From mboxrd@z Thu Jan 1 00:00:00 1970 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=unavailable 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 5EEC2C433DB for ; Mon, 22 Feb 2021 13:46:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2893764E74 for ; Mon, 22 Feb 2021 13:46:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231693AbhBVNpg (ORCPT ); Mon, 22 Feb 2021 08:45:36 -0500 Received: from mail.kernel.org ([198.145.29.99]:56570 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231401AbhBVMns (ORCPT ); Mon, 22 Feb 2021 07:43:48 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7F6F964F46; Mon, 22 Feb 2021 12:40:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1613997638; bh=DqPe8wRoULr4RNVGmXD6I2OYreAZrv8WcbdJLjc/IFQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Wfrp7Ps/GOxLFGwx7BRx7D04BFEs5Lx0MwNgfvI7zC+UNrp6Z0zeI0gIAvpiHXnuU rc+N1K7fYpLrzAtntxRP570mjyJ+tTHTHoH/Aq6jKWyhfr2YPwlmrrNfOExsFHwkp2 xqgZgTk3Z7QldwT8WuJzIlESM0DR2uXmynzR5RV8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jan Beulich , Juergen Gross Subject: [PATCH 4.4 25/35] Xen/x86: dont bail early from clear_foreign_p2m_mapping() Date: Mon, 22 Feb 2021 13:36:21 +0100 Message-Id: <20210222121021.674569025@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210222121013.581198717@linuxfoundation.org> References: <20210222121013.581198717@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 @@ -763,17 +763,15 @@ 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);