Messages in this thread | | | Date | Sun, 25 Aug 2013 21:26:47 -0400 | From | Chris Metcalf <> | Subject | Re: [PATCH v2] tile: support KVM for tilegx |
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On 8/25/2013 7:39 AM, Gleb Natapov wrote: > On Mon, Aug 12, 2013 at 04:24:11PM -0400, Chris Metcalf wrote: >> This change provides the initial framework support for KVM on tilegx. >> Basic virtual disk and networking is supported. >> > This needs to be broken down to more reviewable patches.
I already broke out one pre-requisite patch that wasn't strictly KVM-related:
https://lkml.org/lkml/2013/8/12/339
In addition, we've separately arranged to support booting our kernels in a way that is compatible with the Tilera booter running at the highest privilege level, which enables multiple kernel privilege levels:
https://lkml.org/lkml/2013/5/2/468
How would you recommend further breaking down this patch? It's pretty much just the basic support for minimal KVM. I suppose I could break out all the I/O related stuff into a separate patch, though it wouldn't amount to much; perhaps the console could also be broken out separately. Any other suggestions?
> Also can you > describe the implementation a little bit? Does tile arch has vitalization > extension this implementation uses, or is it trap and emulate approach? > If later does it run unmodified guest kernels? What userspace are you > using with this implementation?
We could do full virtualization via trap and emulate, but we've elected to do a para-virtualized approach. Userspace runs at PL (privilege level) 0, the guest kernel runs at PL1, and the host runs at PL2. We have available per-PL resources for various things, and take advantage of having two on-chip timers (for example) to handle timing for the host and guest kernels. We run the same userspace with either the host or the guest.
-- Chris Metcalf, Tilera Corp. http://www.tilera.com
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