From nobody Fri Apr 3 02:58:26 2026 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2B5DB401A15; Wed, 25 Mar 2026 17:13:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.158.5 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774458811; cv=none; b=BfSBSK7kxlJV4gZlvPQOF+CiMQXnAbLtRUCefES7o9I34Q/VQJV3TDKs9uS8NvSWG0HrkQRz9StUHR2g4Iby9Zq/rsPk1jJk7rbqhZ3sjeRri017DLWNC5iHmEPnGXzHbWJHNN+bk/N/wjUVb42Ept2MrvOlvBVKEvrs3byQxYs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774458811; c=relaxed/simple; bh=UQtUEHaQsqRmHnv53TrlrarbtmDWCkbdmo7byFNh86I=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=DQUvs1WpnY57i/RsKUED/EDkc0Gv7n69cFEvIroDWh5/8saIwa1HJGOdRKLjCKhFUalLfbHeo1b6OhfYo42Rbh0y4DrnQYxWNRXjMRx+10soy9K12NWe40kofQthWoCtR+wyjfPx+5O7wKsLNkZYaWb6HFldk3X+KTcryyoTVwI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=McwHpgFp; arc=none smtp.client-ip=148.163.158.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="McwHpgFp" Received: from pps.filterd (m0356516.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 62PA09r8124777; Wed, 25 Mar 2026 17:13:18 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:date:from:in-reply-to:message-id :mime-version:references:subject:to; s=pp1; bh=8c26P9cAngHTk0pkx z5TB+Mqm0wiAwcu3yunCC1wMDY=; b=McwHpgFp8Y4Uiybw8qohLxAFB3BpRzn5D E98hfOPjCZxjGLFMI4g2Rv3t9GH99GlrorksV7eSwTsZI/NPloelh3K3vS1auTe7 6XTTmrmrq3tYzbn4yfOBQ9jVtnPZSjkdCkagbTJvQgjAAVuDMDs6LvjDZ7/bInHY 8iydiicD/RAS0CQHUvq2pHIGyy8LzrfT64/jQYOCz8nrWcSpjxo6ZCfC/1HVI2dv QMUcDdPjJcDHBxFiT4n0sRP99C0gDcMkSqR9WHJAv2u4jEnN2S4uWeWn56LEjZFQ 2gOnikayGrtrshVxAe0oc4gnbiuwgu3hpcJVF/aLu1LG8ZzWh3P3g== Received: from ppma13.dal12v.mail.ibm.com (dd.9e.1632.ip4.static.sl-reverse.com [50.22.158.221]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4d1ktv0qx5-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 25 Mar 2026 17:13:17 +0000 (GMT) Received: from pps.filterd (ppma13.dal12v.mail.ibm.com [127.0.0.1]) by ppma13.dal12v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 62PG1BRc011824; Wed, 25 Mar 2026 17:13:17 GMT Received: from smtprelay07.fra02v.mail.ibm.com ([9.218.2.229]) by ppma13.dal12v.mail.ibm.com (PPS) with ESMTPS id 4d27vk79c0-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 25 Mar 2026 17:13:16 +0000 Received: from smtpav03.fra02v.mail.ibm.com (smtpav03.fra02v.mail.ibm.com [10.20.54.102]) by smtprelay07.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 62PHDDlH44040584 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 25 Mar 2026 17:13:13 GMT Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2DE2F20040; Wed, 25 Mar 2026 17:13:13 +0000 (GMT) Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 01A7520043; Wed, 25 Mar 2026 17:13:13 +0000 (GMT) Received: from p-imbrenda.aag-de.ibm.com (unknown [9.52.223.175]) by smtpav03.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 25 Mar 2026 17:13:12 +0000 (GMT) From: Claudio Imbrenda To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, borntraeger@de.ibm.com, frankja@linux.ibm.com, nrb@linux.ibm.com, seiden@linux.ibm.com, gra@linux.ibm.com, schlameuss@linux.ibm.com, hca@linux.ibm.com, david@kernel.org Subject: [PATCH v4 04/10] KVM: s390: Fix gmap_link() Date: Wed, 25 Mar 2026 18:13:05 +0100 Message-ID: <20260325171311.182210-5-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260325171311.182210-1-imbrenda@linux.ibm.com> References: <20260325171311.182210-1-imbrenda@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: 4vKJH0UNDNF2zjngFjAsiLL0SSmDa6uX X-Authority-Analysis: v=2.4 cv=aMr9aL9m c=1 