Re: [RFC PATCH v6 10/20] vfio/platform: return info for device and its memory mapped IO regions

[Antonios Motakis]

On Thu, Jun 5, 2014 at 11:14 PM, Alex Williamson
<alex.williamson@xxxxxxxxxx> wrote:
> On Thu, 2014-06-05 at 19:03 +0200, 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 IOCTLs:
>>  - VFIO_DEVICE_GET_INFO
>>  - VFIO_DEVICE_GET_REGION_INFO
>>
>> IRQ info is provided by one of the latter patches.
>>
>> Signed-off-by: Antonios Motakis <a.motakis@xxxxxxxxxxxxxxxxxxxxxx>
>> ---
>>  drivers/vfio/platform/vfio_platform.c         | 79 +++++++++++++++++++++++++--
>>  drivers/vfio/platform/vfio_platform_private.h | 17 ++++++
>>  2 files changed, 90 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/vfio/platform/vfio_platform.c b/drivers/vfio/platform/vfio_platform.c
>> index 1df76d8..eeaebc4 100644
>> --- a/drivers/vfio/platform/vfio_platform.c
>> +++ b/drivers/vfio/platform/vfio_platform.c
>> @@ -34,17 +34,66 @@
>>  #define DRIVER_AUTHOR   "Antonios Motakis <a.motakis@xxxxxxxxxxxxxxxxxxxxxx>"
>>  #define DRIVER_DESC     "VFIO for platform devices - User Level meta-driver"
>>
>> +static int vfio_platform_regions_init(struct vfio_platform_device *vdev)
>> +{
>> +     int cnt = 0, i;
>> +
>> +     while (platform_get_resource(vdev->pdev, IORESOURCE_MEM, cnt))
>> +             cnt++;
>> +
>> +     vdev->region = kzalloc(sizeof(struct vfio_platform_region) * cnt,
>> +                             GFP_KERNEL);
>> +     if (!vdev->region)
>> +             return -ENOMEM;
>> +
>> +     for (i = 0; i < cnt;  i++) {
>> +             struct resource *res =
>> +                     platform_get_resource(vdev->pdev, IORESOURCE_MEM, i);
>> +
>> +             if (!res)
>> +                     goto err;
>> +
>> +             vdev->region[i].addr = res->start;
>> +             vdev->region[i].size = resource_size(res);
>> +             vdev->region[i].flags = 0;
>> +     }
>> +
>> +     vdev->num_regions = cnt;
>> +
>> +     return 0;
>> +err:
>> +     kfree(vdev->region);
>> +     return -EINVAL;
>> +}
>> +
>> +static void vfio_platform_regions_cleanup(struct vfio_platform_device *vdev)
>> +{
>> +     vdev->num_regions = 0;
>> +     kfree(vdev->region);
>> +}
>> +
>>  static void vfio_platform_release(void *device_data)
>>  {
>> +     struct vfio_platform_device *vdev = device_data;
>> +
>> +     vfio_platform_regions_cleanup(vdev);
>> +
>>       module_put(THIS_MODULE);
>>  }
>>
>>  static int vfio_platform_open(void *device_data)
>>  {
>> +     struct vfio_platform_device *vdev = device_data;
>> +     int ret;
>> +
>>       if (!try_module_get(THIS_MODULE))
>>               return -ENODEV;
>>
>> -     return 0;
>> +     ret = vfio_platform_regions_init(vdev);
>> +     if (ret)
>> +             module_put(THIS_MODULE);
>> +
>> +     return ret;
>
> The user can call VFIO_GROUP_GET_DEVICE_FD for a single device more than
> once, vfio_pci maintains a reference count to make sure we only allocate
> and initialize on the first open and cleanup on the last close.
>

Ack

>>  }
>>
>>  static long vfio_platform_ioctl(void *device_data,
>> @@ -65,18 +114,36 @@ static long vfio_platform_ioctl(void *device_data,
>>                       return -EINVAL;
>>
>>               info.flags = VFIO_DEVICE_FLAGS_PLATFORM;
>> -             info.num_regions = 0;
>> +             info.num_regions = vdev->num_regions;
>>               info.num_irqs = 0;
>>
>>               return copy_to_user((void __user *)arg, &info, minsz);
>>
>> -     } else if (cmd == VFIO_DEVICE_GET_REGION_INFO)
>> -             return -EINVAL;
>> +     } else if (cmd == VFIO_DEVICE_GET_REGION_INFO) {
>> +             struct vfio_region_info info;
>> +
>> +             minsz = offsetofend(struct vfio_region_info, offset);
>> +
>> +             if (copy_from_user(&info, (void __user *)arg, minsz))
>> +                     return -EFAULT;
>> +
>> +             if (info.argsz < minsz)
>> +                     return -EINVAL;
>> +
>> +             if (info.index >= vdev->num_regions)
>> +                     return -EINVAL;
>> +
>> +             /* map offset to the physical address  */
>> +             info.offset = VFIO_PLATFORM_INDEX_TO_OFFSET(info.index);
>> +             info.size = vdev->region[info.index].size;
>> +             info.flags = vdev->region[info.index].flags;
>> +
>> +             return copy_to_user((void __user *)arg, &info, minsz);
>>
>> -     else if (cmd == VFIO_DEVICE_GET_IRQ_INFO)
>> +     } else if (cmd == VFIO_DEVICE_GET_IRQ_INFO) {
>>               return -EINVAL;
>>
>> -     else if (cmd == VFIO_DEVICE_SET_IRQS)
>> +     } else if (cmd == VFIO_DEVICE_SET_IRQS)
>>               return -EINVAL;
>>
>>       else if (cmd == VFIO_DEVICE_RESET)
>> diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
>> index 4ae88f8..3448f918 100644
>> --- a/drivers/vfio/platform/vfio_platform_private.h
>> +++ b/drivers/vfio/platform/vfio_platform_private.h
>> @@ -15,8 +15,25 @@
>>  #ifndef VFIO_PLATFORM_PRIVATE_H
>>  #define VFIO_PLATFORM_PRIVATE_H
>>
>> +#define VFIO_PLATFORM_OFFSET_SHIFT   40
>> +#define VFIO_PLATFORM_OFFSET_MASK (((u64)(1) << VFIO_PLATFORM_OFFSET_SHIFT) - 1)
>> +
>> +#define VFIO_PLATFORM_OFFSET_TO_INDEX(off)   \
>> +     (off >> VFIO_PLATFORM_OFFSET_SHIFT)
>> +
>> +#define VFIO_PLATFORM_INDEX_TO_OFFSET(index) \
>> +     ((u64)(index) << VFIO_PLATFORM_OFFSET_SHIFT)
>> +
>> +struct vfio_platform_region {
>> +     u64                     addr;
>> +     resource_size_t         size;
>> +     u32                     flags;
>> +};
>> +
>>  struct vfio_platform_device {
>>       struct platform_device          *pdev;
>> +     struct vfio_platform_region     *region;
>
> "regions" (plural) has slightly better consistency.  Thanks,
>

Ack as well.


-- 
Antonios Motakis
Virtual Open Systems
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