KVM: PPC: Book3S: Get/set guest FP regs using the GET/SET_ONE_REG interface

This enables userspace to get and set all the guest floating-point
state using the KVM_[GS]ET_ONE_REG ioctls.  The floating-point state
includes all of the traditional floating-point registers and the
FPSCR (floating point status/control register), all the VMX/Altivec
vector registers and the VSCR (vector status/control register), and
on POWER7, the vector-scalar registers (note that each FP register
is the high-order half of the corresponding VSR).

Most of these are implemented in common Book 3S code, except for VSX
on POWER7.  Because HV and PR differ in how they store the FP and VSX
registers on POWER7, the code for these cases is not common.  On POWER7,
the FP registers are the upper halves of the VSX registers vsr0 - vsr31.
PR KVM stores vsr0 - vsr31 in two halves, with the upper halves in the
arch.fpr[] array and the lower halves in the arch.vsr[] array, whereas
HV KVM on POWER7 stores the whole VSX register in arch.vsr[].

Signed-off-by: Paul Mackerras <paulus@samba.org>
[agraf: fix whitespace, vsx compilation]
Signed-off-by: Alexander Graf <agraf@suse.de>

Documentation/virtual/kvm/api.txt

@@ -1759,6 +1759,17 @@ registers, find a list below:
   PPC   | KVM_REG_PPC_PMC6      | 32
   PPC   | KVM_REG_PPC_PMC7      | 32
   PPC   | KVM_REG_PPC_PMC8      | 32
+  PPC   | KVM_REG_PPC_FPR0      | 64
+          ...
+  PPC   | KVM_REG_PPC_FPR31     | 64
+  PPC   | KVM_REG_PPC_VR0       | 128
+          ...
+  PPC   | KVM_REG_PPC_VR31      | 128
+  PPC   | KVM_REG_PPC_VSR0      | 128
+          ...
+  PPC   | KVM_REG_PPC_VSR31     | 128
+  PPC   | KVM_REG_PPC_FPSCR     | 64
+  PPC   | KVM_REG_PPC_VSCR      | 32
 
 4.69 KVM_GET_ONE_REG
 

arch/powerpc/include/asm/kvm.h

@@ -360,4 +360,24 @@ struct kvm_book3e_206_tlb_params {
 #define KVM_REG_PPC_PMC7	(KVM_REG_PPC | KVM_REG_SIZE_U32 | 0x1e)
 #define KVM_REG_PPC_PMC8	(KVM_REG_PPC | KVM_REG_SIZE_U32 | 0x1f)
 
+/* 32 floating-point registers */
+#define KVM_REG_PPC_FPR0	(KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x20)
+#define KVM_REG_PPC_FPR(n)	(KVM_REG_PPC_FPR0 + (n))
+#define KVM_REG_PPC_FPR31	(KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x3f)
+
+/* 32 VMX/Altivec vector registers */
+#define KVM_REG_PPC_VR0		(KVM_REG_PPC | KVM_REG_SIZE_U128 | 0x40)
+#define KVM_REG_PPC_VR(n)	(KVM_REG_PPC_VR0 + (n))
+#define KVM_REG_PPC_VR31	(KVM_REG_PPC | KVM_REG_SIZE_U128 | 0x5f)
+
+/* 32 double-width FP registers for VSX */
+/* High-order halves overlap with FP regs */
+#define KVM_REG_PPC_VSR0	(KVM_REG_PPC | KVM_REG_SIZE_U128 | 0x60)
+#define KVM_REG_PPC_VSR(n)	(KVM_REG_PPC_VSR0 + (n))
+#define KVM_REG_PPC_VSR31	(KVM_REG_PPC | KVM_REG_SIZE_U128 | 0x7f)
+
+/* FP and vector status/control registers */
+#define KVM_REG_PPC_FPSCR	(KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x80)
+#define KVM_REG_PPC_VSCR	(KVM_REG_PPC | KVM_REG_SIZE_U32 | 0x81)
+
 #endif /* __LINUX_KVM_POWERPC_H */

arch/powerpc/include/asm/kvm_ppc.h

@@ -200,6 +200,8 @@ static inline u32 kvmppc_set_field(u64 inst, int msb, int lsb, int value)
 union kvmppc_one_reg {
 	u32	wval;
 	u64	dval;
+	vector128 vval;
+	u64	vsxval[2];
 };
 
