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=-16.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 CD2D0C43214 for ; Wed, 11 Aug 2021 10:15:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A0DB5604AC for ; Wed, 11 Aug 2021 10:15:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236929AbhHKKPo (ORCPT ); Wed, 11 Aug 2021 06:15:44 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:30064 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237006AbhHKKPn (ORCPT ); Wed, 11 Aug 2021 06:15:43 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1628676918; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=BI5vzL+WQhFoK9aWbzI6xFmh8bAxjrkTftn2LSBR450=; b=MqCBjGubIxhb50NK3wtY+3uKigl+e9s3ijqwjXjB+/NBlEUitJZJehscCejH0kNHOJN7yN WmkjgHT4kuJD515LeUo/CzkEtFYGQNZlJ87pTruKuBeiL80J8GVoqo1nwa+rTV0yAq8qAa OXLOU03GH4N8KTi+E6eD8knWTmNBw5E= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-351-dPnXXrX1P8eVelAA0CPV2Q-1; Wed, 11 Aug 2021 06:15:15 -0400 X-MC-Unique: dPnXXrX1P8eVelAA0CPV2Q-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 885A9C73A0; Wed, 11 Aug 2021 10:15:11 +0000 (UTC) Received: from localhost (unknown [10.39.192.118]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 824F55D740; Wed, 11 Aug 2021 10:14:58 +0000 (UTC) From: Cornelia Huck To: Jason Gunthorpe , David Airlie , Tony Krowiak , Alex Williamson , Christian Borntraeger , Jonathan Corbet , Daniel Vetter , Diana Craciun , dri-devel@lists.freedesktop.org, Eric Auger , Eric Farman , Harald Freudenberger , Vasily Gorbik , Heiko Carstens , intel-gfx@lists.freedesktop.org, intel-gvt-dev@lists.freedesktop.org, Jani Nikula , Jason Herne , Joonas Lahtinen , kvm@vger.kernel.org, Kirti Wankhede , linux-doc@vger.kernel.org, linux-s390@vger.kernel.org, Matthew Rosato , Peter Oberparleiter , Halil Pasic , Rodrigo Vivi , Vineeth Vijayan , Zhi Wang Cc: "Raj, Ashok" , Christoph Hellwig , Leon Romanovsky , Max Gurtovoy , Yishai Hadas , Zhenyu Wang Subject: Re: [PATCH v4 09/14] vfio/pci: Change vfio_pci_try_bus_reset() to use the dev_set In-Reply-To: <9-v4-9ea22c5e6afb+1adf-vfio_reflck_jgg@nvidia.com> Organization: Red Hat GmbH References: <9-v4-9ea22c5e6afb+1adf-vfio_reflck_jgg@nvidia.com> User-Agent: Notmuch/0.32.1 (https://notmuchmail.org) Date: Wed, 11 Aug 2021 12:14:56 +0200 Message-ID: <87wnosuw2n.fsf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Thu, Aug 05 2021, Jason Gunthorpe wrote: > vfio_pci_try_bus_reset() is triggering a reset of the entire_dev set if > any device within it has accumulated a needs_reset. This reset can only be > done once all of the drivers operating the PCI devices to be reset are in > a known safe state. > > Make this clearer by directly operating on the dev_set instead of the > vfio_pci_device. Rename the function to vfio_pci_dev_set_try_reset(). > > Use the device list inside the dev_set to check that all drivers are in a > safe state instead of working backwards from the pci_device. > > The dev_set->lock directly prevents devices from joining/leaving the set, > or changing their state, which further implies the pci_device cannot > change drivers or that the vfio_device be freed, eliminating the need for > get/put's. > > If a pci_device to be reset is not in the dev_set then the reset cannot be > used as we can't know what the state of that driver is. Directly measure > this by checking that every pci_device is in the dev_set - which > effectively proves that VFIO drivers are attached to everything. > > Remove the odd interaction around vfio_pci_set_power_state() - have the > only caller avoid its redundant vfio_pci_set_power_state() instead of > avoiding it inside vfio_pci_dev_set_try_reset(). > > This restructuring corrects a call to pci_dev_driver() without holding the > device_lock() and removes a hard wiring to &vfio_pci_driver. > > Signed-off-by: Jason Gunthorpe > --- > drivers/vfio/pci/vfio_pci.c | 182 +++++++++++++++++------------------- > 1 file changed, 86 insertions(+), 96 deletions(-) Reviewed-by: Cornelia Huck