From patchwork Mon Aug 16 13:02:24 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 498061 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=-24.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 AE617C4338F for ; Mon, 16 Aug 2021 13:06:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 92C1D6328D for ; Mon, 16 Aug 2021 13:06:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237616AbhHPNGw (ORCPT ); Mon, 16 Aug 2021 09:06:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:58138 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237623AbhHPNF7 (ORCPT ); Mon, 16 Aug 2021 09:05:59 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 05E21632A6; Mon, 16 Aug 2021 13:05:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1629119128; bh=T58+ZDJpuIz0/xl5FMUPFATYbXSotiuG2+KTjl149x8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hevun3DEflO+v9xhyy8xP+LMFBaEHDt147whmZGoX/KakGfe+kfMOhm/DPNKVSyJg RYdwBpZJW0zfa+ukNSFqr0j3sY5kZechYnAVV5LWwLCwkg3j9i4Zb6d6KoCGejmYlz 3zpTozZZFrAezc+4/bwnSbLGV/Vfb5HokvjYWJgM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Thomas Gleixner , Marc Zyngier , Bjorn Helgaas Subject: [PATCH 5.4 52/62] PCI/MSI: Enforce MSI[X] entry updates to be visible Date: Mon, 16 Aug 2021 15:02:24 +0200 Message-Id: <20210816125430.005879743@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210816125428.198692661@linuxfoundation.org> References: <20210816125428.198692661@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Thomas Gleixner commit b9255a7cb51754e8d2645b65dd31805e282b4f3e upstream. Nothing enforces the posted writes to be visible when the function returns. Flush them even if the flush might be redundant when the entry is masked already as the unmask will flush as well. This is either setup or a rare affinity change event so the extra flush is not the end of the world. While this is more a theoretical issue especially the logic in the X86 specific msi_set_affinity() function relies on the assumption that the update has reached the hardware when the function returns. Again, as this never has been enforced the Fixes tag refers to a commit in: git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git Fixes: f036d4ea5fa7 ("[PATCH] ia32 Message Signalled Interrupt support") Signed-off-by: Thomas Gleixner Tested-by: Marc Zyngier Reviewed-by: Marc Zyngier Acked-by: Bjorn Helgaas Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210729222542.515188147@linutronix.de Signed-off-by: Greg Kroah-Hartman --- drivers/pci/msi.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -338,6 +338,9 @@ void __pci_write_msi_msg(struct msi_desc if (unmasked) __pci_msix_desc_mask_irq(entry, 0); + + /* Ensure that the writes are visible in the device */ + readl(base + PCI_MSIX_ENTRY_DATA); } else { int pos = dev->msi_cap; u16 msgctl; @@ -358,6 +361,8 @@ void __pci_write_msi_msg(struct msi_desc pci_write_config_word(dev, pos + PCI_MSI_DATA_32, msg->data); } + /* Ensure that the writes are visible in the device */ + pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &msgctl); } skip: