Re: [Qemu-ppc] [Qemu-devel] [PATCH v4 4/4] spapr_pci: populate ibm, loc-code

[Nikunj A Dadhania]

Alexey Kardashevskiy <address@hidden> writes:

> On 05/19/2015 04:56 PM, Nikunj A Dadhania wrote:
>> Alexey Kardashevskiy <address@hidden> writes:
>>
>>> On 05/19/2015 02:51 PM, Nikunj A Dadhania wrote:
>>>> Alexey Kardashevskiy <address@hidden> writes:
>>>>
>>>>> On 05/07/2015 05:21 PM, Nikunj A Dadhania wrote:
>>>>>> Each hardware instance has a platform unique location code.  The OF
>>>>>> device tree that describes a part of a hardware entity must include
>>>>>> the “ibm,loc-code” property with a value that represents the location
>>>>>> code for that hardware entity.
>>>>>>
>>>>>> Populate ibm,loc-code.
>>>>>>
>>>>>> 1) PCI passthru devices need to identify with its own ibm,loc-code
>>>>>>       available on the host. In failure cases use:
>>>>>>       vfio_<name>:<phb-index>:<slot>.<fn>
>>>>>>
>>>>>> 2) Emulated devices encode as following:
>>>>>>       qemu_<name>:<phb-index>:<slot>.<fn>
>>>>>>
>>>>>> Signed-off-by: Nikunj A Dadhania <address@hidden>
>>>>>> ---
>>>>>>     hw/ppc/spapr_pci.c | 98 
>>>>>> +++++++++++++++++++++++++++++++++++++++++++++++-------
>>>>>>     1 file changed, 86 insertions(+), 12 deletions(-)
>>>>>>
>>>>>> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
>>>>>> index 12f1b9c..d901007 100644
>>>>>> --- a/hw/ppc/spapr_pci.c
>>>>>> +++ b/hw/ppc/spapr_pci.c
>>>>>> @@ -769,6 +769,81 @@ static uint32_t 
>>>>>> spapr_phb_get_pci_drc_index(sPAPRPHBState *phb,
>>>>>>         return drck->get_index(drc);
>>>>>>     }
>>>>>>
>>>>>> +static bool spapr_phb_vfio_get_devspec_value(PCIDevice *pdev, char 
>>>>>> **value)
>>>>>
>>>>> Does it have to be a separate function?
>>>>
>>>> For better readability, i would prefer it this way.
>>>
>>> This is why I asked - I was having problems understanding the difference
>>> between these two having 6 words names ;) Do not insist though.
>>>
>>
>> This is what I have now, simplified:
>>
>> +static char *spapr_phb_vfio_get_loc_code(sPAPRPHBState *sphb,  PCIDevice 
>> *pdev)
>> +{
>> +    char *path = NULL, *buf = NULL;
>> +    char *host = NULL;
>> +
>> +    /* Get the PCI VFIO host id */
>> +    host = object_property_get_str(OBJECT(pdev), "host", NULL);
>> +    if (!host) {
>> +        goto err_out;
>> +    }
>> +
>> +    /* Construct the path of the file that will give us the DT location */
>> +    path = g_strdup_printf("/sys/bus/pci/devices/%s/devspec", host);
>> +    g_free(host);
>> +    if (path && !g_file_get_contents(path, &buf, NULL, NULL)) {
>> +        goto err_out;
>> +    }
>> +    g_free(path);
>> +
>> +    /* Construct and read from host device tree the loc-code */
>> +    path = g_strdup_printf("/proc/device-tree%s/ibm,loc-code", buf);
>> +    g_free(buf);
>> +    if (path && !g_file_get_contents(path, &buf, NULL, NULL)) {
>> +        goto err_out;
>> +    }
>> +    return buf;
>> +
>> +err_out:
>> +    g_free(path);
>> +    return NULL;
>> +}
>> +
>> +static char *spapr_phb_get_loc_code(sPAPRPHBState *sphb, PCIDevice *pdev)
>> +{
>> +    if (object_dynamic_cast(OBJECT(pdev), "vfio-pci")) {
>> +        char *buf = spapr_phb_vfio_get_loc_code(sphb, pdev);
>> +
>> +        /*
>> +         * In case of failures reading the loc-code, make it up
>> +         * indicating a vfio device
>> +         */
>> +        if (!buf) {
>> +            buf = g_strdup_printf("vfio_%s:%02d:%02d.%1d", pdev->name,
>> +                                  sphb->index, PCI_SLOT(pdev->devfn),
>> +                                  PCI_FUNC(pdev->devfn));
>> +        }
>> +        return buf;
>> +    } else {
>> +        return g_strdup_printf("qemu_%s:%02d:%02d.%1d", pdev->name,
>> +                               sphb->index, PCI_SLOT(pdev->devfn),
>> +                               PCI_FUNC(pdev->devfn));
>> +    }
>> +}
>
>
> I'd do this but I do not insist :)

That is fine as well.

>
> static char *spapr_phb_get_loc_code(sPAPRPHBState *sphb, PCIDevice *pdev)
> {
>      char *buf;
>      char *devtype = "qemu";
>
>      if (object_dynamic_cast(OBJECT(pdev), "vfio-pci")) {
>          buf = spapr_phb_vfio_get_loc_code(sphb, pdev);
>          if (buf) {
>              return buf;
>          }
>          devtype = "vfio";

That has to be a snprintf.

>      }
>
>      /*
>       * In case of failures reading the loc-code, make it up
>       * indicating a vfio device
>       */
>      buf = g_strdup_printf("%s_%s:%02d:%02d.%1d",
>                            devtype, pdev->name,
>                            sphb->index, PCI_SLOT(pdev->devfn),
>                            PCI_FUNC(pdev->devfn));
>      return buf;
> }

Regards
Nikunj