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Fri, 07 Feb 2020 11:40:02 +0000 Received: from b01ledav006.gho.pok.ibm.com (b01ledav006.gho.pok.ibm.com [9.57.199.111]) by b01cxnp23034.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 017Be0wR50069946 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 7 Feb 2020 11:40:00 GMT Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4C295AC059; Fri, 7 Feb 2020 11:40:00 +0000 (GMT) Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3CAACAC05F; Fri, 7 Feb 2020 11:40:00 +0000 (GMT) Received: from localhost.localdomain (unknown [9.114.17.106]) by b01ledav006.gho.pok.ibm.com (Postfix) with ESMTP; Fri, 7 Feb 2020 11:40:00 +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 01/35] mm:gup/writeback: add callbacks for inaccessible pages Date: Fri, 7 Feb 2020 06:39:24 -0500 Message-Id: <20200207113958.7320-2-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 bulkscore=0 phishscore=0 impostorscore=0 malwarescore=0 suspectscore=2 mlxlogscore=986 priorityscore=1501 adultscore=0 lowpriorityscore=0 spamscore=0 clxscore=1015 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2002070089 Content-Transfer-Encoding: quoted-printable 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: From: Claudio Imbrenda With the introduction of protected KVM guests on s390 there is now a concept of inaccessible pages. These pages need to be made accessible before the host can access them. While cpu accesses will trigger a fault that can be resolved, I/O accesses will just fail. We need to add a callback into architecture code for places that will do I/O, namely when writeback is started or when a page reference is taken. Signed-off-by: Claudio Imbrenda Signed-off-by: Christian Borntraeger --- include/linux/gfp.h | 6 ++++++ mm/gup.c | 2 ++ mm/page-writeback.c | 1 + 3 files changed, 9 insertions(+) diff --git a/include/linux/gfp.h b/include/linux/gfp.h index e5b817cb86e7..be2754841369 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -485,6 +485,12 @@ static inline void arch_free_page(struct page *page,= int order) { } #ifndef HAVE_ARCH_ALLOC_PAGE static inline void arch_alloc_page(struct page *page, int order) { } #endif +#ifndef HAVE_ARCH_MAKE_PAGE_ACCESSIBLE +static inline int arch_make_page_accessible(struct page *page) +{ + return 0; +} +#endif =20 struct page * __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, int preferred= _nid, diff --git a/mm/gup.c b/mm/gup.c index 7646bf993b25..a01262cd2821 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -257,6 +257,7 @@ static struct page *follow_page_pte(struct vm_area_st= ruct *vma, page =3D ERR_PTR(-ENOMEM); goto out; } + arch_make_page_accessible(page); } if (flags & FOLL_TOUCH) { if ((flags & FOLL_WRITE) && @@ -1870,6 +1871,7 @@ static int gup_pte_range(pmd_t pmd, unsigned long a= ddr, unsigned long end, =20 VM_BUG_ON_PAGE(compound_head(page) !=3D head, page); =20 + arch_make_page_accessible(page); SetPageReferenced(page); pages[*nr] =3D page; (*nr)++; diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 2caf780a42e7..0f0bd14571b1 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -2806,6 +2806,7 @@ int __test_set_page_writeback(struct page *page, bo= ol keep_write) inc_lruvec_page_state(page, NR_WRITEBACK); inc_zone_page_state(page, NR_ZONE_WRITE_PENDING); } + arch_make_page_accessible(page); unlock_page_memcg(page); return ret; =20 --=20 2.24.0