Re: [PATCH 11/22] KVM: arm64: Use a struct for stage-1 walk context

[Leonardo Bras <leo.bras@arm.com>]

On Wed, Sep 23, 2026 at 01:23:22PM -0700, Oliver Upton wrote:
> On Wed, Sep 23, 2026 at 06:03:39PM +0100, Leonardo Bras wrote:
> > > @@ -482,15 +490,15 @@ static int walk_s1(struct kvm_vcpu *vcpu, struct s1_walk_info *wi,
> > >  	while (1) {
> > >  		u64 index;
> > >  
> > > -		va_bottom = (3 - level) * stride + wi->pgshift;
> > > +		va_bottom = (3 - ws.level) * stride + wi->pgshift;
> > >  		index = (va & GENMASK_ULL(va_top, va_bottom)) >> (va_bottom - 3);
> > >  
> > > -		ipa = baddr | index;
> > > +		ws.desc_ipa = ws.desc_pa = baddr | index;
> > >  
> > >  		if (wi->s2) {
> > >  			struct kvm_walk_access s2_access = {
> > >  				.type	= WALK_ACCESS_S1PTW,
> > > -				.ia	= ipa,
> > > +				.ia	= ws.desc_ipa,
> > 
> > I only see desc_ipa being used here, and at this point, desc_ipa is the 
> > same as desc_pa, and we are copying it's value to this new struct.
> 
> This distinction is intentional, we overloaded @ipa to mean either the
> IPA of the descriptor or the PA of the descriptor depending on the
> presence of a stage-2 && where we are in the PTW.
> 
> I'm happy to burn another 8 bytes if it means the code is legible and
> more easily debuggable with something like bpftrace.

Oh, ok, I see the point now.

Thanks!
Leo