On Mon, Oct 30, 2023 at 2:21 PM Akihiko Odaki <akihiko.od...@daynix.com> wrote:
> On 2023/10/30 21:14, Yuri Benditovich wrote: > > > > > > On Mon, Oct 30, 2023 at 7:14 AM Akihiko Odaki <akihiko.od...@daynix.com > > <mailto:akihiko.od...@daynix.com>> wrote: > > > > vhost requires eBPF for RSS. When eBPF is not available, virtio-net > > implicitly disables RSS even if the user explicitly requests it. > Return > > an error instead of implicitly disabling RSS if RSS is requested but > not > > available. > > > > > > I think that suggesting RSS feature when in fact it is not available is > > not a good idea, this rather desinforms the guest. > > Existing behavior (IMHO) makes more sense. > > We can extend this discussion if needed, of course. > > This change is not to advertise RSS when it's not available; it instead > reports an error to the user. > > For example, think of the following command line: > qemu-system-x86_64 -device virtio-net,rss=on,netdev=n -netdev user,id=n > > Before this change, it gives no error and the user will not know RSS is > not available. With this change it now gives an error as follows: > qemu-system-x86_64: -device virtio-net,rss=on,netdev=n: Can't load eBPF RSS > Does this mean failure to run QEMU if the RSS required in the command line and EBPF can't be loaded? (for example if we run the system with kernel < 5.8)? I'm not sure this is user-friendly behavior...
