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

[Alexander Graf <agraf@suse.de>]

On 05/19/2015 11:58 AM, Nikunj A Dadhania wrote:
> Alexey Kardashevskiy <aik@ozlabs.ru> writes:
>
>> On 05/19/2015 06:14 PM, Nikunj A Dadhania wrote:
>>> Alexey Kardashevskiy <aik@ozlabs.ru> writes:
>>>
>>>> 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 :)
>>> 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

Make it const char *devtype?


Alex