From nobody Mon Feb 9 16:34:29 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=fail(p=none dis=none) header.from=arm.com ARC-Seal: i=1; a=rsa-sha256; t=1617875339; cv=none; d=zohomail.com; s=zohoarc; b=jdLFHyPUUSKVB4MwA0sypD3OWFqgV36Ldk0q8LZ8ZU5nCz9OR6vc2ADuZJz2ej40yNlNUSvKXy2Lb3N1PS0tPgBKnkZwKheDzKf086oWaSm75mEEsrvRf0cUp4gkGUmSPGR4+uoufQBNgJTP8mrr/apMZQzkXczQJmHD88nPfAM= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1617875339; h=Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:Message-ID:References:Sender:Subject:To; bh=BvFB2j6a8xFhw8wQgYNiTzp9vwUCZ12yT3GpmRc3Yts=; b=T7bBSSLFuCNoHJJ3QAYGoeA06pIAGlS62zA0vHCFjhR3/pHzQ2LUgce6iS86yARmtYpK0Or1AhuHa+TUgGd8+aFJgq8i+A3sXBFPaRP3gaWkgCqHxspC29AGt+Tkpx9kN52n+YrfUnsPPbrwnKNs5SiQwusG1ug7J40KzuVRyGc= ARC-Authentication-Results: i=1; mx.zohomail.com; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1617875339768442.8208680455489; Thu, 8 Apr 2021 02:48:59 -0700 (PDT) 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 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-Outflank-Mailman: Message body and most headers restored to incoming version 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> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" 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); } =20 + /* + * The variable max_init_domid is initialized with zero, so here i= t's + * very important to use the pre-increment operator to call + * domain_create() with a domid > 0. (domid =3D=3D 0 is reserved f= or Dom0) + */ d =3D 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_d= omctl) { if ( dom =3D=3D DOMID_FIRST_RESERVED ) dom =3D 1; - if ( is_free_domid(dom) ) + if ( (dom !=3D 0) && is_free_domid(dom) ) break; } =20 --=20 2.17.1