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Wed, 4 Feb 2026 15:03:03 +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, nsg@linux.ibm.com, nrb@linux.ibm.com, seiden@linux.ibm.com, gra@linux.ibm.com, schlameuss@linux.ibm.com, hca@linux.ibm.com, svens@linux.ibm.com, agordeev@linux.ibm.com, gor@linux.ibm.com, david@kernel.org, gerald.schaefer@linux.ibm.com Subject: [PATCH v7 13/29] KVM: s390: KVM page table management functions: allocation Date: Wed, 4 Feb 2026 16:02:42 +0100 Message-ID: <20260204150259.60425-14-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260204150259.60425-1-imbrenda@linux.ibm.com> References: <20260204150259.60425-1-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-Spam-Details-Enc: AW1haW4tMjYwMjA0MDExMyBTYWx0ZWRfX2gb73XrOvkCa E6oQTTev2NneT4uw/poewtbnnnMiHy7kpHq1LURMtkW5M1j+USr8WvqbebJKnAW2VQBslyuJduF iexRk/br0x/lp1g4KaOrbRVW8fEeP51sMZQfjOGCzenzNbJSWmLF+5dKQOCbiwOToxVvyBHJOTv fAd8ILYsPzzA97I9BTGK10FAKueuVZAahqnLkPWPE+fZID+C61vmbQfFpFp7X9UANTNFpABy63R uvCR+L2HtrvwXO1yQzgqWLV8LxGUJMR8Do8LYduJorYkt7OBMcCwHLP1jgMvabtg1FhXN+pF2Eo MO8N+PRD2cBNvUbp56DGxAkxNi5t9rAtHYtRLwrakOWwmvuUOJrBMB3ORXdZ75BSl4++rpskGJC 4OMu74XSEcHYXmG3w+toDvhiYEs6kxIQhrPqYUr6ekCmJq6RATekdXGITcn0wEq09YvFWsLnHN4 PTVzLrhR6uDhcASchGw== X-Proofpoint-GUID: _zcMZEaWR1ccVvGANlvtJbHz7sxLxAu2 X-Proofpoint-ORIG-GUID: _zcMZEaWR1ccVvGANlvtJbHz7sxLxAu2 X-Authority-Analysis: v=2.4 cv=LesxKzfi c=1 sm=1 tr=0 ts=69835fad cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=HzLeVaNsDn8A:10 a=VkNPw1HP01LnGYTKEx00:22 a=VnNF1IyMAAAA:8 a=20KFwNOVAAAA:8 a=ciOewYurfqE_QU1RCzEA:9 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-02-04_04,2026-02-04_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 impostorscore=0 spamscore=0 lowpriorityscore=0 clxscore=1015 adultscore=0 suspectscore=0 priorityscore=1501 phishscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2601150000 definitions=main-2602040113 Content-Type: text/plain; charset="utf-8" Add page table management functions to be used for KVM guest (gmap) page tables. This patch adds the boilerplate and functions for the allocation and deallocation of DAT tables. Signed-off-by: Claudio Imbrenda --- arch/s390/kvm/Makefile | 1 + arch/s390/kvm/dat.c | 103 +++++++++++++++++++++++++++++++++++++ arch/s390/kvm/dat.h | 77 +++++++++++++++++++++++++++ arch/s390/mm/page-states.c | 1 + 4 files changed, 182 insertions(+) create mode 100644 arch/s390/kvm/dat.c diff --git a/arch/s390/kvm/Makefile b/arch/s390/kvm/Makefile index 9a723c48b05a..84315d2f75fb 100644 --- a/arch/s390/kvm/Makefile +++ b/arch/s390/kvm/Makefile @@ -9,6 +9,7 @@ ccflags-y :=3D -Ivirt/kvm -Iarch/s390/kvm =20 kvm-y +=3D kvm-s390.o intercept.o interrupt.o priv.o sigp.o kvm-y +=3D diag.o gaccess.o guestdbg.o vsie.o pv.o gmap-vsie.o +kvm-y +=3D dat.o =20 