From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A03453E51FC; Thu, 1 Oct 2026 23:07:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790896040; cv=none; b=DHrBvarTdEjiqvqhWvT43BYLVSUny41qTPH3qdO+1kVq36gLd/FUSOl7Quf18zSsyjpmXWpsLowUB7ttXDl+JYNwURp1OptiW7yprmcl7INnZlLIq5TUmOVgf30YjkXjES7j5OIt/tsCBy89kGEJcHxH4tCj3XvhjtHkqSCn6Pc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790896040; c=relaxed/simple; bh=PqJ80S6Vs8Wg5pX65UgwrGW/vOcciXfmy+v16R1QBZY=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=aFhBFKXToHUzFdatGz0iFTf41KT+KFJfqt0DxZjlehJqVngYk1PjTA8R2axD+CO2RIYbugCLslln5O4nENqq+xXZzyixkj9Gx1iG7TDlRal4nCOJFU/llHT2vc11sTkVvfoW6OgKzh2/cEn9mxm2AEGHOdiTyoKYN/0umZLB6IM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=R4MC/xRJ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="R4MC/xRJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D7ECB1F000FF; Thu, 1 Oct 2026 23:07:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790896039; bh=lYDN2EBTMqVMIwPcPNFaRe6IY/Q4nRv3WEjn49Ix3aA=; h=Date:From:To:Cc:Subject:In-Reply-To; b=R4MC/xRJSxcbXpvObFnBkQY3uBp5iyJ8NHdLiZtJfPZTDVbB+32qsrgbom+lZwHDG ysSxG/KPS9Hha9XS0NxAhqX/Isyec6XuaR5YptUFide6IvrAEFeTccwKp/d3XiaxLG rNJFwF6e4Hj8v7zeA95HbTYKELnAQoh/1mXrJPqEAYDMSLm0e0dxScBJno01qDdiHu nr0J5cyJn5Lip9FVSTjaao3bIvCsqoVSmMUFKsosp9N+aAtP5l2Ef/Bkudk7ufN5xI uh69jnzZj+Drh/g8AWftmXKTRvY+ll2xDZKc+hJ5gZwAEwovEqT1UMJyz4lIQMXpJr dRAU+qxmkmVsA== Date: Thu, 1 Oct 2026 18:07:17 -0500 From: Bjorn Helgaas To: Vladimir Nedoshivin Cc: Nirmal Patel , linux-pci@vger.kernel.org, Jonathan Derrick , Lorenzo Pieralisi , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Manivannan Sadhasivam , Rob Herring , Bjorn Helgaas , Rickey Bartlett , linux-kernel@vger.kernel.org Subject: Re: [PATCH] PCI: vmd: Enable interrupt ordering quirk for Arrow Lake Message-ID: <20261001230717.GA2742668@bhelgaas> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260910200539.10862-1-gvozd188@mail.ru> On Fri, Sep 11, 2026 at 12:05:39AM +0400, Vladimir Nedoshivin wrote: > Intel Arrow Lake VMD device 0xad0b is affected by ARL004. The VMD may > signal an MSI before preceding posted writes from the child device have > reached memory, which can cause the demuxed handler to observe stale > completion data. > > The existing VMD_FEAT_INTERRUPT_QUIRK implements Intel's documented > workaround by issuing a configuration-space read to the MSI initiator > before dispatching the interrupt. > > Enable the existing quirk for 0xad0b as well as 0x7d0b and make the > comments describe both MTL016 and ARL004. > > Tested on an MSI Vector 17 HX AI with Intel VMD 8086:ad0b and an NVMe > device behind VMD. With the quirk enabled, the NVMe completion stalls > observed without the workaround are no longer reproduced. > > Link: https://bugs.launchpad.net/bugs/2166325 > Signed-off-by: Vladimir Nedoshivin Applied on pci/controller/vmd, thanks! I added the erratum source and text to the commit logs of both the Meteor Lake quirk and this one: PCI: vmd: Flush DMA writes before handling MSI on Arrow Lake Per the Intel Core Ultra Processors (Series 2) Specification Update (ID 834774 of 9/1/2026), the Arrow Lake VMD device 0xad0b is affected by an MSI erratum: ARL004: MSI from VMD-Owned Device May Pass Memory Write Problem When the storage subsystem is configured to operate in RAID 0 or 1 mode, a Message Signaled Interrupt (MSI) from an Intel® Volume Management Device (Intel® VMD) owned device may interrupt a core before a previous write from the device is completed. Workaround None identified. The VMD MSI interrupt-handler should initially perform a dummy register read to the MSI initiator device prior to any writes to ensure proper PCIe ordering. ... > --- > drivers/pci/controller/vmd.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c > index e45ef8cb16e..9d97a832785 100644 > --- a/drivers/pci/controller/vmd.c > +++ b/drivers/pci/controller/vmd.c > @@ -94,7 +94,8 @@ enum vmd_features { > VMD_FEAT_USE_BIOS_INFO = (1 << 6), > > /* > - * Meteor Lake VMD (device ID 0x7d0b) is affected by erratum MTL016: > + * Some Intel VMD devices are affected by interrupt ordering errata, > + * including MTL016 (0x7d0b) and ARL004 (0xad0b): > * the VMD may signal its MSI before the posted writes that carry the > * child device's DMA data have landed in memory. The demuxed handler > * then runs against a not-yet-coherent completion queue and misses the > @@ -131,7 +132,7 @@ static DEFINE_RAW_SPINLOCK(list_lock); > * @enabled: true if driver enabled IRQ > * @virq: the virtual IRQ value provided to the requesting driver. > * @flush_addr: config space address of the initiating device, read before > - * demuxing to flush its posted writes (MTL016); NULL if the > + * demuxing to flush its posted writes; NULL if the > * VMD is not affected. > * > * Every MSI/MSI-X IRQ requested for a device in a VMD domain will be mapped to > @@ -1300,7 +1301,7 @@ static const struct pci_device_id vmd_ids[] = { > {PCI_VDEVICE(INTEL, 0x7d0b), > .driver_data = VMD_FEATS_CLIENT | VMD_FEAT_INTERRUPT_QUIRK,}, > {PCI_VDEVICE(INTEL, 0xad0b), > - .driver_data = VMD_FEATS_CLIENT,}, > + .driver_data = VMD_FEATS_CLIENT | VMD_FEAT_INTERRUPT_QUIRK,}, > {PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_VMD_9A0B), > .driver_data = VMD_FEATS_CLIENT,}, > {PCI_VDEVICE(INTEL, 0xb60b), > > base-commit: 95ac22dd4bf13373f90bb6d51bcd1fd1d8f5db54 > -- > 2.53.0 >