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=-14.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 62A3CC48BCD for ; Thu, 10 Jun 2021 00:26:48 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 270A860E0C for ; Thu, 10 Jun 2021 00:26:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 270A860E0C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:References: List-Owner; bh=h/RLT3Qw0fnVB/zQyvFS4R9HJaUKmNmlQTxEdjcj9jY=; b=C3ANLDtbxG4idy 1rOUKjW/ltPEXu3U0uoYpf/8KBl30fYk8+l+X3wgEwS4mhO69/NckfdKR/fTb4m5VBVm8fzLiGM25 sJvrYi++BrcUjvIvtOozg/Ic3vfYafoW05CfckrHdah6EYuJx0cKj4kVMY8Y9xAWyV5wnpSvVx3H1 2ML/LD3fGbcCappqF7AnrXKTa089I9bbItMwylmhMQLKzWp5FKQW9Jr2oh7kw+/7fvvCvMhxBsPDc SuqoX1qhfPJ2lZKKGimLYwmtvIsbaVbi1ashx+xpwxA+ZMaJiMvbacCLEQ30MJBcS3SnYFnosFUb+ CTevPPfo2956t3LX33Hg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lr8TO-00G9ew-MJ; Thu, 10 Jun 2021 00:23:02 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1lr8TK-00G9e9-GT; Thu, 10 Jun 2021 00:23:00 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8A202613EC; Thu, 10 Jun 2021 00:22:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1623284577; bh=1ou36G5z4ISmBgYTkl+QY1b+Z7f8tmx56db6O6BZH8Y=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=hCUqCStiKTi+c41zEsR2OLq8QrOXGEoOPTv38uAT1iLZdW20i5YPJLmaoum1R40Fa JjPYE7SYJrswOPcKfWRp53d7cnspY8PQXIdb7mkFstOhs+5UlJkLT27iYQx1e1tSce p4enlJ8nQ1Bus7Cyj2RXNd0N/dTkjrvgke+nllfp56NjeSr7F6z+kpgED9FSCFmeRy f3zWJE8+LM0IORF+/Wpy4XcXGJ3RWBKpAFwD5P4uEm818Kz95xATb1h3pQ1hC6AHw8 lecsdK2j8UWPwnSac/foW+ozyVT3qy1Ue3iTsZssbT5uhQZjytcfq40HtwrMKGntML 4JKYEeKA0UJbg== Date: Wed, 9 Jun 2021 19:22:56 -0500 From: Bjorn Helgaas To: Punit Agrawal Cc: robh+dt@kernel.org, linux-rockchip@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, alexandru.elisei@arm.com, wqu@suse.com, robin.murphy@arm.com, pgwipeout@gmail.com, ardb@kernel.org, briannorris@chromium.org, shawn.lin@rock-chips.com, Bjorn Helgaas , Leonardo Bras Subject: Re: [PATCH v3 1/4] PCI: of: Clear 64-bit flag for non-prefetchable memory below 4GB Message-ID: <20210610002256.GA2680171@bjorn-Precision-5520> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210607112856.3499682-2-punitagrawal@gmail.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210609_172258_609487_75AF7E47 X-CRM114-Status: GOOD ( 24.57 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org [+cc Leonardo] On Mon, Jun 07, 2021 at 08:28:53PM +0900, Punit Agrawal wrote: > Some host bridges advertise non-prefetchable memory windows that are > entirely located below 4GB but are marked as 64-bit address memory. > > Since commit 9d57e61bf723 ("of/pci: Add IORESOURCE_MEM_64 to resource > flags for 64-bit memory addresses"), the OF PCI range parser takes a > stricter view and treats 64-bit address ranges as advertised while > before such ranges were treated as 32-bit. > > A PCI root port modelled as a PCI-to-PCI bridge cannot forward 64-bit > non-prefetchable memory ranges. As a result, the change in behaviour > due to the commit causes failure to allocate 32-bit BAR from a 64-bit > non-prefetchable window. > > In order to not break platforms where non-prefetchable memory ranges > lie entirely below 4GB, clear the 64-bit flag. I don't think we should care about the address width DT supplies for a host bridge window. Prior to 9d57e61bf723, I don't think we *did* care because of_bus_pci_get_flags() threw