KVM: arm64: Rely on visibility to let PIR*_ELx/TCR2_ELx UNDEF

With a visibility defined for these registers, there is no need
to check again for S1PIE or TCRX being implemented as perform_access()
already handles it.

Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20241023145345.1613824-27-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

Author: Marc Zyngier

arch/arm64/kvm/sys_regs.c

@@ -369,18 +369,6 @@ static bool access_rw(struct kvm_vcpu *vcpu,
 	return true;
 }
 
-static bool check_s1pie_access_rw(struct kvm_vcpu *vcpu,
-				  struct sys_reg_params *p,
-				  const struct sys_reg_desc *r)
-{
-	if (!kvm_has_s1pie(vcpu->kvm)) {
-		kvm_inject_undefined(vcpu);
-		return false;
-	}
-
-	return access_rw(vcpu, p, r);
-}
-
 /*
  * See note at ARMv7 ARM B1.14.4 (TL;DR: S/W ops are not easily virtualized).
  */
@@ -445,10 +433,6 @@ static bool access_vm_reg(struct kvm_vcpu *vcpu,
 	bool was_enabled = vcpu_has_cache_enabled(vcpu);
 	u64 val, mask, shift;
 
-	if (reg_to_encoding(r) == SYS_TCR2_EL1 &&
-	    !kvm_has_tcr2(vcpu->kvm))
-		return undef_access(vcpu, p, r);
-
 	BUG_ON(!p->is_write);
 
 	get_access_mask(r, &mask, &shift);
@@ -467,18 +451,6 @@ static bool access_vm_reg(struct kvm_vcpu *vcpu,
 	return true;
 }
 
-static bool access_tcr2_el2(struct kvm_vcpu *vcpu,
-			    struct sys_reg_params *p,
-			    const struct sys_reg_desc *r)
-{
-	if (!kvm_has_tcr2(vcpu->kvm)) {
-		kvm_inject_undefined(vcpu);
-		return false;
-	}
-
-	return access_rw(vcpu, p, r);
-}
-
 static bool access_actlr(struct kvm_vcpu *vcpu,
 			 struct sys_reg_params *p,
 			 const struct sys_reg_desc *r)
@@ -2937,7 +2909,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	EL2_REG(TTBR0_EL2, access_rw, reset_val, 0),
 	EL2_REG(TTBR1_EL2, access_rw, reset_val, 0),
 	EL2_REG(TCR_EL2, access_rw, reset_val, TCR_EL2_RES1),
-	EL2_REG_FILTERED(TCR2_EL2, access_tcr2_el2, reset_val, TCR2_EL2_RES1,
+	EL2_REG_FILTERED(TCR2_EL2, access_rw, reset_val, TCR2_EL2_RES1,
 			 tcr2_el2_visibility),
 	EL2_REG_VNCR(VTTBR_EL2, reset_val, 0),
 	EL2_REG_VNCR(VTCR_EL2, reset_val, 0),
@@ -2966,9 +2938,9 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	EL2_REG(HPFAR_EL2, access_rw, reset_val, 0),
 
 	EL2_REG(MAIR_EL2, access_rw, reset_val, 0),
-	EL2_REG_FILTERED(PIRE0_EL2, check_s1pie_access_rw, reset_val, 0,
+	EL2_REG_FILTERED(PIRE0_EL2, access_rw, reset_val, 0,
 			 s1pie_el2_visibility),
-	EL2_REG_FILTERED(PIR_EL2, check_s1pie_access_rw, reset_val, 0,
+	EL2_REG_FILTERED(PIR_EL2, access_rw, reset_val, 0,
 			 s1pie_el2_visibility),
 	EL2_REG(AMAIR_EL2, access_rw, reset_val, 0),