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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 36EDDC4332F for ; Fri, 11 Nov 2022 23:39:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233900AbiKKXjO (ORCPT ); Fri, 11 Nov 2022 18:39:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57604 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230105AbiKKXjN (ORCPT ); Fri, 11 Nov 2022 18:39:13 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F27E2B623; Fri, 11 Nov 2022 15:39:12 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D207FB82836; Fri, 11 Nov 2022 23:39:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1AB48C433C1; Fri, 11 Nov 2022 23:39:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1668209949; bh=Vlb+/7QojmhhvH1wfSO9VCLJ7Gp43IqzkXJWqxZOk0c=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=DDta3/Dz1CRlZBWgtSaqjUxwEJCUBrvTLhf6rLi5V6AIPcQoLraYaQN2FK+pXV14N sh/2rxaYiZrJRFXkdYH7zi7f3Y7tSJuED20GyZiNYt1rbqOHU6+cJ2rI7UxsGVV5YA atztOz3slba/5EuGcfJ9KSx5VWjjZhg+xVd8K/q6ijvWFR3UP1thFKg4Zf8V8xlvzO 6vH6J1PcvgKA7UDLZkxPEdTcARWY2s3efkbfKwns6MK4xkIhatNqG58rzaWBpJY02m P4g3flw86vTnoTs4KhQzqLLviznl5MG/qEbIJDA+Y9sTRsWwEBe07OdlAhZZOQb9/D uTdnowRJ99v1Q== Date: Fri, 11 Nov 2022 17:39:07 -0600 From: Bjorn Helgaas To: "Michael S. Tsirkin" Cc: linux-kernel@vger.kernel.org, Wei Gong , Bjorn Helgaas , linux-pci@vger.kernel.org Subject: Re: [PATCH v2] pci: fix device presence detection for VFs Message-ID: <20221111233907.GA763281@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221026060912.173250-1-mst@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, Oct 26, 2022 at 02:11:21AM -0400, Michael S. Tsirkin wrote: > virtio uses the same driver for VFs and PFs. Accordingly, > pci_device_is_present is used to detect device presence. This function > isn't currently working properly for VFs since it attempts reading > device and vendor ID. As VFs are present if and only if PF is present, > just return the value for that device. > > Reported-by: Wei Gong > Signed-off-by: Michael S. Tsirkin Applied as below to pci/enumeration for v6.2, thanks! commit 98b04dd0b457 ("PCI: Fix pci_device_is_present() for VFs by checking PF") Author: Michael S. Tsirkin Date: Wed Oct 26 02:11:21 2022 -0400 PCI: Fix pci_device_is_present() for VFs by checking PF pci_device_is_present() previously didn't work for VFs because it reads the Vendor and Device ID, which are 0xffff for VFs, which looks like they aren't present. Check the PF instead. Wei Gong reported that if virtio I/O is in progress when the driver is unbound or "0" is written to /sys/.../sriov_numvfs, the virtio I/O operation hangs, which may result in output like this: task:bash state:D stack: 0 pid: 1773 ppid: 1241 flags:0x00004002 Call Trace: schedule+0x4f/0xc0 blk_mq_freeze_queue_wait+0x69/0xa0 blk_mq_freeze_queue+0x1b/0x20 blk_cleanup_queue+0x3d/0xd0 virtblk_remove+0x3c/0xb0 [virtio_blk] virtio_dev_remove+0x4b/0x80 ... device_unregister+0x1b/0x60 unregister_virtio_device+0x18/0x30 virtio_pci_remove+0x41/0x80 pci_device_remove+0x3e/0xb0 This happened because pci_device_is_present(VF) returned "false" in virtio_pci_remove(), so it called virtio_break_device(). The broken vq meant that vring_interrupt() skipped the vq.callback() that would have completed the virtio I/O operation via virtblk_done(). [bhelgaas: commit log, simplify to always use pci_physfn(), add stable tag] Link: https://lore.kernel.org/r/20221026060912.173250-1-mst@redhat.com Reported-by: Wei Gong Tested-by: Wei Gong Signed-off-by: Michael S. Tsirkin Signed-off-by: Bjorn Helgaas Cc: stable@vger.kernel.org diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 9f3cc829dfee..fba95486caaf 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -6447,6 +6447,8 @@ bool pci_device_is_present(struct pci_dev *pdev) { u32 v; + /* Check PF if pdev is a VF, since VF Vendor/Device IDs are 0xffff */ + pdev = pci_physfn(pdev); if (pci_dev_is_disconnected(pdev)) return false; return pci_bus_read_dev_vendor_id(pdev->bus, pdev->devfn, &v, 0);