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Wed, 4 Feb 2026 15:03:02 +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 10/29] KVM: s390: Enable KVM_GENERIC_MMU_NOTIFIER Date: Wed, 4 Feb 2026 16:02:39 +0100 Message-ID: <20260204150259.60425-11-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: AW1haW4tMjYwMjA0MDExMyBTYWx0ZWRfX1bR9wHgpCccQ ijr78ARjMXdVw1BuAruwTJb/bTqNKvWtPhaRzMFP/Vyebe4od2brHQ/P2ELrBKZWnKxdCP+zOjN jWhlnl5R8EoHJz1a8z9jP1dE4YUWNZSeWqhN0i2Od51HlUaf0VTQcCkW0HgFaG7qrMtWBhe0dXS 32r5qJePwBH++gCgJuhZBay4UmbRpNXh07LjVuD+21a+93fIZsMIq/PkLmuziT+bJ0sMZ0HT2N4 Ef4UYidptSRSg2cMk4dZp+wfrEvzIafpXd0ypsMF0xbDMK+kYxSqXne+MWz7sn7Km2o7XHv9afk 0A60KgJH/xMnxAPwsTPI2+v0k8tRPMJKliGVNWbNj1SSvbb7iYnxRgv8a1QVwBGp8KDTIe6O8ht loc+9rtLNw3odAzDm4OZ2r8KCj2PhND/Mg6sWYiiIu6ohWY1qRMvzTHuxWJScj9qcT8H5qi9Xms ewoGEWi6bzvrhG6Cj9g== X-Authority-Analysis: v=2.4 cv=UuRu9uwB c=1 sm=1 tr=0 ts=69835fab cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=HzLeVaNsDn8A:10 a=VkNPw1HP01LnGYTKEx00:22 a=VnNF1IyMAAAA:8 a=sWpJ-_il0aw9mM0vlR0A:9 X-Proofpoint-ORIG-GUID: JBhZwtGI8A2FbpnkPh3cIxmHSgMeWUr7 X-Proofpoint-GUID: JBhZwtGI8A2FbpnkPh3cIxmHSgMeWUr7 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 spamscore=0 bulkscore=0 adultscore=0 clxscore=1015 phishscore=0 malwarescore=0 lowpriorityscore=0 priorityscore=1501 impostorscore=0 suspectscore=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" Enable KVM_GENERIC_MMU_NOTIFIER, for now with empty placeholder callbacks. Also enable KVM_MMU_LOCKLESS_AGING and define KVM_HAVE_MMU_RWLOCK. Signed-off-by: Claudio Imbrenda Acked-by: Christian Borntraeger Reviewed-by: Steffen Eiden Reviewed-by: Christoph Schlameuss --- arch/s390/include/asm/kvm_host.h | 1 + arch/s390/kvm/Kconfig | 2 ++ arch/s390/kvm/kvm-s390.c | 45 +++++++++++++++++++++++++++++++- 3 files changed, 47 insertions(+), 1 deletion(-) diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_h= ost.h index 3dbddb7c60a9..6ba99870fc32 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -27,6 +27,7 @@ #include #include =20 +#define KVM_HAVE_MMU_RWLOCK #define KVM_MAX_VCPUS 255 =20 #define KVM_INTERNAL_MEM_SLOTS 1 diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig index f4ec8c1ce214..917ac740513e 100644 --- a/arch/s390/kvm/Kconfig +++ b/arch/s390/kvm/Kconfig @@ -30,6 +30,8 @@ config KVM select KVM_VFIO select MMU_NOTIFIER select VIRT_XFER_TO_GUEST_WORK + select KVM_GENERIC_MMU_NOTIFIER + select KVM_MMU_LOCKLESS_AGING help Support hosting paravirtualized guest machines using the SIE virtualization capability on the mainframe. This should work diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index cd39b2f099ca..ec92e6361eab 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -4805,7 +4805,7 @@ int __kvm_s390_handle_dat_fault(struct kvm_vcpu *vcpu= , gfn_t gfn, gpa_t gaddr, u rc =3D fixup_user_fault(vcpu->arch.gmap->mm, vmaddr, fault_flags, &unlock= ed); if (!rc) rc =3D __gmap_link(vcpu->arch.gmap, gaddr, vmaddr); - scoped_guard(spinlock, &vcpu->kvm->mmu_lock) { + scoped_guard(read_lock, &vcpu->kvm->mmu_lock) { kvm_release_faultin_page(vcpu->kvm, page, false, writable); } mmap_read_unlock(vcpu->arch.gmap->mm); @@ -6021,6 +6021,49 @@ void kvm_arch_commit_memory_region(struct kvm *kvm, return; } =20 +/** + * kvm_test_age_gfn() - test young + * @kvm: the kvm instance + * @range: the range of guest addresses whose young status needs to be cle= ared + * + * Context: called by KVM common code without holding the kvm mmu lock + * Return: true if any page in the given range is young, otherwise 0. + */ +bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range) +{ + return false; +} + +/** + * kvm_age_gfn() - clear young + * @kvm: the kvm instance + * @range: the range of guest addresses whose young status needs to be cle= ared + * + * Context: called by KVM common code without holding the kvm mmu lock + * Return: true if any page in the given range was young, otherwise 0. + */ +bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range) +{ + return false; +} + +/** + * kvm_unmap_gfn_range() - Unmap a range of guest addresses + * @kvm: the kvm instance + * @range: the range of guest page frames to invalidate + * + * This function always returns false because every DAT table modification + * has to use the appropriate DAT table manipulation instructions, which w= ill + * keep the TLB coherent, hence no additional TLB flush is ever required. + * + * Context: called by KVM common code with the kvm mmu write lock held + * Return: false + */ +bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range) +{ + return false; +} + static inline unsigned long nonhyp_mask(int i) { unsigned int nonhyp_fai =3D (sclp.hmfai << i * 2) >> 30; --=20 2.52.0