kvm-$(CONFIG_VFIO_PCI_ZDEV_KVM) +=3D pci.o obj-$(CONFIG_KVM) +=3D kvm.o diff --git a/arch/s390/kvm/dat.c b/arch/s390/kvm/dat.c new file mode 100644 index 000000000000..c324a27f379f --- /dev/null +++ b/arch/s390/kvm/dat.c @@ -0,0 +1,103 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KVM guest address space mapping code + * + * Copyright IBM Corp. 2007, 2020, 2024 + * Author(s): Claudio Imbrenda + * Martin Schwidefsky + * David Hildenbrand + * Janosch Frank + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include "dat.h" + +int kvm_s390_mmu_cache_topup(struct kvm_s390_mmu_cache *mc) +{ + void *o; + + for ( ; mc->n_crsts < KVM_S390_MMU_CACHE_N_CRSTS; mc->n_crsts++) { + o =3D (void *)__get_free_pages(GFP_KERNEL_ACCOUNT | __GFP_COMP, CRST_ALL= OC_ORDER); + if (!o) + return -ENOMEM; + mc->crsts[mc->n_crsts] =3D o; + } + for ( ; mc->n_pts < KVM_S390_MMU_CACHE_N_PTS; mc->n_pts++) { + o =3D (void *)__get_free_page(GFP_KERNEL_ACCOUNT); + if (!o) + return -ENOMEM; + mc->pts[mc->n_pts] =3D o; + } + for ( ; mc->n_rmaps < KVM_S390_MMU_CACHE_N_RMAPS; mc->n_rmaps++) { + o =3D kzalloc(sizeof(*mc->rmaps[0]), GFP_KERNEL_ACCOUNT); + if (!o) + return -ENOMEM; + mc->rmaps[mc->n_rmaps] =3D o; + } + return 0; +} + +static inline struct page_table *dat_alloc_pt_noinit(struct kvm_s390_mmu_c= ache *mc) +{ + struct page_table *res; + + res =3D kvm_s390_mmu_cache_alloc_pt(mc); + if (res) + __arch_set_page_dat(res, 1); + return res; +} + +static inline struct crst_table *dat_alloc_crst_noinit(struct kvm_s390_mmu= _cache *mc) +{ + struct crst_table *res; + + res =3D kvm_s390_mmu_cache_alloc_crst(mc); + if (res) + __arch_set_page_dat(res, 1UL << CRST_ALLOC_ORDER); + return res; +} + +struct crst_table *dat_alloc_crst_sleepable(unsigned long init) +{ + struct page *page; + void *virt; + + page =3D alloc_pages(GFP_KERNEL_ACCOUNT | __GFP_COMP, CRST_ALLOC_ORDER); + if (!page) + return NULL; + virt =3D page_to_virt(page); + __arch_set_page_dat(virt, 1UL << CRST_ALLOC_ORDER); + crst_table_init(virt, init); + return virt; +} + +void dat_free_level(struct crst_table *table, bool owns_ptes) +{ + unsigned int i; + + for (i =3D 0; i < _CRST_ENTRIES; i++) { + if (table->crstes[i].h.fc || table->crstes[i].h.i) + continue; + if (!is_pmd(table->crstes[i])) + dat_free_level(dereference_crste(table->crstes[i]), owns_ptes); + else if (owns_ptes) + dat_free_pt(dereference_pmd(table->crstes[i].pmd)); + } + dat_free_crst(table); +} diff --git a/arch/s390/kvm/dat.h b/arch/s390/kvm/dat.h index d5e1a45813bc..a053f0d49bae 100644 --- a/arch/s390/kvm/dat.h +++ b/arch/s390/kvm/dat.h @@ -418,6 +418,46 @@ struct vsie_rmap { =20 static_assert(sizeof(struct vsie_rmap) =3D=3D 2 * sizeof(long)); =20 +#define KVM_S390_MMU_CACHE_N_CRSTS 6 +#define KVM_S390_MMU_CACHE_N_PTS 2 +#define KVM_S390_MMU_CACHE_N_RMAPS 