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 14D1A296BA8; Wed, 1 Oct 2025 23:56:04 +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=1759362967; cv=none; b=r2wistJ/SnaXIKIv/U74vX3wHM5+psNz5B9g1y3lyzfeqv6NWiS1WOlPsAkyH0/V9Y++fyN7pkWOac5MUkyiqFOGlX66ri3BdaBJPOCy9jT26/mH4vUP70LUIpfJsHlClgUhZCpGE/YZZ2gUjyjH0um5TQL9aAC4JKWvC28LpK8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759362967; c=relaxed/simple; bh=ILkjc/XVyx6bQd0jLKnZzkgG0gPtYYukDOQdK37yZo4=; h=Mime-Version:Content-Type:Date:Message-Id:From:Subject:Cc:To: References:In-Reply-To; b=eYxQ8pB308FCAPcWaKzCkNdj8JsKjzHgVXCZi/Ysyuxppvr38XPS+h0zgNtleuK5FsXr54ExDa7Rd3uUKn2DSwCsog2rHb5sTQWjUNzk+U1JFvt7KOZi4lVEc92phLta3Z9VjslYz3Ha45QDXRVUeSNx8LFzqBsYTS683ECRCOk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OOJYzq/d; 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="OOJYzq/d" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A4126C4CEF1; Wed, 1 Oct 2025 23:55:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1759362964; bh=ILkjc/XVyx6bQd0jLKnZzkgG0gPtYYukDOQdK37yZo4=; h=Date:From:Subject:Cc:To:References:In-Reply-To:From; b=OOJYzq/d9GisZWtqu9cNN5RFi3FocdFAYpWPhUh2NCuSnPRxyxBP3x1IHCSv1xUUO bEdCEO+Vas16q+omPselXFEFb7cDvooOz1rAbQ+RVKbWxndUsP+bl5lO+qL2GWdZj2 BjXO3hTDcObebkjFTKK88bDcGj8s3bmuYoV0OEuof03/1V62oXgDdHjY7JLxFRNpb2 TUyq4QuFJg+jmzmh/nCFYPF8j4dmmVDxY22+sKrV57gXwK6mg9TLKcbEunAjFk/sK8 Vwnx7glv/LyvQ/ISNgyKBbMKIYVYTHCIV/Pl61l1hsmjcgwqGmUWd2YWArY447pMg5 s7w45BbsVUyFg== Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Thu, 02 Oct 2025 01:55:57 +0200 Message-Id: From: "Danilo Krummrich" Subject: Re: [PATCH 0/2] rust: pci: expose is_virtfn() and reject VFs in nova-core Cc: "Joel Fernandes" , "Zhi Wang" , "Alistair Popple" , "Alexandre Courbot" , "Timur Tabi" , "Surath Mitra" , "David Airlie" , "Simona Vetter" , "Bjorn Helgaas" , =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= , "Miguel Ojeda" , "Alex Gaynor" , "Boqun Feng" , "Gary Guo" , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , "Benno Lossin" , "Andreas Hindborg" , "Alice Ryhl" , "Trevor Gross" , "nouveau@lists.freedesktop.org" , "linux-pci@vger.kernel.org" , "rust-for-linux@vger.kernel.org" , "LKML" , "Jason Gunthorpe" , "Alex Williamson" To: "John Hubbard" References: <20250930220759.288528-1-jhubbard@nvidia.com> <1FA2746D-6F73-4D5A-A0DC-803D0563A5D7@nvidia.com> In-Reply-To: On Thu Oct 2, 2025 at 1:51 AM CEST, John Hubbard wrote: > On 10/1/25 4:47 PM, Joel Fernandes wrote: >>> On Oct 1, 2025, at 7:00=E2=80=AFPM, John Hubbard = wrote: >>> =EF=BB=BFOn 10/1/25 3:52 PM, Danilo Krummrich wrote: >>>>> On Thu Oct 2, 2025 at 12:38 AM CEST, John Hubbard wrote: >>>>> On 10/1/25 6:52 AM, Zhi Wang wrote: >>>>>> On 1.10.2025 13.32, Danilo Krummrich wrote: >>>>>>> On Wed Oct 1, 2025 at 3:22 AM CEST, John Hubbard wrote: >>>>>>>> On 9/30/25 5:29 PM, Alistair Popple wrote: >>>>>>>>> On 2025-10-01 at 08:07 +1000, John Hubbard = wrote... >>>>> ... >> Here is my opinion and correct me if I missed something: >>=20 >> It feels premature to remove the option of nova-core binding to a VF, si= nce other options to disable auto probing do exist as Jason pointed out. >>=20 >> Taking a parallel with VFIO pass through for instance, the user already = has to do some diligence like preventing drivers from binding and then maki= ng vfio-pci bind to the device IDs. This case is similar though slightly di= fferent, but VFIO setup requires some configuration anyway so will it reall= y improve anything? >>=20 >> I quietly suggest holding on till there is a real need or we are sure no= va cannot bind to, or operate on a VF. This=20 > > I'm confident that nova-core cannot properly handle a VF with *today's* c= ode. > There is no expectation at all for a VF to show up--yet. > > Which is why I think it's appropriate to skip it right now. I agree with John. If a driver does not support a certain device, it is not the user's responsibility to prevent probing. Currently nova-core does not support VFs= , so it should never get probed for them in the first place.