From: Rusty Russell <rusty@rustcorp.com.au>
To: Peter Maydell <peter.maydell@linaro.org>,
Dong Aisheng <b29396@freescale.com>
Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
c.dall@virtualopensystems.com, marc.zyngier@arm.com
Subject: Re: [RFC PATCH 1/1] KVM: ARM: add vgic state save and restore support
Date: Tue, 04 Dec 2012 11:44:11 +1030 [thread overview]
Message-ID: <87boeaipp8.fsf@rustcorp.com.au> (raw)
In-Reply-To: <CAFEAcA-wopCCZrX2-eak-YAVpR2ZorGAyBVpcHUxjbxewVCFeg@mail.gmail.com>
Peter Maydell <peter.maydell@linaro.org> writes:
> On 3 December 2012 10:36, Dong Aisheng <b29396@freescale.com> wrote:
>> and via current ONE_REG interface we do not know which CPU
>> is performing the register access, so the banked registers are not
>> suppported well,
>
> Actually you do, because it's a vcpu ioctl. That does raise a
> different question, though. ONE_REG is currently aimed as a vcpu
> ioctl for CPU state save/restore -- how does it need to change
> to handle device state save/restore where the device is not per-cpu?
Good question. I'd prefer to stretch the existing interface, than
create an identical one for non-per-cpu resources, but I could be swayed
if there were many other cases.
The simplest method is to give it a new type and mirror the non-per-cpu
regs on all vcpus. Then a completely naive implementation save/restore
will Just Work, with redundant data. Or we could pick a CPU, but that
means your discovery logic becomes more complex unless you know which
CPU it is (lowest number?).
Cheers,
Rusty.
next prev parent reply other threads:[~2012-12-04 2:17 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-03 10:36 [RFC PATCH 1/1] KVM: ARM: add vgic state save and restore support Dong Aisheng
2012-12-03 12:02 ` Peter Maydell
2012-12-03 13:22 ` Peter Maydell
2012-12-04 12:27 ` Dong Aisheng
2012-12-04 12:45 ` Peter Maydell
2012-12-04 13:37 ` Dong Aisheng
2012-12-06 15:45 ` Peter Maydell
2012-12-04 1:14 ` Rusty Russell [this message]
2012-12-04 11:44 ` Dong Aisheng
2012-12-04 12:05 ` Peter Maydell
2012-12-04 12:53 ` Dong Aisheng
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