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From: Juan Quintela <quintela@redhat.com>
In-Reply-To: <20180110100929.15986.71777.stgit@pasha-VirtualBox> (Pavel
	Dovgalyuk's message of "Wed, 10 Jan 2018 13:09:30 +0300")
References: <20180110100929.15986.71777.stgit@pasha-VirtualBox>
Reply-To: quintela@redhat.com
Date: Wed, 10 Jan 2018 11:47:13 +0100
Message-ID: <874lnuyor2.fsf@secure.laptop>
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Subject: Re: [Qemu-devel] [PATCH v3] hpet: recover timer offset correctly
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To: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
Cc: qemu-devel@nongnu.org, mst@redhat.com, dgilbert@redhat.com, maria.klimushenkova@ispras.ru, dovgaluk@ispras.ru, pbonzini@redhat.com

Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru> wrote:
> HPET saves its state by calculating the current time and recovers timer
> offset using this calculated value. But these calculations include
> divisions and multiplications. Therefore the timer state cannot be recovered
> precise enough.
> This patch introduces saving of the original value of the offset to
> preserve the determinism of the timer.
>
> Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
> Signed-off-by: Maria Klimushenkova <maria.klimushenkova@ispras.ru>
> Reviewed-by: Juan Quintela <quintela@redhat.com>
>
> --
> v3: Added compat property for correct migration.

Yeap, Much better.

> @@ -762,6 +787,7 @@ static Property hpet_device_properties[] = {
>      DEFINE_PROP_UINT8("timers", HPETState, num_timers, HPET_MIN_TIMERS),
>      DEFINE_PROP_BIT("msi", HPETState, flags, HPET_MSI_SUPPORT, false),
>      DEFINE_PROP_UINT32(HPET_INTCAP, HPETState, intcap, 0),
> +    DEFINE_PROP_BOOL("hpet-offset-saved", HPETState, hpet_offset_saved, true),
>      DEFINE_PROP_END_OF_LIST(),
>  };

I am thinking about the name, but I can't suggest anything else that is
short and descriptive, so ....

Later, Juan.