diff mbox

[v2,2/7] s390x/pci: rework PCI STORE

Message ID 1510854715-7081-3-git-send-email-pmorel@linux.vnet.ibm.com (mailing list archive)
State New, archived
Headers show

Commit Message

Pierre Morel Nov. 16, 2017, 5:51 p.m. UTC
Enhance the fault detection, correction of the fault reporting.

Signed-off-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
Reviewed-by: Yi Min Zhao <zyimin@linux.vnet.ibm.com>
Signed-off-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
---
 hw/s390x/s390-pci-inst.c | 39 ++++++++++++++++++++++-----------------
 1 file changed, 22 insertions(+), 17 deletions(-)

Comments

Cornelia Huck Nov. 21, 2017, 10:38 a.m. UTC | #1
On Thu, 16 Nov 2017 18:51:50 +0100
Pierre Morel <pmorel@linux.vnet.ibm.com> wrote:

> Enhance the fault detection, correction of the fault reporting.
> 
> Signed-off-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
> Reviewed-by: Yi Min Zhao <zyimin@linux.vnet.ibm.com>
> Signed-off-by: Pierre Morel <pmorel@linux.vnet.ibm.com>

Same double s-o-b.

> ---
>  hw/s390x/s390-pci-inst.c | 39 ++++++++++++++++++++++-----------------
>  1 file changed, 22 insertions(+), 17 deletions(-)
> 
> diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c
> index ded1556..df0c8f0 100644
> --- a/hw/s390x/s390-pci-inst.c
> +++ b/hw/s390x/s390-pci-inst.c
> @@ -470,6 +470,12 @@ int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
>      pcias = (env->regs[r2] >> 16) & 0xf;
>      len = env->regs[r2] & 0xf;
>      offset = env->regs[r2 + 1];
> +    data = env->regs[r1];
> +
> +    if (!(fh & FH_MASK_ENABLE)) {
> +        setcc(cpu, ZPCI_PCI_LS_INVAL_HANDLE);
> +        return 0;
> +    }
>  
>      pbdev = s390_pci_find_dev_by_fh(s390_get_phb(), fh);
>      if (!pbdev) {
> @@ -479,12 +485,7 @@ int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
>      }
>  
>      switch (pbdev->state) {
> -    case ZPCI_FS_RESERVED:
> -    case ZPCI_FS_STANDBY:
> -    case ZPCI_FS_DISABLED:
>      case ZPCI_FS_PERMANENT_ERROR:
> -        setcc(cpu, ZPCI_PCI_LS_INVAL_HANDLE);
> -        return 0;
>      case ZPCI_FS_ERROR:
>          setcc(cpu, ZPCI_PCI_LS_ERR);
>          s390_set_status_code(env, r2, ZPCI_PCI_ST_BLOCKED);
> @@ -493,9 +494,13 @@ int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
>          break;
>      }
>  
> -    data = env->regs[r1];
> -    if (pcias < 6) {
> -        if ((8 - (offset & 0x7)) < len) {
> +    /* Test that the pcias is valid and do the appropriates operations */
> +    switch (pcias) {
> +    case 0 ... 5:

Make this
case 0...5:
?

> +        /* Check length:
> +         * A length of 0 is invalid and length should not cross a double word
> +         */
> +        if (!len || (len > (8 - (offset & 0x7)))) {
>              program_interrupt(env, PGM_OPERAND, 4);
>              return 0;
>          }
> @@ -513,21 +518,21 @@ int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
>              program_interrupt(env, PGM_OPERAND, 4);
>              return 0;
>          }
> -    } else if (pcias == 15) {
> -        if ((4 - (offset & 0x3)) < len) {
> -            program_interrupt(env, PGM_OPERAND, 4);
> -            return 0;
> -        }
> -
> -        if (zpci_endian_swap(&data, len)) {
> +        break;
> +    case 15:
> +        /* ZPCI uses the pseudo BAR number 15 as configuration space */
> +        /* possible access lengths are 1,2,4 and must not cross a word */
> +        if (!len || (len > (4 - (offset & 0x3))) || len == 3) {
>              program_interrupt(env, PGM_OPERAND, 4);
>              return 0;
>          }
> -
> +        /* len = 1,2,4 so we do not need to test */
> +        zpci_endian_swap(&data, len);
>          pci_host_config_write_common(pbdev->pdev, offset,
>                                       pci_config_size(pbdev->pdev),
>                                       data, len);
> -    } else {
> +        break;
> +    default:
>          DPRINTF("pcistg invalid space\n");
>          setcc(cpu, ZPCI_PCI_LS_ERR);
>          s390_set_status_code(env, r2, ZPCI_PCI_ST_INVAL_AS);

