From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D0FDA3612ED; Mon, 11 May 2026 23:59:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778543971; cv=none; b=eD9uZ8VxhWWf8k3svko35IBD8CP7dcQulMQ2DscK4JfdBvnd86gTXyxyyVPvNtxOImY61l5RVb+cQCgb9FV5Z7ZmPZ36Sgzgj1a28Cnl0AlA7+tDDkoWMnvIeuWtGyMoYhP4YNn9CY5jZgEQ2hx0Zdzd+AQEHk+O7lcE/4aiLHI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778543971; c=relaxed/simple; bh=OOezJdOY2CaICsn492imL9pnwELutNX20BeZitAgQiI=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Jx1dcypiqcymiHD/nX7vz6//eioi29uDdtFc/AqEvFp0xAs51T8oTgfOYcWmX8c3feywVwNrS/gsUuRa81UM3I7HadhBWbx2oOgTJi6TJo4oNwTG+NRQlrY22Oofjsv3ONZehc1FMeLkGW+KwZ2ryrAsw8r/IcYiEMHrouFs6SI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=EQHND40Z; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="EQHND40Z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 09714C2BCB0; Mon, 11 May 2026 23:59:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778543971; bh=OOezJdOY2CaICsn492imL9pnwELutNX20BeZitAgQiI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=EQHND40ZiFWaqBVBpzKZg8hhRxoeA8e7pv9gtIVHIamMk8JoJLZGfPMNFfCXRRhgn WE0BbYOyLUcAYpKzKoyruoVyHx64HJO+z0d0WVvq5u+qm1cQ0krL3K8+dEwyp8LF3d t8UjF3HbllDqLDBPGpUc8AOG2KaqcNFWOqXqrapfnLHda/6jRGR7mezS1F9e6C8TS5 ezJswPsl3sGWzU2xcQzE6rfOvuDTlFqMmltTHZh7yoiPMLLOPQhZWVAoZSkg2GvQNe Tg7AdD/UPlwHUpdOwYW3ZqyepX232dfEAOvFnTN6b1B9c4tlFJqmYSuvxveDqGMgfr M6MVmdQr/Vqcg== Date: Mon, 11 May 2026 16:59:30 -0700 From: Jakub Kicinski To: =?UTF-8?B?w43DsWlnbw==?= Huguet Cc: =?UTF-8?B?w43DsWlnbw==?= Huguet , Andrew Lunn , "David S . Miller" , Eric Dumazet , Paolo Abeni , Shuah Khan , Sabrina Dubroca , Filip Pokryvka , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH net-next 0/5] netdevsim: get link via ethtool, set via sysfs Message-ID: <20260511165930.14c7b6b9@kernel.org> In-Reply-To: References: <20260510164337.7611-1-ihuguet@riseup.net> <20260510095246.5c8f6d0b@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Mon, 11 May 2026 11:50:32 +0200 =C3=8D=C3=B1igo Huguet wrote: > On Sun, May 10, 2026 at 6:52=E2=80=AFPM Jakub Kicinski = wrote: > > Could you please explain your motivation? Feels quite trivial, > > so it's not immediately obvious why we need tests. > > =20 >=20 > We use netdevsim for some userspace CI testing here at Red Hat. Specifica= lly, > There are some tests that require reacting to carrier changes on a device > matched by permanent MAC address from userspace. As veths don't have a > permanent MAC address, we need netdevsim for this test case. >=20 > As you say, it's pretty trivial, but IMHO there's nothing against it, as = it > will help to resemble better a typical Ethernet device. >=20 > Note: we know that there's no guarantee regarding netdevsim's uAPI and we= 're > ready to adapt for any change, but the truth is that there's no reasonable > replacement of netdevsim for these kinds of cases where veth is not enoug= h. All code require maintenance. I'm trying to push back on netdevsim use across the board. It was essentially a workaround for us not having any real HW CI upstream. But that's no longer the case. Well, we still don't have any crypto-capable HW :/ I think you'd be better off implementing whatever you need in a small OOT module instead adding fake tests upstream.