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=-19.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 7FA0CC19F39 for ; Tue, 24 Aug 2021 17:39:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 62B7061357 for ; Tue, 24 Aug 2021 17:39:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240343AbhHXRkJ (ORCPT ); Tue, 24 Aug 2021 13:40:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:43370 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242244AbhHXRhN (ORCPT ); Tue, 24 Aug 2021 13:37:13 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C355461BF4; Tue, 24 Aug 2021 17:07:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1629824874; bh=CxL4seaQPq+aQ8H0R+cHUBfV2Q6lhuouE3GD6ILzpE4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=swuwX7DWqRrYXe7PDLDVZuj3jthbVVHn74ZJFo19trIzbHwRq9NcsRazLAlRwu5io 3fu6+3aOGysT4lROMkG20Qr9o/9ICIHj493CU6HSzzkY9k4gKFGH0X/wF/zYkYXxnG FYLmeUpaUVth66wDj1706J4NaYiOirw1cosTEA+ngAioniWCHPTsk9HyJuiPMb9vYD Cytb6EnNGhgC3xERpUd8StgBzZS3YHNdw8a/UxPK0ynh7cwepGr2ArnctnpJXQMxl9 bNCfv+mPq5bPQt3EaEVrCUcYQF/Se17JPy6fUgtA0yrwRMbtFq3xoxvMBaYPp4YJOF u8vHY5WZDlwmw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Thomas Gleixner , Marc Zyngier , Greg Kroah-Hartman Subject: [PATCH 4.4 10/31] PCI/MSI: Protect msi_desc::masked for multi-MSI Date: Tue, 24 Aug 2021 13:07:22 -0400 Message-Id: <20210824170743.710957-11-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210824170743.710957-1-sashal@kernel.org> References: <20210824170743.710957-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.4.282-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-4.4.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 4.4.282-rc1 X-KernelTest-Deadline: 2021-08-26T17:07+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thomas Gleixner commit 77e89afc25f30abd56e76a809ee2884d7c1b63ce upstream. Multi-MSI uses a single MSI descriptor and there is a single mask register when the device supports per vector masking. To avoid reading back the mask register the value is cached in the MSI descriptor and updates are done by clearing and setting bits in the cache and writing it to the device. But nothing protects msi_desc::masked and the mask register from being modified concurrently on two different CPUs for two different Linux interrupts which belong to the same multi-MSI descriptor. Add a lock to struct device and protect any operation on the mask and the mask register with it. This makes the update of msi_desc::masked unconditional, but there is no place which requires a modification of the hardware register without updating the masked cache. msi_mask_irq() is now an empty wrapper which will be cleaned up in follow up changes. The problem goes way back to the initial support of multi-MSI, but picking the commit which introduced the mask cache is a valid cut off point (2.6.30). Fixes: f2440d9acbe8 ("PCI MSI: Refactor interrupt masking code") Signed-off-by: Thomas Gleixner Tested-by: Marc Zyngier Reviewed-by: Marc Zyngier Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210729222542.726833414@linutronix.de Signed-off-by: Greg Kroah-Hartman --- drivers/base/core.c | 1 + drivers/pci/msi.c | 19 ++++++++++--------- include/linux/device.h | 1 + include/linux/msi.h | 2 +- 4 files changed, 13 insertions(+), 10 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 7e419aaf3c24..23517100c9a5 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -710,6 +710,7 @@ void device_initialize(struct device *dev) device_pm_init(dev); set_dev_node(dev, -1); #ifdef CONFIG_GENERIC_MSI_IRQ + raw_spin_lock_init(&dev->msi_lock); INIT_LIST_HEAD(&dev->msi_list); #endif } diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index e3865e274389..dffa5c5bcc76 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -187,24 +187,25 @@ static inline __attribute_const__ u32 msi_mask(unsigned x) * reliably as devices without an INTx disable bit will then generate a * level IRQ which will never be cleared. */ -u32 __pci_msi_desc_mask_irq(struct msi_desc *desc, u32 mask, u32 flag) +void __pci_msi_desc_mask_irq(struct msi_desc *desc, u32 mask, u32 flag) { - u32 mask_bits = desc->masked; + raw_spinlock_t *lock = &desc->dev->msi_lock; + unsigned long flags; if (pci_msi_ignore_mask || !desc->msi_attrib.maskbit) - return 0; + return; - mask_bits &= ~mask; - mask_bits |= flag; + raw_spin_lock_irqsave(lock, flags); + desc->masked &= ~mask; + desc->masked |= flag; pci_write_config_dword(msi_desc_to_pci_dev(desc), desc->mask_pos, - mask_bits); - - return mask_bits; + desc->masked); + raw_spin_unlock_irqrestore(lock, flags); } static void msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag) { - desc->masked = __pci_msi_desc_mask_irq(desc, mask, flag); + __pci_msi_desc_mask_irq(desc, mask, flag); } /* diff --git a/include/linux/device.h b/include/linux/device.h index eb891c9c4b62..df0199e768d4 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -794,6 +794,7 @@ struct device { struct dev_pin_info *pins; #endif #ifdef CONFIG_GENERIC_MSI_IRQ + raw_spinlock_t msi_lock; struct list_head msi_list; #endif diff --git a/include/linux/msi.h b/include/linux/msi.h index d0d50cf00b4d..037f47fe76e6 100644 --- a/include/linux/msi.h +++ b/include/linux/msi.h @@ -128,7 +128,7 @@ void __pci_read_msi_msg(struct msi_desc *entry, struct msi_msg *msg); void __pci_write_msi_msg(struct msi_desc *entry, struct msi_msg *msg); u32 __pci_msix_desc_mask_irq(struct msi_desc *desc, u32 flag); -u32 __pci_msi_desc_mask_irq(struct msi_desc *desc, u32 mask, u32 flag); +void __pci_msi_desc_mask_irq(struct msi_desc *desc, u32 mask, u32 flag); void pci_msi_mask_irq(struct irq_data *data); void pci_msi_unmask_irq(struct irq_data *data); -- 2.30.2