubt, add a compat flag.
>
> Personally I'm confident about the migration compatibility with patch
> "virtio-net: Do not clear VIRTIO_NET_F_HASH_REPORT". virtio-net already does
> the same thing when the tap implementation on the destination implements
> virtio-net header support while the counterpart of the source does not.
Trust me there's been so many times where we were very sure and
problems come up later. Just don't enable new functionality for
old machine types, problem solved. Why is this hard?
--
MST
next prev parent reply other threads:[~2023-11-01 9:14 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-30 5:12 [PATCH v6 00/21] virtio-net RSS/hash report fixes and improvements Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 01/21] tap: Remove tap_probe_vnet_hdr_len() Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 02/21] tap: Remove qemu_using_vnet_hdr() Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 03/21] net: Move virtio-net header length assertion Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 04/21] net: Remove receive_raw() Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 05/21] tap: Remove tap_receive() Akihiko Odaki
2023-10-30 18:52 ` Zhang, Chen
2023-10-31 4:57 ` Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 06/21] net: Remove flag propagation Akihiko Odaki
2023-11-10 7:35 ` Pavel Dovgalyuk
2023-11-11 14:27 ` Akihiko Odaki
2023-11-13 8:14 ` Pavel Dovgalyuk
2023-10-30 5:12 ` [PATCH v6 07/21] tap: Shrink zeroed virtio-net header Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 08/21] virtio-net: Copy header only when necessary Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 09/21] virtio-net: Disable RSS on reset Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 10/21] virtio-net: Unify the logic to update NIC state for RSS Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 11/21] virtio-net: Return an error when vhost cannot enable RSS Akihiko Odaki
2023-10-30 12:14 ` Yuri Benditovich
2023-10-30 12:21 ` Akihiko Odaki
2023-10-30 12:51 ` Yuri Benditovich
2023-10-30 13:14 ` Akihiko Odaki
2023-11-01 4:19 ` Jason Wang
2023-11-01 4:50 ` Akihiko Odaki
2023-11-01 6:38 ` Michael S. Tsirkin
2023-11-01 8:35 ` Akihiko Odaki
2023-11-01 9:09 ` Michael S. Tsirkin [this message]
2023-11-01 9:15 ` Akihiko Odaki
2023-11-02 9:09 ` Yuri Benditovich
2023-11-02 9:33 ` Michael S. Tsirkin
2023-11-02 10:20 ` Yuri Benditovich
2023-11-02 11:26 ` Michael S. Tsirkin
2023-11-02 12:00 ` Yuri Benditovich
2023-11-02 13:18 ` Michael S. Tsirkin
2023-11-02 14:56 ` Akihiko Odaki
2023-11-03 9:35 ` Yuri Benditovich
2023-11-03 9:55 ` Akihiko Odaki
2023-11-03 13:14 ` Yuri Benditovich
2023-11-11 15:28 ` Akihiko Odaki
2023-11-13 11:44 ` Yuri Benditovich
2023-11-13 12:44 ` Akihiko Odaki
2023-11-13 17:26 ` Yuri Benditovich
2023-11-14 7:03 ` Akihiko Odaki
2023-11-14 22:09 ` Yuri Benditovich
2023-11-15 6:09 ` Akihiko Odaki
2023-11-16 5:14 ` Jason Wang
2023-10-30 5:12 ` [PATCH v6 12/21] virtio-net: Enable software RSS Akihiko Odaki
2023-10-30 12:42 ` Yuri Benditovich
2023-10-30 5:12 ` [PATCH v6 13/21] virtio-net: Always set populate_hash Akihiko Odaki
2023-10-30 19:02 ` Zhang, Chen
2023-10-31 4:47 ` Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 14/21] virtio-net: Do not write hashes to peer buffer Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 15/21] virtio-net: Do not clear VIRTIO_NET_F_HASH_REPORT Akihiko Odaki
2023-11-03 13:26 ` Yuri Benditovich
2023-10-30 5:12 ` [PATCH v6 16/21] ebpf: Fix RSS error handling Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 17/21] ebpf: Use standard section name Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 18/21] ebpf: Simplify error handling Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 19/21] ebpf: Return 0 when configuration fails Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 20/21] ebpf: Refactor tun_rss_steering_prog() Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 21/21] ebpf: Add a separate target for skeleton Akihiko Odaki
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20231101050838-mutt-send-email-mst@kernel.org \
--to=mst@redhat.com \
--cc=akihiko.odaki@daynix.com \
--cc=andrew@daynix.com \
--cc=jasowang@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=yuri.benditovich@daynix.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).