From patchwork Tue Oct 18 14:23:45 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Henry Wang X-Patchwork-Id: 13010692 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 56EECC4332F for ; Tue, 18 Oct 2022 14:24:14 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.425044.672806 (Exim 4.92) (envelope-from ) id 1oknVm-0006kL-BX; Tue, 18 Oct 2022 14:24:06 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 425044.672806; Tue, 18 Oct 2022 14:24:06 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1oknVm-0006kE-8e; Tue, 18 Oct 2022 14:24:06 +0000 Received: by outflank-mailman (input) for mailman id 425044; Tue, 18 Oct 2022 14:24:05 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1oknVl-0006SO-4J for xen-devel@lists.xenproject.org; Tue, 18 Oct 2022 14:24:05 +0000 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by se1-gles-flk1.inumbo.com (Halon) with ESMTP id 844bcd63-4ef0-11ed-8fd0-01056ac49cbb; Tue, 18 Oct 2022 16:24:03 +0200 (CEST) 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 D14D1113E; Tue, 18 Oct 2022 07:24:09 -0700 (PDT) Received: from entos-skylake.shanghai.arm.com (entos-skylake.shanghai.arm.com [10.169.212.207]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 90AF63F792; Tue, 18 Oct 2022 07:24:01 -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: 844bcd63-4ef0-11ed-8fd0-01056ac49cbb From: Henry Wang To: xen-devel@lists.xenproject.org Cc: Andrew Cooper , Stefano Stabellini , Julien Grall , Bertrand Marquis , Volodymyr Babchuk Subject: [PATCH v5 1/2] arm/p2m: Rework p2m_init() Date: Tue, 18 Oct 2022 14:23:45 +0000 Message-Id: <20221018142346.52272-2-Henry.Wang@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20221018142346.52272-1-Henry.Wang@arm.com> References: <20221018142346.52272-1-Henry.Wang@arm.com> From: Andrew Cooper p2m_init() is mostly trivial initialisation, but has two fallible operations which are on either side of the backpointer trigger for teardown to take actions. p2m_free_vmid() is idempotent with a failed p2m_alloc_vmid(), so rearrange p2m_init() to perform all trivial setup, then set the backpointer, then perform all fallible setup. This will simplify a future bugfix which needs to add a third fallible operation. No practical change. Signed-off-by: Andrew Cooper Reviewed-by: Julien Grall Reviewed-by: Bertrand Marquis --- v5 changes: - Correct typo in commit message, add reviewed-by from Arm maintainers. --- xen/arch/arm/p2m.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c index f17500ddf3..6826f63150 100644 --- a/xen/arch/arm/p2m.c +++ b/xen/arch/arm/p2m.c @@ -1754,7 +1754,7 @@ void p2m_final_teardown(struct domain *d) int p2m_init(struct domain *d) { struct p2m_domain *p2m = p2m_get_hostp2m(d); - int rc = 0; + int rc; unsigned int cpu; rwlock_init(&p2m->lock); @@ -1763,11 +1763,6 @@ int p2m_init(struct domain *d) INIT_PAGE_LIST_HEAD(&d->arch.paging.p2m_freelist); p2m->vmid = INVALID_VMID; - - rc = p2m_alloc_vmid(d); - if ( rc != 0 ) - return rc; - p2m->max_mapped_gfn = _gfn(0); p2m->lowest_mapped_gfn = _gfn(ULONG_MAX); @@ -1783,8 +1778,6 @@ int p2m_init(struct domain *d) p2m->clean_pte = is_iommu_enabled(d) && !iommu_has_feature(d, IOMMU_FEAT_COHERENT_WALK); - rc = p2m_alloc_table(d); - /* * Make sure that the type chosen to is able to store the an vCPU ID * between 0 and the maximum of virtual CPUS supported as long as @@ -1797,13 +1790,20 @@ int p2m_init(struct domain *d) p2m->last_vcpu_ran[cpu] = INVALID_VCPU_ID; /* - * Besides getting a domain when we only have the p2m in hand, - * the back pointer to domain is also used in p2m_teardown() - * as an end-of-initialization indicator. + * "Trivial" initialisation is now complete. Set the backpointer so + * p2m_teardown() and friends know to do something. */ p2m->domain = d; - return rc; + rc = p2m_alloc_vmid(d); + if ( rc ) + return rc; + + rc = p2m_alloc_table(d); + if ( rc ) + return rc; + + return 0; } /*