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

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 05/19/2015 04:56 PM, Nikunj A Dadhania wrote:
> Alexey Kardashevskiy <aik@ozlabs.ru> writes:
>
>> On 05/19/2015 02:51 PM, Nikunj A Dadhania wrote:
>>> Alexey Kardashevskiy <aik@ozlabs.ru> 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 <nikunj@linux.vnet.ibm.com>
>>>>> ---
>>>>>     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 :)

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";
     }

     /*
      * 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;
}



-- 
Alexey