Re: [PATCH v15 2/3] mem_sharing: allow forking domain with IOMMU enabled

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Mon, Apr 20, 2020 at 08:19:12AM -0600, Tamas K Lengyel wrote:
> On Mon, Apr 20, 2020 at 1:57 AM Roger Pau Monné <roger.pau@xxxxxxxxxx> wrote:
> >
> > On Fri, Apr 17, 2020 at 10:06:32AM -0700, Tamas K Lengyel wrote:
> > > diff --git a/xen/include/public/memory.h b/xen/include/public/memory.h
> > > index d36d64b8dc..1d2149def3 100644
> > > --- a/xen/include/public/memory.h
> > > +++ b/xen/include/public/memory.h
> > > @@ -536,7 +536,9 @@ struct xen_mem_sharing_op {
> > >          } debug;
> > >          struct mem_sharing_op_fork {      /* OP_FORK */
> > >              domid_t parent_domain;        /* IN: parent's domain id */
> > > -            uint16_t pad[3];              /* Must be set to 0 */
> > > +#define XENMEM_FORK_WITH_IOMMU_ALLOWED 1  /* Allow forking domain with 
> > > IOMMU */
> >
> > Since this is a flags field, can you express this is as: (1u << 0).
> 
> I was thinking of doing that then it won't fit into a single line. For
> this particular flag it would also make no difference.

Right, but when new flags are added it looks weird IMO to have:

#define XENMEM_FORK_WITH_IOMMU_ALLOWED 1
#define XENMEM_FOO_BAR_WITH_FOO        (1u << 1)

Thanks, Roger.