Commit b1a9a9b9 authored by Mark Rutland's avatar Mark Rutland Committed by Marc Zyngier
Browse files

KVM: arm64: Remove ISB after writing FPEXC32_EL2 



The value of FPEX32_EL2 has no effect on execution in AArch64 state, and
consequently there's no need for an ISB after writing to it in the hyp
code (which executes in AArch64 state). When performing an exception
return to AArch32 state, the exception return will provide the necessary
context synchronization event.

Remove the redundant ISB.

Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Fuad Tabba <tabba@google.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Will Deacon <will@kernel.org>
Tested-by: default avatarFuad Tabba <tabba@google.com>
Reviewed-by: default avatarFuad Tabba <tabba@google.com>
Link: https://patch.msgid.link/20260106173707.3292074-4-mark.rutland@arm.com


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent acd8bfaa

arch/arm64/kvm/hyp/include/hyp/switch.h

+1 −3
Original line number Diff line number Diff line
@@ -59,10 +59,8 @@ static inline void __activate_traps_fpsimd32(struct kvm_vcpu *vcpu) 
	 * If FP/ASIMD is not implemented, FPEXC is UNDEFINED and any access to

	 * it will cause an exception.

	 */

	if (vcpu_el1_is_32bit(vcpu) && system_supports_fpsimd()) {

	if (vcpu_el1_is_32bit(vcpu) && system_supports_fpsimd())

		write_sysreg(1 << 30, fpexc32_el2);

		isb();

	}

}



static inline void __activate_cptr_traps_nvhe(struct kvm_vcpu *vcpu)