Messages in this thread | | | Subject | Re: [PATCH 05/16] KVM-HDR: Implement wallclock over KVM - KVM Virtual Memory | From | Glauber Costa <> | Date | Wed, 26 Jan 2011 10:20:03 -0200 |
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On Wed, 2011-01-26 at 13:13 +0200, Avi Kivity wrote: > On 01/24/2011 08:06 PM, Glauber Costa wrote: > > As a proof of concept to KVM - Kernel Virtual Memory, this patch > > implements wallclock grabbing on top of it. At first, it may seem > > as a waste of work to just redo it, since it is working well. But over the > > time, other MSRs were added - think ASYNC_PF - and more will probably come. > > After this patch, we won't need to ever add another virtual MSR to KVM. > > > > So instead of adding MSRs, we're adding area identifiers. What did we gain?
* No risk of namespace clashes of any kind, * less need for userspace coordination for feature enablement, * more robust mechanism that can do discovery even on early boot, * more informative result values can be passed on to guest kernel, * more flexibility, since we go back to userspace if we can't handle some request. Also, some requests are better handled by userspace anyway. But again, maybe this is a separate issue here... * size information goes together with base, allowing for extending structures (well, maybe I should add versioning explicitly?)
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