From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1695C477999; Thu, 6 Aug 2026 14:39:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.158.5 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786027176; cv=none; b=NmQ+hpRiu2nLApLPCw3QmcVPjeuGn3p9p2yBr67wLod3/E9pt6quoYRtFeHKrxhKplTDM5eYWNhkcVd5ea3YPKK7oN1BNfLmsgqqLS2T9CTEjJH2mHoIre3Q2O4vmvKbAiUN/DiRgnVYgY7HI1uCPAQLmCXAjAaAcGyBWx8EXuQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786027176; c=relaxed/simple; bh=9F/Uq/xyvj96/U1grsSBt1mIaNmrxXUYd1WuQpsJoTU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ptWekgSuiGM6G7eAFE31RaYlYUJhsysNn7IZjzDRjs/kzKx5DdLzdHY21POkvi433aiLhoojj4IdP9MUdoCn7xc+5mAmVUPMaBIl9bjJp46pNZ8zstjPSGbR0wQQ+NCuP/b3JGQUpOU3yy89AY2nGN8g3akEKXiI5OlYODddzBU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=shmZvp0t; arc=none smtp.client-ip=148.163.158.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="shmZvp0t" Received: from pps.filterd (m0356516.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 676DhH0E994756; Thu, 6 Aug 2026 14:39:32 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=pp1; bh=vLbzfK Ycs8AFnqn49rygHRdKSEov+6B+VOA7S1PSy4c=; b=shmZvp0thz48LonFCRhb3x mpcAg78h647KCuW2uXCuRZTis/bUdz8A0asiab6jUF4BXsVloLGCjJ+rT3FsQSFj IZncFXRwyTO59xc41381dRxGMR4pvQNYGZfvCBbgHsZNh2ZpJd15PQ/9kfi3kmSR B/t+ulMkIibCksN0Zn0Bty3TEgD9F3FW6gLz6uZa1RDdsmhSK7prttjmgLGbIBR8 sROQRYbi9zHxf/QY569Xa2EK+5KlSB+2FSAWwcGKTFUpWwhxEZHXAU8D52+g4F37 7/m+2rwGnOfxFxhggWKHFhJ6yyHn9I5+hi0HZX96H9kA7TSlYoIpzp++YMMECZYA == Received: from ppma12.dal12v.mail.ibm.com (dc.9e.1632.ip4.static.sl-reverse.com [50.22.158.220]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4fs67j0e1x-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 06 Aug 2026 14:39:31 +0000 (GMT) Received: from pps.filterd (ppma12.dal12v.mail.ibm.com [127.0.0.1]) by ppma12.dal12v.mail.ibm.com (8.18.1.7/8.18.1.7) with ESMTP id 676EQIi8010671; Thu, 6 Aug 2026 14:39:30 GMT Received: from smtprelay01.fra02v.mail.ibm.com ([9.218.2.227]) by ppma12.dal12v.mail.ibm.com (PPS) with ESMTPS id 4fsu4qups1-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 06 Aug 2026 14:39:30 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (smtpav06.fra02v.mail.ibm.com [10.20.54.105]) by smtprelay01.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 676EdRgP28967184 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 6 Aug 2026 14:39:27 GMT Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3568A20049; Thu, 6 Aug 2026 14:39:27 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DDCC320040; Thu, 6 Aug 2026 14:39:26 +0000 (GMT) Received: from [9.224.77.173] (unknown [9.224.77.173]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTP; Thu, 6 Aug 2026 14:39:26 +0000 (GMT) Message-ID: Date: Thu, 6 Aug 2026 16:39:26 +0200 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/1] KVM: s390: Fix memory corruption by not reinjecting CK machine checks To: Claudio Imbrenda Cc: Janosch Frank , KVM , David Hildenbrand , linux-s390 , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Sven Schnelle References: <20260806125241.210170-1-borntraeger@linux.ibm.com> <20260806125241.210170-2-borntraeger@linux.ibm.com> <20260806163739.7b1ee8fd@p-imbrenda> Content-Language: en-US From: Christian Borntraeger In-Reply-To: <20260806163739.7b1ee8fd@p-imbrenda> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Info: AW1haW4tMjYwODA2MDExMiBTYWx0ZWRfXxpgygjYTDHCY C6zRBkWJO9+PrJ8ujaEaXqN5XbJfklJ1lsdCcL3GOmDyHf9wh8yCp54fOorCA+aMXgaEj3A8YYT oWgp5WH9y/yf0RX9XyaSESbhaBOR6KA= X-Authority-Analysis: v=2.4 cv=I7VVgtgg c=1 sm=1 tr=0 ts=6a749ca3 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VnNF1IyMAAAA:8 a=VwQbUJbxAAAA:8 a=GFNrkfC1HkkyiMQxMSkA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODA2MDExMiBTYWx0ZWRfX4Q/jBi5FSxnl