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Fri, 07 Feb 2020 11:40:03 +0000 Received: from b01ledav006.gho.pok.ibm.com (b01ledav006.gho.pok.ibm.com [9.57.199.111]) by b01cxnp22034.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 017Be1nE16384406 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 7 Feb 2020 11:40:01 GMT Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 87C2AAC05E; Fri, 7 Feb 2020 11:40:01 +0000 (GMT) Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 79056AC059; Fri, 7 Feb 2020 11:40:01 +0000 (GMT) Received: from localhost.localdomain (unknown [9.114.17.106]) by b01ledav006.gho.pok.ibm.com (Postfix) with ESMTP; Fri, 7 Feb 2020 11:40:01 +0000 (GMT) From: Christian Borntraeger To: Christian Borntraeger , Janosch Frank Cc: KVM , Cornelia Huck , David Hildenbrand , Thomas Huth , Ulrich Weigand , Claudio Imbrenda , Andrea Arcangeli , linux-s390 , Michael Mueller , Vasily Gorbik , linux-mm@kvack.org, Andrew Morton Subject: [PATCH 11/35] KVM: s390/mm: Make pages accessible before destroying the guest Date: Fri, 7 Feb 2020 06:39:34 -0500 Message-Id: <20200207113958.7320-12-borntraeger@de.ibm.com> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20200207113958.7320-1-borntraeger@de.ibm.com> References: <20200207113958.7320-1-borntraeger@de.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.572 definitions=2020-02-07_01:2020-02-07,2020-02-06 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 mlxlogscore=794 spamscore=0 adultscore=0 mlxscore=0 clxscore=1015 malwarescore=0 priorityscore=1501 phishscore=0 suspectscore=0 bulkscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2002070089 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Before we destroy the secure configuration, we better make all pages accessible again. This also happens during reboot, where we reboot into a non-secure guest that then can go again into secure mode. As this "new" secure guest will have a new ID we cannot reuse the old page state. Signed-off-by: Christian Borntraeger Reviewed-by: Thomas Huth Reviewed-by: Cornelia Huck Reviewed-by: David Hildenbrand --- arch/s390/include/asm/pgtable.h | 1 + arch/s390/kvm/pv.c | 2 ++ arch/s390/mm/gmap.c | 35 +++++++++++++++++++++++++++++++++ 3 files changed, 38 insertions(+) diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index dbd1453e6924..3e2ea997c334 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -1669,6 +1669,7 @@ extern int vmem_remove_mapping(unsigned long start, unsigned long size); extern int s390_enable_sie(void); extern int s390_enable_skey(void); extern void s390_reset_cmma(struct mm_struct *mm); +extern void s390_reset_acc(struct mm_struct *mm); /* s390 has a private copy of get unmapped area to deal with cache synonyms */ #define HAVE_ARCH_UNMAPPED_AREA diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c index 4795e61f4e16..392795a92bd9 100644 --- a/arch/s390/kvm/pv.c +++ b/arch/s390/kvm/pv.c @@ -66,6 +66,8 @@ int kvm_s390_pv_destroy_vm(struct kvm *kvm) int rc; u32 ret; + /* make all pages accessible before destroying the guest */ + s390_reset_acc(kvm->mm); rc = uv_cmd_nodata(kvm_s390_pv_handle(kvm), UVC_CMD_DESTROY_SEC_CONF, &ret); WRITE_ONCE(kvm->arch.gmap->guest_handle, 0); diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index 7291452fe5f0..27926a06df32 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -2650,3 +2650,38 @@ void s390_reset_cmma(struct mm_struct *mm) up_write(&mm->mmap_sem); } EXPORT_SYMBOL_GPL(s390_reset_cmma); + +/* + * make inaccessible pages accessible again + */ +static int __s390_reset_acc(pte_t *ptep, unsigned long addr, + unsigned long next, struct mm_walk *walk) +{ + pte_t pte = READ_ONCE(*ptep); + + if (pte_present(pte)) + WARN_ON_ONCE(uv_convert_from_secure(pte_val(pte) & PAGE_MASK)); + return 0; +} + +static const struct mm_walk_ops reset_acc_walk_ops = { + .pte_entry = __s390_reset_acc, +}; + +#include +void s390_reset_acc(struct mm_struct *mm) +{ + /* + * we might be called during + * reset: we walk the pages and clear + * close of all kvm file descriptors: we walk the pages and clear + * exit of process on fd closure: vma already gone, do nothing + */ + if (!mmget_not_zero(mm)) + return; + down_read(&mm->mmap_sem); + walk_page_range(mm, 0, TASK_SIZE, &reset_acc_walk_ops, NULL); + up_read(&mm->mmap_sem); + mmput(mm); +} +EXPORT_SYMBOL_GPL(s390_reset_acc);