Re: [Qemu-devel] [PATCH 3/5] s390: vfio_pci: Use a PCI Group structure

[Pierre Morel <pmorel@linux.ibm.com>]

On 14/05/2019 13:49, Cornelia Huck wrote:
> On Fri, 10 May 2019 16:38:51 +0200
> Pierre Morel <pmorel@linux.ibm.com> wrote:
> 
>> We use a S390PCIGroup structure to hold the information
>> related to zPCI Function group.
>>
>> This allows us to be ready to support multiple groups and to retrieve
>> the group information from the host.
> 
> What if there is no host to retrieve information from?

There is a default group for emulate devices.
I will enhance the comment.

Thanks

> 
>>
>> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
>> ---
>>   hw/s390x/s390-pci-bus.c  | 42 ++++++++++++++++++++++++++++++++++++++++++
>>   hw/s390x/s390-pci-bus.h  | 11 ++++++++++-
>>   hw/s390x/s390-pci-inst.c | 22 +++++++++++++---------
>>   3 files changed, 65 insertions(+), 10 deletions(-)
> 
>> diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c
>> index be28962..8147847 100644
>> --- a/hw/s390x/s390-pci-inst.c
>> +++ b/hw/s390x/s390-pci-inst.c
>> @@ -284,21 +284,25 @@ int clp_service_call(S390CPU *cpu, uint8_t r2, uintptr_t ra)
>>           stq_p(&resquery->edma, ZPCI_EDMA_ADDR);
>>           stl_p(&resquery->fid, pbdev->fid);
>>           stw_p(&resquery->pchid, 0);
>> -        stw_p(&resquery->ug, 1);
>> +        stw_p(&resquery->ug, ZPCI_DEFAULT_FN_GRP);
>>           stl_p(&resquery->uid, pbdev->uid);
>>           stw_p(&resquery->hdr.rsp, CLP_RC_OK);
>>           break;
>>       }
>>       case CLP_QUERY_PCI_FNGRP: {
>>           ClpRspQueryPciGrp *resgrp = (ClpRspQueryPciGrp *)resh;
>> -        resgrp->fr = 1;
>> -        stq_p(&resgrp->dasm, 0);
>> -        stq_p(&resgrp->msia, ZPCI_MSI_ADDR);
>> -        stw_p(&resgrp->mui, DEFAULT_MUI);
>> -        stw_p(&resgrp->i, 128);
>> -        stw_p(&resgrp->maxstbl, 128);
>> -        resgrp->version = 0;
>>   
>> +        ClpReqQueryPciGrp *reqgrp = (ClpReqQueryPciGrp *)reqh;
>> +        S390PCIGroup *grp;
>> +
>> +        grp = s390_grp_find(reqgrp->g);
>> +        if (!grp) {
>> +            /* We do not allow access to unknown groups */
>> +            /* The group must have been obtained with a vfio device */
> 
> What about non-vfio devices? How does this whole feature work for
> emulated devices?

Emulated devices get a default group with predefined values.
The predefined values we used before this series.
I will modify the patch comment to explain the emulated devices case.
Thanks for the comments.

Regards,
Pierre


-- 
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany