KVM: arm64: Simplify warning in kvm_arch_vcpu_load_fp()

At the end of kvm_arch_vcpu_load_fp() we check that no bits are set in
SVCR. We only check this for protected mode despite this mattering
equally for non-protected mode, and the comment above this is confusing.

Remove the comment and simplify the check, moving from WARN_ON() to
WARN_ON_ONCE() to avoid spamming the log.

Signed-off-by: Mark Rutland <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>

Author: mrutland-arm

arch/arm64/kvm/fpsimd.c

@@ -65,12 +65,7 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu)
 	fpsimd_save_and_flush_cpu_state();
 	*host_data_ptr(fp_owner) = FP_STATE_FREE;
 
-	/*
-	 * If normal guests gain SME support, maintain this behavior for pKVM
-	 * guests, which don't support SME.
-	 */
-	WARN_ON(is_protected_kvm_enabled() && system_supports_sme() &&
-		read_sysreg_s(SYS_SVCR));
+	WARN_ON_ONCE(system_supports_sme() && read_sysreg_s(SYS_SVCR));
 }
 
 /*