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

["Tian, Kevin" <kevin.tian@xxxxxxxxx>]

> 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.
> + *
> + * @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

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