Commit f2a4ad6d authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

cpus: allow cpu_get_ticks out of BQL 



Because of cpu_ticks_prev, we cannot use a seqlock.  But then the conversion
is even easier. :)

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 94377115

cpus.c

+20 −15
Original line number Diff line number Diff line
@@ -316,11 +316,26 @@ int64_t cpu_icount_to_ns(int64_t icount) 
    return icount << atomic_read(&timers_state.icount_time_shift);

}



static int64_t cpu_get_ticks_locked(void)

{

    int64_t ticks = timers_state.cpu_ticks_offset;

    if (timers_state.cpu_ticks_enabled) {

        ticks += cpu_get_host_ticks();

    }



    if (timers_state.cpu_ticks_prev > ticks) {

        /* Non increasing ticks may happen if the host uses software suspend.  */

        timers_state.cpu_ticks_offset += timers_state.cpu_ticks_prev - ticks;

        ticks = timers_state.cpu_ticks_prev;

    }



    timers_state.cpu_ticks_prev = ticks;

    return ticks;

}



/* return the time elapsed in VM between vm_start and vm_stop.  Unless

 * icount is active, cpu_get_ticks() uses units of the host CPU cycle

 * counter.

 *

 * Caller must hold the BQL

 */

int64_t cpu_get_ticks(void)

{
@@ -330,19 +345,9 @@ int64_t cpu_get_ticks(void) 
        return cpu_get_icount();

    }



    ticks = timers_state.cpu_ticks_offset;

    if (timers_state.cpu_ticks_enabled) {

        ticks += cpu_get_host_ticks();

    }



    if (timers_state.cpu_ticks_prev > ticks) {

        /* Note: non increasing ticks may happen if the host uses

           software suspend */

        timers_state.cpu_ticks_offset += timers_state.cpu_ticks_prev - ticks;

        ticks = timers_state.cpu_ticks_prev;

    }



    timers_state.cpu_ticks_prev = ticks;

    qemu_spin_lock(&timers_state.vm_clock_lock);

    ticks = cpu_get_ticks_locked();

    qemu_spin_unlock(&timers_state.vm_clock_lock);

    return ticks;

}