From patchwork Thu Apr 8 09:48:17 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luca Fancellu X-Patchwork-Id: 12190499 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 A5A94C43461 for ; Thu, 8 Apr 2021 09:48:52 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 41ABA61154 for ; Thu, 8 Apr 2021 09:48:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 41ABA61154 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.107107.204754 (Exim 4.92) (envelope-from ) id 1lURHI-0004gt-A2; Thu, 08 Apr 2021 09:48:44 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 107107.204754; Thu, 08 Apr 2021 09:48:44 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lURHI-0004ge-4G; Thu, 08 Apr 2021 09:48:44 +0000 Received: by outflank-mailman (input) for mailman id 107107; Thu, 08 Apr 2021 09:48:42 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lURHG-0004WM-PL for xen-devel@lists.xenproject.org; Thu, 08 Apr 2021 09:48:42 +0000 Received: from foss.arm.com (unknown [217.140.110.172]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTP id 01058904-8bb3-44bc-a1ec-534ffde50552; Thu, 08 Apr 2021 09:48:34 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4D38711B3; Thu, 8 Apr 2021 02:48:34 -0700 (PDT) Received: from e125770.cambridge.arm.com (e125770.cambridge.arm.com [10.1.197.16]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D4EE73F694; Thu, 8 Apr 2021 02:48:32 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 01058904-8bb3-44bc-a1ec-534ffde50552 From: Luca Fancellu To: xen-devel@lists.xenproject.org Cc: bertrand.marquis@arm.com, wei.chen@arm.com, Stefano Stabellini , Julien Grall , Volodymyr Babchuk , Andrew Cooper , George Dunlap , Ian Jackson , Jan Beulich , Wei Liu Subject: [PATCH v2 3/4] xen/arm: Reserve domid 0 for Dom0 Date: Thu, 8 Apr 2021 10:48:17 +0100 Message-Id: <20210408094818.8173-4-luca.fancellu@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210408094818.8173-1-luca.fancellu@arm.com> References: <20210408094818.8173-1-luca.fancellu@arm.com> This patch ensure that the domid 0 is allocated only during start_xen() function by the create_dom0(). Add a comment in create_domUs() right before domain_create() to explain the importance of the pre-increment operator on the variable max_init_domid. Add an additional check in do_domctl() to make sure domid 0 is never used when calling domain_create(). Signed-off-by: Luca Fancellu --- xen/arch/arm/domain_build.c | 5 +++++ xen/common/domctl.c | 2 +- 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c index d7c9c7f4d1..3fa5c8e54c 100644 --- a/xen/arch/arm/domain_build.c +++ b/xen/arch/arm/domain_build.c @@ -2508,6 +2508,11 @@ void __init create_domUs(void) GUEST_VPL011_SPI - 32 + 1); } + /* + * The variable max_init_domid is initialized with zero, so here it's + * very important to use the pre-increment operator to call + * domain_create() with a domid > 0. (domid == 0 is reserved for Dom0) + */ d = domain_create(++max_init_domid, &d_cfg, false); if ( IS_ERR(d) ) panic("Error creating domain %s\n", dt_node_name(node)); diff --git a/xen/common/domctl.c b/xen/common/domctl.c index af044e2eda..8258f157ef 100644 --- a/xen/common/domctl.c +++ b/xen/common/domctl.c @@ -419,7 +419,7 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl) { if ( dom == DOMID_FIRST_RESERVED ) dom = 1; - if ( is_free_domid(dom) ) + if ( (dom != 0) && is_free_domid(dom) ) break; }