Other than the nits, looks good.
Cornelia Huck Nov. 21, 2017, 2:25 p.m. UTC | #2
On Tue, 21 Nov 2017 11:38:45 +0100
Cornelia Huck <cohuck@redhat.com> wrote:

> On Thu, 16 Nov 2017 18:51:50 +0100
> Pierre Morel <pmorel@linux.vnet.ibm.com> wrote:

> > @@ -493,9 +494,13 @@ int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
> >          break;
> >      }
> >  
> > -    data = env->regs[r1];
> > -    if (pcias < 6) {
> > -        if ((8 - (offset & 0x7)) < len) {
> > +    /* Test that the pcias is valid and do the appropriates operations */
> > +    switch (pcias) {
> > +    case 0 ... 5:  
> 
> Make this
> case 0...5:
> ?

...only that it confuses the compiler when using numbers. We can either
keep the slightly ugly version, or introduce #defines.
ZPCI_PCIAS_IOREGION_{MIN,MAX} (and maybe ZPCI_PCIAS_CONFIG for 15)?

> 
> > +        /* Check length:
> > +         * A length of 0 is invalid and length should not cross a double word
> > +         */
> > +        if (!len || (len > (8 - (offset & 0x7)))) {
> >              program_interrupt(env, PGM_OPERAND, 4);
> >              return 0;
> >          }
> > @@ -513,21 +518,21 @@ int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
> >              program_interrupt(env, PGM_OPERAND, 4);
> >              return 0;
> >          }
> > -    } else if (pcias == 15) {
> > -        if ((4 - (offset & 0x3)) < len) {
> > -            program_interrupt(env, PGM_OPERAND, 4);
> > -            return 0;
> > -        }
> > -
> > -        if (zpci_endian_swap(&data, len)) {
> > +        break;
> > +    case 15:
> > +        /* ZPCI uses the pseudo BAR number 15 as configuration space */
> > +        /* possible access lengths are 1,2,4 and must not cross a word */
> > +        if (!len || (len > (4 - (offset & 0x3))) || len == 3) {
> >              program_interrupt(env, PGM_OPERAND, 4);
> >              return 0;
> >          }
> > -
> > +        /* len = 1,2,4 so we do not need to test */
> > +        zpci_endian_swap(&data, len);
> >          pci_host_config_write_common(pbdev->pdev, offset,
> >                                       pci_config_size(pbdev->pdev),
> >                                       data, len);
> > -    } else {
> > +        break;
> > +    default:
> >          DPRINTF("pcistg invalid space\n");
> >          setcc(cpu, ZPCI_PCI_LS_ERR);
> >          s390_set_status_code(env, r2, ZPCI_PCI_ST_INVAL_AS);  
> 
> Other than the nits, looks good.
Pierre Morel Nov. 21, 2017, 5:52 p.m. UTC | #3
On 21/11/2017 11:38, Cornelia Huck wrote:
> On Thu, 16 Nov 2017 18:51:50 +0100
> Pierre Morel <pmorel@linux.vnet.ibm.com> wrote:
> 
>> Enhance the fault detection, correction of the fault reporting.
>>
>> Signed-off-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
>> Reviewed-by: Yi Min Zhao <zyimin@linux.vnet.ibm.com>
>> Signed-off-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
> 
> Same double s-o-b.

