KVM: PPC: e500: Save/restore SPE state

This is done lazily.  The SPE save will be done only if the guest has
used SPE since the last preemption or heavyweight exit.  Restore will be
done only on demand, when enabling MSR_SPE in the shadow MSR, in response
to an SPE fault or mtmsr emulation.

For SPEFSCR, Linux already switches it on context switch (non-lazily), so
the only remaining bit is to save it between qemu and the guest.

Signed-off-by: Liu Yu <yu.liu@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 82 insertions, 2 deletions

diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 05cedb5f8210..0ecbecb2f7cc 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -13,6 +13,7 @@
  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  *
  * Copyright IBM Corp. 2007
+ * Copyright 2010-2011 Freescale Semiconductor, Inc.
  *
  * Authors: Hollis Blanchard <hollisb@us.ibm.com>
  *          Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
@@ -78,6 +79,57 @@ void kvmppc_dump_vcpu(struct kvm_vcpu *vcpu)
 	}
 }
 
+#ifdef CONFIG_SPE
+void kvmppc_vcpu_disable_spe(struct kvm_vcpu *vcpu)
+{
+	preempt_disable();
+	enable_kernel_spe();
+	kvmppc_save_guest_spe(vcpu);
+	vcpu->arch.shadow_msr &= ~MSR_SPE;
+	preempt_enable();
+}
+
+static void kvmppc_vcpu_enable_spe(struct kvm_vcpu *vcpu)
+{
+	preempt_disable();
+	enable_kernel_spe();
+	kvmppc_load_guest_spe(vcpu);
+	vcpu->arch.shadow_msr |= MSR_SPE;
+	preempt_enable();
+}
+
+static void kvmppc_vcpu_sync_spe(struct kvm_vcpu *vcpu)
+{
+	if (vcpu->arch.shared->msr & MSR_SPE) {
+		if (!(vcpu->arch.shadow_msr & MSR_SPE))
+			kvmppc_vcpu_enable_spe(vcpu);
+	} else if (vcpu->arch.shadow_msr & MSR_SPE) {
+		kvmppc_vcpu_disable_spe(vcpu);
+	}
+}
+#else
+static void kvmppc_vcpu_sync_spe(struct kvm_vcpu *vcpu)
+{
+}
+#endif
+
+/* Helper function for "full" MSR writes. No need to call this if only EE is
+ * changing. */
+void kvmppc_set_msr(struct kvm_vcpu *vcpu, u32 new_msr)
+{
+	if ((new_msr & MSR_PR) != (vcpu->arch.shared->msr & MSR_PR))
+		kvmppc_mmu_priv_switch(vcpu, new_msr & MSR_PR);
+
+	vcpu->arch.shared->msr = new_msr;
+
+	if (vcpu->arch.shared->msr & MSR_WE) {
+		kvm_vcpu_block(vcpu);
+		kvmppc_set_exit_type(vcpu, EMULATED_MTMSRWE_EXITS);
+	};
+
+	kvmppc_vcpu_sync_spe(vcpu);
+}
+
 static void kvmppc_booke_queue_irqprio(struct kvm_vcpu *vcpu,
                                        unsigned int priority)
 {
@@ -344,10 +396,16 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
 		r = RESUME_GUEST;
 		break;
 
-	case BOOKE_INTERRUPT_SPE_UNAVAIL:
-		kvmppc_booke_queue_irqprio(vcpu, BOOKE_IRQPRIO_SPE_UNAVAIL);
+#ifdef CONFIG_SPE
+	case BOOKE_INTERRUPT_SPE_UNAVAIL: {
+		if (vcpu->arch.shared->msr & MSR_SPE)
+			kvmppc_vcpu_enable_spe(vcpu);
+		else
+			kvmppc_booke_queue_irqprio(vcpu,
+						   BOOKE_IRQPRIO_SPE_UNAVAIL);
 		r = RESUME_GUEST;
 		break;
+	}
 
 	case BOOKE_INTERRUPT_SPE_FP_DATA:
 		kvmppc_booke_queue_irqprio(vcpu, BOOKE_IRQPRIO_SPE_FP_DATA);
@@ -358,6 +416,28 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
 		kvmppc_booke_queue_irqprio(vcpu, BOOKE_IRQPRIO_SPE_FP_ROUND);
 		r = RESUME_GUEST;
 		break;
+#else
+	case BOOKE_INTERRUPT_SPE_UNAVAIL:
+		/*
+		 * Guest wants SPE, but host kernel doesn't support it.  Send
+		 * an "unimplemented operation" program check to the guest.
+		 */
+		kvmppc_core_queue_program(vcpu, ESR_PUO | ESR_SPV);
+		r = RESUME_GUEST;
+		break;
+
+	/*
+	 * These really should never happen without CONFIG_SPE,
+	 * as we should never enable the real MSR[SPE] in the guest.
+	 */
+	case BOOKE_INTERRUPT_SPE_FP_DATA:
+	case BOOKE_INTERRUPT_SPE_FP_ROUND:
+		printk(KERN_CRIT "%s: unexpected SPE interrupt %u at %08lx\n",
+		       __func__, exit_nr, vcpu->arch.pc);
+		run->hw.hardware_exit_reason = exit_nr;
+		r = RESUME_HOST;
+		break;
+#endif
 
 	case BOOKE_INTERRUPT_DATA_STORAGE:
 		kvmppc_core_queue_data_storage(vcpu, vcpu->arch.fault_dear,