Christian Borntraeger <borntraeger@xxxxxxxxxxxxx> writes:
> Am 01.07.24 um 08:08 schrieb Sven Schnelle:
>> Christian Borntraeger <borntraeger@xxxxxxxxxxxxx> writes:
>>
>>> diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
>>> index 1be19cc9d73c..1a49b89706f8 100644
>>> --- a/arch/s390/kvm/priv.c
>>> +++ b/arch/s390/kvm/priv.c
>>> @@ -797,6 +797,36 @@ static int handle_lpswe(struct kvm_vcpu *vcpu)
>>> return 0;
>>> }
>>> +static int handle_lpswey(struct kvm_vcpu *vcpu)
>>> +{
>>> + psw_t new_psw;
>>> + u64 addr;
>>> + int rc;
>>> + u8 ar;
>>> +
>>> + vcpu->stat.instruction_lpswey++;
>>> +
>>> + if (!test_kvm_facility(vcpu->kvm, 193))
>>> + return kvm_s390_inject_program_int(vcpu, PGM_OPERATION);
>>> +
>>> + if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
>>> + return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
>>> +
>>> + addr = kvm_s390_get_base_disp_siy(vcpu, &ar);
>>> + if (addr & 7)
>>> + return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
>>> +
>>> + rc = read_guest(vcpu, addr, ar, &new_psw, sizeof(new_psw));
>>> + if (rc)
>>> + return kvm_s390_inject_prog_cond(vcpu, rc);
>>> +
>>> + vcpu->arch.sie_block->gpsw = new_psw;
>>> + if (!is_valid_psw(&vcpu->arch.sie_block->gpsw))
>>> + return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
>> Shouldn't the gpsw get updated with new_psw after the check? POP
>> says "The operation
>> is suppressed on all addressing and protection exceptions."
>
> Only for exception of the instruction but not for the target PSW.
> POP says:
>
> The other PSW fields which are to be loaded by the
> instruction are not checked for validity before they are
> loaded. However, immediately after loading, a speci-
> fication exception is recognized, and a program inter-
> ruption occurs, when any of the following is true for
> the newly loaded PSW
Ok, sorry for the noise.
