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=-13.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 4C11EC433DB for ; Thu, 4 Feb 2021 23:29:47 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6DBD464FAD for ; Thu, 4 Feb 2021 23:29:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6DBD464FAD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4DWvsL6QxnzDvZl for ; Fri, 5 Feb 2021 10:29:42 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=198.145.29.99; helo=mail.kernel.org; envelope-from=helgaas@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=X90TdtJL; dkim-atps=neutral Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4DWvqR4j35zDvXZ for ; Fri, 5 Feb 2021 10:28:03 +1100 (AEDT) Received: by mail.kernel.org (Postfix) with ESMTPSA id 7861064FB0; Thu, 4 Feb 2021 23:28:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1612481280; bh=wGRr36QX9QaUTjB2KCk2a5Q+NbARpjPfYoF9YwqjOCw=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=X90TdtJLqjMp3JvGEx99shW3s+hF07AO2DI7bX6Vfs8sRTQi7CyvNFcnuSzzl2kcj xblBZXEJb+hqFwbZ5kWxyAlqu2tVyEFttuw6OphrKB4KeqRCpkgwvYOLxFF5ICizjk HyHwyVJ04rEfBM9XWBjpb8/0BbC3jInPccRFjcmCLgpNePc46x3sN8PBTI+whnT6Vw /ITvPUYKJTBrAoNuSu6Fk1ZAXDdnv0EEf877IawUU02p9JItHmXFW3iP3mhqOLMU6g bC/XCqiPUO+I79dYXvZ/3bLGz8asRmTr5mzFhTxOQCmTWFnEKW3bVof73XHK3OgK54 4bDVhzw2Sb89w== Date: Thu, 4 Feb 2021 17:27:58 -0600 From: Bjorn Helgaas To: Kai-Heng Feng Subject: Re: [PATCH 1/2] PCI/AER: Disable AER interrupt during suspend Message-ID: <20210204232758.GA125392@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Joerg Roedel , "open list:PCI ENHANCED ERROR HANDLING \(EEH\) FOR POWERPC" , "open list:PCI SUBSYSTEM" , open list , Lalithambika Krishnakumar , Alex Williamson , Oliver O'Halloran , Bjorn Helgaas , Mika Westerberg , Lu Baolu Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" [+cc Alex] On Thu, Jan 28, 2021 at 12:09:37PM +0800, Kai-Heng Feng wrote: > On Thu, Jan 28, 2021 at 4:51 AM Bjorn Helgaas wrote: > > On Thu, Jan 28, 2021 at 01:31:00AM +0800, Kai-Heng Feng wrote: > > > Commit 50310600ebda ("iommu/vt-d: Enable PCI ACS for platform opt in > > > hint") enables ACS, and some platforms lose its NVMe after resume from > > > firmware: > > > [ 50.947816] pcieport 0000:00:1b.0: DPC: containment event, status:0x1f01 source:0x0000 > > > [ 50.947817] pcieport 0000:00:1b.0: DPC: unmasked uncorrectable error detected > > > [ 50.947829] pcieport 0000:00:1b.0: PCIe Bus Error: severity=Uncorrected (Non-Fatal), type=Transaction Layer, (Receiver ID) > > > [ 50.947830] pcieport 0000:00:1b.0: device [8086:06ac] error status/mask=00200000/00010000 > > > [ 50.947831] pcieport 0000:00:1b.0: [21] ACSViol (First) > > > [ 50.947841] pcieport 0000:00:1b.0: AER: broadcast error_detected message > > > [ 50.947843] nvme nvme0: frozen state error detected, reset controller > > > > > > It happens right after ACS gets enabled during resume. > > > > > > To prevent that from happening, disable AER interrupt and enable it on > > > system suspend and resume, respectively. > > > > Lots of questions here. Maybe this is what we'll end up doing, but I > > am curious about why the error is reported in the first place. > > > > Is this a consequence of the link going down and back up? > > Could be. From the observations, it only happens when firmware suspend > (S3) is used. > Maybe it happens when it's gets powered up, but I don't have equipment > to debug at hardware level. > > If we use non-firmware suspend method, enabling ACS after resume won't > trip AER and DPC. > > > Is it consequence of the device doing a DMA when it shouldn't? > > If it's doing DMA while suspending, the same error should also happen > after NVMe is suspended and before PCIe port suspending. > Furthermore, if non-firmware suspend method is used, there's so such > issue, so less likely to be any DMA operation. > > > Are we doing something in the wrong order during suspend? Or maybe > > resume, since I assume the error is reported during resume? > > Yes the error is reported during resume. The suspend/resume order > seems fine as non-firmware suspend doesn't have this issue. I really feel like we need a better understanding of what's going on here. Disabling the AER interrupt is like closing our eyes and pretending that because we don't see it, it