YJHMiFPd0zfWMG1sX9e/P3/OwWvVWfhdkZLMxIjay1NKYrAtByWHW9vIiCfOeAmVBpgHgii10Si 54ZqzFSjE2BCKOhN/wS2ePTp0bQUBBrbq1fcRDDJAvAvYpY3HVLidGqyC+hvhZjzgJKrdMilV9j Qf2gww6oWmTE0cye62H514yEYCgjNYDyQWgHessIMhaqTuKj/ANwBzuEAM9avy20D7ntoA1S5zM Hh1iL403tonwGVy5jMoRAfVp7Fwyo2S02NhBfB+sZgjvuJKgqNQl5ORt7uliEdAJCsvhMkMt+50 9oXjw+Y3xiXaII15PXbVjzS1shkvYotbmP1vgIPX2/aRQUmqGN3fEytbnKfD/2H7g2yrRlYn7wz nSaSNbXrC6+PsvPklikl1obPo+yUclbXIc68dNNvvwZmUIO8e5UIzZHPQehAmRz6RKITkjLFZz+ fVRyCC/FqDJ7mRD6nFw== X-Proofpoint-ORIG-GUID: 9ejSTsgxTaksRGaUSMCsGJSU3KjSvUTC X-Proofpoint-GUID: 9ejSTsgxTaksRGaUSMCsGJSU3KjSvUTC X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-05_06,2026-08-05_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 impostorscore=0 clxscore=1015 priorityscore=1501 suspectscore=0 malwarescore=0 adultscore=0 lowpriorityscore=0 phishscore=0 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608060112 Am 06.08.26 um 16:37 schrieb Claudio Imbrenda: > On Thu, 6 Aug 2026 14:52:41 +0200 > Christian Borntraeger wrote: > >> Channel-subsystem damage machine checks are for the host channel >> subsystem. The guest channel subsystem is emulated in the userspace VMM. >> There is no point in forwarding such machine checks into the guest. >> >> This also simplifies the machine check reinjection and avoids kfree of a >> stack variable as reported by sashiko. There might be still machine >> checks that have the ck bit set with another bit (like instruction >> damage), mask out the CK bit in s390_backup_mcck_info(), like the CP and >> ED bits already are. >> >> Fixes: 4d62fcc0b692 ("KVM: s390: Inject machine check into the guest") >> Cc: stable@vger.kernel.org >> Signed-off-by: Christian Borntraeger >> --- >> arch/s390/include/asm/nmi.h | 1 + >> arch/s390/kernel/nmi.c | 4 ++-- >> arch/s390/kvm/interrupt.c | 24 ++++++++---------------- >> 3 files changed, 11 insertions(+), 18 deletions(-) >> >> diff --git a/arch/s390/include/asm/nmi.h b/arch/s390/include/asm/nmi.h >> index 6454c1531854..dd26c20bd231 100644 >> --- a/arch/s390/include/asm/nmi.h >> +++ b/arch/s390/include/asm/nmi.h >> @@ -22,6 +22,7 @@ >> #define MCCK_CODE_SYSTEM_DAMAGE BIT(63) >> #define MCCK_CODE_EXT_DAMAGE BIT(63 - 5) >> #define MCCK_CODE_CP BIT(63 - 9) >> +#define MCCK_CODE_CK BIT(63 - 11) >> #define MCCK_CODE_STG_ERROR BIT(63 - 16) >> #define MCCK_CODE_STG_KEY_ERROR BIT(63 - 18) >> #define MCCK_CODE_STG_DEGRAD BIT(63 - 19) >> diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c >> index e17a59d4d5a4..652b98795243 100644 >> --- a/arch/s390/kernel/nmi.c >> +++ b/arch/s390/kernel/nmi.c >> @@ -345,7 +345,7 @@ static void notrace s390_backup_mcck_info(struct pt_regs *regs) >> sie_page = container_of(sie_block, struct sie_page, sie_block); >> mcck_backup = &sie_page->mcck_info; >> mcck_backup->mcic = get_lowcore()->mcck_interruption_code & >> - ~(MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE); >> + ~(MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE | MCCK_CODE_CK); > > ... here, instead of duplicating it? > >> mcck_backup->ext_damage_code = get_lowcore()->external_damage_code; >> mcck_backup->failing_storage_address = get_lowcore()->failing_storage_address; >> } >> @@ -357,7 +357,7 @@ NOKPROBE_SYMBOL(s390_backup_mcck_info); >> #define ED_STP_ISLAND 6 /* External damage STP island check */ >> #define ED_STP_SYNC 7 /* External damage STP sync check */ >> >> -#define MCCK_CODE_NO_GUEST (MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE) >> +#define MCCK_CODE_NO_GUEST (MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE | MCCK_CODE_CK) > > it looks like this macro here should have been used above... ^ Yes, see my comment in the cover letter. We would need to move this define.