From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B805EC88E7F for ; Wed, 16 Sep 2026 18:25:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:MIME-Version:Message-ID:Date:References:In-Reply-To:Subject:Cc: To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Va42xDUxw3Ha13QgHOlSJnNxTf47U1kOlLIt+P89At4=; b=YyngIaC2fVHXHds2rlA9Ss20fL sDmk98+Z0jj7HSLIoUAXFAFYqfrZbsHmg1ytpE+q7Mdj0sR93eV4d0pO4DPKsex9ENAVqA96x5wlB xeJsTcVMBXdXfRMhCsrh60i6VXqveuDjth4WJR4cKCJVCepiRavnof2BHnFVe8UHyBmb5J0A0lmmK +XiDKR2BYw6SK5tKjc9hy3b5U6kX7HoObVJF8o/bmGL3VZV76lRCFpjGHDGNpZDfq9aPLmIBXUcid TZIEj8K+3zL5roe0wGtIjGvXZ0GqFeta2yfCxx2PClRhY5KwJOHHarV+Q3uG6saaSXJutCahT1pIC Yg9EFtwA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x6uJu-00000009xB9-3wfM; Wed, 16 Sep 2026 18:25:22 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x6uJt-00000009xAt-3TrA for kexec@lists.infradead.org; Wed, 16 Sep 2026 18:25:21 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id C4B4F43E53; Wed, 16 Sep 2026 18:25:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BBE651F000FF; Wed, 16 Sep 2026 18:25:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789583119; bh=Va42xDUxw3Ha13QgHOlSJnNxTf47U1kOlLIt+P89At4=; h=From:To:Cc:Subject:In-Reply-To:References:Date; b=P2xA7D7zGPKwhboQgFoFmwpysEtGxI+V2h2GSj6IA/YgBa85bMaQLxzaFxULINGed AEtc+voU6gqXMDlIskNI09FqisQhKRMmOWkHdE/pPbS4SJuP5YF0zkGANb07pGkKVP qqfO/yR7DeItPjTJiYP+hYLH9jbp4YLqDtxavkvkfhVzgCWjsJYlV5//6kBpAC+Imm BzUA36PrUrZwSPeHUiUOhw4Tvq9qAJ+G0AstgyZKggDzIiowzZ/GoYjNGP6iEhFzM4 4g4Q2Mc5YTibk/b+yFZDTdx+Uz5RgNDkfi244moTiPV8DsAQ1jLin/jFLYmuX5gUz8 OQPGZJUyOVkPg== From: Pratyush Yadav To: David Matlack Cc: Zhu Yanjun , kexec@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Adithya Jayachandran , Alexander Graf , Alex Williamson , Bjorn Helgaas , Chris Li , David Rientjes , Jacob Pan , Jason Gunthorpe , Jonathan Corbet , Josh Hilke , Leon Romanovsky , Lukas Wunner , Mike Rapoport , Parav Pandit , Pasha Tatashin , Pranjal Shrivastava , Pratyush Yadav , Saeed Mahameed , Samiullah Khawaja , Shuah Khan , Vipin Sharma , William Tu , Yi Liu Subject: Re: [PATCH v8 03/12] PCI: liveupdate: Track incoming preserved PCI devices In-Reply-To: (David Matlack's message of "Wed, 16 Sep 2026 10:28:52 -0700") References: <20260728221007.2098560-1-dmatlack@google.com> <20260728221007.2098560-4-dmatlack@google.com> Date: Wed, 16 Sep 2026 20:25:12 +0200 Message-ID: <2vxzcxud6ol3.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On Wed, Sep 16 2026, David Matlack wrote: > On Tue, Sep 15, 2026 at 8:31=E2=80=AFPM Zhu Yanjun = wrote: >> =E5=9C=A8 2026/7/28 15:09, David Matlack =E5=86=99=E9=81=93: > >> > CONFIG_64BIT is now required to enable CONFIG_PCI_LIVEUPDATE so that t= he >> > domain and bdf can be guaranteed to fit in an unsigned long and be used >> > as the xarray key. > >> > diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig >> > index 3781e2b5f095..8af20f558086 100644 >> > --- a/drivers/pci/Kconfig >> > +++ b/drivers/pci/Kconfig >> > @@ -273,7 +273,7 @@ config VGA_ARB_MAX_GPUS >> > >> > config PCI_LIVEUPDATE >> > bool "PCI Live Update Support" >> > - depends on PCI && LIVEUPDATE >> > + depends on PCI && LIVEUPDATE && 64BIT >> >> One question about adding 64BIT to the dependency: >> >> As I understand it, enabling CONFIG_64BIT essentially means that we are >> building a 64-bit kernel, and a 32-bit architecture cannot normally >> enable CONFIG_64BIT. >> >> If that is the case, would depends on 64BIT be necessary here? Or is PCI >> Live Update already inherently restricted to 64-bit architectures by the >> existing LIVEUPDATE/architecture configuration, so that this dependency >> would be redundant? >> >> If this problem has already discussed, I am very sorry about this. > > The necessity is that the PCI core needs to store more than 32-bits in > the unsigned long xarray key (see the snippet above). The dependency > on CONFIG_64BIT ensures that unsigned long is big enough. We could > probably remove the dependency but I would rather wait until someone > with a 32-bit build has a real use-case for using PCI_LIVEUPDATE > before putting any effort into it. KHO or live update themselves don't support 32-bit platforms and there are no plans to do so either. So I don't think you even need to have a dependency on 64BIT in PCI_LIVEUPDATE. Only 64 bit architectures define ARCH_SUPPORTS_KEXEC_HANDOVER, so PCI_LIVEUPDATE and others indirectly inherit the dependency. If you'd like to be extra safe, then probably you should add a dependency to 64BIT in KEXEC_HANDOVER directly. Though I think that can be a separate patch independent from this series. --=20 Regards, Pratyush Yadav