From patchwork Wed Sep 16 06:13:28 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ani Sinha X-Patchwork-Id: 11778991 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 20819112E for ; Wed, 16 Sep 2020 06:18:49 +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 C5CAD208E4 for ; Wed, 16 Sep 2020 06:18:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=anisinha-ca.20150623.gappssmtp.com header.i=@anisinha-ca.20150623.gappssmtp.com header.b="CtAL8nJL" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C5CAD208E4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=anisinha.ca Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:53358 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kIQmF-0007Na-OX for patchwork-qemu-devel@patchwork.kernel.org; Wed, 16 Sep 2020 02:18:47 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59436) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kIQhp-0001hW-Fi for qemu-devel@nongnu.org; Wed, 16 Sep 2020 02:14:13 -0400 Received: from mail-pl1-x643.google.com ([2607:f8b0:4864:20::643]:38372) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kIQhn-0005lC-FI for qemu-devel@nongnu.org; Wed, 16 Sep 2020 02:14:13 -0400 Received: by mail-pl1-x643.google.com with SMTP id c3so2624572plz.5 for ; Tue, 15 Sep 2020 23:14:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=anisinha-ca.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=tX9XLbRzvavvjyMGPc0edB0FeNbRKcsKHFO3wqmL2TY=; b=CtAL8nJLWNFsdH7iXEqobHGm3zrCOJZYbETTxmud7Rnuf/1hcBvSnjWiv9EL8V72pz mFDduJd/FDvru8WvMnSdm9dLMLjSouH6mbG/4EKjc9o4nta56Xh9pFgMizWpgXIiTrwO UawBrCxo3hgpVT9pc87WBjZ0HKr4eRfPDp5GEUZvo/BacJxgc5JmItSLXs6K/ugw4jHk M8QE5O2/ugT7oQCqjsCoues4c++gBfWuckSWF+S2SErxOCbjUKLfpEOpgmMWUCkNZY0W tUKFK1v/a3eZA5W1VKXLwihSvNM5RD0tIWtY5AixlilHPPw79qJecRQtIsfhoghcVbUf 1Png== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=tX9XLbRzvavvjyMGPc0edB0FeNbRKcsKHFO3wqmL2TY=; b=a0/dKNFJ4GMw82F4xfoahyvoM5z0aLmuy6MezIEgoEIv+bIm/XsSUAV0Bw5IPzS3kI /8ibfSD6C6nbmhPtA5o26oMDhZTBau8rAS0XcBt7aje459/kzX995xiPu3BOY8SsJMpm 3p507iURloyYDSZW9YH8WsbteT8wXOew2m6NG3QIuIMEYSoHgw/phPOa8+TEg+ixm2CV 3qeqGkJxZyck/Bmdu50lOXY0hIju67r7r9L2ysWca0cDJQ0YXFSPD9tnGVvkiHx5nmgC cwBC/1d2fDJyBRTqhZSP1PuPSh2BV81vNSCMRjlWIeBTIQf8diwuB4JAZ+4uHqwa/NL5 5NUw== X-Gm-Message-State: AOAM531xFuxZQdVh0ECzXrE0Z5w9nduVxVaH6Qu8lr8ggeRxzQHk7AOV gu97F7jqAYtlAbyQ4ZemJh7RYvZfAkTQSOfp X-Google-Smtp-Source: ABdhPJziqO7SF8PYcMidjTSWzmqJ2Byf0cFS5hDjHliajpEiCSIpuL4KXrHtJswzhGcf9ytZecwQeA== X-Received: by 2002:a17:902:8c8c:b029:d1:cc21:9056 with SMTP id t12-20020a1709028c8cb02900d1cc219056mr11302303plo.22.1600236848628; Tue, 15 Sep 2020 23:14:08 -0700 (PDT) Received: from localhost.localdomain ([203.163.234.244]) by smtp.googlemail.com with ESMTPSA id c20sm583164pfc.209.2020.09.15.23.14.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Sep 2020 23:14:07 -0700 (PDT) From: Ani Sinha To: qemu-devel@nongnu.org Subject: [PATCH v4 04/11] Fix a gap where acpi_pcihp_find_hotplug_bus() returns a non-hotpluggable bus Date: Wed, 16 Sep 2020 11:43:28 +0530 Message-Id: <20200916061335.14045-5-ani@anisinha.ca> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200916061335.14045-1-ani@anisinha.ca> References: <20200916061335.14045-1-ani@anisinha.ca> Received-SPF: none client-ip=2607:f8b0:4864:20::643; envelope-from=ani@anisinha.ca; helo=mail-pl1-x643.google.com X-detected-operating-system: by eggs.gnu.org: No matching host in p0f cache. That's all we know. X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_NONE=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: Eduardo Habkost , "Michael S. Tsirkin" , jusual@redhat.com, =?utf-8?q?Philipp?= =?utf-8?q?e_Mathieu-Daud=C3=A9?= , Aleksandar Markovic , Paolo Bonzini , Ani Sinha , Igor Mammedov , Aurelien Jarno , Richard Henderson Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" 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. Signed-off-by: Ani Sinha Reviewed-by: Igor Mammedov --- hw/acpi/pcihp.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) change log: v1: initial patch v4: commit log updated as per suggestion. 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; }