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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT 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 770EFC072B5 for ; Fri, 24 May 2019 15:38:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4B7BA20815 for ; Fri, 24 May 2019 15:38:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389590AbfEXPi0 (ORCPT ); Fri, 24 May 2019 11:38:26 -0400 Received: from libmpq.org ([85.25.94.4]:51036 "EHLO mail.libmpq.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389385AbfEXPi0 (ORCPT ); Fri, 24 May 2019 11:38:26 -0400 X-Greylist: delayed 427 seconds by postgrey-1.27 at vger.kernel.org; Fri, 24 May 2019 11:38:26 EDT Received: from libmpq.org (homer.theraso.int [172.16.50.110]) by mail.libmpq.org (Postfix) with ESMTPSA id BD655395A52; Fri, 24 May 2019 17:31:18 +0200 (CEST) Date: Fri, 24 May 2019 17:31:18 +0200 From: Maik Broemme To: linux-pci Cc: vfio-users Subject: [PATCH] PCI: Mark Intel bridge on SuperMicro Atom C3xxx motherboards to avoid bus reset Message-ID: <20190524153118.GA12862@libmpq.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Operating-System: Linux homer.theraso.int 5.1.4-arch1-1-ARCH X-PGP-Key-FingerPrint: 109D 0AC6 86CF 06BD 4890 17B0 8FB9 9971 4EEB 31F1 Organization: Personal User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org The Intel PCI bridge on SuperMicro Atom C3xxx motherboards do not successfully complete a bus reset when used with certain child devices. After the reset, config accesses to the child may fail. If assigning such device via VFIO it will immediately fail with: vfio-pci 0000:01:00.0: Failed to return from FLR vfio-pci 0000:01:00.0: timed out waiting for pending transaction; performing function level reset anyway Device will disappear from PCI device list: !!! Unknown header type 7f Kernel driver in use: vfio-pci Kernel modules: ddbridge The attached patch will mark the root port as incapable of doing a bus level reset. After that all my tested devices survive a VFIO assignment and several VM reboot cycles. Signed-off-by: Maik Broemme --- drivers/pci/quirks.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 0f16acc323c6..86cd42872708 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -3433,6 +3433,13 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATHEROS, 0x0034, quirk_no_bus_reset); */ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_CAVIUM, 0xa100, quirk_no_bus_reset); +/* + * Root port on some SuperMicro Atom C3xxx motherboards do not successfully + * complete a bus reset when used with certain child devices. After the + * reset, config accesses to the child may fail. + */ +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x19a4, quirk_no_bus_reset); + static void quirk_no_pm_reset(struct pci_dev *dev) { /* -- 2.21.0