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Thu, 12 May 2022 11:32:51 +0000 (GMT) Received: from [9.152.224.243] (unknown [9.152.224.243]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 12 May 2022 11:32:51 +0000 (GMT) Message-ID: <0936ad4b-3a30-5be5-3fc5-7339d86cf56a@linux.ibm.com> Date: Thu, 12 May 2022 13:32:51 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH v9 1/3] s390x: KVM: ipte lock for SCA access should be contained in KVM Content-Language: en-US To: Pierre Morel , kvm@vger.kernel.org Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, borntraeger@de.ibm.com, cohuck@redhat.com, david@redhat.com, thuth@redhat.com, imbrenda@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, wintera@linux.ibm.com, seiden@linux.ibm.com, nrb@linux.ibm.com References: <20220506092403.47406-1-pmorel@linux.ibm.com> <20220506092403.47406-2-pmorel@linux.ibm.com> From: Janosch Frank In-Reply-To: <20220506092403.47406-2-pmorel@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 6tZ-hyUPRiyalysNCHIfWdWbM0fuH8No X-Proofpoint-ORIG-GUID: dW7QprcKj2A0aIQos8-liN34OZ4r3mx5 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_02,2022-05-12_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 suspectscore=0 adultscore=0 impostorscore=0 malwarescore=0 phishscore=0 spamscore=0 lowpriorityscore=0 mlxlogscore=999 priorityscore=1501 bulkscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2205120052 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/6/22 11:24, Pierre Morel wrote: > The former check to chose between SIIF or not SIIF can be done > using the sclp.has_siif instead of accessing per vCPU structures Maybe replace this paragraph with: We can check if SIIF is enabled by testing the sclp_info struct instead of testing the sie control block eca variable. sclp.has_ssif is the only requirement to set ECA_SII anyway so we can go straight to the source for that. Reviewed-by: Janosch Frank > > When accessing the SCA, ipte lock and ipte_unlock do not need > to access any vcpu structures but only the KVM structure. > > Let's simplify the ipte handling. > > Signed-off-by: Pierre Morel > --- > arch/s390/kvm/gaccess.c | 96 ++++++++++++++++++++--------------------- > arch/s390/kvm/gaccess.h | 6 +-- > arch/s390/kvm/priv.c | 6 +-- > 3 files changed, 54 insertions(+), 54 deletions(-) > > diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c > index d53a183c2005..0e1f6dd31882 100644 > --- a/arch/s390/kvm/gaccess.c > +++ b/arch/s390/kvm/gaccess.c > @@ -262,77 +262,77 @@ struct aste { > /* .. more fields there */ > }; > > -int ipte_lock_held(struct kvm_vcpu *vcpu) > +int ipte_lock_held(struct kvm *kvm) > { > - if (vcpu->arch.sie_block->eca & ECA_SII) { > + if (sclp.has_siif) { > int rc; > > - read_lock(&vcpu->kvm->arch.sca_lock); > - rc = kvm_s390_get_ipte_control(vcpu->kvm)->kh != 0; > - read_unlock(&vcpu->kvm->arch.sca_lock); > + read_lock(&kvm->arch.sca_lock); > + rc = kvm_s390_get_ipte_control(kvm)->kh != 0; > + read_unlock(&kvm->arch.sca_lock); > return rc; > } > - return vcpu->kvm->arch.ipte_lock_count != 0; > + return kvm->arch.ipte_lock_count != 0; > } > > -static void ipte_lock_simple(struct kvm_vcpu *vcpu) > +static void ipte_lock_simple(struct kvm *kvm) > { > union ipte_control old, new, *ic; > > - mutex_lock(&vcpu->kvm->arch.ipte_mutex); > - vcpu->kvm->arch.ipte_lock_count++; > - if (vcpu->kvm->arch.ipte_lock_count > 1) > + mutex_lock(&kvm->arch.ipte_mutex); > + kvm->arch.ipte_lock_count++; > + if (kvm->arch.ipte_lock_count > 1) > goto out; > retry: > - read_lock(&vcpu->kvm->arch.sca_lock); > - ic = kvm_s390_get_ipte_control(vcpu->kvm); > + read_lock(&kvm->arch.sca_lock); > + ic = kvm_s390_get_ipte_control(kvm); > do { > old = READ_ONCE(*ic); > if (old.k) { > - read_unlock(&vcpu->kvm->arch.sca_lock); > + read_unlock(&kvm->arch.sca_lock); > cond_resched(); > goto retry; > } > new = old; > new.k = 1; > } while (cmpxchg(&ic->val, old.val, new.val) != old.val); > - read_unlock(&vcpu->kvm->arch.sca_lock); > + read_unlock(&kvm->arch.sca_lock); > out: > - mutex_unlock(&vcpu->kvm->arch.ipte_mutex); > + mutex_unlock(&kvm->arch.ipte_mutex); > } > > -static void ipte_unlock_simple(struct kvm_vcpu *vcpu) > +static void ipte_unlock_simple(struct kvm *kvm) > { > union ipte_control old, new, *ic; > > - mutex_lock(&vcpu->kvm->arch.ipte_mutex); > - vcpu->kvm->arch.ipte_lock_count--; > - if (vcpu->kvm->arch.ipte_lock_count) > + mutex_lock(&kvm->arch.ipte_mutex); > + kvm->arch.ipte_lock_count--; > + if (kvm->arch.ipte_lock_count) > goto out; > - read_lock(&vcpu->kvm->arch.sca_lock); > - ic = kvm_s390_get_ipte_control(vcpu->kvm); > + read_lock(&kvm->arch.sca_lock); > + ic = kvm_s390_get_ipte_control(kvm); > do { > old = READ_ONCE(*ic); > new = old; > new.k = 0; > } while (cmpxchg(&ic->val, old.val, new.val) != old.val); > - read_unlock(&vcpu->kvm->arch.sca_lock); > - wake_up(&vcpu->kvm->arch.ipte_wq); > + read_unlock(&kvm->arch.sca_lock); > + wake_up(&kvm->arch.ipte_wq); > out: > - mutex_unlock(&vcpu->kvm->arch.ipte_mutex); > + mutex_unlock(&kvm->arch.ipte_mutex); > } > > -static void ipte_lock_siif(struct kvm_vcpu *vcpu) > +static void ipte_lock_siif(struct kvm *kvm) > { > union ipte_control old, new, *ic; > > retry: > - read_lock(&vcpu->kvm->arch.sca_lock); > - ic = kvm_s390_get_ipte_control(vcpu->kvm); > + read_lock(&kvm->arch.sca_lock); > + ic = kvm_s390_get_ipte_control(kvm); > do { > old = READ_ONCE(*ic); > if (old.kg) { > - read_unlock(&vcpu->kvm->arch.sca_lock); > + read_unlock(&kvm->arch.sca_lock); > cond_resched(); > goto retry; > } > @@ -340,15 +340,15 @@ static void ipte_lock_siif(struct kvm_vcpu *vcpu) > new.k = 1; > new.kh++; > } while (cmpxchg(&ic->val, old.val, new.val) != old.val); > - read_unlock(&vcpu->kvm->arch.sca_lock); > + read_unlock(&kvm->arch.sca_lock); > } > > -static void ipte_unlock_siif(struct kvm_vcpu *vcpu) > +static void ipte_unlock_siif(struct kvm *kvm) > { > union ipte_control old, new, *ic; > > - read_lock(&vcpu->kvm->arch.sca_lock); > - ic = kvm_s390_get_ipte_control(vcpu->kvm); > + read_lock(&kvm->arch.sca_lock); > + ic = kvm_s390_get_ipte_control(kvm); > do { > old = READ_ONCE(*ic); > new = old; > @@ -356,25 +356,25 @@ static void ipte_unlock_siif(struct kvm_vcpu *vcpu) > if (!new.kh) > new.k = 0; > } while (cmpxchg(&ic->val, old.val, new.val) != old.val); > - read_unlock(&vcpu->kvm->arch.sca_lock); > + read_unlock(&kvm->arch.sca_lock); > if (!new.kh) > - wake_up(&vcpu->kvm->arch.ipte_wq); > + wake_up(&kvm->arch.ipte_wq); > } > > -void ipte_lock(struct kvm_vcpu *vcpu) > +void ipte_lock(struct kvm *kvm) > { > - if (vcpu->arch.sie_block->eca & ECA_SII) > - ipte_lock_siif(vcpu); > + if (sclp.has_siif) > + ipte_lock_siif(kvm); > else > - ipte_lock_simple(vcpu); > + ipte_lock_simple(kvm); > } > > -void ipte_unlock(struct kvm_vcpu *vcpu) > +void ipte_unlock(struct kvm *kvm) > { > - if (vcpu->arch.sie_block->eca & ECA_SII) > - ipte_unlock_siif(vcpu); > + if (sclp.has_siif) > + ipte_unlock_siif(kvm); > else > - ipte_unlock_simple(vcpu); > + ipte_unlock_simple(kvm); > } > > static int ar_translation(struct kvm_vcpu *vcpu, union asce *asce, u8 ar, > @@ -1075,7 +1075,7 @@ int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, > try_storage_prot_override = storage_prot_override_applicable(vcpu); > need_ipte_lock = psw_bits(*psw).dat && !asce.r; > if (need_ipte_lock) > - ipte_lock(vcpu); > + ipte_lock(vcpu->kvm); > /* > * Since we do the access further down ultimately via a move instruction > * that does key checking and returns an error in case of a protection > @@ -1113,7 +1113,7 @@ int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, > rc = trans_exc(vcpu, rc, ga, ar, mode, prot); > out_unlock: > if (need_ipte_lock) > - ipte_unlock(vcpu); > + ipte_unlock(vcpu->kvm); > if (nr_pages > ARRAY_SIZE(gpa_array)) > vfree(gpas); > return rc; > @@ -1185,10 +1185,10 @@ int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar, > rc = get_vcpu_asce(vcpu, &asce, gva, ar, mode); > if (rc) > return rc; > - ipte_lock(vcpu); > + ipte_lock(vcpu->kvm); > rc = guest_range_to_gpas(vcpu, gva, ar, NULL, length, asce, mode, > access_key); > - ipte_unlock(vcpu); > + ipte_unlock(vcpu->kvm); > > return rc; > } > @@ -1451,7 +1451,7 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg, > * tables/pointers we read stay valid - unshadowing is however > * always possible - only guest_table_lock protects us. > */ > - ipte_lock(vcpu); > + ipte_lock(vcpu->kvm); > > rc = gmap_shadow_pgt_lookup(sg, saddr, &pgt, &dat_protection, &fake); > if (rc) > @@ -1485,7 +1485,7 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg, > pte.p |= dat_protection; > if (!rc) > rc = gmap_shadow_page(sg, saddr, __pte(pte.val)); > - ipte_unlock(vcpu); > + ipte_unlock(vcpu->kvm); > mmap_read_unlock(sg->mm); > return rc; > } > diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h > index 1124ff282012..9408d6cc8e2c 100644 > --- a/arch/s390/kvm/gaccess.h > +++ b/arch/s390/kvm/gaccess.h > @@ -440,9 +440,9 @@ int read_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data, > return access_guest_real(vcpu, gra, data, len, 0); > } > > -void ipte_lock(struct kvm_vcpu *vcpu); > -void ipte_unlock(struct kvm_vcpu *vcpu); > -int ipte_lock_held(struct kvm_vcpu *vcpu); > +void ipte_lock(struct kvm *kvm); > +void ipte_unlock(struct kvm *kvm); > +int ipte_lock_held(struct kvm *kvm); > int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra); > > /* MVPG PEI indication bits */ > diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c > index 5beb7a4a11b3..0e8603acc105 100644 > --- a/arch/s390/kvm/priv.c > +++ b/arch/s390/kvm/priv.c > @@ -443,7 +443,7 @@ static int handle_ipte_interlock(struct kvm_vcpu *vcpu) > vcpu->stat.instruction_ipte_interlock++; > if (psw_bits(vcpu->arch.sie_block->gpsw).pstate) > return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP); > - wait_event(vcpu->kvm->arch.ipte_wq, !ipte_lock_held(vcpu)); > + wait_event(vcpu->kvm->arch.ipte_wq, !ipte_lock_held(vcpu->kvm)); > kvm_s390_retry_instr(vcpu); > VCPU_EVENT(vcpu, 4, "%s", "retrying ipte interlock operation"); > return 0; > @@ -1472,7 +1472,7 @@ static int handle_tprot(struct kvm_vcpu *vcpu) > access_key = (operand2 & 0xf0) >> 4; > > if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT) > - ipte_lock(vcpu); > + ipte_lock(vcpu->kvm); > > ret = guest_translate_address_with_key(vcpu, address, ar, &gpa, > GACC_STORE, access_key); > @@ -1509,7 +1509,7 @@ static int handle_tprot(struct kvm_vcpu *vcpu) > } > > if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT) > - ipte_unlock(vcpu); > + ipte_unlock(vcpu->kvm); > return ret; > } >