removed.
Thanks

> 
>> ---
>>   hw/s390x/s390-pci-inst.c | 39 ++++++++++++++++++++++-----------------
>>   1 file changed, 22 insertions(+), 17 deletions(-)
>>
>> diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c
>> index ded1556..df0c8f0 100644
>> --- a/hw/s390x/s390-pci-inst.c
>> +++ b/hw/s390x/s390-pci-inst.c
>> @@ -470,6 +470,12 @@ int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
>>       pcias = (env->regs[r2] >> 16) & 0xf;
>>       len = env->regs[r2] & 0xf;
>>       offset = env->regs[r2 + 1];
>> +    data = env->regs[r1];
>> +
>> +    if (!(fh & FH_MASK_ENABLE)) {
>> +        setcc(cpu, ZPCI_PCI_LS_INVAL_HANDLE);
>> +        return 0;
>> +    }
>>   
>>       pbdev = s390_pci_find_dev_by_fh(s390_get_phb(), fh);
>>       if (!pbdev) {
>> @@ -479,12 +485,7 @@ int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
>>       }
>>   
>>       switch (pbdev->state) {
>> -    case ZPCI_FS_RESERVED:
>> -    case ZPCI_FS_STANDBY:
>> -    case ZPCI_FS_DISABLED:
>>       case ZPCI_FS_PERMANENT_ERROR:
>> -        setcc(cpu, ZPCI_PCI_LS_INVAL_HANDLE);
>> -        return 0;
>>       case ZPCI_FS_ERROR:
>>           setcc(cpu, ZPCI_PCI_LS_ERR);
>>           s390_set_status_code(env, r2, ZPCI_PCI_ST_BLOCKED);
>> @@ -493,9 +494,13 @@ int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
>>           break;
>>       }
>>   
>> -    data = env->regs[r1];
>> -    if (pcias < 6) {
>> -        if ((8 - (offset & 0x7)) < len) {
>> +    /* Test that the pcias is valid and do the appropriates operations */
>> +    switch (pcias) {
>> +    case 0 ... 5:
> 
> Make this
> case 0...5:
> ?

Compiler complains.
a blanc around the three points seems right.


> 
>> +        /* Check length:
>> +         * A length of 0 is invalid and length should not cross a double word
>> +         */
>> +        if (!len || (len > (8 - (offset & 0x7)))) {
>>               program_interrupt(env, PGM_OPERAND, 4);
>>               return 0;
>>           }
>> @@ -513,21 +518,21 @@ int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
>>               program_interrupt(env, PGM_OPERAND, 4);
>>               return 0;
>>           }
>> -    } else if (pcias == 15) {
>> -        if ((4 - (offset & 0x3)) < len) {
>> -            program_interrupt(env, PGM_OPERAND, 4);
>> -            return 0;
>> -        }
>> -
>> -        if (zpci_endian_swap(&data, len)) {
>> +        break;
>> +    case 15:
>> +        /* ZPCI uses the pseudo BAR number 15 as configuration space */
>> +        /* possible access lengths are 1,2,4 and must not cross a word */
>> +        if (!len || (len > (4 - (offset & 0x3))) || len == 3) {
>>               program_interrupt(env, PGM_OPERAND, 4);
>>               return 0;
>>           }
>> -
>> +        /* len = 1,2,4 so we do not need to test */
>> +        zpci_endian_swap(&data, len);
>>           pci_host_config_write_common(pbdev->pdev, offset,
>>                                        pci_config_size(pbdev->pdev),
>>                                        data, len);
>> -    } else {
>> +        break;
>> +    default:
>>           DPRINTF("pcistg invalid space\n");
>>           setcc(cpu, ZPCI_PCI_LS_ERR);
>>           s390_set_status_code(env, r2, ZPCI_PCI_ST_INVAL_AS);
> 
> Other than the nits, looks good.
> 


Thanks for reviewing, I remove the double signature

Regards,

Pierre
Pierre Morel Nov. 21, 2017, 6:03 p.m. UTC | #4
On 21/11/2017 15:25, Cornelia Huck wrote:
> On Tue, 21 Nov 2017 11:38:45 +0100
> Cornelia Huck <cohuck@redhat.com> wrote:
> 
>> On Thu, 16 Nov 2017 18:51:50 +0100
>> Pierre Morel <pmorel@linux.vnet.ibm.com> wrote:
> 
>>> @@ -493,9 +494,13 @@ int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
>>>           break;
>>>       }
>>>   
>>> -    data = env->regs[r1];
>>> -    if (pcias < 6) {
>>> -        if ((8 - (offset & 0x7)) < len) {
>>> +    /* Test that the pcias is valid and do the appropriates operations */
>>> +    switch (pcias) {
>>> +    case 0 ... 5:
>>
>> Make this
>> case 0...5:
>> ?
> 
> ...only that it confuses the compiler when using numbers. We can either

I did not see this as I replied to the previous email, sorry.

> keep the slightly ugly version, or introduce #defines.
> ZPCI_PCIAS_IOREGION_{MIN,MAX} (and maybe ZPCI_PCIAS_CONFIG for 15)?


I agree something is missing.
But I am not sure that a #define brings clarity.
I would prefer to add a comment.
	/* A ZPCI PCI card may use any BAR from BAR 0 to BAR 5 */

?


>>> +         * A length of 0 is invalid and length should not cross a double word
>>> +         */
>>> +        if (!len || (len > (8 - (offset & 0x7)))) {
>>>               program_interrupt(env, PGM_OPERAND, 4);
>>>               return 0;
>>>           }
>>> @@ -513,21 +518,21 @@ int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
>>>               program_interrupt(env, PGM_OPERAND, 4);
>>>               return 0;
>>>           }
>>> -    } else if (pcias == 15) {
>>> -        if ((4 - (offset & 0x3)) < len) {
>>> -            program_interrupt(env, PGM_OPERAND, 4);
>>> -            return 0;
>>> -        }
>>> -
>>> -        if (zpci_endian_swap(&data, len)) {
>>> +        break;
>>> +    case 15:
>>> +        /* ZPCI uses the pseudo BAR number 15 as configuration space */
>>> +        /* possible access lengths are 1,2,4 and must not cross a word */
>>> +        if (!len || (len > (4 - (offset & 0x3))) || len == 3) {
>>>               program_interrupt(env, PGM_OPERAND, 4);
>>>               return 0;
>>>           }
>>> -
>>> +        /* len = 1,2,4 so we do not need to test */
>>> +        zpci_endian_swap(&data, len);
>>>           pci_host_config_write_common(pbdev->pdev, offset,
>>>                                        pci_config_size(pbdev->pdev),
>>>                                        data, len);
>>> -    } else {
>>> +        break;
>>> +    default:
>>>           DPRINTF("pcistg invalid space\n");
>>>           setcc(cpu, ZPCI_PCI_LS_ERR);
>>>           s390_set_status_code(env, r2, ZPCI_PCI_ST_INVAL_AS);
>>
>> Other than the nits, looks good.
>
Cornelia Huck Nov. 22, 2017, 1:25 p.m. UTC | #5
On Tue, 21 Nov 2017 19:03:17 +0100
Pierre Morel <pmorel@linux.vnet.ibm.com> wrote:

> On 21/11/2017 15:25, Cornelia Huck wrote:
> > On Tue, 21 Nov 2017 11:38:45 +0100
> > Cornelia Huck <cohuck@redhat.com> wrote:
> >   
> >> On Thu, 16 Nov 2017 18:51:50 +0100
> >> Pierre Morel <pmorel@linux.vnet.ibm.com> wrote:  
> >   
> >>> @@ -493,9 +494,13 @@ int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
> >>>           break;
> >>>       }
> >>>   
> >>> -    data = env->regs[r1];
> >>> -    if (pcias < 6) {
> >>> -        if ((8 - (offset & 0x7)) < len) {
> >>> +    /* Test that the pcias is valid and do the appropriates operations */
> >>> +    switch (pcias) {
> >>> +    case 0 ... 5:  
> >>
> >> Make this
> >> case 0...5:
> >> ?  
> > 
> > ...only that it confuses the compiler when using numbers. We can either  
> 
> I did not see this as I replied to the previous email, sorry.
> 
> > keep the slightly ugly version, or introduce #defines.
> > ZPCI_PCIAS_IOREGION_{MIN,MAX} (and maybe ZPCI_PCIAS_CONFIG for 15)?  
> 
> 
> I agree something is missing.
> But I am not sure that a #define brings clarity.
> I would prefer to add a comment.
> 	/* A ZPCI PCI card may use any BAR from BAR 0 to BAR 5 */
> 
> ?

It's more a speaking value vs. magic numbers thing. A comment does not
hurt either, though :)

(And we get rid of the spacing as well.)

> 
> 
> >>> +         * A length of 0 is invalid and length should not cross a double word
> >>> +         */
> >>> +        if (!len || (len > (8 - (offset & 0x7)))) {
> >>>               program_interrupt(env, PGM_OPERAND, 4);
> >>>               return 0;
> >>>           }
> >>> @@ -513,21 +518,21 @@ int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
> >>>               program_interrupt(env, PGM_OPERAND, 4);
> >>>               return 0;
> >>>           }
> >>> -    } else if (pcias == 15) {
> >>> -        if ((4 - (offset & 0x3)) < len) {
> >>> -            program_interrupt(env, PGM_OPERAND, 4);
> >>> -            return 0;
> >>> -        }
> >>> -
> >>> -        if (zpci_endian_swap(&data, len)) {
> >>> +        break;
> >>> +    case 15:
> >>> +        /* ZPCI uses the pseudo BAR number 15 as configuration space */
> >>> +        /* possible access lengths are 1,2,4 and must not cross a word */
> >>> +        if (!len || (len > (4 - (offset & 0x3))) || len == 3) {
> >>>               program_interrupt(env, PGM_OPERAND, 4);
> >>>               return 0;
> >>>           }
> >>> -
> >>> +        /* len = 1,2,4 so we do not need to test */
> >>> +        zpci_endian_swap(&data, len);
> >>>           pci_host_config_write_common(pbdev->pdev, offset,
> >>>                                        pci_config_size(pbdev->pdev),
> >>>                                        data, len);
> >>> -    } else {
> >>> +        break;
> >>> +    default:
> >>>           DPRINTF("pcistg invalid space\n");
> >>>           setcc(cpu, ZPCI_PCI_LS_ERR);
> >>>           s390_set_status_code(env, r2, ZPCI_PCI_ST_INVAL_AS);  
> >>
> >> Other than the nits, looks good.  
> >   
> 
>
Pierre Morel Nov. 22, 2017, 9:12 p.m. UTC | #6
On 22/11/2017 14:25, Cornelia Huck wrote:
> On Tue, 21 Nov 2017 19:03:17 +0100
> Pierre Morel <pmorel@linux.vnet.ibm.com> wrote:
> 
>> On 21/11/2017 15:25, Cornelia Huck wrote:
>>> On Tue, 21 Nov 2017 11:38:45 +0100
>>> Cornelia Huck <cohuck@redhat.com> wrote:
>>>    
>>>> On Thu, 16 Nov 2017 18:51:50 +0100
>>>> Pierre Morel <pmorel@linux.vnet.ibm.com> wrote:
>>>    
>>>>> @@ -493,9 +494,13 @@ int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
>>>>>            break;
>>>>>        }
>>>>>    
>>>>> -    data = env->regs[r1];
>>>>> -    if (pcias < 6) {
>>>>> -        if ((8 - (offset & 0x7)) < len) {
>>>>> +    /* Test that the pcias is valid and do the appropriates operations */
>>>>> +    switch (pcias) {
>>>>> +    case 0 ... 5:
>>>>
>>>> Make this
>>>> case 0...5:
>>>> ?
>>>
>>> ...only that it confuses the compiler when using numbers. We can either
>>
>> I did not see this as I replied to the previous email, sorry.
>>
>>> keep the slightly ugly version, or introduce #defines.
>>> ZPCI_PCIAS_IOREGION_{MIN,MAX} (and maybe ZPCI_PCIAS_CONFIG for 15)?
>>
>>
>> I agree something is missing.
>> But I am not sure that a #define brings clarity.
>> I would prefer to add a comment.
>> 	/* A ZPCI PCI card may use any BAR from BAR 0 to BAR 5 */
>>
>> ?
> 
> It's more a speaking value vs. magic numbers thing. A comment does not
> hurt either, though :)
> 
> (And we get rid of the spacing as well.)

OK, thanks.

> 
>>
>>
>>>>> +         * A length of 0 is invalid and length should not cross a double word
>>>>> +         */
>>>>> +        if (!len || (len > (8 - (offset & 0x7)))) {
>>>>>                program_interrupt(env, PGM_OPERAND, 4);
>>>>>                return 0;
>>>>>            }
>>>>> @@ -513,21 +518,21 @@ int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
>>>>>                program_interrupt(env, PGM_OPERAND, 4);
>>>>>                return 0;
>>>>>            }
>>>>> -    } else if (pcias == 15) {
>>>>> -        if ((4 - (offset & 0x3)) < len) {
>>>>> -            program_interrupt(env, PGM_OPERAND, 4);
>>>>> -            return 0;
>>>>> -        }
>>>>> -
>>>>> -        if (zpci_endian_swap(&data, len)) {
>>>>> +        break;
>>>>> +    case 15:
>>>>> +        /* ZPCI uses the pseudo BAR number 15 as configuration space */
>>>>> +        /* possible access lengths are 1,2,4 and must not cross a word */
>>>>> +        if (!len || (len > (4 - (offset & 0x3))) || len == 3) {
>>>>>                program_interrupt(env, PGM_OPERAND, 4);
>>>>>                return 0;
>>>>>            }
>>>>> -
>>>>> +        /* len = 1,2,4 so we do not need to test */
>>>>> +        zpci_endian_swap(&data, len);
>>>>>            pci_host_config_write_common(pbdev->pdev, offset,
>>>>>                                         pci_config_size(pbdev->pdev),
>>>>>                                         data, len);
>>>>> -    } else {
>>>>> +        break;
>>>>> +    default:
>>>>>            DPRINTF("pcistg invalid space\n");
>>>>>            setcc(cpu, ZPCI_PCI_LS_ERR);
>>>>>            s390_set_status_code(env, r2, ZPCI_PCI_ST_INVAL_AS);
>>>>
>>>> Other than the nits, looks good.
>>>    
>>
>>
>
diff mbox

Patch

diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c
index ded1556..df0c8f0 100644
--- a/hw/s390x/s390-pci-inst.c
+++ b/hw/s390x/s390-pci-inst.c
@@ -470,6 +470,12 @@  int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
     pcias = (env->regs[r2] >> 16) & 0xf;
     len = env->regs[r2] & 0xf;
     offset = env->regs[r2 + 1];
+    data = env->regs[r1];
+
+    if (!(fh & FH_MASK_ENABLE)) {
+        setcc(cpu, ZPCI_PCI_LS_INVAL_HANDLE);
+        return 0;
+    }
 
     pbdev = s390_pci_find_dev_by_fh(s390_get_phb(), fh);
     if (!pbdev) {
@@ -479,12 +485,7 @@  int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
     }
 
     switch (pbdev->state) {
-    case ZPCI_FS_RESERVED:
-    case ZPCI_FS_STANDBY:
-    case ZPCI_FS_DISABLED:
     case ZPCI_FS_PERMANENT_ERROR:
-        setcc(cpu, ZPCI_PCI_LS_INVAL_HANDLE);
-        return 0;
     case ZPCI_FS_ERROR:
         setcc(cpu, ZPCI_PCI_LS_ERR);
         s390_set_status_code(env, r2, ZPCI_PCI_ST_BLOCKED);
@@ -493,9 +494,13 @@  int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
         break;
     }
 
-    data = env->regs[r1];
-    if (pcias < 6) {
-        if ((8 - (offset & 0x7)) < len) {
+    /* Test that the pcias is valid and do the appropriates operations */
+    switch (pcias) {
+    case 0 ... 5:
+        /* Check length:
+         * A length of 0 is invalid and length should not cross a double word
+         */
+        if (!len || (len > (8 - (offset & 0x7)))) {
             program_interrupt(env, PGM_OPERAND, 4);
             return 0;
         }
@@ -513,21 +518,21 @@  int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
             program_interrupt(env, PGM_OPERAND, 4);
             return 0;
         }
-    } else if (pcias == 15) {
-        if ((4 - (offset & 0x3)) < len) {
-            program_interrupt(env, PGM_OPERAND, 4);
-            return 0;
-        }
-
-        if (zpci_endian_swap(&data, len)) {
+        break;
+    case 15:
+        /* ZPCI uses the pseudo BAR number 15 as configuration space */
+        /* possible access lengths are 1,2,4 and must not cross a word */
+        if (!len || (len > (4 - (offset & 0x3))) || len == 3) {
             program_interrupt(env, PGM_OPERAND, 4);
             return 0;
         }
-
+        /* len = 1,2,4 so we do not need to test */
+        zpci_endian_swap(&data, len);
         pci_host_config_write_common(pbdev->pdev, offset,
                                      pci_config_size(pbdev->pdev),
                                      data, len);
-    } else {
+        break;
+    default:
         DPRINTF("pcistg invalid space\n");
         setcc(cpu, ZPCI_PCI_LS_ERR);
         s390_set_status_code(env, r2, ZPCI_PCI_ST_INVAL_AS);