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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 20A95C4332F for ; Thu, 14 Apr 2022 08:03:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240813AbiDNIGI (ORCPT ); Thu, 14 Apr 2022 04:06:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55748 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240637AbiDNIFs (ORCPT ); Thu, 14 Apr 2022 04:05:48 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BB9874CD65; Thu, 14 Apr 2022 01:03:24 -0700 (PDT) Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 23E6jcjC021502; Thu, 14 Apr 2022 08:03:24 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=HbOorGJ6AVbyEOEBqTWCa9wVpQz5MuqdUsuMkIcwE0Y=; b=DtYVxqocNDl+52VFOSAmaODhiiZ9tnOLIyTtrLVt3FJ0AdU9wZ05HqALBQb2zxNeXuAN ZEhdtTvaLXBgx0ZLfFkGwLqaPu/fUTir9XCo+qhNv+vX6ZuigQXw7OjqaBuR3ZoTAMlc sOQjtuoMev6jD1l+37ki7bBtF+zqSRfUirCo2DZSLQJ+8DaF+zWrDnU7mw7sQll7sxMj YpyYThOKQocIgdXIK524IGN+udZTLkB+OHXvHbOQVbQjGlTi658HoKS4h92JbctKJmmf 6hRphKpIW7QIHjSx1VDpzRaQ2X6KCc5hcczXNLb51gcOja9a14CZzxg5EMtUL8CwUsRM qw== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 3feemjscwy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 14 Apr 2022 08:03:24 +0000 Received: from m0098410.ppops.net (m0098410.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.43/8.16.0.43) with SMTP id 23E7prBS031177; Thu, 14 Apr 2022 08:03:24 GMT Received: from ppma03ams.nl.ibm.com (62.31.33a9.ip4.static.sl-reverse.com [169.51.49.98]) by mx0a-001b2d01.pphosted.com with ESMTP id 3feemjscw7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 14 Apr 2022 08:03:23 +0000 Received: from pps.filterd (ppma03ams.nl.ibm.com [127.0.0.1]) by ppma03ams.nl.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 23E7mHFg016643; Thu, 14 Apr 2022 08:03:21 GMT Received: from b06avi18626390.portsmouth.uk.ibm.com (b06avi18626390.portsmouth.uk.ibm.com [9.149.26.192]) by ppma03ams.nl.ibm.com with ESMTP id 3fb1s8yxgf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 14 Apr 2022 08:03:21 +0000 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 23E7ojxf23069054 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 14 Apr 2022 07:50:45 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6AC57AE04D; Thu, 14 Apr 2022 08:03:18 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E5108AE053; Thu, 14 Apr 2022 08:03:17 +0000 (GMT) Received: from localhost.localdomain (unknown [9.145.1.140]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 14 Apr 2022 08:03:17 +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 v10 02/19] KVM: s390: pv: handle secure storage violations for protected guests Date: Thu, 14 Apr 2022 10:02:53 +0200 Message-Id: <20220414080311.1084834-3-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220414080311.1084834-1-imbrenda@linux.ibm.com> References: <20220414080311.1084834-1-imbrenda@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: DIvK64dqeBZUISdp3HC0tdvwXbwLfLWe X-Proofpoint-ORIG-GUID: 16TXxYy1A49Zt0EcHN_QEK6Dk72W1RlV X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.858,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-04-14_02,2022-04-13_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 suspectscore=0 mlxscore=0 impostorscore=0 adultscore=0 lowpriorityscore=0 priorityscore=1501 mlxlogscore=645 clxscore=1015 spamscore=0 bulkscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2204140040 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org With upcoming patches, protected guests will be able to trigger secure storage violations in normal operation. A secure storage violation is triggered when a protected guest tries to access secure memory that has been mapped erroneously, or that belongs to a different protected guest or to the ultravisor. With upcoming patches, protected guests will be able to trigger secure storage violations in normal operation. This happens for example if a protected guest is rebooted with lazy destroy enabled and the new guest is also protected. When the new protected guest touches pages that have