From: Gleb Natapov <gleb@redhat.com>
To: Gerd Hoffmann <kraxel@redhat.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH v4 05/11] suspend: add infrastructure
Date: Tue, 14 Feb 2012 10:37:53 +0200 [thread overview]
Message-ID: <20120214083753.GZ18866@redhat.com> (raw)
In-Reply-To: <4F3A18DA.4070405@redhat.com>
On Tue, Feb 14, 2012 at 09:18:34AM +0100, Gerd Hoffmann wrote:
> Hi,
>
> > Shouldn't we stop the whole VM at some point, not only vcpu that
> > does ACPI IO? May be I missed where it is done in the patch series.
>
> It isn't hidden elsewhere, qemu doesn't do it. The code was like that
> before, and I think the reason is that the guest has to stop the other
> cpus before entering s3.
>
Current code calls qemu_system_reset_request() which takes care of
stopping (and reseting) all vcpus (and rest of the machine) by setting
reset_requested flag immediately on suspend. We cannot just stop
current cpu on S3 and delay reset till wakeup since guest can leave
other vcpus in spinning state and they will take 100% of host cpu while
guest is suspended. I think it is also important to reset all device
immediately to ensure that no device will do DMA into main memory after
suspend. Technically if this happens it would be a guest bug since
guest should make sure that devices are stopped before entering S3,
but I wouldn't want to debug such bug report :)
--
Gleb.
next prev parent reply other threads:[~2012-02-14 8:37 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-09 17:05 [Qemu-devel] [PATCH v4 00/11] initial suspend support Gerd Hoffmann
2012-02-09 17:05 ` [Qemu-devel] [PATCH v4 01/11] acpi: move around structs Gerd Hoffmann
2012-02-09 17:05 ` [Qemu-devel] [PATCH v4 02/11] acpi: add ACPIREGS Gerd Hoffmann
2012-02-09 17:05 ` [Qemu-devel] [PATCH v4 03/11] acpi: don't pass overflow_time to acpi_pm1_evt_get_sts Gerd Hoffmann
2012-02-09 17:05 ` [Qemu-devel] [PATCH v4 04/11] acpi: add acpi_pm1_evt_write_en Gerd Hoffmann
2012-02-09 17:05 ` [Qemu-devel] [PATCH v4 05/11] suspend: add infrastructure Gerd Hoffmann
2012-02-13 9:21 ` Gleb Natapov
2012-02-14 8:18 ` Gerd Hoffmann
2012-02-14 8:37 ` Gleb Natapov [this message]
2012-02-14 8:57 ` Gerd Hoffmann
2012-02-14 9:08 ` Gleb Natapov
2012-02-14 14:49 ` Gerd Hoffmann
2012-02-09 17:05 ` [Qemu-devel] [PATCH v4 06/11] suspend: switch acpi s3 to new infrastructure Gerd Hoffmann
2012-02-09 17:05 ` [Qemu-devel] [PATCH v4 07/11] suspend: add system_wakeup monitor command Gerd Hoffmann
2012-02-09 17:05 ` [Qemu-devel] [PATCH v4 08/11] suspend: make ps/2 devices wakeup the guest Gerd Hoffmann
2012-02-09 17:05 ` [Qemu-devel] [PATCH v4 09/11] suspend: make serial ports " Gerd Hoffmann
2012-02-09 17:05 ` [Qemu-devel] [PATCH v4 10/11] suspend: make rtc alarm " Gerd Hoffmann
2012-02-09 17:05 ` [Qemu-devel] [PATCH v4 11/11] suspend: pmtimer s3 wakeup Gerd Hoffmann
2012-02-10 12:43 ` [Qemu-devel] [PATCH 12/11] suspend: add qmp events Gerd Hoffmann
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