sm=1 tr=0 ts=69c417ad cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=Yq5XynenixoA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VnNF1IyMAAAA:8 a=jDauOpCy_z-6rDg_B6MA:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMzI1MDEyMSBTYWx0ZWRfXzy6py7uo+WEL +CknDwosQi24V6ekUIkqzmbFXZ0ki8jw1k82SXYO++GmB1ili52fajaQZNNqQAkdk0ncyJhkqjc LCY22Eu7ghIToUD+SEDqz6wvviQRert/+VqMK0SsXvTcZUphWqE9ZYarsbfths+e57Fzh4wCUb4 LW1hK1pPoNAuxbytQ5TpPkE1xq13RnAw3gfg8alQ8I4BdZBTQu6oMHqxWssu7bE/Gmv6IRs1Ks7 CeDAEhunYeWp6pVtndH07sYun8LB2sFPdgOn/CWb4rbyquqT93J9YfCbT0ZCIfclkx+/6AQnT9Y nkS0nwxym1CO3Jg2huU19K9KU3pqYXcAAG6+j8iAmEUP3/80WDwFQ0WC2pMRtxPgWFd2QbAiKRK cCyyBUtWYcije3O3yUi7YKtJnFmVIQLWZBqYW7xlfz3YdnCjwaq2s8jAJiyJx6nupSpD0Gyq+LJ C1780fIsyAK1kznrfVw== X-Proofpoint-GUID: 4vKJH0UNDNF2zjngFjAsiLL0SSmDa6uX X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-03-25_05,2026-03-24_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 lowpriorityscore=0 adultscore=0 impostorscore=0 malwarescore=0 suspectscore=0 phishscore=0 priorityscore=1501 bulkscore=0 clxscore=1015 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2603050001 definitions=main-2603250121 Content-Type: text/plain; charset="utf-8" The slow path of the fault handler ultimately called gmap_link(), which assumed the fault was a major fault, and blindly called dat_link(). In case of minor faults, things were not always handled properly; in particular the prefix and vsie marker bits were ignored. Move dat_link() into gmap.c, renaming it accordingly. Once moved, the new _gmap_link() function will be able to correctly honour the prefix and vsie markers. This will cause spurious unshadows in some uncommon cases. Signed-off-by: Claudio Imbrenda Fixes: 94fd9b16cc67 ("KVM: s390: KVM page table management functions: lifec= ycle management") Fixes: a2c17f9270cc ("KVM: s390: New gmap code") Reviewed-by: Steffen Eiden --- arch/s390/kvm/dat.c | 48 ------------------------------------- arch/s390/kvm/dat.h | 2 -- arch/s390/kvm/gmap.c | 56 ++++++++++++++++++++++++++++++++++++++++---- 3 files changed, 52 insertions(+), 54 deletions(-) diff --git a/arch/s390/kvm/dat.c b/arch/s390/kvm/dat.c index 4d44c0f9ad45..7b8d70fe406d 100644 --- a/arch/s390/kvm/dat.c +++ b/arch/s390/kvm/dat.c @@ -997,54 +997,6 @@ bool dat_test_age_gfn(union asce asce, gfn_t start, gf= n_t end) return _dat_walk_gfn_range(start, end, asce, &test_age_ops, 0, NULL) > 0; } =20 -int dat_link(struct kvm_s390_mmu_cache *mc, union asce asce, int level, - bool uses_skeys, struct guest_fault *f) -{ - union crste oldval, newval; - union pte newpte, oldpte; - union pgste pgste; - int rc =3D 0; - - rc =3D dat_entry_walk(mc, f->gfn, asce, DAT_WALK_ALLOC_CONTINUE, level, &= f->crstep, &f->ptep); - if (rc =3D=3D -EINVAL || rc =3D=3D -ENOMEM) - return rc; - if (rc) - return -EAGAIN; - - if (WARN_ON_ONCE(unlikely(get_level(f->crstep, f->ptep) > level))) - return -EINVAL; - - if (f->ptep) { - pgste =3D pgste_get_lock(f->ptep); - oldpte =3D *f->ptep; - newpte =3D _pte(f->pfn, f->writable, f->write_attempt | oldpte.s.d, !f->= page); - newpte.s.sd =3D oldpte.s.sd; - oldpte.s.sd =3D 0; - if (oldpte.val =3D=3D _PTE_EMPTY.val || oldpte.h.pfra =3D=3D f->pfn) { - pgste =3D __dat_ptep_xchg(f->ptep, pgste, newpte, f->gfn, asce, uses_sk= eys); - if (f->callback) - f->callback(f); - } else { - rc =3D -EAGAIN; - } - pgste_set_unlock(f->ptep, pgste); - } else { - oldval =3D READ_ONCE(*f->crstep); - newval =3D _crste_fc1(f->pfn, oldval.h.tt, f->writable, - f->write_attempt | oldval.s.fc1.d); - newval.s.fc1.sd =3D oldval.s.fc1.sd; - if (oldval.val !