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Wed, 10 Jun 2026 16:52:48 +0000 (GMT) Received: from p-imbrenda.ehn-de.ibm.com (unknown [9.224.75.30]) by smtpav07.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 10 Jun 2026 16:52:48 +0000 (GMT) From: Claudio Imbrenda To: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org, kvm@vger.kernel.org, linux-s390@vger.kernel.org, borntraeger@de.ibm.com, frankja@linux.ibm.com, david@kernel.org, seiden@linux.ibm.com, nrb@linux.ibm.com, schlameuss@linux.ibm.com, gra@linux.ibm.com Subject: [PATCH v2 4/5] KVM: s390: vsie: Add missing radix_tree_preload() in _gaccess_shadow_fault() Date: Wed, 10 Jun 2026 18:52:46 +0200 Message-ID: <20260610165247.238366-5-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260610165247.238366-1-imbrenda@linux.ibm.com> References: <20260610165247.238366-1-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: 8bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=HppG3UTS c=1 sm=1 tr=0 ts=6a299666 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=FelO9ux0wxsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=uAbxVGIbfxUO_5tXvNgY:22 a=VnNF1IyMAAAA:8 a=VwQbUJbxAAAA:8 a=5WtQGhaX4H0GvqE0kYQA:9 X-Proofpoint-GUID: o5KNSC1hRgppjCyKnnedZxHSSIk6Tfy7 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjEwMDE1NiBTYWx0ZWRfX0F9rTgTAhXVQ ArU6Lww8BI8RT3pr+gqZQqJUvfmiKFFvlKZc7sE0f1o5bYxZoX/Rsp+tNkBNqcZKhyxOr89Wqfk wd/VP26+a0bUyC0WeBzFP5DENALKSTemUoDqUkI8RYpvmPmzSgp/qry/zwoJoCWkGhpG7OLP96g stKahPTuW9WSqkB/04t7UVJClIH9B7/D3wYxcz1+8dUkaUYVXKRgEaL1XUM6A8XQm2+BpGmeQW5 mKoB91bH91VHG3AaUzlmnVHgFWxG1A951xgp1H6Lju09kaAd//McBrxmtNqUuWuV5+YhL3u8zrE SzYjWCjn+uLj/z94UmiKlBqOc30wD3lZgTQ5f8y7dMNFqx/n9hNoyzu1E4d5WMX0Ux7bIpkiWtZ OJsfFdy72fkqmmRQj5Xyrux32DKD27u6CyhKDeu8y0cPdH48iqd4Lz19rBUN8jp3aJN1L0pXsgf uTs2fwfgT/x90CGLrJw== X-Proofpoint-ORIG-GUID: o5KNSC1hRgppjCyKnnedZxHSSIk6Tfy7 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-06-10_03,2026-06-09_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 adultscore=0 phishscore=0 malwarescore=0 impostorscore=0 priorityscore=1501 clxscore=1015 bulkscore=0 spamscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2605210000 definitions=main-2606100156 Add missing radix_tree_preload() in _gaccess_shadow_fault() to guarantee forward progress. The core of _gaccess_shadow_fault() has been split into ___gaccess_shadow_fault() in order to simplify locking. Fixes: e38c884df921 ("KVM: s390: Switch to new gmap") Signed-off-by: Claudio Imbrenda CC: stable@vger.kernel.org # 7.1 --- arch/s390/kvm/gaccess.c | 49 +++++++++++++++++++++++++---------------- 1 file changed, 30 insertions(+), 19 deletions(-) diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c index 20e28b183c1a..c072b6872bf8 100644 --- a/arch/s390/kvm/gaccess.c +++ b/arch/s390/kvm/gaccess.c @@ -1582,35 +1582,46 @@ static int _gaccess_do_shadow(struct kvm_s390_mmu_cache *mc, struct gmap *sg, return _do_shadow_crste(sg, saddr, host, table, entries + LEVEL_MEM, w->p); } +static inline int ___gaccess_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg, gpa_t saddr, + unsigned long seq, struct pgtwalk *walk) +{ + struct gmap *parent; + int rc; + + if (kvm_s390_array_needs_retry_safe(vcpu->kvm, seq, walk->raw_entries)) + return -EAGAIN; + parent = READ_ONCE(sg->parent); + if (!parent) + return -EAGAIN; + scoped_guard(spinlock, &parent->children_lock) { + if (READ_ONCE(sg->parent) != parent) + return -EAGAIN; + sg->invalidated = false; + rc = _gaccess_do_shadow(vcpu->arch.mc, sg, saddr, walk); + } + if (!rc) + kvm_s390_release_faultin_array(vcpu->kvm, walk->raw_entries, false); + return rc; +} + static inline int _gaccess_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg, gpa_t saddr, unsigned long seq, struct pgtwalk *walk) { - struct gmap *parent; int rc; if (kvm_s390_array_needs_retry_unsafe(vcpu->kvm, seq, walk->raw_entries)) return -EAGAIN; -again: rc = kvm_s390_mmu_cache_topup(vcpu->arch.mc); if (rc) return rc; - scoped_guard(read_lock, &vcpu->kvm->mmu_lock) { - if (kvm_s390_array_needs_retry_safe(vcpu->kvm, seq, walk->raw_entries)) - return -EAGAIN; - parent = READ_ONCE(sg->parent); - if (!parent) - return -EAGAIN; - scoped_guard(spinlock, &parent->children_lock) { - if (READ_ONCE(sg->parent) != parent) - return -EAGAIN; - sg->invalidated = false; - rc = _gaccess_do_shadow(vcpu->arch.mc, sg, saddr, walk); - } - if (rc == -ENOMEM) - goto again; - if (!rc) - kvm_s390_release_faultin_array(vcpu->kvm, walk->raw_entries, false); - } + + do { + radix_tree_preload(GFP_KERNEL); + scoped_guard(read_lock, &vcpu->kvm->mmu_lock) + rc = ___gaccess_shadow_fault(vcpu, sg, saddr, seq, walk); + radix_tree_preload_end(); + } while (rc == -ENOMEM); + return rc; } -- 2.54.0