Re: [Xen-devel] [PATCH v7 2/3] Differentiate IO/mem resources tracked by ioreq server

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

On 8/21/2015 2:35 PM, Tian, Kevin wrote:
> > From: Yu Zhang [mailto:yu.c.zhang@xxxxxxxxxxxxxxx]
> > Sent: Friday, August 21, 2015 11:31 AM
> >
> > Currently in ioreq server, guest write-protected ram pages are
> > tracked in the same rangeset with device mmio resources. Yet
> > unlike device mmio, which can be in big chunks, the guest write-
> > protected pages may be discrete ranges with 4K bytes each. This
> > patch uses a seperate rangeset for the guest ram pages.
> >
> > Note: Previously, a new hypercall or subop was suggested to map
> > write-protected pages into ioreq server. However, it turned out
> > handler of this new hypercall would be almost the same with the
> > existing pair - HVMOP_[un]map_io_range_to_ioreq_server, and there's
> > already a type parameter in this hypercall. So no new hypercall
> > defined, only a new type is introduced.
> >
> > Signed-off-by: Yu Zhang <yu.c.zhang@xxxxxxxxxxxxxxx>
> > ---
> >   tools/libxc/include/xenctrl.h    | 31 ++++++++++++++++++++
> >   tools/libxc/xc_domain.c          | 61
> > ++++++++++++++++++++++++++++++++++++++++
> >   xen/arch/x86/hvm/hvm.c           | 23 ++++++++++++++-
> >   xen/include/asm-x86/hvm/domain.h |  4 +--
> >   xen/include/public/hvm/hvm_op.h  |  1 +
> >   5 files changed, 117 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
> > index de3c0ad..eb1a526 100644
> > --- a/tools/libxc/include/xenctrl.h
> > +++ b/tools/libxc/include/xenctrl.h
> > @@ -2010,6 +2010,37 @@ int
> > xc_hvm_unmap_io_range_from_ioreq_server(xc_interface *xch,
> >                                               int is_mmio,
> >                                               uint64_t start,
> >                                               uint64_t end);
> > +/**
> > + * This function registers a range of write-protected memory for emulation.
> > + *
> > + * @parm xch a handle to an open hypervisor interface.
> > + * @parm domid the domain id to be serviced
> > + * @parm id the IOREQ Server id.
> > + * @parm start start of range
> > + * @parm end end of range (inclusive).
> > + * @return 0 on success, -1 on failure.
> > + */
> > +int xc_hvm_map_mem_range_to_ioreq_server(xc_interface *xch,
> > +                                         domid_t domid,
> > +                                         ioservid_t id,
> > +                                         xen_pfn_t start,
> > +                                         xen_pfn_t end);
> > +
> > +/**
> > + * This function deregisters a range of write-protected memory for emulation.
> > + *
s>> + * @parm xch a handle to an open hypervisor interface.
> > + * @parm domid the domain id to be serviced
> > + * @parm id the IOREQ Server id.
> > + * @parm start start of range
> > + * @parm end end of range (inclusive).
> > + * @return 0 on success, -1 on failure.
> > + */
> > +int xc_hvm_unmap_mem_range_from_ioreq_server(xc_interface *xch,
> > +                                             domid_t domid,
> > +                                             ioservid_t id,
> > +                                             xen_pfn_t start,
> > +                                             xen_pfn_t end);
> >
> >   /**
> >    * This function registers a PCI device for config space emulation.
> > diff --git a/tools/libxc/xc_domain.c b/tools/libxc/xc_domain.c
> > index 2ee26fb..34f138d 100644
> > --- a/tools/libxc/xc_domain.c
> > +++ b/tools/libxc/xc_domain.c
> > @@ -1552,6 +1552,67 @@ int
> > xc_hvm_unmap_io_range_from_ioreq_server(xc_interface *xch, domid_t domid,
> >       return rc;
> >   }
> >
> > +int xc_hvm_map_mem_range_to_ioreq_server(xc_interface *xch,
> > +                                         domid_t domid,
> > +                                         ioservid_t id,
> > +                                         xen_pfn_t start,
> > +                                         xen_pfn_t end)
> > +{
> Given that this memory range is write-protected, it might be clearer
> to have wp in function name. Otherwise it's easy to mistake the
> interface as both r/w covered for the range. Or if you want this
> interface to be more generic, then a flag parameter would be required
> to further specify wp attribute.
>
> Thanks
> Kevin
Thanks, Kevin. Maybe xc_hvm_[un]map_wp_mem_range_to_ioreq_server
is clearer.

Yu
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