On Mon, Oct 23, 2023 at 10:28:13AM +0100, Joao Martins wrote:
> > so it's probably
> > best to add a range check plus type cast, rather than an
> > expensive div_u64() here.
>
> OK
Just keep it simple, we don't need to optimize for 32 bit. div_u64
will make the compiler happy.
> >> +struct iommu_hwpt_get_dirty_bitmap {
> >> + __u32 size;
> >> + __u32 hwpt_id;
> >> + __u32 flags;
> >> + __u32 __reserved;
> >> + __aligned_u64 iova;
> >> + __aligned_u64 length;
> >> + __aligned_u64 page_size;
> >> + __aligned_u64 *data;
> >> +};
> >> +#define IOMMU_HWPT_GET_DIRTY_BITMAP _IO(IOMMUFD_TYPE, \
> >> + IOMMUFD_CMD_HWPT_GET_DIRTY_BITMAP)
> >> +
> >
> > This is a flawed definition for an ioctl data structure. While
> > it appears that you have tried hard to follow the recommendations
> > in Documentation/driver-api/ioctl.rst, you accidentally added
> > a pointer here, which breaks compat mode handling because of
> > the uninitialized padding after the 32-bit 'data' pointer.
> >
> Right
oops how did we all miss that extra character :|
Jason
