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

["Yu, Zhang" <yu.c.zhang@linux.intel.com>]

On 8/21/2015 2:35 PM, Tian, Kevin wrote:
>> From: Yu Zhang [mailto:yu.c.zhang@linux.intel.com]
>> 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@linux.intel.com>
>> ---
>>   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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