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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 096F8C433E1 for ; Mon, 17 Aug 2020 15:38:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C2B7F208E4 for ; Mon, 17 Aug 2020 15:38:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597678714; bh=gVKeEKKY+TbImxEgUxvijJBzrR3by6I8snMip+JEKHA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=vHlpeOMiYdXDo7S9T8lBmtFwXi7k7DSFtLOrrXZx04hK5bNvVe/T7WAQXEQA5Rah8 AlBLH4jXN9jZZlKKR5ZxxvFvJ8pxjPawiXbNIy7nZgYg8uuce4Ff0bv0eRfLp82+Wn y80P8BxBWoDcEFw2/+JuIIqjxN1KTUSYwS9s3qm8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387418AbgHQPie (ORCPT ); Mon, 17 Aug 2020 11:38:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:59046 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730312AbgHQPcO (ORCPT ); Mon, 17 Aug 2020 11:32:14 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C499220786; Mon, 17 Aug 2020 15:32:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597678333; bh=gVKeEKKY+TbImxEgUxvijJBzrR3by6I8snMip+JEKHA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lf4f76l1q/nQ6V1AfK4Vcp0pu4GMnrCYZrPzB5m6yFWpiKdxbCJsIuY11RSa/sj0k IJRHHRyUxnYGDQy4py3FpqdXPepEN1CyMe2I9iHBpk5KXifqwEELbZD6nVMDRxxcC8 3K1FpKe1tnXFABNCVidM6M1p6uCMxTmcSK+Zy+GY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Wei Hu , Lorenzo Pieralisi , Michael Kelley , Sasha Levin Subject: [PATCH 5.8 298/464] PCI: hv: Fix a timing issue which causes kdump to fail occasionally Date: Mon, 17 Aug 2020 17:14:11 +0200 Message-Id: <20200817143848.081418490@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200817143833.737102804@linuxfoundation.org> References: <20200817143833.737102804@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wei Hu [ Upstream commit d6af2ed29c7c1c311b96dac989dcb991e90ee195 ] Kdump could fail sometime on Hyper-V guest because the retry in hv_pci_enter_d0() releases child device structures in hv_pci_bus_exit(). Although there is a second asynchronous device relations message sending from the host, if this message arrives to the guest after hv_send_resource_allocated() is called, the retry would fail. Fix the problem by moving retry to hv_pci_probe() and start the retry from hv_pci_query_relations() call. This will cause a device relations message to arrive to the guest synchronously; the guest would then be able to rebuild the child device structures before calling hv_send_resource_allocated(). Link: https://lore.kernel.org/r/20200727071731.18516-1-weh@microsoft.com Fixes: c81992e7f4aa ("PCI: hv: Retry PCI bus D0 entry on invalid device state") Signed-off-by: Wei Hu [lorenzo.pieralisi@arm.com: fixed a comment and commit log] Signed-off-by: Lorenzo Pieralisi Reviewed-by: Michael Kelley Signed-off-by: Sasha Levin --- drivers/pci/controller/pci-hyperv.c | 71 +++++++++++++++-------------- 1 file changed, 37 insertions(+), 34 deletions(-) diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c index bf40ff09c99d6..d0033ff6c1437 100644 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -2759,10 +2759,8 @@ static int hv_pci_enter_d0(struct hv_device *hdev) struct pci_bus_d0_entry *d0_entry; struct hv_pci_compl comp_pkt; struct pci_packet *pkt; - bool retry = true; int ret; -enter_d0_retry: /* * Tell the host that the bus is ready to use, and moved into the * powered-on state. This includes telling the host which region @@ -2789,38 +2787,6 @@ static int hv_pci_enter_d0(struct hv_device *hdev) if (ret) goto exit; - /* - * In certain case (Kdump) the pci device of interest was - * not cleanly shut down and resource is still held on host - * side, the host could return invalid device status. - * We need to explicitly request host to release the resource - * and try to enter D0 again. - */ - if (comp_pkt.completion_status < 0 && retry) { - retry = false; - - dev_err(&hdev->device, "Retrying D0 Entry\n"); - - /* - * Hv_pci_bus_exit() calls hv_send_resource_released() - * to free up resources of its child devices. - * In the kdump kernel we need to set the - * wslot_res_allocated to 255 so it scans all child - * devices to release resources allocated in the - * normal kernel before panic happened. - */ - hbus->wslot_res_allocated = 255; - - ret = hv_pci_bus_exit(hdev, true); - - if (ret == 0) { - kfree(pkt); - goto enter_d0_retry; - } - dev_err(&hdev->device, - "Retrying D0 failed with ret %d\n", ret); - } - if (comp_pkt.completion_status < 0) { dev_err(&hdev->device, "PCI Pass-through VSP failed D0 Entry with status %x\n", @@ -3058,6 +3024,7 @@ static int hv_pci_probe(struct hv_device *hdev, struct hv_pcibus_device *hbus; u16 dom_req, dom; char *name; + bool enter_d0_retry = true; int ret; /* @@ -3178,11 +3145,47 @@ static int hv_pci_probe(struct hv_device *hdev, if (ret) goto free_fwnode; +retry: ret = hv_pci_query_relations(hdev); if (ret) goto free_irq_domain; ret = hv_pci_enter_d0(hdev); + /* + * In certain case (Kdump) the pci device of interest was + * not cleanly shut down and resource is still held on host + * side, the host could return invalid device status. + * We need to explicitly request host to release the resource + * and try to enter D0 again. + * Since the hv_pci_bus_exit() call releases structures + * of all its child devices, we need to start the retry from + * hv_pci_query_relations() call, requesting host to send + * the synchronous child device relations message before this + * information is needed in hv_send_resources_allocated() + * call later. + */ + if (ret == -EPROTO && enter_d0_retry) { + enter_d0_retry = false; + + dev_err(&hdev->device, "Retrying D0 Entry\n"); + + /* + * Hv_pci_bus_exit() calls hv_send_resources_released() + * to free up resources of its child devices. + * In the kdump kernel we need to set the + * wslot_res_allocated to 255 so it scans all child + * devices to release resources allocated in the + * normal kernel before panic happened. + */ + hbus->wslot_res_allocated = 255; + ret = hv_pci_bus_exit(hdev, true); + + if (ret == 0) + goto retry; + + dev_err(&hdev->device, + "Retrying D0 failed with ret %d\n", ret); + } if (ret) goto free_irq_domain; -- 2.25.1