Re: [PATCH] KVM: handle exit due to INVD in VMX

[Gleb Natapov <gleb@redhat.com>]

On Sun, Oct 31, 2010 at 11:26:09AM -0700, Alexander Graf wrote:
> 
> On 31.10.2010, at 11:22, Gleb Natapov wrote:
> 
> > On Sun, Oct 31, 2010 at 11:00:08AM -0700, Alexander Graf wrote:
> >> 
> >> On 31.10.2010, at 07:36, Gleb Natapov wrote:
> >> 
> >>> Call into emulator when INVD instruction is executed by a guest.
> >> 
> >> Why? This is a poor patch description.
> > Why what? Why we need to handle INVD exit instead of stopping with
> > unhandled exit error?
> 
> Ah, so we get the exit already, but don't handle it? That's an important piece of information that belongs in the patch description. Another thing I as a reader would also like to know is where this got triggered, so which guests would break without the patch.
> 
I'll add it to the patch description. The guest that triggered it was
open firmware, but I do not think this info belongs to patch description
too.

> I'm also wondering why nobody has seen it before. Is this a regression? Is this exit a side-effect of another feature bit of VMX, so only newer CPUs are affected?
> 
I guess nobody seen it because not many guests use the instruction.
Actually this instruction is useful only for firmware use. This is not a
regression.

--
			Gleb.