From: Daniil Tatianin <d-tatianin@yandex-team.ru>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Daniil Tatianin <d-tatianin@yandex-team.ru>,
Paolo Bonzini <pbonzini@redhat.com>,
Eric Blake <eblake@redhat.com>,
Markus Armbruster <armbru@redhat.com>,
qemu-devel@nongnu.org
Subject: [PATCH v1] mc146818rtc: add a way to generate RTC interrupts via QMP
Date: Sat, 27 Apr 2024 10:58:01 +0300 [thread overview]
Message-ID: <20240427075801.491673-1-d-tatianin@yandex-team.ru> (raw)
This can be used to force-synchronize the time in guest after a long
stop-cont pause, which can be useful for serverless-type workload.
Also add a comment to highlight the fact that this (and one other QMP
command) only works for the MC146818 RTC controller.
Signed-off-by: Daniil Tatianin <d-tatianin@yandex-team.ru>
---
Changes since v0:
- Rename to rtc-inject-irq to match other similar API
- Add a comment to highlight that this only works for the I386 RTC
---
hw/rtc/mc146818rtc.c | 20 ++++++++++++++++++++
include/hw/rtc/mc146818rtc.h | 1 +
qapi/misc-target.json | 16 ++++++++++++++++
3 files changed, 37 insertions(+)
diff --git a/hw/rtc/mc146818rtc.c b/hw/rtc/mc146818rtc.c
index f4c1869232..8501b55cbd 100644
--- a/hw/rtc/mc146818rtc.c
+++ b/hw/rtc/mc146818rtc.c
@@ -107,6 +107,11 @@ static void rtc_coalesced_timer_update(MC146818RtcState *s)
static QLIST_HEAD(, MC146818RtcState) rtc_devices =
QLIST_HEAD_INITIALIZER(rtc_devices);
+/*
+ * NOTE:
+ * The two QMP functions below are _only_ implemented for the MC146818.
+ * All other RTC devices ignore this.
+ */
void qmp_rtc_reset_reinjection(Error **errp)
{
MC146818RtcState *s;
@@ -116,6 +121,21 @@ void qmp_rtc_reset_reinjection(Error **errp)
}
}
+void qmp_rtc_inject_irq(Error **errp)
+{
+ MC146818RtcState *s;
+
+ /*
+ * See:
+ * https://www.kernel.org/doc/Documentation/virtual/kvm/timekeeping.txt
+ */
+ QLIST_FOREACH(s, &rtc_devices, link) {
+ s->cmos_data[RTC_REG_B] |= REG_B_UIE;
+ s->cmos_data[RTC_REG_C] |= REG_C_IRQF | REG_C_UF;
+ qemu_irq_raise(s->irq);
+ }
+}
+
static bool rtc_policy_slew_deliver_irq(MC146818RtcState *s)
{
kvm_reset_irq_delivered();
diff --git a/include/hw/rtc/mc146818rtc.h b/include/hw/rtc/mc146818rtc.h
index 97cec0b3e8..6cd9761d80 100644
--- a/include/hw/rtc/mc146818rtc.h
+++ b/include/hw/rtc/mc146818rtc.h
@@ -56,5 +56,6 @@ MC146818RtcState *mc146818_rtc_init(ISABus *bus, int base_year,
void mc146818rtc_set_cmos_data(MC146818RtcState *s, int addr, int val);
int mc146818rtc_get_cmos_data(MC146818RtcState *s, int addr);
void qmp_rtc_reset_reinjection(Error **errp);
+void qmp_rtc_inject_irq(Error **errp);
#endif /* HW_RTC_MC146818RTC_H */
diff --git a/qapi/misc-target.json b/qapi/misc-target.json
index 4e0a6492a9..d84a5d07a2 100644
--- a/qapi/misc-target.json
+++ b/qapi/misc-target.json
@@ -19,6 +19,22 @@
{ 'command': 'rtc-reset-reinjection',
'if': 'TARGET_I386' }
+##
+# @rtc-inject-irq:
+#
+# Inject an RTC interrupt.
+#
+# Since: 9.1
+#
+# Example:
+#
+# -> { "execute": "rtc-inject-irq" }
+# <- { "return": {} }
+#
+##
+{ 'command': 'rtc-inject-irq',
+ 'if': 'TARGET_I386' }
+
##
# @SevState:
#
--
2.34.1
next reply other threads:[~2024-04-27 7:59 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-27 7:58 Daniil Tatianin [this message]
2024-04-29 8:51 ` [PATCH v1] mc146818rtc: add a way to generate RTC interrupts via QMP Markus Armbruster
2024-04-29 9:34 ` Daniil Tatianin
2024-04-29 9:40 ` Philippe Mathieu-Daudé
2024-04-29 9:43 ` Daniil Tatianin
2024-04-29 9:46 ` Philippe Mathieu-Daudé
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