A high level try at KVM for ARM
michael.hope at linaro.org
Mon Jan 9 20:30:17 UTC 2012
On Tue, Jan 10, 2012 at 4:07 AM, Peter Maydell <peter.maydell at linaro.org> wrote:
> On 9 January 2012 02:36, Michael Hope <michael.hope at linaro.org> wrote:
>> I've taken a stab at the medium term requirements for KVM on ARM:
> I've marked this up with my initial comments.
Added replies which are:
> "virtio over AMBA" still requires some model, so presumably we'll still be using vexpress. Also we're calling it "virtio-mmio" now (since it's not really AMBA specific).
Changed to virtio-mmio and was explicit about it being vexpress+virtio
> I can see why this para is here, but I think we should be aiming to keep the changes required to the guest (kernel config or boot loader arrangements) as minimal as possible.
Agreed. I've added 'minimised' and 'eliminate if reasonable'. One
less thing is good.
> I realised recently that we could probably model the vexpress compact flash adaptor relatively cheaply which then gives you something that looks like an IDE disk and avoids the performance problems of SD card emulation. Need to check this.
If it's really cheap (~2 days) then yes, otherwise virtio first.
> I suspect we want LPAE guests in 1.0.
I'd rather have LPAE in a 1.1 so we can get 1.0 to people and get
feedback on it. We can call these 0.9/1.0 instead if need be.
> Migration: between-same-version migration should be straightforward enough (there are only a few bits missing). Cross-qemu-version migration is harder as it requires that we pay much more attention to avoiding migration structure version bumps and also to providing back-compat versions of board models (like the x86 "pc-0.14", "pc-0.15" etc) so you can make newer qemu versions act like old ones. I would prefer not to commit to this too early.
won't there only be one model at the first release? Providing it's
tagged as vexpress-1.0 and fails if you try to load a later version,
is that enough?
> is "KSM" Kernel SamePage Merging?
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