Re: [Xen-devel] [RFC PATCH v2 1/8] arm/mem_access: Add (TCR_|TTBCR_)* defines

[Julien Grall <julien.grall@xxxxxxx>]

On 07/06/17 16:07, Julien Grall wrote:
> On 07/06/17 15:56, Sergej Proskurin wrote:
> > Hi Julien,
> >
> > [...]
> >
> >
> > > Also, a lot of the new defines you add are for TCR_EL1 and not TCR_EL2.
> > > Please make the distinction in the name to avoid misusing them.
> > >
> > > > +
> > > > +#define TCR_TB_31       (31)
> > > >     #ifdef CONFIG_ARM_64
> > > >     #define TCR_PS(x)       ((x)<<16)
> > > >   #define TCR_TBI         (_AC(0x1,UL)<<20)
> > > > +#define TCR_TBI0        (_AC(0x1,UL)<<37)
> > > > +#define TCR_TBI1        (_AC(0x1,UL)<<38)
> > > Those fields don't exist in TCR_EL2.
> > This is not entirely correct. All of the introduced fields are also
> > available in TCR_EL2, however, only if HCR_EL2.E2H==1. I will comment
> > that appropriately. Do you think that we should use nevertheless
> > different names for the introduced defines?
>
> This was added by ARMv8.1. HCR_EL2.E2H = 1 as is to run Host Operating
> System in EL2 (e.g for Type-2 hypervisor). This will very never be used
> by Xen.
>
> In any case, the naming gives the impression it also exists when
> HCR_EL2.E2H = 0.
To clarify my point. They should be named with TCR_EL1_TB* as this is 
how it is used in Xen.
Cheers,

--
Julien Grall

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