From patchwork Thu Aug 3 17:12:32 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Williamson X-Patchwork-Id: 13340359 X-Patchwork-Delegate: bhelgaas@google.com 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 7025FC001DB for ; Thu, 3 Aug 2023 17:13:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234248AbjHCRNd (ORCPT ); Thu, 3 Aug 2023 13:13:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36002 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233986AbjHCRNc (ORCPT ); Thu, 3 Aug 2023 13:13:32 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 41A651996 for ; Thu, 3 Aug 2023 10:12:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1691082765; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=/vpgghRxsUnXsE3t1IVpXcHF3Kir76KUPEpQodsytdc=; b=dRaxHXxtul4/nItsJLzNjooYsp0XppAQqvAhdgLuhLSJ46x4WIbws1L9yZAcUFMQUxGL0T xBJssd9us4Exw1rkqTTls/ynuo9maIRRV/Oe/YFMzOxWW+eVQ3m1kEQfuHEZ+D+e2GttoD LjM4F7I1luyUq6p/snakGxHuc5P0M+s= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-133-4v-D9ERYOlCrWtZJWtpaRg-1; Thu, 03 Aug 2023 13:12:43 -0400 X-MC-Unique: 4v-D9ERYOlCrWtZJWtpaRg-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 7423F8870D1; Thu, 3 Aug 2023 17:12:43 +0000 (UTC) Received: from omen.home.shazbot.org (unknown [10.22.10.229]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0D7894021C9; Thu, 3 Aug 2023 17:12:42 +0000 (UTC) From: Alex Williamson To: bhelgaas@google.com Cc: Alex Williamson , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, eric.auger@redhat.com Subject: [PATCH v2 1/2] PCI/VPD: Add runtime power management to sysfs interface Date: Thu, 3 Aug 2023 11:12:32 -0600 Message-Id: <20230803171233.3810944-2-alex.williamson@redhat.com> In-Reply-To: <20230803171233.3810944-1-alex.williamson@redhat.com> References: <20230803171233.3810944-1-alex.williamson@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Unlike default access to config space through sysfs, the vpd read and write function don't actively manage the runtime power management state of the device during access. Since commit 7ab5e10eda02 ("vfio/pci: Move the unused device into low power state with runtime PM"), the vfio-pci driver will use runtime power management and release unused devices to make use of low power states. Attempting to access VPD information in this low power state can result in incorrect information or kernel crashes depending on the system behavior. Wrap the vpd read/write bin attribute handlers in runtime PM and take into account the potential quirk to select the correct device to wake. Signed-off-by: Alex Williamson --- drivers/pci/vpd.c | 34 ++++++++++++++++++++++++++++++++-- 1 file changed, 32 insertions(+), 2 deletions(-) diff --git a/drivers/pci/vpd.c b/drivers/pci/vpd.c index a4fc4d0690fe..81217dd4789f 100644 --- a/drivers/pci/vpd.c +++ b/drivers/pci/vpd.c @@ -275,8 +275,23 @@ static ssize_t vpd_read(struct file *filp, struct kobject *kobj, size_t count) { struct pci_dev *dev = to_pci_dev(kobj_to_dev(kobj)); + struct pci_dev *vpd_dev = dev; + ssize_t ret; + + if (dev->dev_flags & PCI_DEV_FLAGS_VPD_REF_F0) { + vpd_dev = pci_get_func0_dev(dev); + if (!vpd_dev) + return -ENODEV; + } + + pci_config_pm_runtime_get(vpd_dev); + ret = pci_read_vpd(vpd_dev, off, count, buf); + pci_config_pm_runtime_put(vpd_dev); + + if (dev != vpd_dev) + pci_dev_put(vpd_dev); - return pci_read_vpd(dev, off, count, buf); + return ret; } static ssize_t vpd_write(struct file *filp, struct kobject *kobj, @@ -284,8 +299,23 @@ static ssize_t vpd_write(struct file *filp, struct kobject *kobj, size_t count) { struct pci_dev *dev = to_pci_dev(kobj_to_dev(kobj)); + struct pci_dev *vpd_dev = dev; + ssize_t ret; + + if (dev->dev_flags & PCI_DEV_FLAGS_VPD_REF_F0) { + vpd_dev = pci_get_func0_dev(dev); + if (!vpd_dev) + return -ENODEV; + } + + pci_config_pm_runtime_get(vpd_dev); + ret = pci_write_vpd(vpd_dev, off, count, buf); + pci_config_pm_runtime_put(vpd_dev); + + if (dev != vpd_dev) + pci_dev_put(vpd_dev); - return pci_write_vpd(dev, off, count, buf); + return ret; } static BIN_ATTR(vpd, 0600, vpd_read, vpd_write, 0); From patchwork Thu Aug 3 17:12:33 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Williamson X-Patchwork-Id: 13340361 X-Patchwork-Delegate: bhelgaas@google.com 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 1B455EB64DD for ; Thu, 3 Aug 2023 17:13:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234744AbjHCRNt (ORCPT ); Thu, 3 Aug 2023 13:13:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234648AbjHCRNl (ORCPT ); Thu, 3 Aug 2023 13:13:41 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2BAA32D64 for ; Thu, 3 Aug 2023 10:12:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1691082769; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=i4rNHvY4SBHV3GZTxHfmC+xvKSqh+4xt/RUop3WDQyg=; b=IunNoGDIKzFYTekbjV+BCbTpEe8fnqjTNeGXo6uw1mBGTcZKFg6TY3v/DEKlm9oUfyL1xb yXHjECVyidy66HMxd/celMUZUaCiM0tZqyT6cLhAYewsjDkhIjmHOUxrJBTCgEaQihZp8G 93+e1iPbiXFzZ61JnUrPzl4TfvnnSFs= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-241-it8Yw8nBOjSFtKIOfzR0Dg-1; Thu, 03 Aug 2023 13:12:45 -0400 X-MC-Unique: it8Yw8nBOjSFtKIOfzR0Dg-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 02099104458B; Thu, 3 Aug 2023 17:12:44 +0000 (UTC) Received: from omen.home.shazbot.org (unknown [10.22.10.229]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8C1004021CE; Thu, 3 Aug 2023 17:12:43 +0000 (UTC) From: Alex Williamson To: bhelgaas@google.com Cc: Alex Williamson , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, eric.auger@redhat.com Subject: [PATCH v2 2/2] PCI: Fix runtime PM race with PME polling Date: Thu, 3 Aug 2023 11:12:33 -0600 Message-Id: <20230803171233.3810944-3-alex.williamson@redhat.com> In-Reply-To: <20230803171233.3810944-1-alex.williamson@redhat.com> References: <20230803171233.3810944-1-alex.williamson@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Testing that a device is not currently in a low power state provides no guarantees that the device is not immenently transitioning to such a state. We need to increment the PM usage counter before accessing the device. Since we don't wish to wake the device for PME polling, do so only if the device is already active by using pm_runtime_get_if_active(). Signed-off-by: Alex Williamson --- drivers/pci/pci.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 60230da957e0..bc266f290b2c 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -2415,10 +2415,13 @@ static void pci_pme_list_scan(struct work_struct *work) mutex_lock(&pci_pme_list_mutex); list_for_each_entry_safe(pme_dev, n, &pci_pme_list, list) { - if (pme_dev->dev->pme_poll) { - struct pci_dev *bridge; + struct pci_dev *pdev = pme_dev->dev; + + if (pdev->pme_poll) { + struct pci_dev *bridge = pdev->bus->self; + struct device *dev = &pdev->dev; + int pm_status; - bridge = pme_dev->dev->bus->self; /* * If bridge is in low power state, the * configuration space of subordinate devices @@ -2426,14 +2429,20 @@ static void pci_pme_list_scan(struct work_struct *work) */ if (bridge && bridge->current_state != PCI_D0) continue; + /* - * If the device is in D3cold it should not be - * polled either. + * If the device is in a low power state it + * should not be polled either. */ - if (pme_dev->dev->current_state == PCI_D3cold) + pm_status = pm_runtime_get_if_active(dev, true); + if (!pm_status) continue; - pci_pme_wakeup(pme_dev->dev, NULL); + if (pdev->current_state != PCI_D3cold) + pci_pme_wakeup(pdev, NULL); + + if (pm_status > 0) + pm_runtime_put(dev); } else { list_del(&pme_dev->list); kfree(pme_dev);