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Fri, 06 Nov 2026 16:08:26 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (smtpav02.fra02v.mail.ibm.com [10.20.54.101]) by smtprelay05.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 6A6G8MLk50463044 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 6 Nov 2026 16:08:22 GMT Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5527E2004B; Fri, 6 Nov 2026 16:08:22 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E256A20063; Fri, 6 Nov 2026 16:08:21 +0000 (GMT) Received: from a46lp73.lnxne.boe (unknown [9.87.84.240]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTP; Fri, 6 Nov 2026 16:08:21 +0000 (GMT) From: Steffen Eiden Date: Fri, 06 Nov 2026 17:07:53 +0100 Subject: [PATCH v3 20/23] KVM: s390: arm64: Finalize page fault handling X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261106-sysreg-v3-20-75e95980fb10@linux.ibm.com> References: <20261106-sysreg-v3-0-75e95980fb10@linux.ibm.com> In-Reply-To: <20261106-sysreg-v3-0-75e95980fb10@linux.ibm.com> To: Marc Zyngier , Oliver Upton , Fuad Tabba , Joey Gouly , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Mark Rutland , Andreas Grapentin , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , David Hildenbrand , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Sven Schnelle , Friedrich Welter , Gautam Gala , Hariharan Mari , Hendrik Brueckner , Nico Boehr , Ulrich Weigand , Arnd Bergmann , Paolo Bonzini Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-s390@vger.kernel.org, Steffen Eiden X-Mailer: b4 0.14.3 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: A1KLRjZm6OfQ-xEs7CApG9vK_SywaM2a X-Proofpoint-GUID: A1KLRjZm6OfQ-xEs7CApG9vK_SywaM2a X-Authority-Analysis: v=2.4 cv=MqLHeGae c=1 sm=1 tr=0 ts=6aedfb7b cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=IkcTkHD0fZMA:10 a=zJRp6_cAMcgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VnNF1IyMAAAA:8 a=Ycfx71k22ath6WJvB3EA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Info: AW1haW4tMjYxMTA2MDA2MiBTYWx0ZWRfX9wp3kv1cXFuJ SKe0ZtwAfURLTFzx0biVhH6DLO2Ur0O7aRKxjEzqH6p7o7caUPG+E/rulMB2qW83jTnG9te35Ds vAgpbxVhsa6bjWX7cb696pmf8Y11mRI= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMTA2MDA2MiBTYWx0ZWRfX2i4AFsWsbsuZ gnkfURWL70mTo2RCJKV13xtTWTwAkzEzgfJkDSEYAgIRFwHpRFJve9b4RDVXrj2b3IhlIqymx1+ quBsbBpqrtVmQOS+t9MbiEQb9L7tulyMKesaXt7GBYcIUQftxmWMpBqsOT/cbazNXSCfhTX0DFM 0i6E688dPZQuPuP7GWsWgHL6d/ZWJRA9GdmeO/jTnSar4Z5py8DQaAz93JtvDh6k8K3c3N2/rc6 mRAaj/V2X8mTyZqUDAuTKOO5yE0E0BwyOa8shnChQvRDSRvkIiq8dFjyHOmxPbqpVCwWuGrYhjz 15DxrFrw8v1KcQdRA0ZfjL/gM4miCRV+EyMYM1k0o+qp3dQX0+iSmZvfFdJvirbW+8nvZB+j/5l 1TnLvqR7AOOmiJY+aEjeCQDQvcZpyxLoPiEHwmbRYdOPcIfhri+NtmOP17UHCd8QM1cr5WiQz8t nAnK+eG15p6LQUn3OLA== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.138,FMLib:17.12.100.49 definitions=2026-11-06_05,2026-11-06_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 phishscore=0 priorityscore=1501 adultscore=0 clxscore=1015 malwarescore=0 impostorscore=0 spamscore=0 lowpriorityscore=0 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2611040001 definitions=main-2611060062 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261106_080844_365726_2E1A59C2 X-CRM114-Status: GOOD ( 26.84 ) X-Spam-Score: -2.6 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-16.