From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: ACJfBosDHlaa/KGMt2raZWsj2olj4jAIpeM64kddIhX8gNBzhg5EHxG9MkUdE6Nd4cy8Pjmeq1Rs ARC-Seal: i=1; a=rsa-sha256; t=1516350458; cv=none; d=google.com; s=arc-20160816; b=zE3w/yZD9QnopWYyPh3e5OLRiS3C/IgM6UXOG5/m0y6m1kRdv/hVAgJHBZ0zyn4P3O KzXy+nFvT0MABheP3gfJO/dvyGcmIiucywVPFYRUn8KohojLEE5J2ubpQN9SP51oAKut t+Yu9fk1muNWmMnZqKnJnlNY1R2p7jCBqtIpjBMMVtKbaGcb+JH7oRVXA4dKXEBAbDIC pgh16G2e/qtHLIQkWtFU1L8Z/6A0pm6hVAmh9rVT4y3WsQOXoGgA+Q6cxOgW0rmKdOio fSFkMRaqzH3XPpHlQXfM8oCgnXS3cQiArve447ETsPRDIcg3YdyOcdCk5gHoTf77qh05 Wcuw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=message-id:content-transfer-encoding:in-reply-to:mime-version :user-agent:date:from:references:cc:to:subject :arc-authentication-results; bh=23bEKoFcfy9Cu1++0v8ag3HmPyTQvyJkEkROmy+KrmQ=; b=hVhtKPhiGNNzt/GXQGvTJ1cmGeO8a9nnFmUs2AT+qzkkhfO0z3904BSR1lTF+0CQcN sDZ4aynmLQZOOnRmo6/r1PIf7eT0n2qxRnKT2Jzo3ST8h1EPZK6uC697SwnqQxjWkMk8 kp6SCWBbRy/XUnUbIH9yKxIPQH87L2xmpt0IBTKcXKZ6RoXlrAOUso0TbLcgs3GwswlQ BaQFJU8f906GCeaqAWZdIxclBzQPs7ojd2Ag40Y0Kji1QFONELwVcnSLn3zX7cS4UZ0D aYrWFy2zx3B2zJeNqr8dINiF/0zpDE5LTAMi24URCsuNO1+YMy26RFu1hK1UchYQHkmN I69g== ARC-Authentication-Results: i=1; mx.google.com; spf=neutral (google.com: 148.163.156.1 is neither permitted nor denied by best guess record for domain of haoqf@linux.vnet.ibm.com) smtp.mailfrom=haoqf@linux.vnet.ibm.com; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=ibm.com Authentication-Results: mx.google.com; spf=neutral (google.com: 148.163.156.1 is neither permitted nor denied by best guess record for domain of haoqf@linux.vnet.ibm.com) smtp.mailfrom=haoqf@linux.vnet.ibm.com; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=ibm.com Subject: Re: [PATCH 6/6] s390: scrub registers on kernel entry and KVM exit To: Christian Borntraeger , Martin Schwidefsky , linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org Cc: Heiko Carstens , Paolo Bonzini , Cornelia Huck , Greg Kroah-Hartman , Jon Masters , Marcus Meissner , Jiri Kosina References: <1516182519-10623-1-git-send-email-schwidefsky@de.ibm.com> <1516182519-10623-7-git-send-email-schwidefsky@de.ibm.com> From: QingFeng Hao Date: Fri, 19 Jan 2018 16:27:08 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=gbk; format=flowed Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 18011908-0036-0000-0000-000002AF1D1D X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00008405; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000247; SDB=6.00977191; UDB=6.00495433; IPR=6.00757113; BA=6.00005782; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00019125; XFM=3.00000015; UTC=2018-01-19 08:27:34 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18011908-0037-0000-0000-0000430B3D03 Message-Id: <34660999-606f-0cab-6630-4116ad833c77@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-01-19_03:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1801190108 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1589832618248203925?= X-GMAIL-MSGID: =?utf-8?q?1590008698034194853?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: ÔÚ 2018/1/19 15:57, Christian Borntraeger дµÀ: > > On 01/19/2018 07:29 AM, QingFeng Hao wrote: >> >> ÔÚ 2018/1/17 17:48, Martin Schwidefsky дµÀ: >>> Clear all user space registers on entry to the kernel and all KVM guest >>> registers on KVM guest exit if the register does not contain either a >>> parameter or a result value. >> I am not sure if I understand this but it will be safer? > It ist similar to commit 0cb5b30698fd ("kvm: vmx: Scrub hardware GPRs at VM-exit"). > The idea is to minimize potential payload channels. Got it! thanks for your explanation! > >> And can we abstract the operations to be a macro like CLEAR_REG_7? > No, please. > xgr %r7,%r7 > is absolutely clear what it does, a MACRO often is not. nod, this makes sense! -- Regards QingFeng Hao