From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1A2FAC2D0B1 for ; Thu, 6 Feb 2020 08:43:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E1E1821741 for ; Thu, 6 Feb 2020 08:43:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728047AbgBFInh (ORCPT ); Thu, 6 Feb 2020 03:43:37 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:11606 "EHLO mx0b-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727881AbgBFInh (ORCPT ); Thu, 6 Feb 2020 03:43:37 -0500 Received: from pps.filterd (m0127361.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 0168hVNJ048571 for ; Thu, 6 Feb 2020 03:43:36 -0500 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0a-001b2d01.pphosted.com with ESMTP id 2xyhnsbj29-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 06 Feb 2020 03:43:34 -0500 Received: from localhost by e06smtp01.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 6 Feb 2020 08:43:25 -0000 Received: from b06cxnps4075.portsmouth.uk.ibm.com (9.149.109.197) by e06smtp01.uk.ibm.com (192.168.101.131) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 6 Feb 2020 08:43:23 -0000 Received: from b06wcsmtp001.portsmouth.uk.ibm.com (b06wcsmtp001.portsmouth.uk.ibm.com [9.149.105.160]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 0168hLLw57344236 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 6 Feb 2020 08:43:21 GMT Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9C1A7A4066; Thu, 6 Feb 2020 08:43:21 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5A7C8A4062; Thu, 6 Feb 2020 08:43:21 +0000 (GMT) Received: from oc7455500831.ibm.com (unknown [9.152.224.61]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 6 Feb 2020 08:43:21 +0000 (GMT) Subject: Re: [RFCv2 21/37] KVM: S390: protvirt: Introduce instruction data area bounce buffer To: David Hildenbrand , Janosch Frank Cc: KVM , Cornelia Huck , Thomas Huth , Ulrich Weigand , Claudio Imbrenda , Andrea Arcangeli References: <20200203131957.383915-1-borntraeger@de.ibm.com> <20200203131957.383915-22-borntraeger@de.ibm.com> From: Christian Borntraeger Autocrypt: addr=borntraeger@de.ibm.com; prefer-encrypt=mutual; keydata= xsFNBE6cPPgBEAC2VpALY0UJjGmgAmavkL/iAdqul2/F9ONz42K6NrwmT+SI9CylKHIX+fdf J34pLNJDmDVEdeb+brtpwC9JEZOLVE0nb+SR83CsAINJYKG3V1b3Kfs0hydseYKsBYqJTN2j CmUXDYq9J7uOyQQ7TNVoQejmpp5ifR4EzwIFfmYDekxRVZDJygD0wL/EzUr8Je3/j548NLyL 4Uhv6CIPf3TY3/aLVKXdxz/ntbLgMcfZsDoHgDk3lY3r1iwbWwEM2+eYRdSZaR4VD+JRD7p8 0FBadNwWnBce1fmQp3EklodGi5y7TNZ/CKdJ+jRPAAnw7SINhSd7PhJMruDAJaUlbYaIm23A +82g+IGe4z9tRGQ9TAflezVMhT5J3ccu6cpIjjvwDlbxucSmtVi5VtPAMTLmfjYp7VY2Tgr+ T92v7+V96jAfE3Zy2nq52e8RDdUo/F6faxcumdl+aLhhKLXgrozpoe2nL0Nyc2uqFjkjwXXI OBQiaqGeWtxeKJP+O8MIpjyGuHUGzvjNx5S/592TQO3phpT5IFWfMgbu4OreZ9yekDhf7Cvn /fkYsiLDz9W6Clihd/xlpm79+jlhm4E3xBPiQOPCZowmHjx57mXVAypOP2Eu+i2nyQrkapaY IdisDQfWPdNeHNOiPnPS3+GhVlPcqSJAIWnuO7Ofw1ZVOyg/jwARAQABzUNDaHJpc3RpYW4g Qm9ybnRyYWVnZXIgKDJuZCBJQk0gYWRkcmVzcykgPGJvcm50cmFlZ2VyQGxpbnV4LmlibS5j