KVM: x86: Move the check for upper 32 reserved bits of DR6 to separate function

Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Message-Id: <20200522221954.32131-2-krish.sadhukhan@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/x86.c

@@ -1133,7 +1133,7 @@ static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
 	case 4:
 		/* fall through */
 	case 6:
-		if (val & 0xffffffff00000000ULL)
+		if (!kvm_dr6_valid(val))
 			return -1; /* #GP */
 		vcpu->arch.dr6 = (val & DR6_VOLATILE) | kvm_dr6_fixed(vcpu);
 		break;

arch/x86/kvm/x86.h

@@ -360,6 +360,11 @@ static inline bool kvm_dr7_valid(u64 data)
 	/* Bits [63:32] are reserved */
 	return !(data >> 32);
 }
+static inline bool kvm_dr6_valid(u64 data)
+{
+	/* Bits [63:32] are reserved */
+	return !(data >> 32);
+}
 
 void kvm_load_guest_xsave_state(struct kvm_vcpu *vcpu);
 void kvm_load_host_xsave_state(struct kvm_vcpu *vcpu);