From nobody Tue Feb 10 15:46:38 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=1618391687; cv=none; d=zohomail.com; s=zohoarc; b=BEiFYFj2D3RtFJMeDsLfcF3mtofyE+I5pwVF86oGeSIkp7eTwbBmRcAgX3+KfRatww+tY8HNyQWCAvwesyMKO7dUF30o9d/RJ0UVJtpGxOxz9z4+OHCF8QoXKnXmMaAjV6zqRjyoYM2L04ZZey6J4HMOkIDP6Ft4/9tXnEUDhUc= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1618391687; h=Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:Message-ID:References:Sender:Subject:To; bh=kEh9nnPRdfEmcbLlaJBAOR5nBlZa0mem9K6ZUgmQ1/E=; b=B2DsvHpubvkDQbgGwimyyNj7rB6H4SJ6yZ4lR6I6UgeGBLya5rmrWqKv2fBucV4IZXSk5uyBO9mLcRfef2c9VY4x4R/nvoLRa0jfZp8F53xCO8hCqrx8+w8mk+l4PQ5e4P6ZHDoDTAN5kutgnI9stNMv81V/svT1xTF385r+ghE= 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 1618391687459275.54960517183963; Wed, 14 Apr 2021 02:14:47 -0700 (PDT) Received: from list by lists.xenproject.org with outflank-mailman.110391.210718 (Exim 4.92) (envelope-from ) id 1lWbbV-0000f6-Ty; Wed, 14 Apr 2021 09:14:33 +0000 Received: by outflank-mailman (output) from mailman id 110391.210718; Wed, 14 Apr 2021 09:14:33 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lWbbV-0000ex-Q5; Wed, 14 Apr 2021 09:14:33 +0000 Received: by outflank-mailman (input) for mailman id 110391; Wed, 14 Apr 2021 09:14:32 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lWbbU-0000WW-8i for xen-devel@lists.xenproject.org; Wed, 14 Apr 2021 09:14:32 +0000 Received: from foss.arm.com (unknown [217.140.110.172]) by us1-rack-iad1.inumbo.com (Halon) with ESMTP id 0ce19af9-f6a3-457b-b6d4-ff9b5050315a; Wed, 14 Apr 2021 09:14:18 +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 461DF11B3; Wed, 14 Apr 2021 02:14:18 -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 605463F73B; Wed, 14 Apr 2021 02:14:17 -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: 0ce19af9-f6a3-457b-b6d4-ff9b5050315a From: Luca Fancellu To: xen-devel@lists.xenproject.org Cc: bertrand.marquis@arm.com, wei.chen@arm.com, Stefano Stabellini , Julien Grall , Volodymyr Babchuk Subject: [PATCH v4 3/4] xen/arm: Clarify how the domid is decided in create_domUs() Date: Wed, 14 Apr 2021 10:14:03 +0100 Message-Id: <20210414091404.14215-4-luca.fancellu@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210414091404.14215-1-luca.fancellu@arm.com> References: <20210414091404.14215-1-luca.fancellu@arm.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" This patch adds a comment in create_domUs() right before domain_create() to explain the importance of the pre-increment operator on the variable max_init_domid, to ensure that the domid 0 is allocated only during start_xen() function by the create_dom0() and not on any other possible code path to the domain_create() function. Signed-off-by: Luca Fancellu Acked-by: Julien Grall Reviewed-by: Bertrand Marquis --- Changes in v4: - Change to the commit title Changes in v3: - removed check introduced in v2. --- xen/arch/arm/domain_build.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c index 359957dc1b..b1d7b9849f 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)); --=20 2.17.1