Re: [PULL v3 26/32] s390x/pci: use a PCI Group structure

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 11/17/20 12:43 PM, Cornelia Huck wrote:
> On Sun, 01 Nov 2020 14:02:46 -0700
> Alex Williamson <alex.williamson@redhat.com> wrote:
> 
>> From: Pierre Morel <pmorel@linux.ibm.com>
>>
>> We use a S390PCIGroup structure to hold the information related to a
>> zPCI Function group.
>>
>> This allows us to be ready to support multiple groups and to retrieve
>> the group information from the host.
>>
>> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
>> Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
>> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
>> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
>> ---
>>  hw/s390x/s390-pci-bus.c         |   42 +++++++++++++++++++++++++++++++++++++++
>>  hw/s390x/s390-pci-inst.c        |   23 +++++++++++++--------
>>  include/hw/s390x/s390-pci-bus.h |   10 +++++++++
>>  3 files changed, 66 insertions(+), 9 deletions(-)
> 
> I just bisected a regression down to this commit.
> 
> s390x tcg guest on x86, virtio-pci devices are not detected. The
> relevant feature bits are visible to the guest. Same breakage with
> different guest kernels.
> 
> KVM guests and s390x tcg guests on s390x are fine, so I assume an
> endianness issue somewhere. Nothing jumps out to me, though.
> 
>>
>> diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c
>> index 218717397ae1..4c7f06d5cf95 100644
>> --- a/hw/s390x/s390-pci-bus.c
>> +++ b/hw/s390x/s390-pci-bus.c
>> @@ -738,6 +738,46 @@ static void s390_pci_iommu_free(S390pciState *s, PCIBus *bus, int32_t devfn)
>>      object_unref(OBJECT(iommu));
>>  }
>>  
>> +static S390PCIGroup *s390_group_create(int id)
>> +{
>> +    S390PCIGroup *group;
>> +    S390pciState *s = s390_get_phb();
>> +
>> +    group = g_new0(S390PCIGroup, 1);
>> +    group->id = id;
>> +    QTAILQ_INSERT_TAIL(&s->zpci_groups, group, link);
>> +    return group;
>> +}
>> +
>> +S390PCIGroup *s390_group_find(int id)
>> +{
>> +    S390PCIGroup *group;
>> +    S390pciState *s = s390_get_phb();
>> +
>> +    QTAILQ_FOREACH(group, &s->zpci_groups, link) {
>> +        if (group->id == id) {
>> +            return group;
>> +        }
>> +    }
>> +    return NULL;
>> +}
>> +
>> +static void s390_pci_init_default_group(void)
>> +{
>> +    S390PCIGroup *group;
>> +    ClpRspQueryPciGrp *resgrp;
>> +
>> +    group = s390_group_create(ZPCI_DEFAULT_FN_GRP);
>> +    resgrp = &group->zpci_group;
>> +    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;
>> +}
>> +
>>  static void s390_pcihost_realize(DeviceState *dev, Error **errp)
>>  {
>>      PCIBus *b;
>> @@ -766,7 +806,9 @@ static void s390_pcihost_realize(DeviceState *dev, Error **errp)
>>      QTAILQ_INIT(&s->pending_sei);
>>      QTAILQ_INIT(&s->zpci_devs);
>>      QTAILQ_INIT(&s->zpci_dma_limit);
>> +    QTAILQ_INIT(&s->zpci_groups);
>>  
>> +    s390_pci_init_default_group();
>>      css_register_io_adapters(CSS_IO_ADAPTER_PCI, true, false,
>>                               S390_ADAPTER_SUPPRESSIBLE, errp);
>>  }
>> diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c
>> index 4eadd9e79416..c25b2a67efe0 100644
>> --- a/hw/s390x/s390-pci-inst.c
>> +++ b/hw/s390x/s390-pci-inst.c
>> @@ -298,21 +298,25 @@ 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 *group;
>> +
>> +        group = s390_group_find(reqgrp->g);

-        group = s390_group_find(reqgrp->g);
+        group = s390_group_find(ldl_p(&reqgrp->g));

>> +        if (!group) {
>> +            /* We do not allow access to unknown groups */
>> +            /* The group must have been obtained with a vfio device */
>> +            stw_p(&resgrp->hdr.rsp, CLP_RC_QUERYPCIFG_PFGID);
>> +            goto out;
>> +        }
>> +        memcpy(resgrp, &group->zpci_group, sizeof(ClpRspQueryPciGrp));
>>          stw_p(&resgrp->hdr.rsp, CLP_RC_OK);
>>          break;
>>      }
>> @@ -787,7 +791,8 @@ int pcistb_service_call(S390CPU *cpu, uint8_t r1, uint8_t r3, uint64_t gaddr,
>>      }
>>      /* Length must be greater than 8, a multiple of 8 */
>>      /* and not greater than maxstbl */
>> -    if ((len <= 8) || (len % 8) || (len > pbdev->maxstbl)) {
>> +    if ((len <= 8) || (len % 8) ||
>> +        (len > pbdev->pci_group->zpci_group.maxstbl)) {
>>          goto specification_error;
>>      }
>>      /* Do not cross a 4K-byte boundary */