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Thu, 12 May 2022 13:10:25 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 12 May 2022 13:10:25 +0000 (GMT) From: Janis Schoetterl-Glausch To: Paolo Bonzini , Jonathan Corbet , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Heiko Carstens , Vasily Gorbik , Alexander Gordeev Cc: Janis Schoetterl-Glausch , David Hildenbrand , Sven Schnelle , kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org Subject: [PATCH v3 1/2] KVM: s390: Don't indicate suppression on dirtying, failing memop Date: Thu, 12 May 2022 15:10:17 +0200 Message-Id: <20220512131019.2594948-2-scgl@linux.ibm.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220512131019.2594948-1-scgl@linux.ibm.com> References: <20220512131019.2594948-1-scgl@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: asT-5bzCxO9EBOVJOeKQGHprEUJo7oOo X-Proofpoint-ORIG-GUID: tjNBglsIc9n5_qBUmZsHAqdhal8jxyRU X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.858,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-05-12_10,2022-05-12_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 adultscore=0 suspectscore=0 bulkscore=0 mlxscore=0 impostorscore=0 spamscore=0 clxscore=1011 malwarescore=0 lowpriorityscore=0 mlxlogscore=999 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2205120061 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org If user space uses a memop to emulate an instruction and that memop fails, the execution of the instruction ends. Instruction execution can end in different ways, one of which is suppression, which requires that the instruction execute like a no-op. A writing memop that spans multiple pages and fails due to key protection may have modified guest memory, as a result, the likely correct ending is termination. Therefore, do not indicate a suppressing instruction ending in this case. Signed-off-by: Janis Schoetterl-Glausch Reviewed-by: Christian Borntraeger Reviewed-by: Claudio Imbrenda --- Documentation/virt/kvm/api.rst | 6 ++++++ arch/s390/kvm/gaccess.c | 22 ++++++++++++++++++---- 2 files changed, 24 insertions(+), 4 deletions(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 4a900cdbc62e..b6aba4f50db7 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -3754,12 +3754,18 @@ in case of KVM_S390_MEMOP_F_CHECK_ONLY), the ioctl returns a positive error number indicating the type of exception. This exception is also raised directly at the corresponding VCPU if the flag KVM_S390_MEMOP_F_INJECT_EXCEPTION is set. +On protection exceptions, unless specified otherwise, the injected +translation-exception identifier (TEID) indicates suppression. If the KVM_S390_MEMOP_F_SKEY_PROTECTION flag is set, storage key protection is also in effect and may cause exceptions if accesses are prohibited given the access key designated by "key"; the valid range is 0..15. KVM_S390_MEMOP_F_SKEY_PROTECTION is available if KVM_CAP_S390_MEM_OP_EXTENSION is > 0. +Since the accessed memory may span multiple pages and those pages might have +different storage keys, it is possible that a protection exception occurs +after memory has been modified. In this case, if the exception is injected, +the TEID does not indicate suppression. Absolute read/write: ^^^^^^^^^^^^^^^^^^^^ diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c index d53a183c2005..227ed0009354 100644 --- a/arch/s390/kvm/gaccess.c +++ b/arch/s390/kvm/gaccess.c @@ -491,8 +491,8 @@ enum prot_type { PROT_TYPE_IEP = 4, }; -static int trans_exc(struct kvm_vcpu *vcpu, int code, unsigned long gva, - u8 ar, enum gacc_mode mode, enum prot_type prot) +static int trans_exc_ending(struct kvm_vcpu *vcpu, int code, unsigned long gva, u8 ar, + enum gacc_mode mode, enum prot_type prot, bool terminate) { struct kvm_s390_pgm_info *pgm = &vcpu->arch.pgm; struct trans_exc_code_bits *tec; @@ -520,6 +520,11 @@ static int trans_exc(struct kvm_vcpu *vcpu, int code, unsigned long gva, tec->b61 = 1; break; } + if (terminate) { + tec->b56 = 0; + tec->b60 = 0; + tec->b61 = 0; + } fallthrough; case PGM_ASCE_TYPE: case PGM_PAGE_TRANSLATION: @@ -552,6 +557,12 @@ static int trans_exc(struct kvm_vcpu *vcpu, int code, unsigned long gva, return code; } +static int trans_exc(struct kvm_vcpu *vcpu, int code, unsigned long gva, u8 ar, + enum gacc_mode mode, enum prot_type prot) +{ + return trans_exc_ending(vcpu, code, gva, ar, mode, prot, false); +} + static int get_vcpu_asce(struct kvm_vcpu *vcpu, union asce *asce, unsigned long ga, u8 ar, enum gacc_mode mode) { @@ -1109,8 +1120,11 @@ int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, data += fragment_len; ga = kvm_s390_logical_to_effective(vcpu, ga + fragment_len); } - if (rc > 0) - rc = trans_exc(vcpu, rc, ga, ar, mode, prot); + if (rc > 0) { + bool terminate = (mode == GACC_STORE) && (idx > 0); + + rc = trans_exc_ending(vcpu, rc, ga, ar, mode, prot, terminate); + } out_unlock: if (need_ipte_lock) ipte_unlock(vcpu);