From patchwork Mon Feb 22 12:13:21 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 386757 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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, 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 2330AC433DB for ; Mon, 22 Feb 2021 12:18:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D53D164F14 for ; Mon, 22 Feb 2021 12:18:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230110AbhBVMSP (ORCPT ); Mon, 22 Feb 2021 07:18:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:45332 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230408AbhBVMQB (ORCPT ); Mon, 22 Feb 2021 07:16:01 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8912064E77; Mon, 22 Feb 2021 12:15:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1613996137; bh=zDWUu+4/o5DA+dicrmVNP3kLcE9gasVVeWw7NqqnmXc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=E/7kQSm1zB6d7stUH6vpqrghtyGCpIK9h1fXGHVWTvXkMKo9WOvF8OUzltPA2Boub JKMPBXNI+BAVzb56ynxH9tZnJkJiezYmR2izYj0saET0uaGr670Icoh+s4JD52OeSk Wf+i+UYZKfg5KiDIiwM2715TuFfhUWJ+M/xU8gKo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jan Beulich , Juergen Gross Subject: [PATCH 5.4 04/13] Xen/x86: dont bail early from clear_foreign_p2m_mapping() Date: Mon, 22 Feb 2021 13:13:21 +0100 Message-Id: <20210222121017.721219755@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210222121013.583922436@linuxfoundation.org> References: <20210222121013.583922436@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jan Beulich commit a35f2ef3b7376bfd0a57f7844bd7454389aae1fc upstream. Its sibling (set_foreign_p2m_mapping()) as well as the sibling of its only caller (gnttab_map_refs()) don't clean up after themselves in case of error. Higher level callers are expected to do so. However, in order for that to really clean up any partially set up state, the operation should not terminate upon encountering an entry in unexpected state. It is particularly relevant to notice here that set_foreign_p2m_mapping() would skip setting up a p2m entry if its grant mapping failed, but it would continue to set up further p2m entries as long as their mappings succeeded. Arguably down the road set_foreign_p2m_mapping() may want its page state related WARN_ON() also converted to an error return. This is part of XSA-361. Signed-off-by: Jan Beulich Cc: stable@vger.kernel.org Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman --- arch/x86/xen/p2m.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -754,17 +754,15 @@ int clear_foreign_p2m_mapping(struct gnt unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i])); unsigned long pfn = page_to_pfn(pages[i]); - if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) { + if (mfn != INVALID_P2M_ENTRY && (mfn & FOREIGN_FRAME_BIT)) + set_phys_to_machine(pfn, INVALID_P2M_ENTRY); + else ret = -EINVAL; - goto out; - } - - set_phys_to_machine(pfn, INVALID_P2M_ENTRY); } if (kunmap_ops) ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, - kunmap_ops, count); -out: + kunmap_ops, count) ?: ret; + return ret; } EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping);