[PATCH v7 06/23] arm64: Drop early setting of MDSCR_EL2.TPMS

Marc Zyngier
2021-02-08T10:09:47Z

When running VHE, we set MDSCR_EL2.TPMS very early on to force
the trapping of EL1 SPE accesses to EL2.

However:
- we are running with HCR_EL2.{E2H,TGE}={1,1}, meaning that there
is no EL1 to trap from

- before entering a guest, we call kvm_arm_setup_debug(), which
sets MDCR_EL2_TPMS in the per-vcpu shadow mdscr_el2, which gets
applied on entry by __activate_traps_common().

The early setting of MDSCR_EL2.TPMS is therefore useless and can
be dropped.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/include/asm/el2_setup.h | 3 ---
1 file changed, 3 deletions(-)

diff --git a/arch/arm64/include/asm/el2_setup.h b/arch/arm64/include/asm/el2_setup.h
index 540116de80bf..56c9e1cef180 100644
--- a/arch/arm64/include/asm/el2_setup.h
+++ b/arch/arm64/include/asm/el2_setup.h
@@ -66,9 +66,6 @@
mov x0, #(MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT)
orr x2, x2, x0 // If we don't have VHE, then
// use EL1&0 translation.
-.else
- orr x2, x2, #MDCR_EL2_TPMS // For VHE, use EL2 translation
- // and disable access from EL1
.endif

.Lskip_spe_\@:
--
2.29.2