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Thu, 30 Jul 2026 16:27:15 +0000 (GMT) Received: from p-imbrenda.ehn-de.ibm.com (unknown [9.224.75.30]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTP; Thu, 30 Jul 2026 16:27:15 +0000 (GMT) From: Claudio Imbrenda To: linux-kernel@vger.kernel.org Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org, borntraeger@de.ibm.com, frankja@linux.ibm.com, david@kernel.org, seiden@linux.ibm.com, nrb@linux.ibm.com, schlameuss@linux.ibm.com, gra@linux.ibm.com Subject: [PATCH v6 05/14] KVM: s390: Fix leaking of PGM_ADDRESSING to userspace Date: Thu, 30 Jul 2026 18:27:05 +0200 Message-ID: <20260730162714.133327-6-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260730162714.133327-1-imbrenda@linux.ibm.com> References: <20260730162714.133327-1-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: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 0B-X1pZpPq8_M6SfU8mX_ftiY3N44oa3 X-Proofpoint-ORIG-GUID: 0B-X1pZpPq8_M6SfU8mX_ftiY3N44oa3 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzMwMDEyMyBTYWx0ZWRfX6AMZe0U8188u +oheCe1KhL6syJ0KEYS+0HEzO32h3VGWCqCpAxpLdn1ndBjkz7Xu1hIjaVbUremENX+RKLZygdM 01a0+g+QMq2jfRDg83tGhxusMLdOZnXkmTdqJDb/O37QZ6m/4BjvfBNqsrHBhf9bEOX5FZ4Tpox j61sIH1IxaVOqtjKArNIj3bb18G+la1KgXkVef4Kk3K4frFvy1qOQqJ8eWem0p5fZJ5nJ1nd9/v 7rufu4C5XHaclNCgJm4ts6WCA+HzbAqq0EtY281q1Ac6V5KRRzOPmORea/af5lCeHwjKnVyTHMb Lmb88bP2Nb6ZAu+d2wQ7TUNPrru6gOlXlJiZ5JT2VBB7VBFzxI8UkuKTEKmrvAk2Tms84a8ZOUw PLMNTRYHm6qKumQ8YTBESFC62iNWmzqudbRwMBytmBnyecLqhzw90chvsqu/gSo6LsPsWN0zQB1 1SAwNomo7xf0E9JMBLw== X-Authority-Analysis: v=2.4 cv=SKFykuvH c=1 sm=1 tr=0 ts=6a6b7b6b cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VnNF1IyMAAAA:8 a=GvWetJuFWLgL5UM2GZoA:9 X-Proofpoint-Spam-Info: AW1haW4tMjYwNzMwMDEyMyBTYWx0ZWRfXy4cylahqaCGc RqNLyyEUN9l9AtZuluelpCHdanEX/O7cdYkZ/KS0mPUHt8XMlHgiV1/oodgFQdB1nTx3VMEeOOS HKFnzGTduBNbaCDKLbAT3Ts7y11NE8o= X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-30_04,2026-07-30_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 clxscore=1015 adultscore=0 lowpriorityscore=0 bulkscore=0 impostorscore=0 phishscore=0 spamscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607300123 If kvm_s390_set_cmma_bits() is asked to set CMMA values outside of a memslot, PGM_ADDRESSING (5) is returned, instead of a negative error value. Same issue with kvm_s390_{g,s}et_skeys(), kvm_s390_keyop(), and dat_reset_reference_bit(). Fix by returning -EFAULT whenever the return value would be > 0, which is consistent with the behaviour before the gmap rewrite. Fixes: e38c884df921 ("KVM: s390: Switch to new gmap") Signed-off-by: Claudio Imbrenda --- arch/s390/kvm/dat.c | 16 ++++++++++------ arch/s390/kvm/dat.h | 2 +- arch/s390/kvm/kvm-s390.c | 16 ++++++++-------- arch/s390/kvm/priv.c | 5 +++-- 4 files changed, 22 insertions(+), 17 deletions(-) diff --git a/arch/s390/kvm/dat.c b/arch/s390/kvm/dat.c index ed4259d17629..171b61959908 100644 --- a/arch/s390/kvm/dat.c +++ b/arch/s390/kvm/dat.c @@ -755,13 +755,15 @@ int dat_cond_set_storage_key(struct kvm_s390_mmu_cache *mmc, union asce asce, gf return rc; } -int dat_reset_reference_bit(union asce asce, gfn_t gfn) +int dat_reset_reference_bit(union asce asce, gfn_t gfn, union skey *skey) { union pgste pgste, old; union crste *crstep; union pte *ptep; int rc; + skey->skey = 0; + rc = dat_entry_walk(NULL, gfn, asce, DAT_WALK_ANY, TABLE_TYPE_PAGE_TABLE, &crstep, &ptep); if (rc) return rc; @@ -771,21 +773,23 @@ int dat_reset_reference_bit(union asce asce, gfn_t gfn) if (!crste.h.fc || !crste.s.fc1.pr) return 0; - return page_reset_referenced(large_crste_to_phys(*crstep, gfn)); + skey->skey = page_reset_referenced(large_crste_to_phys(*crstep, gfn)) << 1; + return 0; } old = pgste_get_lock(ptep); pgste = old; if (!ptep->h.i) { - rc = page_reset_referenced(pte_origin(*ptep)); - pgste.hr = rc >> 1; + skey->skey = page_reset_referenced(pte_origin(*ptep)) << 1; + pgste.hr = skey->r; } - rc |= (pgste.gr << 1) | pgste.gc; + skey->r |= pgste.gr; + skey->c |= pgste.gc; pgste.gr = 0; dat_update_ptep_sd(old, pgste, ptep); pgste_set_unlock(ptep, pgste); - return rc; + return 0; } static long dat_reset_skeys_pte(union pte *ptep, gfn_t gfn, gfn_t next, struct dat_walk *walk) diff --git a/arch/s390/kvm/dat.h b/arch/s390/kvm/dat.h index fad605305e05..141ee7b9f019 100644 --- a/arch/s390/kvm/dat.h +++ b/arch/s390/kvm/dat.h @@ -537,7 +537,7 @@ int dat_set_storage_key(struct kvm_s390_mmu_cache *mc, union asce asce, gfn_t gf union skey skey, bool nq); int dat_cond_set_storage_key(struct kvm_s390_mmu_cache *mmc, union asce asce, gfn_t gfn, union skey skey, union skey *oldkey, bool nq, bool mr, bool mc); -int dat_reset_reference_bit(union asce asce, gfn_t gfn); +int dat_reset_reference_bit(union asce asce, gfn_t gfn, union skey *skey); long dat_reset_skeys(union asce asce, gfn_t start); unsigned long dat_get_ptval(struct page_table *table, struct ptval_param param); diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 19ce7ebb83c5..de3cb6111bd4 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -571,7 +571,7 @@ static int kvm_s390_keyop(struct kvm_s390_mmu_cache *mc, struct kvm *kvm, int op switch (op) { case KVM_S390_KEYOP_SSKE: r = dat_cond_set_storage_key(mc, asce, gfn, skey, &skey, 0, 0, 0); - if (r >= 0) + if (r == 0 || r == 1) return skey.skey; break; case KVM_S390_KEYOP_ISKE: @@ -580,14 +580,14 @@ static int kvm_s390_keyop(struct kvm_s390_mmu_cache *mc, struct kvm *kvm, int op return skey.skey; break; case KVM_S390_KEYOP_RRBE: - r = dat_reset_reference_bit(asce, gfn); - if (r > 0) - return r << 1; + r = dat_reset_reference_bit(asce, gfn, &skey); + if (!r) + return skey.skey; break; default: return -EINVAL; } - return r; + return r > 0 ? -EFAULT : r; } /* Section: device related */ @@ -2214,7 +2214,7 @@ static int kvm_s390_get_skeys(struct kvm *kvm, struct kvm_s390_skeys *args) } kvfree(keys); - return r; + return r <= 0 ? r : -EFAULT; } static int kvm_s390_set_skeys(struct kvm *kvm, struct kvm_s390_skeys *args) @@ -2276,7 +2276,7 @@ static int kvm_s390_set_skeys(struct kvm *kvm, struct kvm_s390_skeys *args) kvm_s390_free_mmu_cache(mc); out: kvfree(keys); - return r; + return r <= 0 ? r : -EFAULT; } /* @@ -2386,7 +2386,7 @@ static int kvm_s390_set_cmma_bits(struct kvm *kvm, set_bit(GMAP_FLAG_USES_CMM, &kvm->arch.gmap->flags); - return r; + return r <= 0 ? r : -EFAULT; } /** diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c index ad0ddc433a73..ea5a99537346 100644 --- a/arch/s390/kvm/priv.c +++ b/arch/s390/kvm/priv.c @@ -289,6 +289,7 @@ static int handle_iske(struct kvm_vcpu *vcpu) static int handle_rrbe(struct kvm_vcpu *vcpu) { unsigned long gaddr; + union skey skey; int reg1, reg2; int rc; @@ -307,12 +308,12 @@ static int handle_rrbe(struct kvm_vcpu *vcpu) gaddr = kvm_s390_logical_to_effective(vcpu, gaddr); gaddr = kvm_s390_real_to_abs(vcpu, gaddr); scoped_guard(read_lock, &vcpu->kvm->mmu_lock) - rc = dat_reset_reference_bit(vcpu->arch.gmap->asce, gpa_to_gfn(gaddr)); + rc = dat_reset_reference_bit(vcpu->arch.gmap->asce, gpa_to_gfn(gaddr), &skey); if (rc > 0) return kvm_s390_inject_program_int(vcpu, rc); if (rc < 0) return rc; - kvm_s390_set_psw_cc(vcpu, rc); + kvm_s390_set_psw_cc(vcpu, (skey.skey >> 1) & 3); return 0; } -- 2.55.0