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=-19.4 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,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 9EFFEC4338F for ; Mon, 16 Aug 2021 13:13:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8A67D632F8 for ; Mon, 16 Aug 2021 13:13:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239126AbhHPNOC (ORCPT ); Mon, 16 Aug 2021 09:14:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:59346 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239165AbhHPNJh (ORCPT ); Mon, 16 Aug 2021 09:09:37 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1623E60E78; Mon, 16 Aug 2021 13:08:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1629119322; bh=l1J3cUOpunTQ8o17C2aFrfjoXBOzj2SuOrbj0vRcA7g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KyFx4SIKcMHDlT2layOUai3UmvA6N02qFlOAWBOo7Ja9Gqauz7inL2hwF4s703Zwb 1/ACbj+HSdDvMrzr6Pj4dQZRRbWVTin/8adWXglDWF11UgYshvFZUczJSvp9zVo+Bv 7hZsC54G7yqJvh4CimE2/R8NgH/ojhpchO6wBoxE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Thomas Gleixner , Marc Zyngier , Ashok Raj , Bjorn Helgaas Subject: [PATCH 5.10 79/96] PCI/MSI: Enable and mask MSI-X early Date: Mon, 16 Aug 2021 15:02:29 +0200 Message-Id: <20210816125437.619336857@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210816125434.948010115@linuxfoundation.org> References: <20210816125434.948010115@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thomas Gleixner commit 438553958ba19296663c6d6583d208dfb6792830 upstream. The ordering of MSI-X enable in hardware is dysfunctional: 1) MSI-X is disabled in the control register 2) Various setup functions 3) pci_msi_setup_msi_irqs() is invoked which ends up accessing the MSI-X table entries 4) MSI-X is enabled and masked in the control register with the comment that enabling is required for some hardware to access the MSI-X table Step #4 obviously contradicts #3. The history of this is an issue with the NIU hardware. When #4 was introduced the table access actually happened in msix_program_entries() which was invoked after enabling and masking MSI-X. This was changed in commit d71d6432e105 ("PCI/MSI: Kill redundant call of irq_set_msi_desc() for MSI-X interrupts") which removed the table write from msix_program_entries(). Interestingly enough nobody noticed and either NIU still works or it did not get any testing with a kernel 3.19 or later. Nevertheless this is inconsistent and there is no reason why MSI-X can't be enabled and masked in the control register early on, i.e. move step #4 above to step #1. This preserves the NIU workaround and has no side effects on other hardware. Fixes: d71d6432e105 ("PCI/MSI: Kill redundant call of irq_set_msi_desc() for MSI-X interrupts") Signed-off-by: Thomas Gleixner Tested-by: Marc Zyngier Reviewed-by: Ashok Raj Reviewed-by: Marc Zyngier Acked-by: Bjorn Helgaas Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210729222542.344136412@linutronix.de Signed-off-by: Greg Kroah-Hartman --- drivers/pci/msi.c | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-) --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -779,18 +779,25 @@ static int msix_capability_init(struct p u16 control; void __iomem *base; - /* Ensure MSI-X is disabled while it is set up */ - pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0); + /* + * Some devices require MSI-X to be enabled before the MSI-X + * registers can be accessed. Mask all the vectors to prevent + * interrupts coming in before they're fully set up. + */ + pci_msix_clear_and_set_ctrl(dev, 0, PCI_MSIX_FLAGS_MASKALL | + PCI_MSIX_FLAGS_ENABLE); pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &control); /* Request & Map MSI-X table region */ base = msix_map_region(dev, msix_table_size(control)); - if (!base) - return -ENOMEM; + if (!base) { + ret = -ENOMEM; + goto out_disable; + } ret = msix_setup_entries(dev, base, entries, nvec, affd); if (ret) - return ret; + goto out_disable; ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX); if (ret) @@ -801,14 +808,6 @@ static int msix_capability_init(struct p if (ret) goto out_free; - /* - * Some devices require MSI-X to be enabled before we can touch the - * MSI-X registers. We need to mask all the vectors to prevent - * interrupts coming in before they're fully set up. - */ - pci_msix_clear_and_set_ctrl(dev, 0, - PCI_MSIX_FLAGS_MASKALL | PCI_MSIX_FLAGS_ENABLE); - msix_program_entries(dev, entries); ret = populate_msi_sysfs(dev); @@ -843,6 +842,9 @@ out_avail: out_free: free_msi_irqs(dev); +out_disable: + pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0); + return ret; }