[PATCH 4/6 v2] KVM: PPC: Book3E: Add AltiVec support

[Mihai Caraman]

Add KVM Book3E AltiVec support. KVM Book3E FPU support gracefully reuse host
infrastructure so follow the same approach for AltiVec.

Signed-off-by: Mihai Caraman <mihai.caraman at freescale.com>
---
v2:
 - integrate Paul's FP/VMX/VSX changes

 arch/powerpc/kvm/booke.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 65 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 4cc9b26..4ba75f6 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -100,6 +100,19 @@ static inline bool kvmppc_supports_spe(void)
 	return false;
 }
 
+/*
+ * Always returns true if AltiVec unit is present,
+ * see kvmppc_core_check_processor_compat().
+ */
+static inline bool kvmppc_supports_altivec(void)
+{
+#ifdef CONFIG_ALTIVEC
+	if (cpu_has_feature(CPU_FTR_ALTIVEC))
+		return true;
+#endif
+	return false;
+}
+
 #ifdef CONFIG_SPE
 void kvmppc_vcpu_disable_spe(struct kvm_vcpu *vcpu)
 {
@@ -178,6 +191,40 @@ static void kvmppc_vcpu_sync_fpu(struct kvm_vcpu *vcpu)
 #endif
 }
 
+/*
+ * Simulate AltiVec unavailable fault to load guest state
+ * from thread to AltiVec unit.
+ * It requires to be called with preemption disabled.
+ */
+static inline void kvmppc_load_guest_altivec(struct kvm_vcpu *vcpu)
+{
+#ifdef CONFIG_ALTIVEC
+	if (kvmppc_supports_altivec()) {
+		if (!(current->thread.regs->msr & MSR_VEC)) {
+			enable_kernel_altivec();
+			load_vr_state(&vcpu->arch.vr);
+			current->thread.vr_save_area = &vcpu->arch.vr;
+			current->thread.regs->msr |= MSR_VEC;
+		}
+	}
+#endif
+}
+
+/*
+ * Save guest vcpu AltiVec state into thread.
+ * It requires to be called with preemption disabled.
+ */
+static inline void kvmppc_save_guest_altivec(struct kvm_vcpu *vcpu)
+{
+#ifdef CONFIG_ALTIVEC
+	if (kvmppc_supports_altivec()) {
+		if (current->thread.regs->msr & MSR_VEC)
+			giveup_altivec(current);
+		current->thread.vr_save_area = NULL;
+	}
+#endif
+}
+
 static void kvmppc_vcpu_sync_debug(struct kvm_vcpu *vcpu)
 {
 	/* Synchronize guest's desire to get debug interrupts into shadow MSR */
@@ -749,6 +796,17 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
 	kvmppc_load_guest_fp(vcpu);
 #endif
 
+#ifdef CONFIG_ALTIVEC
+	/* Save userspace AltiVec state in stack */
+	if (kvmppc_supports_altivec())
+		enable_kernel_altivec();
+	/*
+	 * Since we can't trap on MSR_VEC in GS-mode, we consider the guest
+	 * as always using the AltiVec.
+	 */
+	kvmppc_load_guest_altivec(vcpu);
+#endif
+
 	/* Switch to guest debug context */
 	debug = vcpu->arch.shadow_dbg_reg;
 	switch_booke_debug_regs(&debug);
@@ -771,6 +829,10 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
 	kvmppc_save_guest_fp(vcpu);
 #endif
 
+#ifdef CONFIG_ALTIVEC
+	kvmppc_save_guest_altivec(vcpu);
+#endif
+
 out:
 	vcpu->mode = OUTSIDE_GUEST_MODE;
 	return ret;
@@ -1014,7 +1076,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
 		break;
 
 	case BOOKE_INTERRUPT_SPE_ALTIVEC_UNAVAIL: {
-		if (kvmppc_supports_spe()) {
+		if (kvmppc_supports_spe() || kvmppc_supports_altivec()) {
 			bool enabled = false;
 
 #if !defined(CONFIG_KVM_BOOKE_HV) && defined(CONFIG_SPE)
@@ -1040,7 +1102,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
 	}
 
 	case BOOKE_INTERRUPT_SPE_FP_DATA_ALTIVEC_ASSIST:
-		if (kvmppc_supports_spe()) {
+		if (kvmppc_supports_spe() || kvmppc_supports_altivec()) {
 			kvmppc_booke_queue_irqprio(vcpu,
 				BOOKE_IRQPRIO_SPE_FP_DATA_ALTIVEC_ASSIST);
 			r = RESUME_GUEST;
@@ -1249,6 +1311,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
 			/* interrupts now hard-disabled */
 			kvmppc_fix_ee_before_entry();
 			kvmppc_load_guest_fp(vcpu);
+			kvmppc_load_guest_altivec(vcpu);
 		}
 	}
 
-- 
1.7.11.7