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

Antonios Motakis
2014-06-06T16:39:19Z

On Thu, Jun 5, 2014 at 11:14 PM, Alex Williamson
<alex.williamson-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> 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-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org>
>> ---
>> 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-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org>"
>> #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