b20+wsF5BBMBAgAjBQJdP/hMAhsDBwsJCAcDAgEGFQgCCQoLBBYCAwECHgECF4AACgkQEXu8 gLWmHHy/pA/+JHjpEnd01A0CCyfVnb5fmcOlQ0LdmoKWLWPvU840q65HycCBFTt6V62cDljB kXFFxMNA4y/2wqU0H5/CiL963y3gWIiJsZa4ent+KrHl5GK1nIgbbesfJyA7JqlB0w/E/SuY NRQwIWOo/uEvOgXnk/7+rtvBzNaPGoGiiV1LZzeaxBVWrqLtmdi1iulW/0X/AlQPuF9dD1Px hx+0mPjZ8ClLpdSp5d0yfpwgHtM1B7KMuQPQZGFKMXXTUd3ceBUGGczsgIMipZWJukqMJiJj QIMH0IN7XYErEnhf0GCxJ3xAn/J7iFpPFv8sFZTvukntJXSUssONnwiKuld6ttUaFhSuSoQg OFYR5v7pOfinM0FcScPKTkrRsB5iUvpdthLq5qgwdQjmyINt3cb+5aSvBX2nNN135oGOtlb5 tf4dh00kUR8XFHRrFxXx4Dbaw4PKgV3QLIHKEENlqnthH5t0tahDygQPnSucuXbVQEcDZaL9 WgJqlRAAj0pG8M6JNU5+2ftTFXoTcoIUbb0KTOibaO9zHVeGegwAvPLLNlKHiHXcgLX1tkjC DrvE2Z0e2/4q7wgZgn1kbvz7ZHQZB76OM2mjkFu7QNHlRJ2VXJA8tMXyTgBX6kq1cYMmd/Hl OhFrAU3QO1SjCsXA2CDk9MM1471mYB3CTXQuKzXckJnxHkHOwU0ETpw8+AEQAJjyNXvMQdJN t07BIPDtbAQk15FfB0hKuyZVs+0lsjPKBZCamAAexNRk11eVGXK/YrqwjChkk60rt3q5i42u PpNMO9aS8cLPOfVft89Y654Qd3Rs1WRFIQq9xLjdLfHh0i0jMq5Ty+aiddSXpZ7oU6E+ud+X Czs3k5RAnOdW6eV3+v10sUjEGiFNZwzN9Udd6PfKET0J70qjnpY3NuWn5Sp1ZEn6lkq2Zm+G 9G3FlBRVClT30OWeiRHCYB6e6j1x1u/rSU4JiNYjPwSJA8EPKnt1s/Eeq37qXXvk+9DYiHdT PcOa3aNCSbIygD3jyjkg6EV9ZLHibE2R/PMMid9FrqhKh/cwcYn9FrT0FE48/2IBW5mfDpAd YvpawQlRz3XJr2rYZJwMUm1y+49+1ZmDclaF3s9dcz2JvuywNq78z/VsUfGz4Sbxy4ShpNpG REojRcz/xOK+FqNuBk+HoWKw6OxgRzfNleDvScVmbY6cQQZfGx/T7xlgZjl5Mu/2z+ofeoxb vWWM1YCJAT91GFvj29Wvm8OAPN/+SJj8LQazd9uGzVMTz6lFjVtH7YkeW/NZrP6znAwv5P1a DdQfiB5F63AX++NlTiyA+GD/ggfRl68LheSskOcxDwgI5TqmaKtX1/8RkrLpnzO3evzkfJb1 D5qh3wM1t7PZ+JWTluSX8W25ABEBAAHCwV8EGAECAAkFAk6cPPgCGwwACgkQEXu8gLWmHHz8 2w//VjRlX+tKF3szc0lQi4X0t+pf88uIsvR/a1GRZpppQbn1jgE44hgF559K6/yYemcvTR7r 6Xt7cjWGS4wfaR0+pkWV+2dbw8Xi4DI07/fN00NoVEpYUUnOnupBgychtVpxkGqsplJZQpng v6fauZtyEcUK3dLJH3TdVQDLbUcL4qZpzHbsuUnTWsmNmG4Vi0NsEt1xyd/Wuw+0kM/oFEH1 4BN6X9xZcG8GYUbVUd8+bmio8ao8m0tzo4pseDZFo4ncDmlFWU6hHnAVfkAs4tqA6/fl7RLN JuWBiOL/mP5B6HDQT9JsnaRdzqF73FnU2+WrZPjinHPLeE74istVgjbowvsgUqtzjPIG5pOj cAsKoR0M1womzJVRfYauWhYiW/KeECklci4TPBDNx7YhahSUlexfoftltJA8swRshNA/M90/ i9zDo9ySSZHwsGxG06ZOH5/MzG6HpLja7g8NTgA0TD5YaFm/oOnsQVsf2DeAGPS2xNirmknD jaqYefx7yQ7FJXXETd2uVURiDeNEFhVZWb5CiBJM5c6qQMhmkS4VyT7/+raaEGgkEKEgHOWf ZDP8BHfXtszHqI3Fo1F4IKFo/AP8GOFFxMRgbvlAs8z/+rEEaQYjxYJqj08raw6P4LFBqozr nS4h0HDFPrrp1C2EMVYIQrMokWvlFZbCpsdYbBI= Date: Thu, 6 Feb 2020 09:43:21 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 20020608-4275-0000-0000-0000039E7451 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 20020608-4276-0000-0000-000038B2A0EB Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.572 definitions=2020-02-05_06:2020-02-04,2020-02-05 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 malwarescore=0 mlxlogscore=895 bulkscore=0 priorityscore=1501 adultscore=0 suspectscore=0 lowpriorityscore=0 clxscore=1015 impostorscore=0 spamscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2002060068 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 05.02.20 