Re: IOCTL_PRIVCMD_MMAPBATCH on Xen 4.13.0

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

On Sun, May 17, 2020 at 07:56:07PM +0200, Manuel Bouyer wrote:
> On Sun, May 17, 2020 at 07:32:59PM +0200, Manuel Bouyer wrote:
> > I've been looking a bit deeper in the Xen kernel.
> > The mapping is failed in ./arch/x86/mm/p2m.c:p2m_get_page_from_gfn(),
> >         /* Error path: not a suitable GFN at all */
> >     if ( !p2m_is_ram(*t) && !p2m_is_paging(*t) && !p2m_is_pod(*t) ) {
> >         gdprintk(XENLOG_ERR, "p2m_get_page_from_gfn2: %d is_ram %ld 
> > is_paging %ld is_pod %ld\n", *t, p2m_is_ram(*t), p2m_is_paging(*t), 
> > p2m_is_pod(*t) );
> >         return NULL;
> >     }
> > 
> > *t is 4, which translates to p2m_mmio_dm
> > 
> > it looks like p2m_get_page_from_gfn() is not ready to handle this case
> > for dom0.
> 
> And so it looks like I need to implement osdep_xenforeignmemory_map_resource()
> for NetBSD

FWIW, FreeBSD doesn't have osdep_xenforeignmemory_map_resource
implemented and still works fine with 4.13.0 (is able to create HVM
guests), but that's a PVH dom0, not a PV one.

Regards, Roger.