From patchwork Tue Nov 29 04:15:21 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bjorn Helgaas X-Patchwork-Id: 9450893 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 63B466074E for ; Tue, 29 Nov 2016 04:15:40 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5DD1D27CEA for ; Tue, 29 Nov 2016 04:15:40 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 50A1927F95; Tue, 29 Nov 2016 04:15:40 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DD18C27CEA for ; Tue, 29 Nov 2016 04:15:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932248AbcK2EPj (ORCPT ); Mon, 28 Nov 2016 23:15:39 -0500 Received: from mail.kernel.org ([198.145.29.136]:36088 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932199AbcK2EPi (ORCPT ); Mon, 28 Nov 2016 23:15:38 -0500 Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 788A620204; Tue, 29 Nov 2016 04:15:37 +0000 (UTC) Received: from localhost (unknown [69.71.4.155]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 05ECB20149; Tue, 29 Nov 2016 04:15:28 +0000 (UTC) Subject: [PATCH v4 4/7] PCI: Don't update VF BARs while VF memory space is enabled From: Bjorn Helgaas To: Gavin Shan Cc: clsoto@us.ibm.com, benh@kernel.crashing.org, linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, mpe@ellerman.id.au Date: Mon, 28 Nov 2016 22:15:21 -0600 Message-ID: <20161129041521.21453.33146.stgit@bhelgaas-glaptop.roam.corp.google.com> In-Reply-To: <20161129035218.21453.93986.stgit@bhelgaas-glaptop.roam.corp.google.com> References: <20161129035218.21453.93986.stgit@bhelgaas-glaptop.roam.corp.google.com> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-Virus-Scanned: ClamAV using ClamSMTP Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If we update a VF BAR while it's enabled, there are two potential problems: 1) Any driver that's using the VF has a cached BAR value that is stale after the update, and 2) We can't update 64-bit BARs atomically, so the intermediate state (new lower dword with old upper dword) may conflict with another device, and an access by a driver unrelated to the VF may cause a bus error. Warn about attempts to update VF BARs while they are enabled. This is a programming error, so use dev_WARN() to get a backtrace. Signed-off-by: Bjorn Helgaas Reviewed-by: Gavin Shan --- drivers/pci/iov.c | 8 ++++++++ 1 file changed, 8 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c index d00ed5c..a800ba2 100644 --- a/drivers/pci/iov.c +++ b/drivers/pci/iov.c @@ -584,6 +584,7 @@ void pci_iov_update_resource(struct pci_dev *dev, int resno) struct resource *res = dev->resource + resno; int vf_bar = resno - PCI_IOV_RESOURCES; struct pci_bus_region region; + u16 cmd; u32 new; int reg; @@ -595,6 +596,13 @@ void pci_iov_update_resource(struct pci_dev *dev, int resno) if (!iov) return; + pci_read_config_word(dev, iov->pos + PCI_SRIOV_CTRL, &cmd); + if ((cmd & PCI_SRIOV_CTRL_VFE) && (cmd & PCI_SRIOV_CTRL_MSE)) { + dev_WARN(&dev->dev, "can't update enabled VF BAR%d %pR\n", + vf_bar, res); + return; + } + /* * Ignore unimplemented BARs, unused resource slots for 64-bit * BARs, and non-movable resources, e.g., those described via