Re: [Xen-devel] [PATCH v7 5/5] x86/ioreq server: Synchronously reset outstanding p2m_ioreq_server entries when an ioreq server unmaps.

[Yu Zhang <yu.c.zhang@xxxxxxxxxxxxxxx>]

On 3/14/2017 6:51 PM, Jan Beulich wrote:
> > > > On 14.03.17 at 08:42, <yu.c.zhang@xxxxxxxxxxxxxxx> wrote:
> > So you mean change the definition of to
> > xen_dm_op_map_mem_type_to_ioreq_server
> > to something like this?
> >
> > struct xen_dm_op_map_mem_type_to_ioreq_server {
> >       ioservid_t id;      /* IN - ioreq server id */
> >       uint16_t type;      /* IN - memory type */
> >       uint32_t flags;     /* IN - types of accesses to be forwarded to the
> >                              ioreq server. flags with 0 means to unmap the
> >                              ioreq server */
> >
> >       uint64_t opaque;    /* only used for hypercall continuation, should
> >                              be set to zero by the caller */
> > };
> Yes, with the field marked IN OUT and "should" replaced by "has to".
Got it. BTW, I can define this opaque field in patch 2/5 - the 
introduction of this dm_op,
or add it in this patch 5/5 when we use it in the hypercall 
continuation. Which one do
you incline?

> > If so, is there any approach in hypervisor to differentiate the first
> > call from the continued
> > hypercall? Do we need some form of check on this opaque?
> I don't see a need (other than - of course - the obvious upper
> bound imposed here), due to ...
>
> > And yes, not
> > playing by this
> > will only harm the guest the device model controls.
> ... this.
OK. I'm fine with this too. :-)

Thanks
Yu

> Jan

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