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 Replace the temporary -ENOEXEC returns of the arm64-on-s390 page fault handling with exception injection into the guest, mirroring arm64's kvm_handle_guest_abort(). Translation faults beyond the physical address range are injected as an address size fault, while faults falling between the VM's IPA size and that range are injected as a synchronous external abort. Instruction aborts and stage-1 walk faults on host addresses that back no guest page are injected as synchronous external aborts as well, and a PGM-addressing from the fault-in path is injected as an address size fault, the closest arm64 equivalent. Injected faults return 1 so the vCPU re-enters the guest with the pending exception instead of exiting to userspace. Co-developed-by: Andreas Grapentin Signed-off-by: Andreas Grapentin Signed-off-by: Steffen Eiden --- arch/s390/include/asm/kvm_host_arm64.h | 1 + arch/s390/kvm/arm64/arm.c | 6 +++ arch/s390/kvm/arm64/mmu.c | 74 +++++++++++++++++++++++----------- arch/s390/kvm/arm64/sys_regs.c | 4 ++ 4 files changed, 62 insertions(+), 23 deletions(-) diff --git a/arch/s390/include/asm/kvm_host_arm64.h b/arch/s390/include/asm/kvm_host_arm64.h index 79549434a1d6..20f51cf9ce37 100644 --- a/arch/s390/include/asm/kvm_host_arm64.h +++ b/arch/s390/include/asm/kvm_host_arm64.h @@ -426,5 +426,6 @@ static inline bool vgic_host_has_gicv5(void) } void kvm_adjust_pc(struct kvm_vcpu *vcpu); +size_t kvm_parange_to_address_sanitized(u32 id_parange); #endif /* ASM_KVM_HOST_ARM64_H */ diff --git a/arch/s390/kvm/arm64/arm.c b/arch/s390/kvm/arm64/arm.c index 91e9f4a75ce7..b5a0f8c1e9a4 100644 --- a/arch/s390/kvm/arm64/arm.c +++ b/arch/s390/kvm/arm64/arm.c @@ -63,9 +63,15 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) static u64 kvm_max_guest_address(void) { + u64 mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1); + u64 id_pa_addr; u64 max_addr; + id_pa_addr = kvm_parange_to_address_sanitized( + SYS_FIELD_GET(ID_AA64MMFR0_EL1, PARANGE, mmfr0)); + max_addr = min_t(u64, TASK_SIZE_MAX, sclp.hamax); + max_addr = min_t(u64, max_addr, id_pa_addr); max_addr = max_t(u64, max_addr, SZ_1G - 1); return ALIGN_DOWN(max_addr + 1, SZ_1G) - 1; } diff --git a/arch/s390/kvm/arm64/mmu.c b/arch/s390/kvm/arm64/mmu.c index 31e0d036896f..7a6f6ba326c1 100644 --- a/arch/s390/kvm/arm64/mmu.c +++ b/arch/s390/kvm/arm64/mmu.c @@ -16,7 +16,8 @@ static inline bool kvm_s390_cur_gmap_fault_is_write(struct kvm_vcpu *vcpu) /* * user_mem_abort() - handle a dat fault for the gmap of a vcpu * - * Return: 0 on success, < 0 in case of error. + * Return: 0 if the fault was resolved, 1 if an exception was injected into + * the guest; the caller resumes the vCPU in both cases. < 0 in case of error. * Context: The mm lock must not be held before calling. May sleep. */ static int user_mem_abort(struct kvm_vcpu *vcpu, gpa_t fault_ipa, @@ -32,12 +33,14 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, gpa_t fault_ipa, ret = kvm_s390_faultin_gfn(vcpu, NULL, &f); if (ret <= 0) return ret; - if (ret == PGM_ADDRESSING) + if (ret == PGM_ADDRESSING) { /* - * Without the relevant sysregs we cannot do anything for now. - * Go back to userspace with an error. TODO sysreg handling + * There is no page with the requested address. Inject size fault + * which is the closest arm match to PGM-addressing */ - return -ENOEXEC; + kvm_inject_size_fault(vcpu); + return 1; + } KVM_BUG_ON(ret, vcpu->kvm); return -EINVAL; } @@ -70,6 +73,35 @@ static int kvm_handle_pic(struct kvm_vcpu *vcpu, bool *translation) return 0; } +size_t kvm_parange_to_address_sanitized(u32 id_parange) +{ + static u32 ranges_map[8] = { + [ID_AA64MMFR0_EL1_PARANGE_32] = 32, + [ID_AA64MMFR0_EL1_PARANGE_36] = 36, + [ID_AA64MMFR0_EL1_PARANGE_40] = 40, + [ID_AA64MMFR0_EL1_PARANGE_42] = 42, + [ID_AA64MMFR0_EL1_PARANGE_44] = 44, + [ID_AA64MMFR0_EL1_PARANGE_48] = 48, + [ID_AA64MMFR0_EL1_PARANGE_52] = 52, + [ID_AA64MMFR0_EL1_PARANGE_56] = 56, + }; + u32 parange; + + /* + * Future values must be higher than we know already. + * See ARM DDI 0487C.a. Return a safe limit. + */ + parange = ranges_map[min(id_parange, ID_AA64MMFR0_EL1_PARANGE_56)]; + return BIT_ULL(parange); +} + +static size_t kvm_get_pa_address(struct kvm *kvm) +{ + u32 id_parange = get_idreg_field_enum(kvm, ID_AA64MMFR0_EL1, PARANGE); + + return kvm_parange_to_address_sanitized(id_parange); +} + int kvm_handle_guest_abort(struct kvm_vcpu *vcpu) { struct kvm_memory_slot *memslot; @@ -98,16 +130,17 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu) } if (translation) { - /* - * For both cases: - * Without the relevant sysregs we cannot do anything for now. - * Go back to userspace with an error. TODO sysreg handling - */ - if (fault_ipa >= BIT_ULL(get_kvm_ipa_limit())) - return -ENOEXEC; + /* Beyond the PA range programmed for the guest */ + if (fault_ipa >= kvm_get_pa_address(vcpu->kvm)) { + kvm_inject_size_fault(vcpu); + return 1; + } - if (fault_ipa >= vcpu->kvm->arch.guest_phys_size) - return -ENOEXEC; + /* Falls between the IPA range and the PA range? */ + if (fault_ipa >= vcpu->kvm->arch.guest_phys_size) { + fault_ipa |= FAR_TO_FIPA_OFFSET(kvm_vcpu_get_hfar(vcpu)); + return kvm_inject_sea(vcpu, is_iabt, fault_ipa); + } } trace_kvm_guest_fault(*vcpu_pc(vcpu), kvm_vcpu_get_esr(vcpu), @@ -121,23 +154,18 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu) hva = gfn_to_hva_memslot_prot(memslot, gfn, &writable); write_fault = kvm_s390_cur_gmap_fault_is_write(vcpu); if (kvm_is_error_hva(hva) || (write_fault && !writable)) { - ret = -ENOEXEC; /* * The guest has put either its instructions or its page-tables * somewhere it shouldn't have. Userspace won't be able to do * anything about this (there's no syndrome for a start). - * - * Without the relevant sysregs we cannot do anything for now. - * Go back to userspace with an error. TODO sysreg handling */ - if (is_iabt) + if (is_iabt) { + ret = kvm_inject_sea_iabt(vcpu, kvm_vcpu_get_hfar(vcpu)); goto out_unlock; + } if (kvm_vcpu_abt_iss1tw(vcpu)) { - /* - * Without the relevant sysregs we cannot do anything for now. - * Go back to userspace with an error. TODO sysreg handling - */ + ret = kvm_inject_sea_dabt(vcpu, kvm_vcpu_get_hfar(vcpu)); goto out_unlock; } diff --git a/arch/s390/kvm/arm64/sys_regs.c b/arch/s390/kvm/arm64/sys_regs.c index 417a05ce9015..951a02d89fc5 100644 --- a/arch/s390/kvm/arm64/sys_regs.c +++ b/arch/s390/kvm/arm64/sys_regs.c @@ -317,6 +317,10 @@ static int arm64_check_features(struct kvm_vcpu *vcpu, if (SYS_FIELD_GET(ID_AA64MMFR0_EL1, PARANGE, val) > SYS_FIELD_GET(ID_AA64MMFR0_EL1, PARANGE, host_val)) return -E2BIG; + if (kvm_parange_to_address_sanitized( + SYS_FIELD_GET(ID_AA64MMFR0_EL1, PARANGE, val)) < + vcpu->kvm->arch.guest_phys_size) + return -E2BIG; break; case SYS_CTR_EL0: /* forbid upgrading from VIPT to PIPT */ -- 2.56.0