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| author | Yishai Hadas <yishaih@nvidia.com> | 2026-03-17 19:17:50 +0300 |
|---|---|---|
| committer | Alex Williamson <alex@shazbot.org> | 2026-03-19 21:32:09 +0300 |
| commit | c995498636c704641c9e809c31b59445b48f7adc (patch) | |
| tree | ed6e9484b07d1922246bc1201df4822d3d596bcd /include | |
| parent | 50ff3f404617c5d15832fec3711978104c4c9efd (diff) | |
| download | linux-c995498636c704641c9e809c31b59445b48f7adc.tar.xz | |
vfio: Adapt drivers to use the core helper vfio_check_precopy_ioctl
Introduce a core helper function for VFIO_MIG_GET_PRECOPY_INFO and adapt
all drivers to use it.
It centralizes the common code and ensures that output flags are cleared
on entry, in case user opts in to VFIO_DEVICE_FEATURE_MIG_PRECOPY_INFOv2.
This preventing any unintended echoing of userspace data back to
userspace.
Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
Link: https://lore.kernel.org/r/20260317161753.18964-4-yishaih@nvidia.com
Signed-off-by: Alex Williamson <alex@shazbot.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/vfio.h | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/include/linux/vfio.h b/include/linux/vfio.h index 7c1d33283e04..50b474334a19 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -16,6 +16,7 @@ #include <linux/cdev.h> #include <uapi/linux/vfio.h> #include <linux/iova_bitmap.h> +#include <linux/uaccess.h> struct kvm; struct iommufd_ctx; @@ -285,6 +286,44 @@ static inline int vfio_check_feature(u32 flags, size_t argsz, u32 supported_ops, return 1; } +/** + * vfio_check_precopy_ioctl - Validate user input for the VFIO_MIG_GET_PRECOPY_INFO ioctl + * @vdev: The vfio device + * @cmd: Cmd from the ioctl + * @arg: Arg from the ioctl + * @info: Driver pointer to hold the userspace input to the ioctl + * + * For use in a driver's get_precopy_info. Checks that the inputs to the + * VFIO_MIG_GET_PRECOPY_INFO ioctl are correct. + + * Returns 0 on success, otherwise errno. + */ + +static inline int +vfio_check_precopy_ioctl(struct vfio_device *vdev, unsigned int cmd, + unsigned long arg, struct vfio_precopy_info *info) +{ + unsigned long minsz; + + if (cmd != VFIO_MIG_GET_PRECOPY_INFO) + return -ENOTTY; + + minsz = offsetofend(struct vfio_precopy_info, dirty_bytes); + + if (copy_from_user(info, (void __user *)arg, minsz)) + return -EFAULT; + + if (info->argsz < minsz) + return -EINVAL; + + /* keep v1 behaviour as is for compatibility reasons */ + if (vdev->precopy_info_v2) + /* flags are output, set its initial value to 0 */ + info->flags = 0; + + return 0; +} + struct vfio_device *_vfio_alloc_device(size_t size, struct device *dev, const struct vfio_device_ops *ops); #define vfio_alloc_device(dev_struct, member, dev, ops) \ |