Re: NMI vs #PF clash

[Steven Rostedt]

On Tue, 2012-05-22 at 17:20 +0300, Avi Kivity wrote:
> On 05/22/2012 05:09 PM, Steven Rostedt wrote:
> >> > 
> >> > Or we could just have the NMI always restore the cr2 register.
> >> 
> >> IMO that's best.
> > 
> > OK, I can whip up a patch, but I wont push that in till 3.6.
> > 
> 
> Thanks.  Something I've noticed is that writing cr2 is slow, so you may
> want to write it only if it has changed (which should be very rare).
> 

Is reading it fast? Then we could do a two reads and only write when
needed.

Something like this pseudo assembly
 
	mov cr2, rax
	push rax

	call do_nmi

	pop rax
	mov cr2, rbx
	cmp rax, rbx
	be skip
	mov rax, cr2
skip:


-- Steve



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