On Thu, Jul 14, 2011 at 04:20:03PM +0300, Avi Kivity wrote: > On 07/14/2011 04:10 PM, Joerg Roedel wrote: >> Yes, otherwise we need to copy the vmload/vmsave switched state back and >> forth between both VMCBs which is a waste of cycles. > > Just to be sure I understand this: the root cause is because VMRUN > doesn't actually switch this state. So we have to copy the state. Okay. Right. > What about an L2 guest executing VMLOAD or VMSAVE which isn't > intercepted? Don't we have to redirect it's reads and writes to > host_vmcb? Yes, that needs to target the host_vmcb then. This is buggy in the patch-set. Thanks for pointing this out :) >> Hmm, how about naming them l1_vmcb and l2_vmcb? The comment explaining >> why vmload/vmsave always happens on l1_vmcb is needed anyway then. > > In a later patch you introduce n_vmcb. I think it makes sense to name > that vmcb02? Just for my understanding, what stands the first '0' for? The '1' and '2' make sense, but the '0' seems to be redundant? > Even the exising code would be good to document. So when a reader sees > some bit, they can compare it to the document and see why it's that way. I tried to put comments into the code to document the most complicated parts. But there is certainly room for improvement. Overall, I think the best place is to keep those comments in the code and not open another document for it. >> The long-term plan is certainly to merge code with nested-vmx where >> possible and move logic into generic KVM code. The first item that comes >> to mind here is to create a single place where a vmexit is emulated and >> let all other place which do that today just signal that it is required. > > I'm not very concerned about reuse with nvmx except for architectural > code like interrupts. Of course, if it turns out simple I'm all for it, > but if it's hard or uglifies the code, let it be. Yes, the interrupt code is another part that probably can be made generic. The nested-mmu code is already generic. Nested-VMX should be able to make use of it with only minor modifications. Joerg -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
