Re: [Qemu-devel] [RFC PATCH] vfio: Add sysfsdev property for pci & platform

[Eric Auger]

On 01/26/2016 06:08 PM, Alex Williamson wrote:
> On Tue, 2016-01-26 at 16:03 +0100, Eric Auger wrote:
>>
>> Hi Alex,
>>
>> I did a try with both legacy cmd line and new one and it works fine for
>> vfio platform too:
>> -device vfio-calxeda-xgmac,host="fff51000.ethernet"
>> -device
>> vfio-calxeda-xgmac,sysfsdev="/sys/bus/platform/devices/fff51000.ethernet"
>>
>> Tested-by: Eric Auger <address@hidden>
>> Reviewed-by: Eric Auger <address@hidden>
> 
> Thanks!
> 
>> just 1 question below.
> ...
>>> diff --git a/hw/vfio/platform.c b/hw/vfio/platform.c
>>> index 289b498..99f0642 100644
>>> --- a/hw/vfio/platform.c
>>> +++ b/hw/vfio/platform.c
>>> @@ -559,38 +559,45 @@ static int vfio_base_device_init(VFIODevice *vbasedev)
>>>  {
>>>      VFIOGroup *group;
>>>      VFIODevice *vbasedev_iter;
>>> -    char path[PATH_MAX], iommu_group_path[PATH_MAX], *group_name;
>>> +    char *tmp, group_path[PATH_MAX], *group_name;
>>>      ssize_t len;
>>>      struct stat st;
>>>      int groupid;
>>>      int ret;
>>>  
>>> -    /* name must be set prior to the call */
>>> -    if (!vbasedev->name || strchr(vbasedev->name, '/')) {
>>> -        return -EINVAL;
>>> -    }
>>> +    /* @sysfsdev takes precedence over @host */
>>> +    if (vbasedev->sysfsdev) {
>>> +        g_free(vbasedev->name);
>>> +        vbasedev->name = g_strdup(basename(vbasedev->sysfsdev));
>> do we need the g_strdup here?
> 
> 
> Versus pointing ->name to the offset within sysfsdev where the name
> starts?  My concern was that both @sysfsdev and @name are allocated via
> device properties and presumably automatically collected when the
> device is destroyed.  If I set one within the buffer of another, I'd
> likely get a double free.  So creating a new string buffer seemed like
> the safest approach.  Agree?  Thanks,
Yes I agree

Best Regards

Eric
> 
> Alex
>