16 +struct kvm_s390_mmu_cache { + void *crsts[KVM_S390_MMU_CACHE_N_CRSTS]; + void *pts[KVM_S390_MMU_CACHE_N_PTS]; + void *rmaps[KVM_S390_MMU_CACHE_N_RMAPS]; + short int n_crsts; + short int n_pts; + short int n_rmaps; +}; + +void dat_free_level(struct crst_table *table, bool owns_ptes); +struct crst_table *dat_alloc_crst_sleepable(unsigned long init); + +int kvm_s390_mmu_cache_topup(struct kvm_s390_mmu_cache *mc); + +#define GFP_KVM_S390_MMU_CACHE (GFP_ATOMIC | __GFP_ACCOUNT | __GFP_NOWARN) + +static inline struct page_table *kvm_s390_mmu_cache_alloc_pt(struct kvm_s3= 90_mmu_cache *mc) +{ + if (mc->n_pts) + return mc->pts[--mc->n_pts]; + return (void *)__get_free_page(GFP_KVM_S390_MMU_CACHE); +} + +static inline struct crst_table *kvm_s390_mmu_cache_alloc_crst(struct kvm_= s390_mmu_cache *mc) +{ + if (mc->n_crsts) + return mc->crsts[--mc->n_crsts]; + return (void *)__get_free_pages(GFP_KVM_S390_MMU_CACHE | __GFP_COMP, CRST= _ALLOC_ORDER); +} + +static inline struct vsie_rmap *kvm_s390_mmu_cache_alloc_rmap(struct kvm_s= 390_mmu_cache *mc) +{ + if (mc->n_rmaps) + return mc->rmaps[--mc->n_rmaps]; + return kzalloc(sizeof(struct vsie_rmap), GFP_KVM_S390_MMU_CACHE); +} + static inline struct crst_table *crste_table_start(union crste *crstep) { return (struct crst_table *)ALIGN_DOWN((unsigned long)crstep, _CRST_TABLE= _SIZE); @@ -717,4 +757,41 @@ static inline void pgste_set_unlock(union pte *ptep, u= nion pgste pgste) WRITE_ONCE(*pgste_of(ptep), pgste); } =20 +static inline void dat_free_pt(struct page_table *pt) +{ + free_page((unsigned long)pt); +} + +static inline void _dat_free_crst(struct crst_table *table) +{ + free_pages((unsigned long)table, CRST_ALLOC_ORDER); +} + +#define dat_free_crst(x) _dat_free_crst(_CRSTP(x)) + +static inline void kvm_s390_free_mmu_cache(struct kvm_s390_mmu_cache *mc) +{ + if (!mc) + return; + while (mc->n_pts) + dat_free_pt(mc->pts[--mc->n_pts]); + while (mc->n_crsts) + _dat_free_crst(mc->crsts[--mc->n_crsts]); + while (mc->n_rmaps) + kfree(mc->rmaps[--mc->n_rmaps]); + kfree(mc); +} + +DEFINE_FREE(kvm_s390_mmu_cache, struct kvm_s390_mmu_cache *, if (_T) kvm_s= 390_free_mmu_cache(_T)) + +static inline struct kvm_s390_mmu_cache *kvm_s390_new_mmu_cache(void) +{ + struct kvm_s390_mmu_cache *mc __free(kvm_s390_mmu_cache) =3D NULL; + + mc =3D kzalloc(sizeof(*mc), GFP_KERNEL_ACCOUNT); + if (mc && !kvm_s390_mmu_cache_topup(mc)) + return_ptr(mc); + return NULL; +} + #endif /* __KVM_S390_DAT_H */ diff --git a/arch/s390/mm/page-states.c b/arch/s390/mm/page-states.c index 01f9b39e65f5..5bee173db72e 100644 --- a/arch/s390/mm/page-states.c +++ b/arch/s390/mm/page-states.c @@ -13,6 +13,7 @@ #include =20 int __bootdata_preserved(cmma_flag); +EXPORT_SYMBOL(cmma_flag); =20 void arch_free_page(struct page *page, int order) { --=20 2.52.0