Re: [PATCH] Xen: ARM: Zero reserved fields of xatp before making hypervisor call

[Juergen Gross <jgross@suse.com>]

On 19/12/16 03:56, Jiandi An wrote:
> Ensure all reserved fields of xatp are zero before making hypervisor
> call to XEN in xen_map_device_mmio().  xenmem_add_to_physmap_one() in
> XEN fails the mapping request if extra.res reserved field in xatp is
> not zero for XENMAPSPACE_dev_mmio request.
> 
> Signed-off-by: Jiandi An <anjiandi@codeaurora.org>
> ---
>  drivers/xen/arm-device.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/xen/arm-device.c b/drivers/xen/arm-device.c
> index 778acf8..208273b 100644
> --- a/drivers/xen/arm-device.c
> +++ b/drivers/xen/arm-device.c
> @@ -87,6 +87,9 @@ static int xen_map_device_mmio(const struct resource *resources,
>  			idxs[j] = XEN_PFN_DOWN(r->start) + j;
>  		}
>  
> +		/* Ensure reserved fields are set to zero */
> +		memset(&xatp, 0, sizeof(xatp));
> +
>  		xatp.domid = DOMID_SELF;
>  		xatp.size = nr;
>  		xatp.space = XENMAPSPACE_dev_mmio;

Instead of setting xatp to 0 in each iteration I'd prefer a static
initialization of .domid and .space:

	struct xen_add_to_physmap_range xatp = {
		.domid = DOMID_SELF,
		.space = XENMAPSPACE_dev_mmio
	};


Juergen