From patchwork Wed Jun 5 03:38:14 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexey Kardashevskiy X-Patchwork-Id: 1110290 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 45JZL53qvdz9s3l for ; Wed, 5 Jun 2019 13:39:57 +1000 (AEST) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=ozlabs.ru Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 45JZL52pWczDqX7 for ; Wed, 5 Jun 2019 13:39:57 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=ozlabs.ru (client-ip=107.173.13.209; helo=ozlabs.ru; envelope-from=aik@ozlabs.ru; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ozlabs.ru Received: from ozlabs.ru (ozlabs.ru [107.173.13.209]) by lists.ozlabs.org (Postfix) with ESMTP id 45JZJq5NJwzDqLT for ; Wed, 5 Jun 2019 13:38:51 +1000 (AEST) Received: from fstn1-p1.ozlabs.ibm.com (localhost [IPv6:::1]) by ozlabs.ru (Postfix) with ESMTP id B779EAE8000F; Tue, 4 Jun 2019 23:38:16 -0400 (EDT) From: Alexey Kardashevskiy To: linuxppc-dev@lists.ozlabs.org Subject: [PATCH kernel] powerpc/pci/of: Fix OF flags parsing for 64bit BARs Date: Wed, 5 Jun 2019 13:38:14 +1000 Message-Id: <20190605033814.127962-1-aik@ozlabs.ru> X-Mailer: git-send-email 2.17.1 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Shawn Anastasio , Alexey Kardashevskiy , Michael Roth , Sam Bobroff , Oliver O'Halloran , David Gibson Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" When the firmware does PCI BAR resource allocation, it passes the assigned addresses and flags (prefetch/64bit/...) via the "reg" property of a PCI device device tree node so the kernel does not need to do resource allocation. The flags are stored in resource::flags - the lower byte stores PCI_BASE_ADDRESS_SPACE/etc bits and the other bytes are IORESOURCE_IO/etc. Some flags from PCI_BASE_ADDRESS_xxx and IORESOURCE_xxx are duplicated, such as PCI_BASE_ADDRESS_MEM_PREFETCH/PCI_BASE_ADDRESS_MEM_TYPE_64/etc. When parsing the "reg" property, we copy the prefetch flag but we skip on PCI_BASE_ADDRESS_MEM_TYPE_64 which leaves the flags out of sync. The missing IORESOURCE_MEM_64 flag comes into play under 2 conditions: 1. we remove PCI_PROBE_ONLY for pseries (by hacking pSeries_setup_arch() or by passing "/chosen/linux,pci-probe-only"); 2. we request resource alignment (by passing pci=resource_alignment= via the kernel cmd line to request PAGE_SIZE alignment or defining ppc_md.pcibios_default_alignment which returns anything but 0). Note that the alignment requests are ignored if PCI_PROBE_ONLY is enabled. With 1) and 2), the generic PCI code in the kernel unconditionally decides to: - reassign the BARs in pci_specified_resource_alignment() (works fine) - write new BARs to the device - this fails for 64bit BARs as the generic code looks at IORESOURCE_MEM_64 (not set) and writes only lower 32bits of the BAR and leaves the upper 32bit unmodified which breaks BAR mapping in the hypervisor. This fixes the issue by copying the flag. This is useful if we want to enforce certain BAR alignment per platform as handling subpage sized BARs is proven to cause problems with hotplug (SLOF already aligns BARs to 64k). Signed-off-by: Alexey Kardashevskiy Reviewed-by: Sam Bobroff Reviewed-by: Oliver O'Halloran Reviewed-by: Shawn Anastasio --- This code is there for ages (from 200x) hence no "Fixes:". Ideally I want to enforce /chosen/linux,pci-probe-only in QEMU as at the moment: - pci=resource_alignment= alone does not do anything; - /chosen/linux,pci-probe-only alone does not cause the kernel to reassign resources; - pci=resource_alignment= with /chosen/linux,pci-probe-only is broken anyway. --- arch/powerpc/kernel/pci_of_scan.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/powerpc/kernel/pci_of_scan.c b/arch/powerpc/kernel/pci_of_scan.c index 24191ea2d9a7..64ad92016b63 100644 --- a/arch/powerpc/kernel/pci_of_scan.c +++ b/arch/powerpc/kernel/pci_of_scan.c @@ -45,6 +45,8 @@ unsigned int pci_parse_of_flags(u32 addr0, int bridge) if (addr0 & 0x02000000) { flags = IORESOURCE_MEM | PCI_BASE_ADDRESS_SPACE_MEMORY; flags |= (addr0 >> 22) & PCI_BASE_ADDRESS_MEM_TYPE_64; + if (flags & PCI_BASE_ADDRESS_MEM_TYPE_64) + flags |= IORESOURCE_MEM_64; flags |= (addr0 >> 28) & PCI_BASE_ADDRESS_MEM_TYPE_1M; if (addr0 & 0x40000000) flags |= IORESOURCE_PREFETCH