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Wed, 1 Apr 2026 02:09:17 +0000 (GMT) Received: by tuxmaker.boeblingen.de.ibm.com (Postfix, from userid 4958) id 7E24CE023F; Wed, 01 Apr 2026 04:09:17 +0200 (CEST) From: Eric Farman To: Christian Borntraeger , Hendrik Brueckner , Janosch Frank , Claudio Imbrenda , David Hildenbrand Cc: Paolo Bonzini , Jonathan Corbet , Shuah Khan , kvm@vger.kernel.org, linux-s390@vger.kernel.org, Eric Farman Subject: [PATCH v1 1/4] KVM: s390: vsie: Allow non-zarch guests Date: Wed, 1 Apr 2026 04:09:12 +0200 Message-ID: <20260401020915.1339228-2-farman@linux.ibm.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260401020915.1339228-1-farman@linux.ibm.com> References: <20260401020915.1339228-1-farman@linux.ibm.com> Precedence: bulk X-Mailing-List: kvm@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: AW1haW4tMjYwNDAxMDAxMCBTYWx0ZWRfX1SbC0nEfjO1l AnyVUJFRFF8eHJUXNv+Jn8W+HpQZIJVB9KYrZ3VRinyQb9J0ZiS9Usdzji18sYChrcNLdXfrORw Uz3wIu0hxHVKlh+K/Zaq7N6hhtORvzcxDloRIzctALzKZxdOP8yZ1lrCMt97vAXdZ7asKxKA6ME jSl2RRbwRJG3l5JG9F8FNpVyZhRCj9bFjfkd91u+lDIC1XnynFm7Gd+lHPWXrYUR6ajUz4DlNQk 5wxuo20JaHrdm+rHnQkDt9pd7kkfMvSI1Jplh2+q5BbX0C2JKNLRSzz1DpCLuhhfXmy3YYLghni 0VvA3UQeas/eNC3JE798O5aRRCJoBxaGjbvIwESSi1N31uq4UxlUZPgPEOUqVZ+c0Kte/kc7c4O q3a/FexKPEt3NN043yKvVMebuiQLUNnm23ideUBEMquK/8swM63aA+SGdpmYvlHNz3ZuwW07/OF j/g72ASQtbdd4A6fiGw== X-Authority-Analysis: v=2.4 cv=QKZlhwLL c=1 sm=1 tr=0 ts=69cc7e52 cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=A5OVakUREuEA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VnNF1IyMAAAA:8 a=TcF5ixnfVCNIaZDrkBwA:9 X-Proofpoint-GUID: GlugZxva1F_IyBqSMkUzvxqEHXB9oDgn X-Proofpoint-ORIG-GUID: GlugZxva1F_IyBqSMkUzvxqEHXB9oDgn X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-04-01_01,2026-03-31_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 phishscore=0 adultscore=0 impostorscore=0 clxscore=1015 spamscore=0 bulkscore=0 priorityscore=1501 suspectscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2603050001 definitions=main-2604010010 Linux/KVM runs in z/Architecture-only mode. Although z/Architecture is built upon a long history of hardware refinements, any other CPU mode is not permitted. Allow a userspace to explicitly enable the use of ESA mode for nested guests, otherwise usage will be rejected. Signed-off-by: Eric Farman --- arch/s390/include/asm/kvm_host.h | 1 + arch/s390/kvm/vsie.c | 8 +++++--- 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm= _host.h index 3039c88daa63..8a4f4a39f7a2 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -656,6 +656,7 @@ struct kvm_arch { int user_stsi; int user_instr0; int user_operexec; + int allow_vsie_esamode; struct s390_io_adapter *adapters[MAX_S390_IO_ADAPTERS]; wait_queue_head_t ipte_wq; int ipte_lock_count; diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c index 72895dddc39a..888370a02ef7 100644 --- a/arch/s390/kvm/vsie.c +++ b/arch/s390/kvm/vsie.c @@ -125,8 +125,9 @@ static int prepare_cpuflags(struct kvm_vcpu *vcpu, st= ruct vsie_page *vsie_page) struct kvm_s390_sie_block *scb_o =3D vsie_page->scb_o; int newflags, cpuflags =3D atomic_read(&scb_o->cpuflags); =20 - /* we don't allow ESA/390 guests */ - if (!(cpuflags & CPUSTAT_ZARCH)) + newflags =3D 0; + /* we don't allow ESA/390 guests unless explicitly enabled */ + if (!(cpuflags & CPUSTAT_ZARCH) && !vcpu->kvm->arch.allow_vsie_esamode) return set_validity_icpt(scb_s, 0x0001U); =20 if (cpuflags & (CPUSTAT_RRF | CPUSTAT_MCDS)) @@ -135,7 +136,8 @@ static int prepare_cpuflags(struct kvm_vcpu *vcpu, st= ruct vsie_page *vsie_page) return set_validity_icpt(scb_s, 0x0007U); =20 /* intervention requests will be set later */ - newflags =3D CPUSTAT_ZARCH; + if (cpuflags & CPUSTAT_ZARCH) + newflags =3D CPUSTAT_ZARCH; if (cpuflags & CPUSTAT_GED && test_kvm_facility(vcpu->kvm, 8)) newflags |=3D CPUSTAT_GED; if (cpuflags & CPUSTAT_GED2 && test_kvm_facility(vcpu->kvm, 78)) { --=20 2.51.0