On 11/20/2014 03:10 PM, Antonios Motakis wrote:
> On Wed, Nov 12, 2014 at 5:36 PM, Alex Williamson
> <alex.williamson@xxxxxxxxxx> wrote:
>> On Wed, 2014-11-12 at 11:32 +0100, Eric Auger wrote:
>>> On 10/27/2014 07:07 PM, Antonios Motakis wrote:
>>>> A VFIO userspace driver will start by opening the VFIO device
>>>> that corresponds to an IOMMU group, and will use the ioctl interface
>>>> to get the basic device info, such as number of memory regions and
>>>> interrupts, and their properties. This patch enables the
>>>> VFIO_DEVICE_GET_INFO ioctl call.
>>>>
>>>> Signed-off-by: Antonios Motakis <a.motakis@xxxxxxxxxxxxxxxxxxxxxx>
>>>> ---
>>>> drivers/vfio/platform/vfio_platform_common.c | 23 ++++++++++++++++++++---
>>>> 1 file changed, 20 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
>>>> index e0fdbc8..cb20526 100644
>>>> --- a/drivers/vfio/platform/vfio_platform_common.c
>>>> +++ b/drivers/vfio/platform/vfio_platform_common.c
>>>> @@ -43,10 +43,27 @@ static int vfio_platform_open(void *device_data)
>>>> static long vfio_platform_ioctl(void *device_data,
>>>> unsigned int cmd, unsigned long arg)
>>>> {
>>>> - if (cmd == VFIO_DEVICE_GET_INFO)
>>>> - return -EINVAL;
>>>> + struct vfio_platform_device *vdev = device_data;
>>>> + unsigned long minsz;
>>>> +
>>>> + if (cmd == VFIO_DEVICE_GET_INFO) {
>>>> + struct vfio_device_info info;
>>>> +
>>>> + minsz = offsetofend(struct vfio_device_info, num_irqs);
>>>> +
>>>> + if (copy_from_user(&info, (void __user *)arg, minsz))
>>>> + return -EFAULT;
>>>> +
>>>> + if (info.argsz < minsz)
>>>> + return -EINVAL;
>>>> +
>>>> + info.flags = vdev->flags;
>>>> + info.num_regions = 0;
>>>> + info.num_irqs = 0;
>>> Seems a bit weird to me to enable the modality but returning zeroed
>>> values. Shouldn't we put that patch after VFIO_DEVICE_GET_REGION_INFO
>>> and VFIO_DEVICE_GET_IRQ_INFO ones?
>>
>> I actually like how Antonios has started from a base framework, exposing
>> a device but none of the resources and then incrementally adds each
>> component. It's also a good showcase of the VFIO ABI that we can do
>> things like this. Thanks,
>
> I also agree with Alex with this. But of course I'm not married with
> any particular splitting style, in case we decide to change this.
Hi Antonios,
please keep as is. I also learn each day about splitting style ;-)
Best Regards
Eric
>
>>
>> Alex
>>
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