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 3188CC4338F for ; Tue, 24 Aug 2021 17:36:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1AA6F60698 for ; Tue, 24 Aug 2021 17:36:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239430AbhHXRhf (ORCPT ); Tue, 24 Aug 2021 13:37:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:39992 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241383AbhHXReF (ORCPT ); Tue, 24 Aug 2021 13:34:05 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id D4AAF61BA4; Tue, 24 Aug 2021 17:06:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1629824791; bh=WJsw457BkyULjCW57iFazQlMjbSKNLdvKqEWxyiKvjg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=u9bB60BHP6UIEpSwciOEnOiZSPjDMFJvIoY+LZ7ZTnq7b+O9B/hEg5lQAaovqOguh yoc+XknauD/is4sjpD6Oyv0iA6UgfMlbyZBvAPG5H8B9VBuIzH53PY3dUUXI6mfNES WaOv3UaULeY9E/fbkan6IG0eZEFABHO8fwFvvcyMQFuK67togGTKHXQaDzAVXb844J K9acW57bDlBK2oOjI4eyK9Ty/5p3lBTxoJq6cO60wflwK68jE6o9B2ANN99mO0heJy QxqEI2+EhaVvmQDNXe+j8dmJQS78M7i3UqFfUN42wyvnRCZIZ62DA/P5hxzw2ePX4x CZ4Ia/8cXa4dg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Thomas Gleixner , Marc Zyngier , Greg Kroah-Hartman Subject: [PATCH 4.9 15/43] PCI/MSI: Protect msi_desc::masked for multi-MSI Date: Tue, 24 Aug 2021 13:05:46 -0400 Message-Id: <20210824170614.710813-16-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210824170614.710813-1-sashal@kernel.org> References: <20210824170614.710813-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.9.281-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-4.9.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 4.9.281-rc1 X-KernelTest-Deadline: 2021-08-26T17:06+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 3b8487e28c84..e82a89325f3d 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 b3977b4c51b6..79b36f1bde0d 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -189,24 +189,25 @@ 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); } static void __iomem *pci_msix_desc_addr(struct msi_desc *desc) diff --git a/include/linux/device.h b/include/linux/device.h index eb865b461acc..ca765188a981 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -812,6 +812,7 @@ 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 debc8aa4ec19..601bff9fbbec 100644 --- a/include/linux/msi.h +++ b/include/linux/msi.h @@ -133,7 +133,7 @@ void __pci_write_msi_msg(struct msi_desc *entry, struct msi_msg *msg); void pci_write_msi_msg(unsigned int irq, 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