[PATCH 3/3] KVM: arm64: Remove ISB after writing FPEXC32_EL2

[Mark Rutland]

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: Mark Rutland <mark.rutland at arm.com>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Fuad Tabba <tabba at google.com>
Cc: Marc Zyngier <maz at kernel.org>
Cc: Mark Brown <broonie at kernel.org>
Cc: Oliver Upton <oliver.upton at linux.dev>
Cc: Will Deacon <will at kernel.org>
---
 arch/arm64/kvm/hyp/include/hyp/switch.h | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index 8dce3da85da35..91aa1862349cb 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -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)
-- 
2.30.2