From: marc.zyngier@arm•com (Marc Zyngier)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v2] ARM/KVM: save and restore generic timer registers
Date: Thu, 20 Jun 2013 19:39:59 +0100 [thread overview]
Message-ID: <51C34C7F.6030309@arm.com> (raw)
In-Reply-To: <20130620183221.GE4563@lvm>
On 20/06/13 19:32, Christoffer Dall wrote:
>> So there is just one thing we absolutely need to make sure here: no vcpu
>> can run before they've all had their timer restored, and hence a stable
>> cntvoff. Otherwise two vcpus will have a different view of time.
>>
>> Can we guarantee this?
>>
>
> Do we need to? User space is free to modify time and all sort of other
> registers at any point during VM execution - it will just break the
> guest that it's running.
>
> I think the key here is that we expect the VM to be stopped for all
> save/restore operations (we can enforce it if we want to, which I am
> going to for the VGIC state, because we don't want to interfere with
> consistent state being written to the hardware).
If that's what we expect, then it's fine by me.
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2013-06-20 18:39 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-11 15:16 [PATCH v2] ARM/KVM: save and restore generic timer registers Andre Przywara
2013-06-19 21:16 ` Christoffer Dall
2013-06-20 10:10 ` Marc Zyngier
2013-06-20 17:09 ` Christoffer Dall
2013-06-20 17:19 ` Marc Zyngier
2013-06-20 18:32 ` Christoffer Dall
2013-06-20 18:39 ` Marc Zyngier [this message]
2013-06-20 19:29 ` Peter Maydell
2013-06-20 20:37 ` Christoffer Dall
2013-06-20 21:55 ` Alexander Graf
2013-06-20 21:59 ` Peter Maydell
2013-06-20 22:02 ` Alexander Graf
2013-06-20 22:48 ` Christoffer Dall
2013-07-05 14:08 ` Andre Przywara
2013-07-05 14:44 ` Marc Zyngier
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