From patchwork Mon Jul 30 21:21:44 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Alex G." 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[98.195.139.126]) by smtp.gmail.com with ESMTPSA id d5-v6sm7897998oia.57.2018.07.30.14.22.02 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 30 Jul 2018 14:22:02 -0700 (PDT) From: Alexandru Gagniuc To: linux-pci@vger.kernel.org, bhelgaas@google.com Cc: keith.busch@intel.com, alex_gagniuc@dellteam.com, austin_bolen@dell.com, shyam_iyer@dell.com, Narendra_K@Dell.com, Stuart_Hayes@Dell.com, lukas@wunner.de, Alexandru Gagniuc , linux-kernel@vger.kernel.org Subject: [PATCH] PCI/MSI: Don't touch MSI bits when the PCI device is disconnected Date: Mon, 30 Jul 2018 16:21:44 -0500 Message-Id: <20180730212146.31909-1-mr.nuke.me@gmail.com> X-Mailer: git-send-email 2.17.1 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 When a PCI device is gone, we don't want to send IO to it if we can avoid it. We expose functionality via the irq_chip structure. As users of that structure may not know about the underlying PCI device, it's our responsibility to guard against removed devices. irq_write_msi_msg is already guarded. pci_msi_(un)mask_irq are not. Guard them for completeness. For example, surprise removal of a PCIe device triggers teardown. This touches the irq_chips ops some point to disable the interrupts. I/O generated here can crash the system on machines with buggy firmware. Not triggering the IO in the first place eliminates the problem. Signed-off-by: Alexandru Gagniuc --- There's another patch by Lukas Wunner that is needed (not yet published) in order to fully block IO on SURPRISE!!! removal. The existing code only sets the PCI_DEV_DISCONNECTED bit in an unreasonably narrow set of circumstances. Lukas' patch fixes that. However, this change is otherwise fully independent, and enjoy! drivers/pci/msi.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index 4d88afdfc843..5f47b5cb0401 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -227,6 +227,9 @@ static void msi_set_mask_bit(struct irq_data *data, u32 flag) { struct msi_desc *desc = irq_data_get_msi_desc(data); + if (pci_dev_is_disconnected(msi_desc_to_pci_dev(desc))) + return; + if (desc->msi_attrib.is_msix) { msix_mask_irq(desc, flag); readl(desc->mask_base); /* Flush write to device */