From: "Philippe Mathieu-Daudé" <philmd@linaro.org>
To: Markus Armbruster <armbru@redhat.com>,
Daniil Tatianin <d-tatianin@yandex-team.ru>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Eric Blake <eblake@redhat.com>,
qemu-devel@nongnu.org
Subject: Re: [PATCH] mc146818rtc: add a way to generate RTC interrupts via QMP
Date: Mon, 29 Apr 2024 11:43:23 +0200 [thread overview]
Message-ID: <d31decf9-72d2-4515-b4b4-526ab7ddedbf@linaro.org> (raw)
In-Reply-To: <11c78645-e87b-4a43-8191-a73540c364a9@linaro.org>
On 26/4/24 11:48, Philippe Mathieu-Daudé wrote:
> Hi Daniil, Markus,
>
> On 26/4/24 10:39, Markus Armbruster wrote:
>> Daniil Tatianin <d-tatianin@yandex-team.ru> writes:
>>
>>> 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.
>>>
>>> Signed-off-by: Daniil Tatianin <d-tatianin@yandex-team.ru>
>>> ---
>>> hw/rtc/mc146818rtc.c | 15 +++++++++++++++
>>> include/hw/rtc/mc146818rtc.h | 1 +
>>> qapi/misc-target.json | 16 ++++++++++++++++
>>> 3 files changed, 32 insertions(+)
>>>
>>> diff --git a/hw/rtc/mc146818rtc.c b/hw/rtc/mc146818rtc.c
>>> index f4c1869232..6980a78d5f 100644
>>> --- a/hw/rtc/mc146818rtc.c
>>> +++ b/hw/rtc/mc146818rtc.c
>>> @@ -116,6 +116,21 @@ void qmp_rtc_reset_reinjection(Error **errp)
>>> }
>>> }
>>> +void qmp_rtc_notify(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);
>>> + }
>>> +}
>>> +
>>
>> Note for later: qmp_rtc_notify() works on all realized mc146818rtc
>> devices. Other kinds of RTC devices are silently ignored. Just like
>> qmp_rtc_reset_reinjection().
>
> IMO to avoid any future ambiguity (in heterogeneous machines), this
> command must take a QOM device path (or a list of) and only notify
> those.
If you disagree, at least please rename the command/method using
"broadcast" for trailer.
next prev parent reply other threads:[~2024-04-29 9:43 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-25 13:37 [PATCH] mc146818rtc: add a way to generate RTC interrupts via QMP Daniil Tatianin
2024-04-26 8:39 ` Markus Armbruster
2024-04-26 9:28 ` Daniil Tatianin
2024-04-26 9:47 ` Markus Armbruster
2024-04-26 9:48 ` Philippe Mathieu-Daudé
2024-04-29 9:43 ` Philippe Mathieu-Daudé [this message]
2024-04-29 11:32 ` Markus Armbruster
2024-04-29 13:39 ` Philippe Mathieu-Daudé
2024-04-29 14:02 ` Markus Armbruster
2024-05-02 7:30 ` Daniil Tatianin
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