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

[Nikunj A Dadhania]

Alexey Kardashevskiy <address@hidden> writes:

> On 05/19/2015 06:14 PM, Nikunj A Dadhania wrote:
>> 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.
>
> No it does not. g_strdup_printf() below is enough

  CC    ppc64-softmmu/hw/ppc/spapr_pci.o
hw/ppc/spapr_pci.c: In function ‘spapr_phb_get_loc_code’:
hw/ppc/spapr_pci.c:807:21: error: initialization discards ‘const’ qualifier 
from pointer target type [-Werror]
     char *devtype = "qemu";
                     ^
hw/ppc/spapr_pci.c:814:17: error: assignment discards ‘const’ qualifier from 
pointer target type [-Werror]
         devtype = "vfio";
                 ^
cc1: all warnings being treated as errors
make[1]: *** [hw/ppc/spapr_pci.o] Error 1
make: *** [subdir-ppc64-softmmu] Error 2

>
>>
>>>       }
>>>
>>>       /*
>>>        * 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
>>
>
>
> -- 
> Alexey