RE: IOCTL_PRIVCMD_MMAPBATCH on Xen 4.13.0

[Paul Durrant <xadimgnik@xxxxxxxxx>]

> -----Original Message-----
> From: Xen-devel <xen-devel-bounces@xxxxxxxxxxxxxxxxxxxx> On Behalf Of Manuel 
> Bouyer
> Sent: 17 May 2020 18:56
> To: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx
> Subject: Re: IOCTL_PRIVCMD_MMAPBATCH on Xen 4.13.0
> 
> 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
> 

It would be a good idea but you shouldn't have to. Also, qemu-trad won't use it 
even if it is there.

  Paul