From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: ACJfBousQmYwTtpykNzBJoRdU/tpRbaAtFTTjlth99MpxbKidwaaS4BJn5o3p1dsqAdfMggNkDn/ ARC-Seal: i=1; a=rsa-sha256; t=1516343393; cv=none; d=google.com; s=arc-20160816; b=XJEVFYI8LeUoK9T4PsA8Mx88+CRA32scRkZEzC9Ocm11YOsiBiXik3JtPA+E3zCAnF POG2eP7WmQEcl2FQNyvMpBRu9rDmmaKgupDFFlNE9g1N9NYmUjUn+j2rsDB1FrpSB54p HooZVkuIm8A07b4qfzpQ15K3Gk9M8hv8JjyBf6BYXx5UbKtl6XETmPt7OLs5T8ICSrWM gFago+pEgE9AikI6qGZ1IZEJ1HNJwCxRch+yAHNoFMvzFrnFtfXemZ/Mylk1yPlwRNJH 3B12atBx5IFlSHkj2RCG/6IGOFn2wTDOiGmvuDdiZ6wcIZ5g3lmkvO2SIcX1MDy0hi0K jfug== 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=sQQnVa3alaOVdhzzK7p62/gecrS0vLh6gbeyH6X+7hs=; b=xc340/dSzklUv5gkr3nWPN7k+nsDgMBVDyCM20XDRtCfZ1BRtFwxbQnm3RNwW1Ak1m ld1/qh7d3S5JUrz/R+UL/b1gLIcsr17mtkcKIjwnEYLh7U4UXZVmUFeIFs7rDQEK1Zhz pX2WCFdCL6HwUlM8Ie43Il7D17JhT4Q19Vdicz6W/YXmOpCGzz75lgm/63Y2xJ7ZYWYR vD4pbohn2PRFZELm5vCp/5fiIGGWYaqgbdL8tUwJ3mneJK6rEJGKqvhN6a1Uyv9JcpKz WRvrQmkSRgn/sFGHROmQj4JAOyE6nzWCTRtoTDkQq3bZT+E3tDNEypYgKqeuRfAztxZI cpZg== 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: 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 14:29:20 +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: <1516182519-10623-7-git-send-email-schwidefsky@de.ibm.com> Content-Type: text/plain; charset=gbk; format=flowed Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 18011906-0024-0000-0000-00000314C9C0 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00008405; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000247; SDB=6.00977152; UDB=6.00495409; IPR=6.00757074; 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=3.00019122; XFM=3.00000015; UTC=2018-01-19 06:29:45 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18011906-0025-0000-0000-000046B078AA Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-01-19_02:,, 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-1801190081 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1589832618248203925?= X-GMAIL-MSGID: =?utf-8?q?1590001290173260186?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 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? And can we abstract the operations to be a macro like CLEAR_REG_7? Thanks > > Suggested-by: Christian Borntraeger > Reviewed-by: Christian Borntraeger > Signed-off-by: Martin Schwidefsky > --- > arch/s390/kernel/entry.S | 41 +++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 41 insertions(+) > > diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S > index 2a22c03..47227d3 100644 > --- a/arch/s390/kernel/entry.S > +++ b/arch/s390/kernel/entry.S > @@ -322,6 +322,12 @@ ENTRY(sie64a) > sie_exit: > lg %r14,__SF_EMPTY+8(%r15) # load guest register save area > stmg %r0,%r13,0(%r14) # save guest gprs 0-13 > + xgr %r0,%r0 # clear guest registers > + xgr %r1,%r1 > + xgr %r2,%r2 > + xgr %r3,%r3 > + xgr %r4,%r4 > + xgr %r5,%r5 > lmg %r6,%r14,__SF_GPRS(%r15) # restore kernel registers > lg %r2,__SF_EMPTY+16(%r15) # return exit reason code > br %r14 > @@ -358,6 +364,7 @@ ENTRY(system_call) > UPDATE_VTIME %r8,%r9,__LC_SYNC_ENTER_TIMER > BPENTER __TI_flags(%r12),_TIF_NOBP > stmg %r0,%r7,__PT_R0(%r11) > + xgr %r0,%r0 > mvc __PT_R8(64,%r11),__LC_SAVE_AREA_SYNC > mvc __PT_PSW(16,%r11),__LC_SVC_OLD_PSW > mvc __PT_INT_CODE(4,%r11),__LC_SVC_ILC > @@ -640,6 +647,14 @@ ENTRY(pgm_check_handler) > 4: lgr %r13,%r11 > la %r11,STACK_FRAME_OVERHEAD(%r15) > stmg %r0,%r7,__PT_R0(%r11) > + xgr %r0,%r0 # clear user space registers > + xgr %r1,%r1 > + xgr %r2,%r2 > + xgr %r3,%r3 > + xgr %r4,%r4 > + xgr %r5,%r5 > + xgr %r6,%r6 > + xgr %r7,%r7 > mvc __PT_R8(64,%r11),__LC_SAVE_AREA_SYNC > stmg %r8,%r9,__PT_PSW(%r11) > mvc __PT_INT_CODE(4,%r11),__LC_PGM_ILC > @@ -706,6 +721,15 @@ ENTRY(io_int_handler) > lmg %r8,%r9,__LC_IO_OLD_PSW > SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_ENTER_TIMER > stmg %r0,%r7,__PT_R0(%r11) > + xgr %r0,%r0 # clear user space registers > + xgr %r1,%r1 > + xgr %r2,%r2 > + xgr %r3,%r3 > + xgr %r4,%r4 > + xgr %r5,%r5 > + xgr %r6,%r6 > + xgr %r7,%r7 > + xgr %r10,%r10 > mvc __PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC > stmg %r8,%r9,__PT_PSW(%r11) > mvc __PT_INT_CODE(12,%r11),__LC_SUBCHANNEL_ID > @@ -924,6 +948,15 @@ ENTRY(ext_int_handler) > lmg %r8,%r9,__LC_EXT_OLD_PSW > SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_ENTER_TIMER > stmg %r0,%r7,__PT_R0(%r11) > + xgr %r0,%r0 # clear user space registers > + xgr %r1,%r1 > + xgr %r2,%r2 > + xgr %r3,%r3 > + xgr %r4,%r4 > + xgr %r5,%r5 > + xgr %r6,%r6 > + xgr %r7,%r7 > + xgr %r10,%r10 > mvc __PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC > stmg %r8,%r9,__PT_PSW(%r11) > lghi %r1,__LC_EXT_PARAMS2 > @@ -1133,6 +1166,14 @@ ENTRY(mcck_int_handler) > .Lmcck_skip: > lghi %r14,__LC_GPREGS_SAVE_AREA+64 > stmg %r0,%r7,__PT_R0(%r11) > + xgr %r0,%r0 # clear user space registers > + xgr %r2,%r2 > + xgr %r3,%r3 > + xgr %r4,%r4 > + xgr %r5,%r5 > + xgr %r6,%r6 > + xgr %r7,%r7 > + xgr %r10,%r10 > mvc __PT_R8(64,%r11),0(%r14) > stmg %r8,%r9,__PT_PSW(%r11) > xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11) -- Regards QingFeng Hao