[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v3 02/11] hvm/hpet: Only call guest_time_hpet(h) one time per action.
>>> On 23.04.14 at 17:42, <dslutz@xxxxxxxxxxx> wrote: > On 4/23/2014 11:07 AM, Jan Beulich wrote: >>>>> On 17.04.14 at 19:42, <dslutz@xxxxxxxxxxx> wrote: >>> v3: >>> Did not add Reviewed-by (Jan Beulich) do to amount of change >>> Added passing of guest_time to hpet_read64() and >>> hpet_stop_timer(). >> But that wasn't as a result of the review of v2, was it? > > Not on this thread. I was using gdb to get answers for a later patch. > >> Especially for >> the hpet_read64() case I fear this is going a little too far, since now >> you call the supposedly expensive function even when the value isn't >> needed. I suppose you could resolve this by passing a known-invalid >> value to the function from hpet_read() (so it knows to call >> guest_time_hpet() itself) and use the always-preset variant on from >> hpet_write(). > > I also considered a case statement on the call (since the value is > needed later when > hpet_write also uses it). I do not think that any value is invalid. With #define STIME_PER_HPET_TICK 16 #define guest_time_hpet(hpet) \ (hvm_get_guest_time(vhpet_vcpu(hpet)) / STIME_PER_HPET_TICK) any value with one or more of the high 4 bits set would be invalid. Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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