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 X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 02EC9C10F27 for ; Tue, 10 Mar 2020 16:04:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D60F521D56 for ; Tue, 10 Mar 2020 16:04:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726599AbgCJQEy (ORCPT ); Tue, 10 Mar 2020 12:04:54 -0400 Received: from foss.arm.com ([217.140.110.172]:39018 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726557AbgCJQEx (ORCPT ); Tue, 10 Mar 2020 12:04:53 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 064631FB; Tue, 10 Mar 2020 09:04:53 -0700 (PDT) Received: from [10.1.196.63] (e123195-lin.cambridge.arm.com [10.1.196.63]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F316A3F67D; Tue, 10 Mar 2020 09:04:51 -0700 (PDT) Subject: Re: [PATCH v2 kvmtool 28/30] arm/fdt: Remove 'linux,pci-probe-only' property To: Andre Przywara Cc: kvm@vger.kernel.org, will@kernel.org, julien.thierry.kdev@gmail.com, sami.mujawar@arm.com, lorenzo.pieralisi@arm.com, maz@kernel.org, Julien Thierry References: <20200123134805.1993-1-alexandru.elisei@arm.com> <20200123134805.1993-29-alexandru.elisei@arm.com> <20200207173829.1ac1884e@donnerap.cambridge.arm.com> From: Alexandru Elisei Message-ID: Date: Tue, 10 Mar 2020 16:04:50 +0000 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20200207173829.1ac1884e@donnerap.cambridge.arm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Hi, On 2/7/20 5:38 PM, Andre Przywara wrote: > On Thu, 23 Jan 2020 13:48:03 +0000 > Alexandru Elisei wrote: > > Hi, > >> From: Julien Thierry >> >> PCI now supports configurable BARs. Get rid of the no longer needed, >> Linux-only, fdt property. > I was just wondering: what is the x86 story here? > Does the x86 kernel never reassign BARs? Or is this dependent on something else? > I see tons of pci kernel command line parameters for pci=, maybe one of them would explicitly allow reassigning? I only see pci=conf1, can you post your kernel command line? Here's mine: [    0.000000] Command line: noapic noacpi pci=conf1 reboot=k panic=1 i8042.direct=1 i8042.dumbkbd=1 i8042.nopnp=1 earlyprintk=serial i8042.noaux=1 console=ttyS0 earlycon root=/dev/vda1 Just for pci=conf1, from Documentation/admin-guide/kernel-parameters.txt: "conf1        [X86] Force use of PCI Configuration Access                 Mechanism 1 (config address in IO port 0xCF8,                 data in IO port 0xCFC, both 32-bit)." But you have a point, I haven't seen an x86 guest reassign BARs, I assumed it's because it trusts the BIOS allocation. I'll try to figure out why this happens (maybe I need a special kernel parameter). Thanks, Alex > > Cheers, > Andre > >> Signed-off-by: Julien Thierry >> Signed-off-by: Alexandru Elisei >> --- >> arm/fdt.c | 1 - >> 1 file changed, 1 deletion(-) >> >> diff --git a/arm/fdt.c b/arm/fdt.c >> index c80e6da323b6..02091e9e0bee 100644 >> --- a/arm/fdt.c >> +++ b/arm/fdt.c >> @@ -130,7 +130,6 @@ static int setup_fdt(struct kvm *kvm) >> >> /* /chosen */ >> _FDT(fdt_begin_node(fdt, "chosen")); >> - _FDT(fdt_property_cell(fdt, "linux,pci-probe-only", 1)); >> >> /* Pass on our amended command line to a Linux kernel only. */ >> if (kvm->cfg.firmware_filename) {