Re: [PATCH v9 07/19] vfio/platform: return info for device memory mapped IO regions

[Antonios Motakis]

On Thu, Nov 20, 2014 at 3:11 PM, Antonios Motakis
<a.motakis@xxxxxxxxxxxxxxxxxxxxxx> wrote:
> On Wed, Nov 12, 2014 at 11:58 AM, Eric Auger <eric.auger@xxxxxxxxxx> wrote:
>> On 10/27/2014 07:07 PM, Antonios Motakis wrote:
>>> This patch enables the IOCTLs VFIO_DEVICE_GET_REGION_INFO ioctl call,
>>> which allows the user to learn about the available MMIO resources of
>>> a device.
>>>
>>> Signed-off-by: Antonios Motakis <a.motakis@xxxxxxxxxxxxxxxxxxxxxx>
>>> ---
>>>  drivers/vfio/platform/vfio_platform_common.c  | 110 +++++++++++++++++++++++++-
>>>  drivers/vfio/platform/vfio_platform_private.h |  22 ++++++
>>>  2 files changed, 128 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
>>> index cb20526..82de752 100644
>>> --- a/drivers/vfio/platform/vfio_platform_common.c
>>> +++ b/drivers/vfio/platform/vfio_platform_common.c
>>> @@ -27,17 +27,97 @@
>>>
>>>  #include "vfio_platform_private.h"
>>>
>>> +static DEFINE_MUTEX(driver_lock);
>>> +
>>> +static int vfio_platform_regions_init(struct vfio_platform_device *vdev)
>>> +{
>>> +     int cnt = 0, i;
>>> +
>>> +     while (vdev->get_resource(vdev, cnt))
>>> +             cnt++;
>>> +
>>> +     vdev->regions = kcalloc(cnt, sizeof(struct vfio_platform_region),
>>> +                             GFP_KERNEL);
>>> +     if (!vdev->regions)
>>> +             return -ENOMEM;
>>> +
>>> +     for (i = 0; i < cnt;  i++) {
>>> +             struct resource *res =
>>> +                     vdev->get_resource(vdev, i);
>>> +
>>> +             if (!res)
>>> +                     goto err;
>>> +
>>> +             vdev->regions[i].addr = res->start;
>>> +             vdev->regions[i].size = resource_size(res);
>>> +             vdev->regions[i].flags = 0;
>>> +
>>> +             switch (resource_type(res)) {
>>> +             case IORESOURCE_MEM:
>>> +                     vdev->regions[i].type = VFIO_PLATFORM_REGION_TYPE_MMIO;
>>> +                     break;
>>> +             case IORESOURCE_IO:
>>> +                     vdev->regions[i].type = VFIO_PLATFORM_REGION_TYPE_PIO;
>>> +                     break;
>>> +             default:
>>> +                     goto err;
>>> +             }
>>> +     }
>>> +
>>> +     vdev->num_regions = cnt;
>>> +
>>> +     return 0;
>>> +err:
>> Isn't it safer to reset vdev->num_regions here?
>> I think in a next patch you will iounmap the num_regions in
>> vfio_platform_regions_cleanup.

Actually, num_regions is only set just before the successful return,
so it seems there is no need to reset it.


>
> Agreed!
>
>> -- Eric
>>> +     kfree(vdev->regions);
>>> +     return -EINVAL;
>>> +}
>>> +
>>> +static void vfio_platform_regions_cleanup(struct vfio_platform_device *vdev)
>>> +{
>>> +     vdev->num_regions = 0;
>>> +     kfree(vdev->regions);
>>> +}
>>> +
>>>  static void vfio_platform_release(void *device_data)
>>>  {
>>> +     struct vfio_platform_device *vdev = device_data;
>>> +
>>> +     mutex_lock(&driver_lock);
>>> +
>>> +     if (!(--vdev->refcnt)) {
>>> +             vfio_platform_regions_cleanup(vdev);
>>> +     }
>>> +
>>> +     mutex_unlock(&driver_lock);
>>> +
>>>       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;
>>>
>>> +     mutex_lock(&driver_lock);
>>> +
>>> +     if (!vdev->refcnt) {
>>> +             ret = vfio_platform_regions_init(vdev);
>>> +             if (ret)
>>> +                     goto err_reg;
>>> +     }
>>> +
>>> +     vdev->refcnt++;
>>> +
>>> +     mutex_unlock(&driver_lock);
>>>       return 0;
>>> +
>>> +err_reg:
>>> +     mutex_unlock(&driver_lock);
>>> +     module_put(THIS_MODULE);
>>> +     return ret;
>>>  }
>>>
>>>  static long vfio_platform_ioctl(void *device_data,
>>> @@ -58,15 +138,33 @@ static long vfio_platform_ioctl(void *device_data,
>>>                       return -EINVAL;
>>>
>>>               info.flags = vdev->flags;
>>> -             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;
>>>
>>> -     else if (cmd == VFIO_DEVICE_GET_IRQ_INFO)
>>> +             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->regions[info.index].size;
>>> +             info.flags = vdev->regions[info.index].flags;
>>> +
>>> +             return copy_to_user((void __user *)arg, &info, minsz);
>>> +
>>> +     } else if (cmd == VFIO_DEVICE_GET_IRQ_INFO)
>>>               return -EINVAL;
>>>
>>>       else if (cmd == VFIO_DEVICE_SET_IRQS)
>>> @@ -134,10 +232,14 @@ struct vfio_platform_device *vfio_platform_remove_common(struct device *dev)
>>>  {
>>>       struct vfio_platform_device *vdev;
>>>
>>> +     mutex_lock(&driver_lock);
>>> +
>>>       vdev = vfio_del_group_dev(dev);
>>>       if (vdev)
>>>               iommu_group_put(dev->iommu_group);
>>>
>>> +     mutex_unlock(&driver_lock);
>>> +
>>>       return vdev;
>>>  }
>>>  EXPORT_SYMBOL_GPL(vfio_platform_remove_common);
>>> diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
>>> index 062b92d..b24729f 100644
>>> --- a/drivers/vfio/platform/vfio_platform_private.h
>>> +++ b/drivers/vfio/platform/vfio_platform_private.h
>>> @@ -15,7 +15,29 @@
>>>  #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;
>>> +     u32                     type;
>>> +#define VFIO_PLATFORM_REGION_TYPE_MMIO       1
>>> +#define VFIO_PLATFORM_REGION_TYPE_PIO        2
>>> +};
>>> +
>>>  struct vfio_platform_device {
>>> +     struct vfio_platform_region     *regions;
>>> +     u32                             num_regions;
>>> +     int                             refcnt;
>>> +
>>>       /*
>>>        * These fields should be filled by the bus specific binder
>>>        */
>>>
>>
--
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