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=-9.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 96884C433E2 for ; Mon, 14 Sep 2020 12:24:18 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 23CD2222EA for ; Mon, 14 Sep 2020 12:24:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="hnLfCmcs" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 23CD2222EA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:43788 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kHnWr-00064E-4u for qemu-devel@archiver.kernel.org; Mon, 14 Sep 2020 08:24:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:34734) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHnUs-0004WF-Qq for qemu-devel@nongnu.org; Mon, 14 Sep 2020 08:22:14 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:40385 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kHnUq-0007J3-MP for qemu-devel@nongnu.org; Mon, 14 Sep 2020 08:22:14 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1600086131; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=x6dmFNjjqKE0UMS6LNjbuT8z9ovZVRpuWGq0pjmwLAE=; b=hnLfCmcsICW7Z8VESh/iLO9YNBQ/0xTaZ4I9FJWKwQhHVzPRrHSP4qt56aujrgcisRxCbt 8Pzn3r/kcNNVMVLIFW0QiGlGUh2MxDRN5phptI1FfBLLooARRLtpKw3/k15k3ZHzeDnAyX BxjgML/zQyuhH42gxsJT4I4b+rv5RR4= 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-83-kUWo7Uk1OZy8vWZk4b-pYw-1; Mon, 14 Sep 2020 08:22:05 -0400 X-MC-Unique: kUWo7Uk1OZy8vWZk4b-pYw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 775F010066FA; Mon, 14 Sep 2020 12:22:04 +0000 (UTC) Received: from localhost (unknown [10.43.2.114]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8AEBD19C4F; Mon, 14 Sep 2020 12:21:57 +0000 (UTC) Date: Mon, 14 Sep 2020 14:21:56 +0200 From: Igor Mammedov To: Ani Sinha Subject: Re: [PATCH 4/9] Fix a gap where acpi_pcihp_find_hotplug_bus() returns a non-hotpluggable bus Message-ID: <20200914142156.4835cfd1@redhat.com> In-Reply-To: <20200911180755.28409-4-ani@anisinha.ca> References: <20200911180755.28409-1-ani@anisinha.ca> <20200911180755.28409-4-ani@anisinha.ca> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=imammedo@redhat.com X-Mimecast-Spam-Score: 0.003 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=207.211.31.120; envelope-from=imammedo@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/14 01:36:47 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -38 X-Spam_score: -3.9 X-Spam_bar: --- X-Spam_report: (-3.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.792, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: jusual@redhat.com, qemu-devel@nongnu.org, "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, 11 Sep 2020 23:37:50 +0530 Ani Sinha wrote: > When ACPI hotplug for the root bus is disabled, the bsel property for that > bus is not set. Please see the following commit: > > 3d7e78aa7777f ("Introduce a new flag for i440fx to disable PCI hotplug on the root bus"). > > As a result, when acpi_pcihp_find_hotplug_bus() is called > with bsel set to 0, it may return the root bus. This can cause devices attached to > the root bus to get hot-unplugged if the user issues the following set of commmands: > > outl 0xae10 0 > outl 0xae08 your_slot > > Thanks to Julia for pointing this out here: > https://www.mail-archive.com/qemu-devel@nongnu.org/msg734548.html > > In this patch, we fix the issue in this function by checking if the bus which is > returned by the function is actually hotpluggable. If not, we simply return NULL. > This avoids the scenario where we were returning a non-hotpluggable bus. > > This patch is based off of tag v5.10 I'd put this type of comment below --- or in cover letter so it won't be committed into git history > Signed-off-by: Ani Sinha Reviewed-by: Igor Mammedov > --- > hw/acpi/pcihp.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c > index 39b1f74442..32ae8b2c0a 100644 > --- a/hw/acpi/pcihp.c > +++ b/hw/acpi/pcihp.c > @@ -147,6 +147,21 @@ static PCIBus *acpi_pcihp_find_hotplug_bus(AcpiPciHpState *s, int bsel) > if (!bsel && !find.bus) { > find.bus = s->root; > } > + > + /* > + * Check if find.bus is actually hotpluggable. If bsel is set to > + * NULL for example on the root bus in order to make it > + * non-hotpluggable, find.bus will match the root bus when bsel > + * is 0. See acpi_pcihp_test_hotplug_bus() above. Since the > + * bus is not hotpluggable however, we should not select the bus. > + * Instead, we should set find.bus to NULL in that case. In the check > + * below, we generalize this case for all buses, not just the root bus. > + * The callers of this function check for a null return value and > + * handle them appropriately. > + */ > + if (find.bus && !qbus_is_hotpluggable(BUS(find.bus))) { > + find.bus = NULL; > + } > return find.bus; > } >