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=-16.2 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 autolearn=ham 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 4A4C8C433ED for ; Fri, 30 Apr 2021 20:51:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1E965613EF for ; Fri, 30 Apr 2021 20:51:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235431AbhD3UwM (ORCPT ); Fri, 30 Apr 2021 16:52:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:40100 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231278AbhD3Uvz (ORCPT ); Fri, 30 Apr 2021 16:51:55 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B94D8613EF; Fri, 30 Apr 2021 20:51:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1619815867; bh=425BKKf9d1upHtLcAyCMH6Ftd/hb03pDS4Y2KILynpY=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=OTERdT9WtjZ9eJb63Jhk9+bIPcpKMIAehxtCv4FKI54U5WCZjqF44V4J0mDkgkER3 +7os0kmxLtgAzDqSZzz27Bf8RK2cMt3702JKM7b7TvOVx43BLRiUxl2kpohVuJ7JzL jw6JjjJYjAIZlMzqihgYLfMsb4mSrPoIPZAeUhARaGEvs663ZupCA46Qyqx+jxSZ2D 2F3gGVzDGGqc89yLT7DTL5Cw7MokLbBxbmsRcLXA7Ma8jaCe0KjSK0NiPPo3WcIPcH d1mYlltyGpcjQqXqdtF2J3Gtmp1pyGaTTQQG5eGqU+11UJwKRyNSKoAQrWqGKycf// CBCFywTJUX4fg== Date: Fri, 30 Apr 2021 15:51:05 -0500 From: Bjorn Helgaas To: Robert Straw Cc: bhelgaas@google.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Alex Williamson Subject: Re: [PATCH] pci: add NVMe FLR quirk to the SM951 SSD Message-ID: <20210430205105.GA683965@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210429230730.201266-1-drbawb@fatalsyntax.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org [+cc Alex, author of ffb0863426eb] Please make your subject line match ffb0863426eb ("PCI: Disable Samsung SM961/PM961 NVMe before FLR") On Thu, Apr 29, 2021 at 06:07:30PM -0500, Robert Straw wrote: > The SM951/PM951, when used in conjunction with the vfio-pci driver and > passed to a KVM guest, can exhibit the fatal state addressed by the > existing `nvme_disable_and_flr` quirk. If the guest cleanly shuts down > the SSD, and vfio-pci attempts an FLR to the device while it is in this > state, the nvme driver will fail when it attempts to bind to the device > after the FLR due to the frozen config area, e.g: > > nvme nvme2: frozen state error detected, reset controller > nvme nvme2: Removing after probe failure status: -12 > > By including this older model (Samsung 950 PRO) of the controller in the > existing quirk: the device is able to be cleanly reset after being used > by a KVM guest. I don't see anything in the PCIe spec about software being required to do something special before initiating an FLR, so I assume this is a hardware defect in the Samsung 950 PRO? Has Samsung published an erratum or at least acknowledged it? There's always the possibility that we are doing something wrong in Linux *after* the FLR, e.g., not waiting long enough, not reinitializing something correctly, etc. > Signed-off-by: Robert Straw > --- > drivers/pci/quirks.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c > index 653660e3b..e339ca238 100644 > --- a/drivers/pci/quirks.c > +++ b/drivers/pci/quirks.c > @@ -3920,6 +3920,7 @@ static const struct pci_dev_reset_methods pci_dev_reset_methods[] = { > reset_ivb_igd }, > { PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IVB_M2_VGA, > reset_ivb_igd }, > + { PCI_VENDOR_ID_SAMSUNG, 0xa802, nvme_disable_and_flr }, > { PCI_VENDOR_ID_SAMSUNG, 0xa804, nvme_disable_and_flr }, > { PCI_VENDOR_ID_INTEL, 0x0953, delay_250ms_after_flr }, > { PCI_VENDOR_ID_CHELSIO, PCI_ANY_ID, > -- > 2.31.1 >