Re: [PATCH v6 06/21] arm64: Move VHE-specific SPE setup to mutate_to_vhe()

[Marc Zyngier]

On 2021-02-04 09:34, Will Deacon wrote:
> On Thu, Feb 04, 2021 at 09:30:08AM +0000, Marc Zyngier wrote:

[...]

> > I think the following patch addresses the above issue, which I'll 
> > squash
> > with the original patch. Please shout if I missed anything.
> >
> > Thanks,
> >
> >         M.
> >
> > diff --git a/arch/arm64/kernel/hyp-stub.S 
> > b/arch/arm64/kernel/hyp-stub.S
> > index aa7e8d592295..3e08dcc924b5 100644
> > --- a/arch/arm64/kernel/hyp-stub.S
> > +++ b/arch/arm64/kernel/hyp-stub.S
> > @@ -115,29 +115,9 @@ SYM_CODE_START_LOCAL(mutate_to_vhe)
> >  	mrs_s	x0, SYS_VBAR_EL12
> >  	msr	vbar_el1, x0
> >
> > -	// Fixup SPE configuration, if supported...
> > -	mrs	x1, id_aa64dfr0_el1
> > -	ubfx	x1, x1, #ID_AA64DFR0_PMSVER_SHIFT, #4
> > -	mov	x2, xzr
> > -	cbz	x1, skip_spe
> > -
> > -	// ... and not owned by EL3
> > -	mrs_s	x0, SYS_PMBIDR_EL1
> > -	and	x0, x0, #(1 << SYS_PMBIDR_EL1_P_SHIFT)
> > -	cbnz	x0, skip_spe
> > -
> > -	// Let the SPE driver in control of the sampling
> > -	mrs_s	x0, SYS_PMSCR_EL1
> > -	bic	x0, x0, #(1 << SYS_PMSCR_EL2_PCT_SHIFT)
> > -	bic	x0, x0, #(1 << SYS_PMSCR_EL2_PA_SHIFT)
> > -	msr_s	SYS_PMSCR_EL1, x0
> > -	mov	x2, #MDCR_EL2_TPMS
> > -
> > -skip_spe:
> > -	// For VHE, use EL2 translation and disable access from EL1
> > +	// Use EL2 translations for SPE and disable access from EL1
> >  	mrs	x0, mdcr_el2
> >  	bic	x0, x0, #(MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT)
> > -	orr	x0, x0, x2
> >  	msr	mdcr_el2, x0
>
> Looks a tonne better, thanks! Be nice if somebody could test it for us.

SPE-equipped machines are the silicon equivalent of hen's teeth...

Alex, any chance you could give this a go?

        M.
--
Jazz is not dead. It just smells funny...