From patchwork Tue Jun 21 13:13:01 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Borntraeger X-Patchwork-Id: 9190761 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id BE5CD6075E for ; Tue, 21 Jun 2016 14:42:37 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AFE4928066 for ; Tue, 21 Jun 2016 14:42:37 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A46E5281AA; Tue, 21 Jun 2016 14:42:37 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2F49A28066 for ; Tue, 21 Jun 2016 14:42:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752258AbcFUOm2 (ORCPT ); Tue, 21 Jun 2016 10:42:28 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:6657 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751958AbcFUOm0 (ORCPT ); Tue, 21 Jun 2016 10:42:26 -0400 Received: from pps.filterd (m0098414.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u5LDADLG040176 for ; Tue, 21 Jun 2016 09:13:17 -0400 Received: from e06smtp13.uk.ibm.com (e06smtp13.uk.ibm.com [195.75.94.109]) by mx0b-001b2d01.pphosted.com with ESMTP id 23n2ekuqwq-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 21 Jun 2016 09:13:17 -0400 Received: from localhost by e06smtp13.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 21 Jun 2016 14:13:16 +0100 Received: from d06dlp03.portsmouth.uk.ibm.com (9.149.20.15) by e06smtp13.uk.ibm.com (192.168.101.143) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Tue, 21 Jun 2016 14:13:12 +0100 X-IBM-Helo: d06dlp03.portsmouth.uk.ibm.com X-IBM-MailFrom: borntraeger@de.ibm.com X-IBM-RcptTo: kvm@vger.kernel.org;linux-s390@vger.kernel.org Received: from b06cxnps3074.portsmouth.uk.ibm.com (d06relay09.portsmouth.uk.ibm.com [9.149.109.194]) by d06dlp03.portsmouth.uk.ibm.com (Postfix) with ESMTP id A4C6E1B08075; Tue, 21 Jun 2016 14:14:23 +0100 (BST) Received: from d06av04.portsmouth.uk.ibm.com (d06av04.portsmouth.uk.ibm.com [9.149.37.216]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u5LDDCjo9568692; Tue, 21 Jun 2016 13:13:12 GMT Received: from d06av04.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av04.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u5LDDAeJ024042; Tue, 21 Jun 2016 07:13:11 -0600 Received: from tuxmaker.boeblingen.de.ibm.com (tuxmaker.boeblingen.de.ibm.com [9.152.85.9]) by d06av04.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id u5LDDAjD024029 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Tue, 21 Jun 2016 07:13:10 -0600 Received: by tuxmaker.boeblingen.de.ibm.com (Postfix, from userid 25651) id 3B68C20F542; Tue, 21 Jun 2016 15:13:10 +0200 (CEST) From: Christian Borntraeger To: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Cc: KVM , Cornelia Huck , linux-s390 , Christian Borntraeger , David Hildenbrand , Martin Schwidefsky Subject: [GIT PULL 23/51] s390/mm: don't fault everything in read-write in gmap_pte_op_fixup() Date: Tue, 21 Jun 2016 15:13:01 +0200 X-Mailer: git-send-email 2.5.5 In-Reply-To: <1466514809-146638-1-git-send-email-borntraeger@de.ibm.com> References: <1466514809-146638-1-git-send-email-borntraeger@de.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16062113-0012-0000-0000-000004239424 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16062113-0013-0000-0000-00001465FDE5 Message-Id: <1466514809-146638-24-git-send-email-borntraeger@de.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2016-06-21_06:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1606210152 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: David Hildenbrand Let's not fault in everything in read-write but limit it to read-only where possible. When restricting access rights, we already have the required protection level in our hands. When reading from guest 2 storage (gmap_read_table), it is obviously PROT_READ. When shadowing a pte, the required protection level is given via the guest 2 provided pte. Based on an initial patch by Martin Schwidefsky. Acked-by: Martin Schwidefsky Signed-off-by: David Hildenbrand Signed-off-by: Christian Borntraeger --- arch/s390/mm/gmap.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index d00e4ab..738d754 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -811,19 +811,22 @@ static pte_t *gmap_pte_op_walk(struct gmap *gmap, unsigned long gaddr, * @gmap: pointer to guest mapping meta data structure * @gaddr: virtual address in the guest address space * @vmaddr: address in the host process address space + * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE * * Returns 0 if the caller can retry __gmap_translate (might fail again), * -ENOMEM if out of memory and -EFAULT if anything goes wrong while fixing * up or connecting the gmap page table. */ static int gmap_pte_op_fixup(struct gmap *gmap, unsigned long gaddr, - unsigned long vmaddr) + unsigned long vmaddr, int prot) { struct mm_struct *mm = gmap->mm; + unsigned int fault_flags; bool unlocked = false; BUG_ON(gmap_is_shadow(gmap)); - if (fixup_user_fault(current, mm, vmaddr, FAULT_FLAG_WRITE, &unlocked)) + fault_flags = (prot == PROT_WRITE) ? FAULT_FLAG_WRITE : 0; + if (fixup_user_fault(current, mm, vmaddr, fault_flags, &unlocked)) return -EFAULT; if (unlocked) /* lost mmap_sem, caller has to retry __gmap_translate */ @@ -875,7 +878,7 @@ static int gmap_protect_range(struct gmap *gmap, unsigned long gaddr, vmaddr = __gmap_translate(gmap, gaddr); if (IS_ERR_VALUE(vmaddr)) return vmaddr; - rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr); + rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr, prot); if (rc) return rc; continue; @@ -957,7 +960,7 @@ int gmap_read_table(struct gmap *gmap, unsigned long gaddr, unsigned long *val) rc = vmaddr; break; } - rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr); + rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr, PROT_READ); if (rc) break; } @@ -1041,7 +1044,7 @@ static int gmap_protect_rmap(struct gmap *sg, unsigned long raddr, radix_tree_preload_end(); if (rc) { kfree(rmap); - rc = gmap_pte_op_fixup(parent, paddr, vmaddr); + rc = gmap_pte_op_fixup(parent, paddr, vmaddr, prot); if (rc) return rc; continue; @@ -1910,10 +1913,12 @@ int gmap_shadow_page(struct gmap *sg, unsigned long saddr, pte_t pte) unsigned long vmaddr, paddr; spinlock_t *ptl; pte_t *sptep, *tptep; + int prot; int rc; BUG_ON(!gmap_is_shadow(sg)); parent = sg->parent; + prot = (pte_val(pte) & _PAGE_PROTECT) ? PROT_READ : PROT_WRITE; rmap = kzalloc(sizeof(*rmap), GFP_KERNEL); if (!rmap) @@ -1955,7 +1960,7 @@ int gmap_shadow_page(struct gmap *sg, unsigned long saddr, pte_t pte) radix_tree_preload_end(); if (!rc) break; - rc = gmap_pte_op_fixup(parent, paddr, vmaddr); + rc = gmap_pte_op_fixup(parent, paddr, vmaddr, prot); if (rc) break; }