didn't happen. An ACS error is triggered by a DMA, right? I'm assuming an MMIO access from the CPU wouldn't trigger this error. And it sounds like the error is triggered before we even start running the driver after resume. If we're powering up an NVMe device from D3cold and it DMAs before the driver touches it, something would be seriously broken. I doubt that's what's happening. Maybe a device could resume some previously programmed DMA after powering up from D3hot. Or maybe the error occurred on suspend, like if the device wasn't quiesced or something, but we didn't notice it until resume? The AER error status bits are RW1CS, which means they can be preserved across hot/warm/cold resets. Can you instrument the code to see whether the AER error status bit is set before enabling ACS? I'm not sure that merely enabling ACS (I assume you mean pci_std_enable_acs(), where we write PCI_ACS_CTRL) should cause an interrupt for a previously-logged error. I suspect that could happen when enabling *AER*, but I wouldn't think it would happen when enabling *ACS*. Does this error happen on multiple machines from different vendors? Wondering if it could be a BIOS issue, e.g., BIOS not cleaning up after it did something to cause an error. > > If we *do* take the error, why doesn't DPC recovery work? > > It works for the root port, but not for the NVMe drive: > [ 50.947816] pcieport 0000:00:1b.0: DPC: containment event, > status:0x1f01 source:0x0000 > [ 50.947817] pcieport 0000:00:1b.0: DPC: unmasked uncorrectable error detected > [ 50.947829] pcieport 0000:00:1b.0: PCIe Bus Error: > severity=Uncorrected (Non-Fatal), type=Transaction Layer, (Receiver > ID) > [ 50.947830] pcieport 0000:00:1b.0: device [8086:06ac] error > status/mask=00200000/00010000 > [ 50.947831] pcieport 0000:00:1b.0: [21] ACSViol (First) > [ 50.947841] pcieport 0000:00:1b.0: AER: broadcast error_detected message > [ 50.947843] nvme nvme0: frozen state error detected, reset controller > [ 50.948400] ACPI: EC: event unblocked > [ 50.948432] xhci_hcd 0000:00:14.0: PME# disabled > [ 50.948444] xhci_hcd 0000:00:14.0: enabling bus mastering > [ 50.949056] pcieport 0000:00:1b.0: PME# disabled > [ 50.949068] pcieport 0000:00:1c.0: PME# disabled > [ 50.949416] e1000e 0000:00:1f.6: PME# disabled > [ 50.949463] e1000e 0000:00:1f.6: enabling bus mastering > [ 50.951606] sd 0:0:0:0: [sda] Starting disk > [ 50.951610] nvme 0000:01:00.0: can't change power state from D3hot > to D0 (config space inaccessible) > [ 50.951730] nvme nvme0: Removing after probe failure status: -19 > [ 50.952360] nvme nvme0: failed to set APST feature (-19) > [ 50.971136] snd_hda_intel 0000:00:1f.3: PME# disabled > [ 51.089330] pcieport 0000:00:1b.0: AER: broadcast resume message > [ 51.089345] pcieport 0000:00:1b.0: AER: device recovery successful > > But I think why recovery doesn't work for NVMe is for another discussion... > > Kai-Heng > > > > > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=209149 > > > Fixes: 50310600ebda ("iommu/vt-d: Enable PCI ACS for platform opt in hint") > > > Signed-off-by: Kai-Heng Feng > > > --- > > > drivers/pci/pcie/aer.c | 18 ++++++++++++++++++ > > > 1 file changed, 18 insertions(+) > > > > > > diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c > > > index 77b0f2c45bc0..0e9a85530ae6 100644 > > > --- a/drivers/pci/pcie/aer.c > > > +++ b/drivers/pci/pcie/aer.c > > > @@ -1365,6 +1365,22 @@ static int aer_probe(struct pcie_device *dev) > > > return 0; > > > } > > > > > > +static int aer_suspend(struct pcie_device *dev) > > > +{ > > > + struct aer_rpc *rpc = get_service_data(dev); > > > + > > > + aer_disable_rootport(rpc); > > > + return 0; > > > +} > > > + > > > +static int aer_resume(struct pcie_device *dev) > > > +{ > > > + struct aer_rpc *rpc = get_service_data(dev); > > > + > > > + aer_enable_rootport(rpc); > > > + return 0; > > > +} > > > + > > > /** > > > * aer_root_reset - reset Root Port hierarchy, RCEC, or RCiEP > > > * @dev: pointer to Root Port, RCEC, or RCiEP > > > @@ -1437,6 +1453,8 @@ static struct pcie_port_service_driver aerdriver = { > > > .service = PCIE_PORT_SERVICE_AER, > > > > > > .probe = aer_probe, > > > + .suspend = aer_suspend, > > > + .resume = aer_resume, > > > .remove = aer_remove, > > > }; > > > > > > -- > > > 2.29.2 > > >