Re: [PATCH 4/8] KVM: SVM: move guest vmsave/vmload to assembly

[Paolo Bonzini]

On 11/7/22 16:23, Peter Zijlstra wrote:
> >   
> > +3:	vmrun %_ASM_AX
> > +4:
> > +	cli
> >   
> > +	/* Pop @svm to RAX while it's the only available register. */
> >   	pop %_ASM_AX
> >   
> >   	/* Save all guest registers.  */
> So Andrew noted that once the vmload has executed any exception taken
> (say at 3) will crash and burn because %gs is scribbled.
>
> Might be good to make a record of this in the code so it can be cleaned
> up some day.

Yeah, it won't happen because clgi/stgi blocks setting kvm_rebooting so 
I thought of killing the three exception fixups after the first.  In the 
end I kept them for simplicity and to keep the normal/SEV-ES versions as 
similar as possible.

Paolo