Re: [PATCH 0/30] nVMX: Nested VMX, v9

[Gleb Natapov <gleb@redhat.com>]

On Thu, May 12, 2011 at 07:08:59PM +0300, Avi Kivity wrote:
> On 05/12/2011 06:57 PM, Gleb Natapov wrote:
> >On Thu, May 12, 2011 at 06:42:28PM +0300, Nadav Har'El wrote:
> >>  So I guess my question is, and Avi and Gleb I'd love your comments about this
> >>  question: Is it really beneficial that I rewrite the "ugly" nested-VMX
> >>  injection code to be somewhat-ugly in exactly the same way that nested-SVM
> >>  injection code? Won't it be more beneficial to rewrite *both* codes to
> >>  be cleaner? This would probably mean changes to the common x86.c, that both
> >>  will use. For example, x86.c's injection code could check the nested case
> >>  itself, perhaps calling a special x86_op to handle the nested injection (exit,
> >>  set interrupt window, etc.) instead of calling the regular
> >>  interrupt_allowed/enable_irq_window and forcing those to be modified in
> >>  mysterious ways.
> >>
> >That is exactly what should be done and what I have in mind when I am
> >asking to change VMX code to be SVM like. To achieve what you outlined
> >above gradually we need to move common VMX and SVM logic into x86.c
> >and then change the logic to be more nested friendly.  If VMX will have
> >different interrupt handling logic we will have to have additional step:
> >making SVM and VMX code similar (so it will be possible to move it
> >into x86.c).  All I am asking is to make this step now, before merge,
> >while the code is still actively developed.
> >
> 
> I don't think it's fair to ask Nadav to do a unification right now.
Definitely. And I am not asking for it!

> Or productive - there's a limit to the size of a patchset that can
> be carried outside.  Also it needs to be done in consideration with
> future changes to interrupt injection, like using the svm interrupt
> queue to avoid an interrupt window exit.
> 
> Are there vmx-only changes that you think can help?
> 
I am asking for vmx-only change actually. To make interrupt handling logic
the same as SVM. This will allow me or you or someone else to handle
unification part later without rewriting VMX.
 
--
			Gleb.