KVM: PPC: BOOK3S: PR: Emulate virtual timebase register

virtual time base register is a per VM, per cpu register that needs
to be saved and restored on vm exit and entry. Writing to VTB is not
allowed in the privileged mode.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[agraf: fix compile error]
Signed-off-by: Alexander Graf <agraf@suse.de>

arch/powerpc/include/asm/kvm_host.h

@@ -505,6 +505,7 @@ struct kvm_vcpu_arch {
 #endif
 	/* Time base value when we entered the guest */
 	u64 entry_tb;
+	u64 entry_vtb;
 	u32 tcr;
 	ulong tsr; /* we need to perform set/clr_bits() which requires ulong */
 	u32 ivor[64];

arch/powerpc/include/asm/reg.h

@@ -1203,6 +1203,15 @@
 				     : "r" ((unsigned long)(v)) \
 				     : "memory")
 
+static inline unsigned long mfvtb (void)
+{
+#ifdef CONFIG_PPC_BOOK3S_64
+	if (cpu_has_feature(CPU_FTR_ARCH_207S))
+		return mfspr(SPRN_VTB);
+#endif
+	return 0;
+}
+
 #ifdef __powerpc64__
 #if defined(CONFIG_PPC_CELL) || defined(CONFIG_PPC_FSL_BOOK3E)
 #define mftb()		({unsigned long rval;				\

arch/powerpc/include/asm/time.h

@@ -102,6 +102,15 @@ static inline u64 get_rtc(void)
 	return (u64)hi * 1000000000 + lo;
 }
 
+static inline u64 get_vtb(void)
+{
+#ifdef CONFIG_PPC_BOOK3S_64
+	if (cpu_has_feature(CPU_FTR_ARCH_207S))
+		return mfvtb();
+#endif
+	return 0;
+}
+
 #ifdef CONFIG_PPC64
 static inline u64 get_tb(void)
 {

arch/powerpc/kvm/book3s.c

@@ -646,6 +646,9 @@ int kvm_vcpu_ioctl_get_one_reg(struct kvm_vcpu *vcpu, struct kvm_one_reg *reg)
 		case KVM_REG_PPC_BESCR:
 			val = get_reg_val(reg->id, vcpu->arch.bescr);
 			break;
+		case KVM_REG_PPC_VTB:
+			val = get_reg_val(reg->id, vcpu->arch.vtb);
+			break;
 		default:
 			r = -EINVAL;
 			break;
@@ -750,6 +753,9 @@ int kvm_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu, struct kvm_one_reg *reg)
 		case KVM_REG_PPC_BESCR:
 			vcpu->arch.bescr = set_reg_val(reg->id, val);
 			break;
+		case KVM_REG_PPC_VTB:
+			vcpu->arch.vtb = set_reg_val(reg->id, val);
+			break;
 		default:
 			r = -EINVAL;
 			break;

arch/powerpc/kvm/book3s_emulate.c

@@ -577,6 +577,9 @@ int kvmppc_core_emulate_mfspr_pr(struct kvm_vcpu *vcpu, int sprn, ulong *spr_val
 		 */
 		*spr_val = vcpu->arch.spurr;
 		break;
+	case SPRN_VTB:
+		*spr_val = vcpu->arch.vtb;
+		break;
 	case SPRN_GQR0:
 	case SPRN_GQR1:
 	case SPRN_GQR2:

arch/powerpc/kvm/book3s_hv.c

@@ -897,9 +897,6 @@ static int kvmppc_get_one_reg_hv(struct kvm_vcpu *vcpu, u64 id,
 	case KVM_REG_PPC_IC:
 		*val = get_reg_val(id, vcpu->arch.ic);
 		break;
-	case KVM_REG_PPC_VTB:
-		*val = get_reg_val(id, vcpu->arch.vtb);
-		break;
 	case KVM_REG_PPC_CSIGR:
 		*val = get_reg_val(id, vcpu->arch.csigr);
 		break;
@@ -1097,9 +1094,6 @@ static int kvmppc_set_one_reg_hv(struct kvm_vcpu *vcpu, u64 id,
 	case KVM_REG_PPC_IC:
 		vcpu->arch.ic = set_reg_val(id, *val);
 		break;
-	case KVM_REG_PPC_VTB:
-		vcpu->arch.vtb = set_reg_val(id, *val);
-		break;
 	case KVM_REG_PPC_CSIGR:
 		vcpu->arch.csigr = set_reg_val(id, *val);
 		break;

arch/powerpc/kvm/book3s_pr.c

@@ -125,6 +125,7 @@ void kvmppc_copy_to_svcpu(struct kvmppc_book3s_shadow_vcpu *svcpu,
 	 * to find the guest purr and spurr value.
 	 */
 	vcpu->arch.entry_tb = get_tb();
+	vcpu->arch.entry_vtb = get_vtb();
 	svcpu->in_use = true;
 }
 
@@ -176,7 +177,7 @@ void kvmppc_copy_from_svcpu(struct kvm_vcpu *vcpu,
 	 */
 	vcpu->arch.purr += get_tb() - vcpu->arch.entry_tb;
 	vcpu->arch.spurr += get_tb() - vcpu->arch.entry_tb;
-
+	vcpu->arch.vtb += get_vtb() - vcpu->arch.entry_vtb;
 	svcpu->in_use = false;
 
 out: