Re: [Qemu-devel] [PATCH v1 0/5][RFC] Refactoring of AIS support

[Halil Pasic <pasic@linux.vnet.ibm.com>]

      

On 10/30/2017 06:38 PM, Pierre Morel wrote:
> On 30/10/2017 18:08, Christian Borntraeger wrote:
>>
>> On 10/30/2017 05:59 PM, Cornelia Huck wrote:
>>> On Mon, 30 Oct 2017 14:48:23 +0100
>>> Christian Borntraeger <borntraeger@de.ibm.com> wrote:
>>>
>>>
>>>> FWIW, I am testing a guest patch that enables zPCI without AIS. Its as simple as
>>>>
>>>>
>>>> diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
>>>> index 7b30af5..9b24836 100644
>>>> --- a/arch/s390/pci/pci.c
>>>> +++ b/arch/s390/pci/pci.c
>>>> @@ -953,7 +953,7 @@ static int __init pci_base_init(void)
>>>>          if (!s390_pci_probe)
>>>>                  return 0;
>>>>   -       if (!test_facility(69) || !test_facility(71) || !test_facility(72))
>>>> +       if (!test_facility(69) || !test_facility(71))
>>>>                  return 0;
>>>>            rc = zpci_debug_init();
>>>> diff --git a/arch/s390/pci/pci_insn.c b/arch/s390/pci/pci_insn.c
>>>> index ea34086..61f8c82 100644
>>>> --- a/arch/s390/pci/pci_insn.c
>>>> +++ b/arch/s390/pci/pci_insn.c
>>>> @@ -7,6 +7,7 @@
>>>>   #include <linux/export.h>
>>>>   #include <linux/errno.h>
>>>>   #include <linux/delay.h>
>>>> +#include <asm/facility.h>
>>>>   #include <asm/pci_insn.h>
>>>>   #include <asm/pci_debug.h>
>>>>   #include <asm/processor.h>
>>>> @@ -93,6 +94,8 @@ int zpci_refresh_trans(u64 fn, u64 addr, u64 range)
>>>>   /* Set Interruption Controls */
>>>>   void zpci_set_irq_ctrl(u16 ctl, char *unused, u8 isc)
>>>>   {
>>>> +       if (!test_facility(72))
>>>> +               return;
>>>>          asm volatile (
>>>>                  "       .insn   rsy,0xeb00000000d1,%[ctl],%[isc],%[u]\n"
>>>>                  : : [ctl] "d" (ctl), [isc] "d" (isc << 27), [u] "Q" (*unused));
>>>>
>>>
>>> Sounds good. Presumably this makes the adapter interrupt handling work
>>> as for virtio (and qdio)? Is there any ais-less pci hardware out in the
>>> wild?

@Connie:
Do you have something in mind, or is curiosity the only reason for asking?

>>>
>>
>> ais is z specific, not PCI specific. So PCI cards should not care as far as I can tell.
>>
>>
> 
> I bet Conny meant PCI hardware globaly, including zPCI adapters.
> I bet none but I will better ask Sebastian or Gerald if they know.
> 

I side with Christian: it is a machine thing and not a card thing. So
the question is if there is a z machine which supports zpci but does
not support AIS. My guess is that such a machine was never produced.

Halil