From patchwork Tue Jun 28 13:56:04 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Claudio Imbrenda X-Patchwork-Id: 12898333 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52D01CCA479 for ; Tue, 28 Jun 2022 13:56:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346914AbiF1N4j (ORCPT ); Tue, 28 Jun 2022 09:56:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33658 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231856AbiF1N43 (ORCPT ); Tue, 28 Jun 2022 09:56:29 -0400 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4C5FE3337F; Tue, 28 Jun 2022 06:56:28 -0700 (PDT) Received: from pps.filterd (m0127361.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 25SDiQfC012143; 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Tue, 28 Jun 2022 13:56:20 +0000 (GMT) Received: from p-imbrenda.boeblingen.de.ibm.com (unknown [9.152.224.40]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 28 Jun 2022 13:56:20 +0000 (GMT) From: Claudio Imbrenda To: kvm@vger.kernel.org Cc: borntraeger@de.ibm.com, frankja@linux.ibm.com, thuth@redhat.com, pasic@linux.ibm.com, david@redhat.com, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, scgl@linux.ibm.com, mimu@linux.ibm.com, nrb@linux.ibm.com Subject: [PATCH v12 03/18] KVM: s390: pv: handle secure storage exceptions for normal guests Date: Tue, 28 Jun 2022 15:56:04 +0200 Message-Id: <20220628135619.32410-4-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220628135619.32410-1-imbrenda@linux.ibm.com> References: <20220628135619.32410-1-imbrenda@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 8ZrXCmnwywm1w-atIcwjK_JtXho9Yh22 X-Proofpoint-ORIG-GUID: GyGRAMoVaYSx6xag7PbZTvJT8vWyzkEJ X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.883,Hydra:6.0.517,FMLib:17.11.122.1 definitions=2022-06-28_07,2022-06-28_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 impostorscore=0 suspectscore=0 clxscore=1015 mlxscore=0 adultscore=0 priorityscore=1501 bulkscore=0 mlxlogscore=482 phishscore=0 malwarescore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2204290000 definitions=main-2206280057 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org With upcoming patches, normal guests might touch secure pages. This patch extends the existing exception handler to convert the pages to non secure also when the exception is triggered by a normal guest. This can happen for example when a secure guest reboots; the first stage of a secure guest is non secure, and in general a secure guest can reboot into non-secure mode. If the secure memory of the previous boot has not been cleared up completely yet (which will be allowed to happen in an upcoming patch), a non-secure guest might touch secure memory, which will need to be handled properly. This means that gmap faults must be handled and not cause termination of the process. The handling is the same as userspace accesses, it's enough to translate the gmap address to a user address and then let the normal user fault code handle it. Signed-off-by: Claudio Imbrenda Reviewed-by: Janosch Frank --- arch/s390/mm/fault.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index af1ac49168fb..ee7871f770fb 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -754,6 +754,7 @@ void do_secure_storage_access(struct pt_regs *regs) struct vm_area_struct *vma; struct mm_struct *mm; struct page *page; + struct gmap *gmap; int rc; /* @@ -783,6 +784,17 @@ void do_secure_storage_access(struct pt_regs *regs) } switch (get_fault_type(regs)) { + case GMAP_FAULT: + mm = current->mm; + gmap = (struct gmap *)S390_lowcore.gmap; + mmap_read_lock(mm); + addr = __gmap_translate(gmap, addr); + mmap_read_unlock(mm); + if (IS_ERR_VALUE(addr)) { + do_fault_error(regs, VM_ACCESS_FLAGS, VM_FAULT_BADMAP); + break; + } + fallthrough; case USER_FAULT: mm = current->mm; mmap_read_lock(mm); @@ -811,7 +823,6 @@ void do_secure_storage_access(struct pt_regs *regs) if (rc) BUG(); break; - case GMAP_FAULT: default: do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP); WARN_ON_ONCE(1);