Re: [Xen-devel] [PATCH] x86/pv: Export pv_hypercall_table[] rather than working around it in several ways

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 24.01.18 at 13:16, <andrew.cooper3@xxxxxxxxxx> wrote:
> The functions in compat.c are thing wrappers around the main hypercalls,
> massaging certain parameters.  However, they second-guess the content of
> pv_hypercall_table[], which is problematic for the shim case.  Instead,
> arrange for them to call via function pointer, which removes the need for
> pv_get_hypercall_handler().
> 
> With pv_hypercall_table[] exported, there is no need for
> pv_hypercall_table_replace(), so its single callsite gets modified to cope.
> The backing code behind __va(__pa()) is substantial, and there is no need to
> calculate it repeatedly (Xen's .rodata is also contiguous in the directmap).
> 
> While adjusting the declarations, guard content in arch/x86/pv with 
> CONFIG_PV.
> 
> The net difference is:
>   add/remove: 0/2 grow/shrink: 4/1 up/down: 176/-321 (-145)
>   function                                     old     new   delta
>   pv_shim_setup_dom                           1130    1266    +136
>   do_sched_op_compat                           176     192     +16
>   compat_physdev_op_compat                      90     106     +16
>   do_physdev_op_compat                          98     106      +8
>   do_event_channel_op_compat                   145     123     -22
>   pv_get_hypercall_handler                      28       -     -28
>   pv_hypercall_table_replace                   271       -    -271
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>



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