Re: [PATCH] VFIO driver: Non-privileged user level PCI drivers

[Arnd Bergmann <arnd@arndb.de>]

On Saturday 29 May 2010, Tom Lyon wrote:
> +/*
> + * Structure for DMA mapping of user buffers
> + * vaddr, dmaaddr, and size must all be page aligned
> + * buffer may only be larger than 1 page if (a) there is
> + * an iommu in the system, or (b) buffer is part of a huge page
> + */
> +struct vfio_dma_map {
> +       __u64   vaddr;          /* process virtual addr */
> +       __u64   dmaaddr;        /* desired and/or returned dma address */
> +       __u64   size;           /* size in bytes */
> +       int     rdwr;           /* bool: 0 for r/o; 1 for r/w */
> +};

Please add a 32 bit padding word at the end of this, otherwise the
size of the data structure is incompatible between 32 x86 applications
and 64 bit kernels.

	Arnd