Add RTC alarm syncing support to host QEMU

This allows QMP clients to implement RTC alarm syncing from guest to
host.

Tracked-On: OAM-100921
Signed-off-by: Zhuocheng Ding <[email protected]>
Signed-off-by: Swee Yee Fonn <[email protected]>

host/qemu/0002-mc146818rtc-add-RTC_ALARM-QMP-event.patch

@@ -0,0 +1,72 @@
+From 2eb9f2c0850c0e92877b0e8db7e8173bea5f584e Mon Sep 17 00:00:00 2001
+From: Zhuocheng Ding <[email protected]>
+Date: Fri, 11 Sep 2020 09:14:30 +0800
+Subject: [PATCH] mc146818rtc: add RTC_ALARM QMP event
+
+Emitted whenever the RTC alarm expire time changes.
+
+Tracked-On: OAM-92864
+Signed-off-by: Zhuocheng Ding <[email protected]>
+---
+ hw/rtc/mc146818rtc.c  |  7 ++++++-
+ qapi/misc-target.json | 18 ++++++++++++++++++
+ 2 files changed, 24 insertions(+), 1 deletion(-)
+
+diff --git a/hw/rtc/mc146818rtc.c b/hw/rtc/mc146818rtc.c
+index 74ae74bc5c..4db9e946d1 100644
+--- a/hw/rtc/mc146818rtc.c
++++ b/hw/rtc/mc146818rtc.c
+@@ -269,6 +269,7 @@ static void check_update_timer(RTCState *s)
+ {
+     uint64_t next_update_time;
+     uint64_t guest_nsec;
++    uint64_t next_alarm_time;
+     int next_alarm_sec;
+
+     /* From the data sheet: "Holding the dividers in reset prevents
+@@ -289,8 +290,12 @@ static void check_update_timer(RTCState *s)
+      * for in next_update_time.
+      */
+     next_alarm_sec = get_next_alarm(s);
+-    s->next_alarm_time = next_update_time +
++    next_alarm_time = next_update_time +
+                          (next_alarm_sec - 1) * NANOSECONDS_PER_SECOND;
++    if (s->next_alarm_time != next_alarm_time) {
++        s->next_alarm_time = next_alarm_time;
++        qapi_event_send_rtc_alarm(s->next_alarm_time);
++    }
+
+     /* If update_in_progress latched the UIP bit, we must keep the timer
+      * programmed to the next second, so that UIP is cleared.  Otherwise,
+diff --git a/qapi/misc-target.json b/qapi/misc-target.json
+index a00fd821eb..a92959d436 100644
+--- a/qapi/misc-target.json
++++ b/qapi/misc-target.json
+@@ -24,6 +24,24 @@
+   'data': { 'offset': 'int' },
+   'if': 'defined(TARGET_ALPHA) || defined(TARGET_ARM) || defined(TARGET_HPPA) || defined(TARGET_I386) || defined(TARGET_MIPS) || defined(TARGET_MIPS64) || defined(TARGET_MOXIE) || defined(TARGET_PPC) || defined(TARGET_PPC64) || defined(TARGET_S390X) || defined(TARGET_SH4) || defined(TARGET_SPARC)' }
+
++##
++# @RTC_ALARM:
++#
++# Emitted when the guest RTC alarm expire time changes.
++#
++# @expire: expire time of guest RTC alarm, measured in host realtime
++#
++# Example:
++#
++# <-   { "event": "RTC_ALARM",
++#        "data": { "expire": 1593499713567502000 },
++#        "timestamp": { "seconds": 1593413313, "microseconds": 568267 } }
++#
++##
++{ 'event': 'RTC_ALARM',
++  'data': { 'expire': 'int' },
++  'if': 'defined(TARGET_I386)' }
++
+ ##
+ # @rtc-reset-reinjection:
+ #
+-- 
+2.25.1
+

host/qemu/0003-mc146818rtc-add-rtc-refresh-timer-QMP-command.patch

@@ -0,0 +1,68 @@
+From 3f588e6de9c64225ca7f3d2df4e2e46e72ab8dc9 Mon Sep 17 00:00:00 2001
+From: Zhuocheng Ding <[email protected]>
+Date: Fri, 11 Sep 2020 09:32:03 +0800
+Subject: [PATCH] mc146818rtc: add rtc-refresh-timer QMP command
+
+If host is suspended for a while, the timers in QEMU will not take the
+time during suspension into account. This command will force QEMU to
+recheck RTC timers, so that these timers will not be delayed.
+
+Tracked-On: OAM-92864
+Signed-off-by: Zhuocheng Ding <[email protected]>
+---
+ hw/rtc/mc146818rtc.c  |  6 ++++++
+ qapi/misc-target.json | 14 ++++++++++++++
+ 2 files changed, 20 insertions(+)
+
+diff --git a/hw/rtc/mc146818rtc.c b/hw/rtc/mc146818rtc.c
+index 4db9e946d1..5ed0f7b100 100644
+--- a/hw/rtc/mc146818rtc.c
++++ b/hw/rtc/mc146818rtc.c
+@@ -45,6 +45,7 @@
+
+ #ifdef TARGET_I386
+ #include "qapi/qapi-commands-misc-target.h"
++#include "qemu/main-loop.h"
+ #include "hw/i386/apic.h"
+ #endif
+
+@@ -119,6 +120,11 @@ void qmp_rtc_reset_reinjection(Error **errp)
+     }
+ }
+
++void qmp_rtc_refresh_timer(Error **errp)
++{
++    qemu_notify_event();
++}
++
+ static bool rtc_policy_slew_deliver_irq(RTCState *s)
+ {
+     apic_reset_irq_delivered();
+diff --git a/qapi/misc-target.json b/qapi/misc-target.json
+index a92959d436..04bdd52eca 100644
+--- a/qapi/misc-target.json
++++ b/qapi/misc-target.json
+@@ -61,6 +61,20 @@
+ { 'command': 'rtc-reset-reinjection',
+   'if': 'defined(TARGET_I386)' }
+
++##
++# @rtc-refresh-timer:
++#
++# This command will refresh the RTC timers, so that the expired timers can
++# trigger their callbacks immediately.
++#
++# Example:
++#
++# -> { "execute": "rtc-refresh-timer" }
++# <- { "return": {} }
++#
++##
++{ 'command': 'rtc-refresh-timer',
++  'if': 'defined(TARGET_I386)' }
+
+ ##
+ # @SevState:
+-- 
+2.25.1
+