From patchwork Thu Aug 6 09:29:02 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Beulich X-Patchwork-Id: 11703043 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9E98B138C for ; Thu, 6 Aug 2020 12:01:13 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 854F722D05 for ; Thu, 6 Aug 2020 12:01:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 854F722D05 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1k3cCs-0002iG-St; Thu, 06 Aug 2020 09:29:02 +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 1k3cCr-0002i4-G8 for xen-devel@lists.xenproject.org; Thu, 06 Aug 2020 09:29:01 +0000 X-Inumbo-ID: c422bb10-8cea-499d-896f-e1bfa38e0de2 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id c422bb10-8cea-499d-896f-e1bfa38e0de2; Thu, 06 Aug 2020 09:29:00 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 5FD1FB66B; Thu, 6 Aug 2020 09:29:17 +0000 (UTC) Subject: [PATCH 3/3] x86: don't override INVALID_M2P_ENTRY with SHARED_M2P_ENTRY From: Jan Beulich To: "xen-devel@lists.xenproject.org" References: Message-ID: <1d83fd35-6ea5-289c-d8db-029c50957f85@suse.com> Date: Thu, 6 Aug 2020 11:29:02 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Andrew Cooper , Wei Liu , =?utf-8?q?Roger_Pau_Monn=C3=A9?= Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" While in most cases code ahead of the invocation of set_gpfn_from_mfn() deals with shared pages, at least in set_typed_p2m_entry() I can't spot such handling (it's entirely possible there's code missing there). Let's try to play safe and add an extra check. Signed-off-by: Jan Beulich --- a/xen/include/asm-x86/mm.h +++ b/xen/include/asm-x86/mm.h @@ -525,9 +525,14 @@ extern const unsigned int *const compat_ #endif /* CONFIG_PV32 */ #define _set_gpfn_from_mfn(mfn, pfn) ({ \ - struct domain *d = page_get_owner(mfn_to_page(_mfn(mfn))); \ - unsigned long entry = (d && (d == dom_cow)) ? \ - SHARED_M2P_ENTRY : (pfn); \ + unsigned long entry = (pfn); \ + if ( entry != INVALID_M2P_ENTRY ) \ + { \ + const struct domain *d; \ + d = page_get_owner(mfn_to_page(_mfn(mfn))); \ + if ( d && (d == dom_cow) ) \ + entry = SHARED_M2P_ENTRY; \ + } \ set_compat_m2p(mfn, (unsigned int)(entry)); \ machine_to_phys_mapping[mfn] = (entry); \ })