12:43, David Hildenbrand wrote: >> #ifdef CONFIG_KVM_S390_PROTECTED_VIRTUALIZATION_HOST >> +static long kvm_s390_guest_sida_op(struct kvm_vcpu *vcpu, >> + struct kvm_s390_mem_op *mop) >> +{ >> + int r = 0; >> + void __user *uaddr = (void __user *)mop->buf; > > Reverse christmas tree :) ack. > >> + >> + if (mop->flags || !mop->size) >> + return -EINVAL; >> + >> + if (mop->size > sida_size(vcpu->arch.sie_block)) >> + return -E2BIG; > > Should be caught by the check below as well (or is this an implicit > overflow check? - see below). > >> + >> + if (mop->size + mop->offset > sida_size(vcpu->arch.sie_block)) >> + return -E2BIG; >> + > > Do we have to care about overflows? (at least the offset is 32-bit, > didn't check the size :)) size and offset are both unsigned. So offset 0xfffffff0 + size 0x100 would not be covered by both checks. Hmm, should we add this as well? @@ -4538,6 +4538,9 @@ static long kvm_s390_guest_sida_op(struct kvm_vcpu *vcpu, if (mop->size > sida_size(vcpu->arch.sie_block)) return -E2BIG; + if (mop->offset > sida_size(vcpu->arch.sie_block)) + return -E2BIG; + if (mop->size + mop->offset > sida_size(vcpu->arch.sie_block)) return -E2BIG; > > >> + switch (mop->op) { >> + case KVM_S390_MEMOP_SIDA_READ: >> + r = 0; >> + if (copy_to_user(uaddr, (void *)sida_origin(vcpu->arch.sie_block) + >> + mop->offset, mop->size)) >> + r = -EFAULT; >> + >> + break; >> + case KVM_S390_MEMOP_SIDA_WRITE: >> + r = 0; >> + if (copy_from_user((void *)vcpu->arch.sie_block->sidad + >> + mop->offset, uaddr, mop->size)) >> + r = -EFAULT; >> + break; >> + } >> + return r; >> +} >> + >> static int kvm_s390_handle_pv_vcpu(struct kvm_vcpu *vcpu, >> struct kvm_pv_cmd *cmd) >> { >> @@ -4708,6 +4743,20 @@ long kvm_arch_vcpu_ioctl(struct file *filp, >> r = kvm_s390_handle_pv_vcpu(vcpu, &args); >> break; >> } >> + case KVM_S390_SIDA_OP: { >> + struct kvm_s390_mem_op mem_op; >> + >> + if (!kvm_s390_pv_is_protected(vcpu->kvm)) { >> + r = -EINVAL; >> + break; >> + } > > Could we race against a VM_DESTROY? Should we protect somehow? As far as I can tell SIDA_OP and the VCPU_DESTROY are both per cpu ioctls and thus protected by the vcpu->mutex. (please double check). > [...] > >> -/* for KVM_S390_MEM_OP */ >> +/* for KVM_S390_MEM_OP and KVM_S390_SIDA_OP */ >> struct kvm_s390_mem_op { >> /* in */ >> __u64 gaddr; /* the guest address */ >> @@ -475,11 +475,17 @@ struct kvm_s390_mem_op { >> __u32 op; /* type of operation */ >> __u64 buf; /* buffer in userspace */ >> __u8 ar; /* the access register number */ >> - __u8 reserved[31]; /* should be set to 0 */ >> + __u8 reserved21[3]; /* should be set to 0 */ >> + __u32 offset; /* offset into the sida */ > > maybe "side_offset"? or define a union, overlying the ar (because that > obviously doesn't apply to this memop). So eventually different layout > for different memop. Will use sida_offset for now, but I have to look into Thomas proposal.