not yet been destroyed, and thus are accounted to the previous protected guest, a secure storage violation is raised. This patch adds handling of secure storage violations for protected guests. This exception is handled by first trying to destroy the page, because it is expected to belong to a defunct protected guest where a destroy should be possible. If that fails, a normal export of the page is attempted. Therefore, pages that trigger the exception will be made non-secure before attempting to use them again for a different secure guest. Signed-off-by: Claudio Imbrenda Acked-by: Janosch Frank --- arch/s390/include/asm/uv.h | 1 + arch/s390/kernel/uv.c | 55 ++++++++++++++++++++++++++++++++++++++ arch/s390/mm/fault.c | 10 +++++++ 3 files changed, 66 insertions(+) diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h index a2d376b8bce3..b96c1cf750a5 100644 --- a/arch/s390/include/asm/uv.h +++ b/arch/s390/include/asm/uv.h @@ -357,6 +357,7 @@ static inline int is_prot_virt_host(void) } int gmap_make_secure(struct gmap *gmap, unsigned long gaddr, void *uvcb); +int gmap_destroy_page(struct gmap *gmap, unsigned long gaddr); int uv_destroy_owned_page(unsigned long paddr); int uv_convert_from_secure(unsigned long paddr); int uv_convert_owned_from_secure(unsigned long paddr); diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c index a5425075dd25..2754471cc789 100644 --- a/arch/s390/kernel/uv.c +++ b/arch/s390/kernel/uv.c @@ -334,6 +334,61 @@ int gmap_convert_to_secure(struct gmap *gmap, unsigned long gaddr) } EXPORT_SYMBOL_GPL(gmap_convert_to_secure); +/** + * gmap_destroy_page - Destroy a guest page. + * @gmap the gmap of the guest + * @gaddr the guest address to destroy + * + * An attempt will be made to destroy the given guest page. If the attempt + * fails, an attempt is made to export the page. If both attempts fail, an + * appropriate error is returned. + */ +int gmap_destroy_page(struct gmap *gmap, unsigned long gaddr) +{ + struct vm_area_struct *vma; + unsigned long uaddr; + struct page *page; + int rc; + + rc = -EFAULT; + mmap_read_lock(gmap->mm); + + uaddr = __gmap_translate(gmap, gaddr); + if (IS_ERR_VALUE(uaddr)) + goto out; + vma = vma_lookup(gmap->mm, uaddr); + if (!vma) + goto out; + /* + * Huge pages should not be able to become secure + */ + if (is_vm_hugetlb_page(vma)) + goto out; + + rc = 0; + /* we take an extra reference here */ + page = follow_page(vma, uaddr, FOLL_WRITE | FOLL_GET); + if (IS_ERR_OR_NULL(page)) + goto out; + rc = uv_destroy_owned_page(page_to_phys(page)); + /* + * Fault handlers can race; it is possible that two CPUs will fault + * on the same secure page. One CPU can destroy the page, reboot, + * re-enter secure mode and import it, while the second CPU was + * stuck at the beginning of the handler. At some point the second + * CPU will be able to progress, and it will not be able to destroy + * the page. In that case we do not want to terminate the process, + * we instead try to export the page. + */ + if (rc) + rc = uv_convert_owned_from_secure(page_to_phys(page)); + put_page(page); +out: + mmap_read_unlock(gmap->mm); + return rc; +} +EXPORT_SYMBOL_GPL(gmap_destroy_page); + /* * To be called with the page locked or with an extra reference! This will * prevent gmap_make_secure from touching the page concurrently. Having 2 diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index e173b6187ad5..af1ac49168fb 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -837,6 +837,16 @@ NOKPROBE_SYMBOL(do_non_secure_storage_access); void do_secure_storage_violation(struct pt_regs *regs) { + unsigned long gaddr = regs->int_parm_long & __FAIL_ADDR_MASK; + struct gmap *gmap = (struct gmap *)S390_lowcore.gmap; + + /* + * If the VM has been rebooted, its address space might still contain + * secure pages from the previous boot. + * Clear the page so it can be reused. + */ + if (!gmap_destroy_page(gmap, gaddr)) + return; /* * Either KVM messed up the secure guest mapping or the same * page is mapped into multiple secure guests. -- 2.34.1