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Thu, 15 Oct 2026 10:48:25 +0000 (GMT) Received: from t83lp65.lnxne.boe (unknown [9.87.84.240]) by smtpav01.dal12v.mail.ibm.com (Postfix) with ESMTP; Thu, 15 Oct 2026 10:48:25 +0000 (GMT) From: Gautam Gala To: borntraeger@linux.ibm.com, imbrenda@linux.ibm.com, kvm@vger.kernel.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: frankja@linux.ibm.com, david@kernel.org, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, svens@linux.ibm.com, pbonzini@redhat.com, seanjc@google.com, shuah@kernel.org Subject: [PATCH v2 1/2] KVM: s390: fix ESSA addressing exception injection in migration mode Date: Thu, 15 Oct 2026 12:48:21 +0200 Message-ID: <20261015104822.77062-2-ggala@linux.ibm.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20261015104822.77062-1-ggala@linux.ibm.com> References: <20261015104822.77062-1-ggala@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMDE1MDA0MiBTYWx0ZWRfXxoNALHs0f8/O yj4OURQn1OobnMOTixiXMLprY/EVydyQhenM6En8Gztx1yjO9dU0rQMG6v5UAwQ5MIjAeu+sKls 6u0yyJftjivE2KUMh/9oXNKWn6+nql8U7yyI5PRsu6iTUW3Z/cwkB0oh/useirw/9HQWanNLuXV D/0u8aqHDkloDGKWEAHy2wpFFNo4HlBZtAvaatG/rYL6PggFEN2laOUsznT2HO4cUirS438x+2z l0VMJqNyiHddc4xh4R78ptZMk63LtBAM+nyQVVfuruZSJFcjNca1ogutkZy2qyC6JwpdUx3P55p roUx+Zo/i7q9rUT3cHE4sE/3mJFctQYpCjTccvkDBNXF2lh1LqDg9170n64JfbviG8zgFCTlQkk P6I9R76dXGJR2BQwWgBSfrunS9LxBrX8X780MkcwKeLeZc6VumuFxjdNRu6Iu6r125ZFxpdiSP7 9Vs+quKGYpEa6O8cecA== X-Proofpoint-GUID: nmOgQ8Wcmjf59zMAQZbcYpz0qBzJ_XVL X-Proofpoint-ORIG-GUID: JMZKFcUSTrjO425VdF3v-8-VEpiVLVqr X-Proofpoint-Spam-Info: AW1haW4tMjYxMDE1MDA0MiBTYWx0ZWRfXwM27od+mjNpy VGxsAvc8Q9PQaRejSHFJSldTqUTfNsF6pRJS96zaw8ovplSLqLBZ01otdTEgrpUs2yaXks9+qaK UgwyRgeTTWpABqCvvO+4l3EOilIZRSE= X-Authority-Analysis: v=2.4 cv=btHZl0ai c=1 sm=1 tr=0 ts=6ad0af7e cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=660iZSQnnn4A:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VnNF1IyMAAAA:8 a=DC66tu63K5JfY2WZsL0A:9 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-10-14_01,2026-10-14_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 malwarescore=0 phishscore=0 impostorscore=0 adultscore=0 lowpriorityscore=0 priorityscore=1501 clxscore=1015 spamscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2610080000 definitions=main-2610150042 __do_essa() treated any negative return from dat_perform_essa() as the normal "no CBRL entry appended" case and returned 0, so a page-table walk failure silently dropped the addressing exception. Return -PGM_ADDRESSING on a walk failure and inject the program interrupt in __do_essa() for the -PGM_ADDRESSING return value. DAT_WALK_ANY is required in the dat_entry_walk() call so that a GFN backed by a large page (segment or region entry) does not return an error: the walk stops early but succeeds, leaving ptep as NULL, which is already handled by the existing "set exception state, return -1" path. Without DAT_WALK_ANY such addresses would fall through to the new error path and incorrectly inject PGM_ADDRESSING. Fixes: e38c884df921 ("KVM: s390: Switch to new gmap") Reported-by: Christian Borntraeger Suggested-by: Claudio Imbrenda Acked-by: Christian Borntraeger Signed-off-by: Gautam Gala --- arch/s390/kvm/gmap/dat.c | 5 ++++- arch/s390/kvm/s390/priv.c | 2 ++ 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/s390/kvm/gmap/dat.c b/arch/s390/kvm/gmap/dat.c index ff80d02c9f56..a2031aece4ed 100644 --- a/arch/s390/kvm/gmap/dat.c +++ b/arch/s390/kvm/gmap/dat.c @@ -1084,6 +1084,7 @@ int dat_set_prefix_notif_bit(union asce asce, gfn_t gfn) * * %1 if the page state has been altered and the page is to be added to the CBRL * * %0 if the page state has been altered, but the page is not to be added to the CBRL * * %-1 if the page state has not been altered and the page is not to be added to the CBRL + * * %PGM_ADDRESSING if the guest page-table walk failed */ int dat_perform_essa(union asce asce, gfn_t gfn, int orc, union essa_state *state, bool *dirty) { @@ -1092,7 +1093,9 @@ int dat_perform_essa(union asce asce, gfn_t gfn, int orc, union essa_state *stat union pte *ptep; int res = 0; - if (dat_entry_walk(NULL, gfn, asce, 0, TABLE_TYPE_PAGE_TABLE, &crstep, &ptep)) { + if (dat_entry_walk(NULL, gfn, asce, DAT_WALK_ANY, TABLE_TYPE_PAGE_TABLE, &crstep, &ptep)) + return PGM_ADDRESSING; + if (!ptep) { *state = (union essa_state) { .exception = 1 }; return -1; } diff --git a/arch/s390/kvm/s390/priv.c b/arch/s390/kvm/s390/priv.c index b3cb2c2c3aa7..9089b8f5d550 100644 --- a/arch/s390/kvm/s390/priv.c +++ b/arch/s390/kvm/s390/priv.c @@ -1168,6 +1168,8 @@ static inline int __do_essa(struct kvm_vcpu *vcpu, const int orc) entries = (vcpu->arch.sie_block->cbrlo & ~PAGE_MASK) >> 3; nappended = dat_perform_essa(vcpu->arch.gmap->asce, gfn, orc, &state, &dirtied); + if (nappended == PGM_ADDRESSING) + return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING); vcpu->run->s.regs.gprs[r1] = state.val; if (nappended < 0) return 0; -- 2.55.0