KVM: arm64: Fix ptrauth ID register masking logic

When a VCPU doesn't have pointer auth, we want to hide all four pointer
auth ID register fields from the guest, not just one of them.

Fixes: 384b40ca ("KVM: arm/arm64: Context-switch ptrauth registers")
Reported-by: NAndrew Murray <andrew.murray@arm.com>
Fscked-up-by: NMarc Zyngier <marc.zyngier@arm.com>
Acked-by: NWill Deacon <will.deacon@arm.com>
Tested-by: NAndrew Murray <andrew.murray@arm.com>
Signed-off-by: NKristina Martsenko <kristina.martsenko@arm.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

arch/arm64/kvm/sys_regs.c

@@ -1088,10 +1088,10 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu,
 	if (id == SYS_ID_AA64PFR0_EL1 && !vcpu_has_sve(vcpu)) {
 		val &= ~(0xfUL << ID_AA64PFR0_SVE_SHIFT);
 	} else if (id == SYS_ID_AA64ISAR1_EL1 && !vcpu_has_ptrauth(vcpu)) {
-		val &= ~(0xfUL << ID_AA64ISAR1_APA_SHIFT) |
+		val &= ~((0xfUL << ID_AA64ISAR1_APA_SHIFT) |
 			 (0xfUL << ID_AA64ISAR1_API_SHIFT) |
 			 (0xfUL << ID_AA64ISAR1_GPA_SHIFT) |
-			(0xfUL << ID_AA64ISAR1_GPI_SHIFT);
+			 (0xfUL << ID_AA64ISAR1_GPI_SHIFT));
 	}
 
 	return val;