On Wed, May 24, 2017 at 3:03 PM, Vitaly Kuznetsov <vkuzn...@redhat.com> wrote: > We have only three call sites for hv_do_hypercall() and we're going to > change HVCALL_SIGNAL_EVENT to doing fast hypercall so we can inline this > function for optimization. > > Hyper-V top level functional specification states that r9-r11 registers > and flags may be clobbered by the hypervisor during hypercall and with > inlining this is somewhat important, add the clobbers.
> + u32 control_hi = control >> 32; > + u32 control_lo = control & 0xFFFFFFFF; > + u32 input_address_hi = input_address >> 32; > + u32 input_address_lo = input_address & 0xFFFFFFFF; > + u32 output_address_hi = output_address >> 32; > + u32 output_address_lo = output_address & 0xFFFFFFFF; Yes, I have noticed it was in older code, but see, all conjunctions above are redundant. Besides that, you may consider to use upper_32_bits() / lower_32_bits() macros. -- With Best Regards, Andy Shevchenko
