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Mon, 27 Jul 2026 15:02:58 +0000 (GMT) Received: from p-imbrenda.ibmuc.com (unknown [9.111.1.146]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 27 Jul 2026 15:02:58 +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 v3 04/10] KVM: s390: cmma: Fix dirty tracking when removing memslot Date: Mon, 27 Jul 2026 17:02:48 +0200 Message-ID: <20260727150254.236021-5-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260727150254.236021-1-imbrenda@linux.ibm.com> References: <20260727150254.236021-1-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-Proofpoint-Spam-Info: AW1haW4tMjYwNzI3MDE0MCBTYWx0ZWRfX5r33fYvp9pH1 7xQ+THuYbV08fgUlCE87MKnSdyP50xtrWXbk1+LK8L46XrLZHyhYa4l8eZKdb7k8Dk17TpPRQu4 Ufni+rxlHZZTB2eb8sJuKgI/3lZoP4M= X-Proofpoint-GUID: pffOg-S3zhRV9P5JNvt1_cgBLfe6sYH2 X-Proofpoint-ORIG-GUID: pffOg-S3zhRV9P5JNvt1_cgBLfe6sYH2 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzI3MDE0MCBTYWx0ZWRfX5I8bKAOndxlh yK3935TfFAXslpsfcfHUPQQm32gxuSo0Ct8+zoOKWQ4l7NVyNV7XFTpCP62oC1xY3EUHP5WboBx kV0NJ4gIx1THUztEC03wCWJsD+hIZFlMuSc/cTL/lbPeI7qJ4tH4vOA3n1fxgWUH6pRei4a0kvE LCv3spTevUTb1rsZfhRfwwwOsklRFC2d4ZiOpKSlx2YJDYuavGtA1RMgW7q3GbhfGDltWkzGykh XwdOMvkTJsgoGma6LRN5Lr2s7P2QwM27VlYpIO6OEk8oWZcRhMbHjOyA/6cWwMwzvwJOSMFrMjF 7fhXegl3ScUugbvmaLKbhOXtpV3hEsl5fFgApeSx0nU7Sioqqsg7zYW5nCUgy8KAjrQJdT81QYD a40XZ2nYYYic6+ExTFNhPN5iJF+ZyG7jOWfS3/JMck62PWLc+ViwIwdI44Ucv0E6Pt2/YmBf82Y PrrLs0KWZpzxBKPvA6g== X-Authority-Analysis: v=2.4 cv=X5Vi7mTe c=1 sm=1 tr=0 ts=6a67732a cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VnNF1IyMAAAA:8 a=VchRnoiWiGOQ40ZGZhEA:9 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=2026-07-27_04,2026-07-24_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 impostorscore=0 lowpriorityscore=0 phishscore=0 priorityscore=1501 malwarescore=0 spamscore=0 suspectscore=0 bulkscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607270140 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 | 16 ++++++++++++++++ 2 files changed, 22 insertions(+), 1 deletion(-) diff --git a/arch/s390/kvm/dat.c b/arch/s390/kvm/dat.c index 171b61959908..3f2d6e8902d7 100644 --- a/arch/s390/kvm/dat.c +++ b/arch/s390/kvm/dat.c @@ -850,6 +850,7 @@ 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); @@ -857,7 +858,11 @@ 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 879fdc42cb71..19294d8dff96 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -5802,11 +5802,19 @@ 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; @@ -5819,7 +5827,15 @@ void kvm_arch_commit_memory_region(struct kvm *kvm, goto out; } + guard(mutex)(&kvm->slots_arch_lock); + 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