Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state

[Jan Kiszka]

On 2011-01-21 19:49, Blue Swirl wrote:
>>> I'd add fourth possible class:
>>>  - device, CPU and machine configuration, like nographic,
>>> win2k_install_hack, no_hpet, smp_cpus etc. Maybe also
>>> irqchip_in_kernel could fit here, though it obviously depends on a
>>> host capability too.
>>
>> I would count everything that cannot be assigned to a concrete device
>> upfront to the dynamic state of a machine, thus class 2. The point is,
>> (potentially) every device of that machine requires access to it, just
>> like (indirectly, via the KVM core services) to some KVM VM state bits.
> 
> The machine class should not be a catch-all, it would be like
> QEMUState or KVMState then. Perhaps each field or variable should be
> listed and given more thought.

Let's start with what is most urgent:

 - vmfd: file descriptor required for any KVM request that has VM scope
   (in-kernel device creation, device state synchronizations, IRQ
   routing etc.)
 - irqchip_in_kernel: VM uses in-kernel irqchip acceleration
   (some devices will have to adjust their behavior depending on this)

pit_in_kernel would be analogue to irqchip, but it's also conceptually
x86-only (irqchips is only used by x86, but not tied to it) and it's not
mandatory for a first round of KVM devices for upstream.

Jan

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