From patchwork Tue Jan 28 13:17:51 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Jan Beulich X-Patchwork-Id: 11354251 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 499D21395 for ; Tue, 28 Jan 2020 13:18:44 +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 3027A20CC7 for ; Tue, 28 Jan 2020 13:18:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3027A20CC7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none 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 4.89) (envelope-from ) id 1iwQkb-0003eo-Vx; Tue, 28 Jan 2020 13:17:53 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1iwQka-0003ei-DS for xen-devel@lists.xenproject.org; Tue, 28 Jan 2020 13:17:52 +0000 X-Inumbo-ID: 961132aa-41d0-11ea-8396-bc764e2007e4 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 961132aa-41d0-11ea-8396-bc764e2007e4; Tue, 28 Jan 2020 13:17:52 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 4111BAD46; Tue, 28 Jan 2020 13:17:51 +0000 (UTC) To: "xen-devel@lists.xenproject.org" From: Jan Beulich Message-ID: <4c53200e-f571-a3de-cb25-6548a40bbb94@suse.com> Date: Tue, 28 Jan 2020 14:17:51 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.4.2 MIME-Version: 1.0 Content-Language: en-US Subject: [Xen-devel] [PATCH] x86/HVM: fix PM timer I/O port range version check X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 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" XOR-ing two arbitrary non-equal values may produce 1 even if both values are different from both 0 and 1 (2 and 3 would fit, for example). Use OR instead, which together with the earlier bailing upon finding "version == old_version" achieves the intended effect. Fixes: f0ad21c499f7 ("x86 hvm: Introduce pmtimer_change_ioport and HVM_PARAM_ACPI_IOPORTS_LOCATION") Signed-off-by: Jan Beulich Reviewed-by: Roger Pau Monné --- a/xen/arch/x86/hvm/pmtimer.c +++ b/xen/arch/x86/hvm/pmtimer.c @@ -326,7 +326,7 @@ int pmtimer_change_ioport(struct domain return 0; /* Only allow changes between versions 0 and 1. */ - if ( (version ^ old_version) != 1 ) + if ( (version | old_version) != 1 ) return -EINVAL; if ( version == 1 )