Re: [PATCH v9 05/11] x86/mm: add HYPERVISOR_memory_op to acquire guest resources

[Paul Durrant <Paul.Durrant@citrix.com>]

> -----Original Message-----
> From: Paul Durrant
> Sent: 10 October 2017 15:10
> To: 'Jan Beulich' <JBeulich@suse.com>
> Cc: Andrew Cooper <Andrew.Cooper3@citrix.com>; Wei Liu
> <wei.liu2@citrix.com>; George Dunlap <George.Dunlap@citrix.com>; Ian
> Jackson <Ian.Jackson@citrix.com>; Stefano Stabellini
> <sstabellini@kernel.org>; xen-devel@lists.xenproject.org; Konrad Rzeszutek
> Wilk <konrad.wilk@oracle.com>; Tim (Xen.org) <tim@xen.org>
> Subject: RE: [PATCH v9 05/11] x86/mm: add HYPERVISOR_memory_op to
> acquire guest resources
> 
> > -----Original Message-----
> > From: Jan Beulich [mailto:JBeulich@suse.com]
> > Sent: 09 October 2017 15:23
> > To: Paul Durrant <Paul.Durrant@citrix.com>
> > Cc: Andrew Cooper <Andrew.Cooper3@citrix.com>; Wei Liu
> > <wei.liu2@citrix.com>; George Dunlap <George.Dunlap@citrix.com>; Ian
> > Jackson <Ian.Jackson@citrix.com>; Stefano Stabellini
> > <sstabellini@kernel.org>; xen-devel@lists.xenproject.org; Konrad
> Rzeszutek
> > Wilk <konrad.wilk@oracle.com>; Tim (Xen.org) <tim@xen.org>
> > Subject: Re: [PATCH v9 05/11] x86/mm: add HYPERVISOR_memory_op to
> > acquire guest resources
> >
> > >>> On 06.10.17 at 14:25, <paul.durrant@citrix.com> wrote:
> > > --- a/xen/common/memory.c
> > > +++ b/xen/common/memory.c
> > > @@ -965,6 +965,67 @@ static long xatp_permission_check(struct domain
> > *d, unsigned int space)
> > >      return xsm_add_to_physmap(XSM_TARGET, current->domain, d);
> > >  }
> > >
> > > +#ifdef CONFIG_X86
> > > +static int acquire_resource(const xen_mem_acquire_resource_t *xmar)
> > > +{
> > > +    struct domain *d, *currd = current->domain;
> > > +    unsigned long mfn_list[2];
> > > +    int rc;
> > > +
> > > +    if ( xmar->nr_frames == 0 || xmar->pad != 0 )
> > > +        return -EINVAL;
> > > +
> > > +    if ( xmar->nr_frames > ARRAY_SIZE(mfn_list) )
> > > +        return -E2BIG;
> > > +
> > > +    d = rcu_lock_domain_by_any_id(xmar->domid);
> > > +    if ( d == NULL )
> > > +        return -ESRCH;
> > > +
> > > +    rc = xsm_domain_memory_map(XSM_TARGET, d);
> >
> > Looking at the description of patch 6 - why is this XSM_TARGET
> > rather than XSM_DM_PRIV?
> 
> Good point. I was using the priv mapping code as a guide, but XSM_DM_PRIV
> is probably the right thing to use in this case.
> 

Actually that's not possible. There is an assertion in xsm_domain_memory_map() that the action is XSM_TARGET.

  Paul

>   Paul
> 
> >
> > Jan


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