Re: kernel device reset support

Avi Kivity
2007-10-13T07:16:40Z

Dong, Eddie wrote:
>> I'll try writing a patch that does what I mean and post it.
>> Either I'll
>> convince you that in-kernel is simpler, or I'll convince myself that
>> it is harder.
>>
>>
> OK, let us see which one is simple.
>
> BTW, you have swapped to N+1 SMP model in this discussion which
> is not there yet. And this is the difference.
>
>

What I'm saying is that it should work with both models.

> For me N+1 model means the device emulation will go to the N+1 thread
> while all CPU execution will still be in its own thread. It looks like
> you
> are proposing different.
>

N+1, for me is that synchronous device emulation (like pio and mmio)
happens in in the vcpu thread and asynchronous device emulation
(handling signals in qemu, performing dma, and injecting interrupts)
happens in the device thread. This minimizes context switching and
heavyweight exits.

--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.