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

[Stefano Stabellini]

On Mon, 19 Dec 2016, Juergen Gross wrote:
> 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@xxxxxxxxxxxxxx>
> > ---
> >  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
> 	};

+1