 #define one_reg_size(id)	\

arch/powerpc/kvm/book3s.c

@@ -490,6 +490,7 @@ int kvm_vcpu_ioctl_get_one_reg(struct kvm_vcpu *vcpu, struct kvm_one_reg *reg)
 	int r;
 	union kvmppc_one_reg val;
 	int size;
+	long int i;
 
 	size = one_reg_size(reg->id);
 	if (size > sizeof(val))
@@ -506,6 +507,29 @@ int kvm_vcpu_ioctl_get_one_reg(struct kvm_vcpu *vcpu, struct kvm_one_reg *reg)
 		case KVM_REG_PPC_DSISR:
 			val = get_reg_val(reg->id, vcpu->arch.shared->dsisr);
 			break;
+		case KVM_REG_PPC_FPR0 ... KVM_REG_PPC_FPR31:
+			i = reg->id - KVM_REG_PPC_FPR0;
+			val = get_reg_val(reg->id, vcpu->arch.fpr[i]);
+			break;
+		case KVM_REG_PPC_FPSCR:
+			val = get_reg_val(reg->id, vcpu->arch.fpscr);
+			break;
+#ifdef CONFIG_ALTIVEC
+		case KVM_REG_PPC_VR0 ... KVM_REG_PPC_VR31:
+			if (!cpu_has_feature(CPU_FTR_ALTIVEC)) {
+				r = -ENXIO;
+				break;
+			}
+			val.vval = vcpu->arch.vr[reg->id - KVM_REG_PPC_VR0];
+			break;
+		case KVM_REG_PPC_VSCR:
+			if (!cpu_has_feature(CPU_FTR_ALTIVEC)) {
+				r = -ENXIO;
+				break;
+			}
+			val = get_reg_val(reg->id, vcpu->arch.vscr.u[3]);
+			break;
+#endif /* CONFIG_ALTIVEC */
 		default:
 			r = -EINVAL;
 			break;
@@ -525,6 +549,7 @@ int kvm_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu, struct kvm_one_reg *reg)
 	int r;
 	union kvmppc_one_reg val;
 	int size;
+	long int i;
 
 	size = one_reg_size(reg->id);
 	if (size > sizeof(val))
@@ -544,6 +569,29 @@ int kvm_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu, struct kvm_one_reg *reg)
 		case KVM_REG_PPC_DSISR:
 			vcpu->arch.shared->dsisr = set_reg_val(reg->id, val);
 			break;
+		case KVM_REG_PPC_FPR0 ... KVM_REG_PPC_FPR31:
+			i = reg->id - KVM_REG_PPC_FPR0;
+			vcpu->arch.fpr[i] = set_reg_val(reg->id, val);
+			break;
+		case KVM_REG_PPC_FPSCR:
+			vcpu->arch.fpscr = set_reg_val(reg->id, val);
+			break;
+#ifdef CONFIG_ALTIVEC
+		case KVM_REG_PPC_VR0 ... KVM_REG_PPC_VR31:
+			if (!cpu_has_feature(CPU_FTR_ALTIVEC)) {
+				r = -ENXIO;
+				break;
+			}
+			vcpu->arch.vr[reg->id - KVM_REG_PPC_VR0] = val.vval;
+			break;
+		case KVM_REG_PPC_VSCR:
+			if (!cpu_has_feature(CPU_FTR_ALTIVEC)) {
+				r = -ENXIO;
+				break;
+			}
+			vcpu->arch.vscr.u[3] = set_reg_val(reg->id, val);
+			break;
+#endif /* CONFIG_ALTIVEC */
 		default:
 			r = -EINVAL;
 			break;

arch/powerpc/kvm/book3s_hv.c

@@ -579,6 +579,27 @@ int kvmppc_get_one_reg(struct kvm_vcpu *vcpu, u64 id, union kvmppc_one_reg *val)
 		i = id - KVM_REG_PPC_PMC1;
 		*val = get_reg_val(id, vcpu->arch.pmc[i]);
 		break;
+#ifdef CONFIG_VSX
+	case KVM_REG_PPC_FPR0 ... KVM_REG_PPC_FPR31:
+		if (cpu_has_feature(CPU_FTR_VSX)) {
+			/* VSX => FP reg i is stored in arch.vsr[2*i] */
+			long int i = id - KVM_REG_PPC_FPR0;
+			*val = get_reg_val(id, vcpu->arch.vsr[2 * i]);
+		} else {
+			/* let generic code handle it */
+			r = -EINVAL;
+		}
+		break;
+	case KVM_REG_PPC_VSR0 ... KVM_REG_PPC_VSR31:
+		if (cpu_has_feature(CPU_FTR_VSX)) {
+			long int i = id - KVM_REG_PPC_VSR0;
+			val->vsxval[0] = vcpu->arch.vsr[2 * i];
+			val->vsxval[1] = vcpu->arch.vsr[2 * i + 1];
+		} else {
+			r = -ENXIO;
+		}
+		break;
+#endif /* CONFIG_VSX */
 	default:
 		r = -EINVAL;
 		break;
@@ -624,6 +645,27 @@ int kvmppc_set_one_reg(struct kvm_vcpu *vcpu, u64 id, union kvmppc_one_reg *val)
 		i = id - KVM_REG_PPC_PMC1;
 		vcpu->arch.pmc[i] = set_reg_val(id, *val);
 		break;
+#ifdef CONFIG_VSX
+	case KVM_REG_PPC_FPR0 ... KVM_REG_PPC_FPR31:
+		if (cpu_has_feature(CPU_FTR_VSX)) {
+			/* VSX => FP reg i is stored in arch.vsr[2*i] */
+			long int i = id - KVM_REG_PPC_FPR0;
+			vcpu->arch.vsr[2 * i] = set_reg_val(id, *val);
+		} else {
+			/* let generic code handle it */
+			r = -EINVAL;
+		}
+		break;
+	case KVM_REG_PPC_VSR0 ... KVM_REG_PPC_VSR31:
+		if (cpu_has_feature(CPU_FTR_VSX)) {
+			long int i = id - KVM_REG_PPC_VSR0;
+			vcpu->arch.vsr[2 * i] = val->vsxval[0];
+			vcpu->arch.vsr[2 * i + 1] = val->vsxval[1];
+		} else {
+			r = -ENXIO;
+		}
+		break;
+#endif /* CONFIG_VSX */
 	default:
 		r = -EINVAL;
 		break;

arch/powerpc/kvm/book3s_pr.c

@@ -953,6 +953,19 @@ int kvmppc_get_one_reg(struct kvm_vcpu *vcpu, u64 id, union kvmppc_one_reg *val)
 	case KVM_REG_PPC_HIOR:
 		*val = get_reg_val(id, to_book3s(vcpu)->hior);
 		break;
+#ifdef CONFIG_VSX
+	case KVM_REG_PPC_VSR0 ... KVM_REG_PPC_VSR31: {
+		long int i = id - KVM_REG_PPC_VSR0;
+
+		if (!cpu_has_feature(CPU_FTR_VSX)) {
+			r = -ENXIO;
+			break;
+		}
+		val->vsxval[0] = vcpu->arch.fpr[i];
+		val->vsxval[1] = vcpu->arch.vsr[i];
+		break;
+	}
+#endif /* CONFIG_VSX */
 	default:
 		r = -EINVAL;
 		break;
@@ -970,6 +983,19 @@ int kvmppc_set_one_reg(struct kvm_vcpu *vcpu, u64 id, union kvmppc_one_reg *val)
 		to_book3s(vcpu)->hior = set_reg_val(id, *val);
 		to_book3s(vcpu)->hior_explicit = true;
 		break;
+#ifdef CONFIG_VSX
+	case KVM_REG_PPC_VSR0 ... KVM_REG_PPC_VSR31: {
+		long int i = id - KVM_REG_PPC_VSR0;
+
+		if (!cpu_has_feature(CPU_FTR_VSX)) {
+			r = -ENXIO;
+			break;
+		}
+		vcpu->arch.fpr[i] = val->vsxval[0];
+		vcpu->arch.vsr[i] = val->vsxval[1];
+		break;
+	}
+#endif /* CONFIG_VSX */
 	default:
 		r = -EINVAL;
 		break;