=3D _CRSTE_EMPTY(oldval.h.tt).val && - crste_origin_large(oldval) !=3D crste_origin_large(newval)) - return -EAGAIN; - if (!dat_crstep_xchg_atomic(f->crstep, oldval, newval, f->gfn, asce)) - return -EAGAIN; - if (f->callback) - f->callback(f); - } - - return rc; -} - static long dat_set_pn_crste(union crste *crstep, gfn_t gfn, gfn_t next, s= truct dat_walk *walk) { union crste newcrste, oldcrste; diff --git a/arch/s390/kvm/dat.h b/arch/s390/kvm/dat.h index 22dafc775335..efedcf96110c 100644 --- a/arch/s390/kvm/dat.h +++ b/arch/s390/kvm/dat.h @@ -540,8 +540,6 @@ int dat_set_slot(struct kvm_s390_mmu_cache *mc, union a= sce asce, gfn_t start, gf u16 type, u16 param); int dat_set_prefix_notif_bit(union asce asce, gfn_t gfn); bool dat_test_age_gfn(union asce asce, gfn_t start, gfn_t end); -int dat_link(struct kvm_s390_mmu_cache *mc, union asce asce, int level, - bool uses_skeys, struct guest_fault *f); =20 int dat_perform_essa(union asce asce, gfn_t gfn, int orc, union essa_state= *state, bool *dirty); long dat_reset_cmma(union asce asce, gfn_t start_gfn); diff --git a/arch/s390/kvm/gmap.c b/arch/s390/kvm/gmap.c index 956be4c01797..03e15b5e0b9a 100644 --- a/arch/s390/kvm/gmap.c +++ b/arch/s390/kvm/gmap.c @@ -631,10 +631,60 @@ static inline bool gmap_1m_allowed(struct gmap *gmap,= gfn_t gfn) return test_bit(GMAP_FLAG_ALLOW_HPAGE_1M, &gmap->flags); } =20 +static int _gmap_link(struct kvm_s390_mmu_cache *mc, struct gmap *gmap, in= t level, + struct guest_fault *f) +{ + union crste oldval, newval; + union pte newpte, oldpte; + union pgste pgste; + int rc =3D 0; + + rc =3D dat_entry_walk(mc, f->gfn, gmap->asce, DAT_WALK_ALLOC_CONTINUE, le= vel, + &f->crstep, &f->ptep); + if (rc =3D=3D -ENOMEM) + return rc; + if (KVM_BUG_ON(rc =3D=3D -EINVAL, gmap->kvm)) + return rc; + if (rc) + return -EAGAIN; + if (KVM_BUG_ON(get_level(f->crstep, f->ptep) > level, gmap->kvm)) + return -EINVAL; + + if (f->ptep) { + pgste =3D pgste_get_lock(f->ptep); + oldpte =3D *f->ptep; + newpte =3D _pte(f->pfn, f->writable, f->write_attempt | oldpte.s.d, !f->= page); + newpte.s.sd =3D oldpte.s.sd; + oldpte.s.sd =3D 0; + if (oldpte.val =3D=3D _PTE_EMPTY.val || oldpte.h.pfra =3D=3D f->pfn) { + pgste =3D gmap_ptep_xchg(gmap, f->ptep, newpte, pgste, f->gfn); + if (f->callback) + f->callback(f); + } else { + rc =3D -EAGAIN; + } + pgste_set_unlock(f->ptep, pgste); + } else { + do { + oldval =3D READ_ONCE(*f->crstep); + newval =3D _crste_fc1(f->pfn, oldval.h.tt, f->writable, + f->write_attempt | oldval.s.fc1.d); + newval.s.fc1.sd =3D oldval.s.fc1.sd; + if (oldval.val !=3D _CRSTE_EMPTY(oldval.h.tt).val && + crste_origin_large(oldval) !=3D crste_origin_large(newval)) + return -EAGAIN; + } while (!gmap_crstep_xchg_atomic(gmap, f->crstep, oldval, newval, f->gf= n)); + if (f->callback) + f->callback(f); + } + + return rc; +} + int gmap_link(struct kvm_s390_mmu_cache *mc, struct gmap *gmap, struct gue= st_fault *f) { unsigned int order; - int rc, level; + int level; =20 lockdep_assert_held(&gmap->kvm->mmu_lock); =20 @@ -646,9 +696,7 @@ int gmap_link(struct kvm_s390_mmu_cache *mc, struct gma= p *gmap, struct guest_fau else if (order >=3D get_order(_SEGMENT_SIZE) && gmap_1m_allowed(gmap, f-= >gfn)) level =3D TABLE_TYPE_SEGMENT; } - rc =3D dat_link(mc, gmap->asce, level, uses_skeys(gmap), f); - KVM_BUG_ON(rc =3D=3D -EINVAL, gmap->kvm); - return rc; + return _gmap_link(mc, gmap, level, f); } =20 static int gmap_ucas_map_one(struct kvm_s390_mmu_cache *mc, struct gmap *g= map, --=20 2.53.0