away that information. My proposal for a commit log, including information about the problem report and a "Fixes:" tag: Alexandru and Qu reported this resource allocation failure on ROCKPro64 v2 and ROCK Pi 4B, both based on the RK3399: pci_bus 0000:00: root bus resource [mem 0xfa000000-0xfbdfffff 64bit] pci 0000:00:00.0: PCI bridge to [bus 01] pci 0000:00:00.0: BAR 14: no space for [mem size 0x00100000] pci 0000:01:00.0: reg 0x10: [mem 0x00000000-0x00003fff 64bit] "BAR 14" is the PCI bridge's 32-bit non-prefetchable window, and our PCI allocation code isn't smart enough to allocate it in a host bridge window marked as 64-bit, even though this should work fine. A DT host bridge description includes the windows from the CPU address space to the PCI bus space. On a few architectures (microblaze, powerpc, sparc), the DT may also describe PCI devices themselves, including their BARs. Before 9d57e61bf723 ("of/pci: Add IORESOURCE_MEM_64 to resource flags for 64-bit memory addresses"), of_bus_pci_get_flags() ignored the fact that some DT addresses described 64-bit windows and BARs. That was a problem because the virtio virtual NIC has a 32-bit BAR and a 64-bit BAR, and the driver couldn't distinguish them. 9d57e61bf723 set IORESOURCE_MEM_64 for those 64-bit DT ranges, which fixed the virtio driver. But it also set IORESOURCE_MEM_64 for host bridge windows, which exposed the fact that the PCI allocator isn't smart enough to put 32-bit resources in those 64-bit windows. Clear IORESOURCE_MEM_64 from host bridge windows since we don't need that information. Fixes: 9d57e61bf723 ("of/pci: Add IORESOURCE_MEM_64 to resource flags for 64-bit memory addresses") Reported-at: https://lore.kernel.org/lkml/7a1e2ebc-f7d8-8431-d844-41a9c36a8911@arm.com/ Reported-by: Alexandru Elisei Reported-by: Qu Wenruo > Suggested-by: Ard Biesheuvel > Link: https://lore.kernel.org/r/7a1e2ebc-f7d8-8431-d844-41a9c36a8911@arm.com > Signed-off-by: Punit Agrawal > Tested-by: Alexandru Elisei > Cc: Bjorn Helgaas > Cc: Rob Herring > --- > drivers/pci/of.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/pci/of.c b/drivers/pci/of.c > index 85dcb7097da4..1e45186a5715 100644 > --- a/drivers/pci/of.c > +++ b/drivers/pci/of.c > @@ -353,6 +353,14 @@ static int devm_of_pci_get_host_bridge_resources(struct device *dev, > dev_warn(dev, "More than one I/O resource converted for %pOF. CPU base address for old range lost!\n", > dev_node); > *io_base = range.cpu_addr; > + } else if (resource_type(res) == IORESOURCE_MEM) { > + if (!(res->flags & IORESOURCE_PREFETCH)) { > + if (res->flags & IORESOURCE_MEM_64) > + if (!upper_32_bits(range.pci_addr + range.size - 1)) { > + dev_warn(dev, "Clearing 64-bit flag for non-prefetchable memory below 4GB\n"); > + res->flags &= ~IORESOURCE_MEM_64; > + } > + } Why do we need to check IORESOURCE_PREFETCH, IORESOURCE_MEM_64, and upper_32_bits()? If I understand this correctly, prior to 9d57e61bf723, IORESOURCE_MEM_64 was *never* set here. Isn't something like this sufficient? } else if (resource_type(res) == IORESOURCE_MEM) { res->flags &= ~IORESOURCE_MEM_64; } I'm not sure we need a warning either. We didn't warn before 9d57e61bf723, and there's nothing the user needs to do anyway. > } > > pci_add_resource_offset(resources, res, res->start - range.pci_addr); > -- > 2.30.2 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel