Re: [PATCH v2] KVM: s390: Fix pfmf and conditional skey emulation

[Christian Borntraeger <borntraeger@xxxxxxxxxx>]

Please re-add the "Fixes" tag. While not relevant for stable, it might be
relevant for backport.

On 08/30/2018 10:21 AM, Janosch Frank wrote:
> On 30.08.2018 10:13, Janosch Frank wrote:
>> We should not return with a lock.
>> We also have to increase the address when we do page clearing.
>>
>> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> 
> It's time for a vacation, patch will be renamed to:
> KVM: s390: Fix skey emulation fault error handling
> 
>> ---
>>
>> I knew there were more instances...
>>
>> ---
>>  arch/s390/kvm/priv.c | 30 ++++++++++++++++++------------
>>  1 file changed, 18 insertions(+), 12 deletions(-)
>>
>> diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
>> index d68f10441a16..8679bd74d337 100644
>> --- a/arch/s390/kvm/priv.c
>> +++ b/arch/s390/kvm/priv.c
>> @@ -280,9 +280,11 @@ static int handle_iske(struct kvm_vcpu *vcpu)
>>  			goto retry;
>>  		}
>>  	}
>> -	if (rc)
>> -		return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
>>  	up_read(&current->mm->mmap_sem);
>> +	if (rc == -EFAULT)
>> +		return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
>> +	if (rc < 0)
>> +		return rc;
>>  	vcpu->run->s.regs.gprs[reg1] &= ~0xff;
>>  	vcpu->run->s.regs.gprs[reg1] |= key;
>>  	return 0;
>> @@ -324,9 +326,11 @@ static int handle_rrbe(struct kvm_vcpu *vcpu)
>>  			goto retry;
>>  		}
>>  	}
>> -	if (rc < 0)
>> -		return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
>>  	up_read(&current->mm->mmap_sem);
>> +	if (rc == -EFAULT)
>> +		return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
>> +	if (rc < 0)
>> +		return rc;
>>  	kvm_s390_set_psw_cc(vcpu, rc);
>>  	return 0;
>>  }
>> @@ -390,12 +394,12 @@ static int handle_sske(struct kvm_vcpu *vcpu)
>>  					      FAULT_FLAG_WRITE, &unlocked);
>>  			rc = !rc ? -EAGAIN : rc;
>>  		}
>> +		up_read(&current->mm->mmap_sem);
>>  		if (rc == -EFAULT)
>>  			return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
>> -
>> -		up_read(&current->mm->mmap_sem);
>> -		if (rc >= 0)
>> -			start += PAGE_SIZE;
>> +		if (rc < 0)
>> +			return rc;
>> +		start += PAGE_SIZE;
>>  	}
>>  
>>  	if (m3 & (SSKE_MC | SSKE_MR)) {
>> @@ -1002,13 +1006,15 @@ static int handle_pfmf(struct kvm_vcpu *vcpu)
>>  						      FAULT_FLAG_WRITE, &unlocked);
>>  				rc = !rc ? -EAGAIN : rc;
>>  			}
>> +			up_read(&current->mm->mmap_sem);
>>  			if (rc == -EFAULT)
>>  				return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
>> -
>> -			up_read(&current->mm->mmap_sem);
>> -			if (rc >= 0)
>> -				start += PAGE_SIZE;
>> +			if (rc == -EAGAIN)
>> +				continue;
>> +			if (rc < 0)
>> +				return rc;
>>  		}
>> +		start += PAGE_SIZE;
>>  	}
>>  	if (vcpu->run->s.regs.gprs[reg1] & PFMF_FSC) {
>>  		if (psw_bits(vcpu->arch.sie_block->gpsw).eaba == PSW_BITS_AMODE_64BIT) {
>>
> 
>