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Wed, 31 Aug 2022 15:21:52 +0000 (GMT) Received: from p-imbrenda (unknown [9.145.11.79]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 31 Aug 2022 15:21:52 +0000 (GMT) Date: Wed, 31 Aug 2022 17:21:51 +0200 From: Claudio Imbrenda To: Janis Schoetterl-Glausch Cc: Christian Borntraeger , Janosch Frank , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , kernel test robot , Dan Carpenter , David Hildenbrand , Sven Schnelle , kvm@vger.kernel.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] KVM: s390: Pass initialized arg even if unused Message-ID: <20220831172151.3e04c64c@p-imbrenda> In-Reply-To: <20220825192540.1560559-1-scgl@linux.ibm.com> References: <20220825192540.1560559-1-scgl@linux.ibm.com> Organization: IBM X-Mailer: Claws Mail 4.1.0 (GTK 3.24.34; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: LWcHmtMXlv8RqadyvTO4zIR9mrj7I-te X-Proofpoint-GUID: lXWEMvgH9t1hMSF6tmvW_9iJy-22h1GI X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.517,FMLib:17.11.122.1 definitions=2022-08-31_09,2022-08-31_03,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 mlxscore=0 impostorscore=0 clxscore=1011 adultscore=0 bulkscore=0 malwarescore=0 suspectscore=0 mlxlogscore=999 spamscore=0 phishscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2207270000 definitions=main-2208310075 Precedence: bulk List-ID: X-Mailing-List: linux-s390@vger.kernel.org On Thu, 25 Aug 2022 21:25:40 +0200 Janis Schoetterl-Glausch wrote: > This silences smatch warnings reported by kbuild bot: > arch/s390/kvm/gaccess.c:859 guest_range_to_gpas() error: uninitialized symbol 'prot'. > arch/s390/kvm/gaccess.c:1064 access_guest_with_key() error: uninitialized symbol 'prot'. > > This is because it cannot tell that the value is not used in this case. > The trans_exc* only examine prot if code is PGM_PROTECTION. > Pass a dummy value for other codes. > > Reported-by: kernel test robot > Reported-by: Dan Carpenter > Signed-off-by: Janis Schoetterl-Glausch Reviewed-by: Claudio Imbrenda > --- > v1 -> v2 > * drop unlikely, WARN_ON_ONCE instead of WARN (thanks Heiko) > > arch/s390/kvm/gaccess.c | 16 +++++++++++++--- > 1 file changed, 13 insertions(+), 3 deletions(-) > > diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c > index 082ec5f2c3a5..0243b6e38d36 100644 > --- a/arch/s390/kvm/gaccess.c > +++ b/arch/s390/kvm/gaccess.c > @@ -489,6 +489,8 @@ enum prot_type { > PROT_TYPE_ALC = 2, > PROT_TYPE_DAT = 3, > PROT_TYPE_IEP = 4, > + /* Dummy value for passing an initialized value when code != PGM_PROTECTION */ > + PROT_NONE, > }; > > static int trans_exc_ending(struct kvm_vcpu *vcpu, int code, unsigned long gva, u8 ar, > @@ -504,6 +506,10 @@ static int trans_exc_ending(struct kvm_vcpu *vcpu, int code, unsigned long gva, > switch (code) { > case PGM_PROTECTION: > switch (prot) { > + case PROT_NONE: > + /* We should never get here, acts like termination */ > + WARN_ON_ONCE(1); > + break; > case PROT_TYPE_IEP: > tec->b61 = 1; > fallthrough; > @@ -968,8 +974,10 @@ static int guest_range_to_gpas(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, > return rc; > } else { > gpa = kvm_s390_real_to_abs(vcpu, ga); > - if (kvm_is_error_gpa(vcpu->kvm, gpa)) > + if (kvm_is_error_gpa(vcpu->kvm, gpa)) { > rc = PGM_ADDRESSING; > + prot = PROT_NONE; > + } > } > if (rc) > return trans_exc(vcpu, rc, ga, ar, mode, prot); > @@ -1112,8 +1120,6 @@ int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, > if (rc == PGM_PROTECTION && try_storage_prot_override) > rc = access_guest_page_with_key(vcpu->kvm, mode, gpas[idx], > data, fragment_len, PAGE_SPO_ACC); > - if (rc == PGM_PROTECTION) > - prot = PROT_TYPE_KEYC; > if (rc) > break; > len -= fragment_len; > @@ -1123,6 +1129,10 @@ int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, > if (rc > 0) { > bool terminate = (mode == GACC_STORE) && (idx > 0); > > + if (rc == PGM_PROTECTION) > + prot = PROT_TYPE_KEYC; > + else > + prot = PROT_NONE; > rc = trans_exc_ending(vcpu, rc, ga, ar, mode, prot, terminate); > } > out_unlock: