| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <fa11436a-dff1-094d-1c69-87f7447d20d0@linux.ibm.com>
Date: Mon, 16 May 2022 16:13:49 +0200
From: Pierre Morel <pmorel@...ux.ibm.com>
To: Janosch Frank <frankja@...ux.ibm.com>, kvm@...r.kernel.org
Cc: linux-s390@...r.kernel.org, linux-kernel@...r.kernel.org,
borntraeger@...ibm.com, cohuck@...hat.com, david@...hat.com,
thuth@...hat.com, imbrenda@...ux.ibm.com, hca@...ux.ibm.com,
gor@...ux.ibm.com, wintera@...ux.ibm.com, seiden@...ux.ibm.com,
nrb@...ux.ibm.com
Subject: Re: [PATCH v9 1/3] s390x: KVM: ipte lock for SCA access should be
contained in KVM
On 5/12/22 13:32, Janosch Frank wrote:
> 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 <frankja@...ux.ibm.com>
OK, thanks,
Regards,
Pierre
>
>>
>> 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 <pmorel@...ux.ibm.com>
>> ---
>> 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;
>> }
>
--
Pierre Morel
IBM Lab Boeblingen
Powered by blists - more mailing lists