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Mon, 13 Jul 2026 15:09:01 +0000 (GMT) Received: from p-imbrenda.ibmuc.com (unknown [9.87.153.197]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 13 Jul 2026 15:09:01 +0000 (GMT) From: Claudio Imbrenda To: linux-kernel@vger.kernel.org Cc: 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 4/7] KVM: s390: cmma: Fix dirty tracking when removing memslot Date: Mon, 13 Jul 2026 17:08:54 +0200 Message-ID: <20260713150857.269954-5-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260713150857.269954-1-imbrenda@linux.ibm.com> References: <20260713150857.269954-1-imbrenda@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Info: AW1haW4tMjYwNzEzMDE1MyBTYWx0ZWRfX4zom+YPoBfJF 1jgIO0OphbhuWMimCQT9KRLDYvPPA//dnHgUHXcLRraXT6YAZMV2jgkK0O1Qs23afTG7JekSgbF 9S3amYMDCjX8oRCgCOKVJareZiSRNxk= X-Authority-Analysis: v=2.4 cv=Mp1iLWae c=1 sm=1 tr=0 ts=6a54ff95 cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=uAbxVGIbfxUO_5tXvNgY:22 a=VnNF1IyMAAAA:8 a=VchRnoiWiGOQ40ZGZhEA:9 X-Proofpoint-GUID: ZtNDdClKLj6cs9099sb2zCmjEz1w-wVV X-Proofpoint-ORIG-GUID: ZtNDdClKLj6cs9099sb2zCmjEz1w-wVV X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzEzMDE1MyBTYWx0ZWRfX6rQLkJSs8nKk YxxLPCzS+g0wbMLjkvFtLPVtZ/9+jOyBURjJ3Dl4AGlocp5PhzqmjtLbKf83NtcH5Yd8HJ0XXVo GH475K4RZ6N9kRbjfkBTblKy5AZJggy8twufBwOaPp0elbvTHHqgriL9lQTSN9Y0AAL+Xa1vWcC A3OywdHzBZhncDHnDbKrhRF05wLb4Fon8Khnatw0iIaXaBalbpsICc4W8korJBqaY927J/PwePd yGyIvsTAUZB/q98OMRepbdEqpZ95D5nVHkQZ887U+DlBXTFYhQGX7rycblAG2JamtYPDljmNv1L xPkMZODdIUM8GmbXYhPxuVXoyECLu1OXr/ZwZDFaA/gJObMr4U05yfwQWBjpMsEiUZ22OPO3AH3 5MODUiysL7HDuZY8JM9BGZvufiKx0upEBAv7unfXf9a2wa+Rh9jx1m3iD8BjPSbJ/TRwrWPZFDf 82EypmMa6kGWjWpNB8g== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-13_03,2026-07-10_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 bulkscore=0 spamscore=0 malwarescore=0 lowpriorityscore=0 impostorscore=0 priorityscore=1501 suspectscore=0 clxscore=1015 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607130153 When a memslot is removed, all ptes that mapped the slot are cleared or even deallocated. If this happens while the system is in migration mode, and if cmma-dirty pages are removed, the cmma-dirty counter will not reflect reality. Fix by appropriately decrementing the cmma-dirty counter when removing a memslot. Fixes: e38c884df921 ("KVM: s390: Switch to new gmap") Signed-off-by: Claudio Imbrenda --- arch/s390/kvm/dat.c | 7 ++++++- arch/s390/kvm/kvm-s390.c | 14 ++++++++++++++ 2 files changed, 20 insertions(+), 1 deletion(-) diff --git a/arch/s390/kvm/dat.c b/arch/s390/kvm/dat.c index 5f1960ec982d..cc0b8b1330c2 100644 --- a/arch/s390/kvm/dat.c +++ b/arch/s390/kvm/dat.c @@ -844,6 +844,7 @@ static long _dat_slot_pte(union pte *ptep, gfn_t gfn, gfn_t next, struct dat_wal struct slot_priv *p = walk->priv; union crste dummy = { .val = p->token }; union pte new_pte, pte = READ_ONCE(*ptep); + union pgste pgste; new_pte = _PTE_TOK(dummy.tok.type, dummy.tok.par); @@ -851,7 +852,11 @@ static long _dat_slot_pte(union pte *ptep, gfn_t gfn, gfn_t next, struct dat_wal if (pte.val == new_pte.val) return 0; - dat_ptep_xchg(ptep, new_pte, gfn, walk->asce, false); + pgste = pgste_get_lock(ptep); + pgste = __dat_ptep_xchg(ptep, pgste, new_pte, gfn, walk->asce, false); + pgste.cmma_d = 0; + pgste_set_unlock(ptep, pgste); + return 0; } diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 9e3b8b5c6aa6..5c2408fc5a8c 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -5796,11 +5796,19 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, return 0; } +static long cmma_d_count_pte(union pte *ptep, gfn_t gfn, gfn_t next, struct dat_walk *walk) +{ + if (pgste_of(ptep)->cmma_d) + atomic64_dec(walk->priv); + return 0; +} + void kvm_arch_commit_memory_region(struct kvm *kvm, struct kvm_memory_slot *old, const struct kvm_memory_slot *new, enum kvm_mr_change change) { + const struct dat_walk_ops ops = { .pte_entry = cmma_d_count_pte, }; struct kvm_s390_mmu_cache *mc = NULL; int rc = 0; @@ -5814,6 +5822,12 @@ void kvm_arch_commit_memory_region(struct kvm *kvm, } scoped_guard(write_lock, &kvm->mmu_lock) { + if (kvm->arch.migration_mode && kvm->arch.use_cmma) { + _dat_walk_gfn_range(old->base_gfn, old->base_gfn + old->npages, + kvm->arch.gmap->asce, &ops, DAT_WALK_IGN_HOLES, + &kvm->arch.cmma_dirty_pages); + } + switch (change) { case KVM_MR_DELETE: rc = dat_delete_slot(mc, kvm->arch.gmap->asce, old->base_gfn, old->npages); -- 2.55.0