Commit f01c5d84 authored by David Gibson's avatar David Gibson Committed by Alexander Graf
Browse files

pseries: Make RTAS time of day functions respect -rtc options 



In the 'pseries' machine the real time clock is provided by a
paravirtualized firmware interface rather than a device per se; the RTAS
get-time-of-day and set-time-of-day calls.

Out current implementations of those work directly off host time (with
an offset), not respecting options such as clock=vm which can be
specified in the -rtc command line option.

This patch reworks the RTAS RTC code to respect those options, primarily
by basing them on the qemu_clock_get_ns(rtc_clock) function instead of
directly on qemu_get_timedate() (which essentially handles host time, not
virtual rtc time).

As a bonus, this means our get-time-of-day function now also returns
nanoseconds.

Signed-off-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
parent e5dad1d7

hw/ppc/spapr_rtc.c

+36 −4
Original line number Diff line number Diff line
@@ -26,14 +26,24 @@ 
 *

 */

#include "cpu.h"

#include "sysemu/sysemu.h"

#include "hw/ppc/spapr.h"

#include "qapi-event.h"



#define NSEC_PER_SEC    1000000000LL



void spapr_rtc_read(sPAPREnvironment *spapr, struct tm *tm, uint32_t *ns)

{

    qemu_get_timedate(tm, spapr->rtc_offset);

    int64_t host_ns = qemu_clock_get_ns(rtc_clock);

    time_t guest_s;



    guest_s = host_ns / NSEC_PER_SEC + spapr->rtc_offset;



    if (tm) {

        gmtime_r(&guest_s, tm);

    }

    if (ns) {

        *ns = 0; /* we don't do nanoseconds, yet */

        *ns = host_ns % NSEC_PER_SEC;

    }

}
@@ -68,6 +78,8 @@ static void rtas_set_time_of_day(PowerPCCPU *cpu, sPAPREnvironment *spapr, 
                                 uint32_t nret, target_ulong rets)

{

    struct tm tm;

    time_t new_s;

    int64_t host_ns;



    if ((nargs != 7) || (nret != 1)) {

        rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
@@ -81,15 +93,35 @@ static void rtas_set_time_of_day(PowerPCCPU *cpu, sPAPREnvironment *spapr, 
    tm.tm_min = rtas_ld(args, 4);

    tm.tm_sec = rtas_ld(args, 5);



    /* Just generate a monitor event for the change */

    new_s = mktimegm(&tm);

    if (new_s == -1) {

        rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);

        return;

    }



    /* Generate a monitor event for the change */

    qapi_event_send_rtc_change(qemu_timedate_diff(&tm), &error_abort);

    spapr->rtc_offset = qemu_timedate_diff(&tm);



    host_ns = qemu_clock_get_ns(rtc_clock);



    spapr->rtc_offset = new_s - host_ns / NSEC_PER_SEC;



    rtas_st(rets, 0, RTAS_OUT_SUCCESS);

}



void spapr_rtc_init(void)

{

    struct tm tm;

    time_t host_s;

    int64_t rtc_ns;



    /* Initialize the RTAS RTC from host time */



    qemu_get_timedate(&tm, 0);

    host_s = mktimegm(&tm);

    rtc_ns = qemu_clock_get_ns(rtc_clock);

    spapr->rtc_offset = host_s - rtc_ns / NSEC_PER_SEC;



    spapr_rtas_register(RTAS_GET_TIME_OF_DAY, "get-time-of-day",

                        rtas_get_time_of_day);

    spapr_rtas_register(RTAS_SET_TIME_OF_DAY, "set-time-of-day",