Hi Marc, On Mon, Feb 01, 2021 at 11:56:22AM +0000, Marc Zyngier wrote: > There isn't much that a VHE kernel needs on top of whatever has > been done for nVHE, so let's move the little we need to the > VHE stub (the SPE setup), and drop the init_el2_state macro. > > No expected functional change. > > Signed-off-by: Marc Zyngier <[email protected]> > Acked-by: David Brazdil <[email protected]> > Acked-by: Catalin Marinas <[email protected]> > --- > arch/arm64/kernel/hyp-stub.S | 28 +++++++++++++++++++++++++--- > 1 file changed, 25 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S > index 373ed2213e1d..6b5c73cf9d52 100644 > --- a/arch/arm64/kernel/hyp-stub.S > +++ b/arch/arm64/kernel/hyp-stub.S > @@ -92,9 +92,6 @@ SYM_CODE_START_LOCAL(mutate_to_vhe) > msr hcr_el2, x0 > isb > > - // Doesn't do much on VHE, but still, worth a shot > - init_el2_state vhe > - > // Use the EL1 allocated stack, per-cpu offset > mrs x0, sp_el1 > mov sp, x0 > @@ -107,6 +104,31 @@ 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
Why do we need to touch pmscr_el1 at all? The SPE driver should take care of that, no? If you drop the pmscr_el1 accesses, I think you can drop the pmbidr_el1 check as well. And actually, then why even check dfr0? Doing the bic for the mdcr_el1.e2pb bits is harmless. > + mov x2, #MDCR_EL2_TPMS > + > +skip_spe: > + // For VHE, use EL2 translation 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 Doesn't this undo the setting of mdcr_el2.hpmn if SPE is not present or unavailable? (This wouldn't be an issue if we removed the skip_spe paths altogether). Will
